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An assessment of acid rock drainage potential of waste rock and implications for long term weathering… Lister, Diane 1994

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AN ASSESSMENT OF ACID ROCK DRAINAGE POTENTIAL OF WASTE ROCK ANDIMPLICATIONS FOR LONG TERM WEATHERING OF THE NORTH DUMP AT ISLANDCOPPER MINE, PORT HARDY, B.C.byDIANE LISTERB.A.Sc., The University of British Columbia, 1989A THESIS SUBMITTED IN PARTIAL FULFILLMENT OFTHE REQUIREMENTS FOR THE DEGREE OFMASTER OF APPLIED SCIENCEinTHE FACULTY OF GRADUATE STUDIES(Department of Mining and Mineral Process Engineering)We accept this thesis as conformingto the required standardTHE UNIVERSITY OF BRITISH COLUMBIAMarch 1994© Diane Lister, 1994In presenting this thesis in partial fulfilment of the requirements for an advanceddegree at the University of British Columbia, I agree that the Library shall make itfreely available for reference and study. I further agree that permission for extensivecopying of this thesis for scholarly purposes may be granted by the head of mydepartment or by his or her representatives. It is understood that copying orpublication of this thesis for financial gain shall not be allowed without my writtenpermission.(Signature)Department of Mining & Mineral Process EngineeringThe University of British ColumbiaVancouver, CanadaDate Ari1 20. 1994DE-6 (2/88)11ABSTRACTIsland Copper Mine, owned by BHP Minerals Canada Ltd., is located at the north end ofVancouver Island, British Columbia. The mine, a copper-molybdenum porphyry deposit andone of Canada’s largest open low grade copper mines, commenced operation in 1971 and withcurrent reserves, mining is expected to continue until late 1995. Over the years of operation,approximately 616 million tonnes of waste rock has been placed both on land (76 milliontonnes) and into Rupert Inlet (540 million tonnes), an adjacent marine fjord.Acid rock drainage, the term used for contaminated drainage resulting from oxidation of certainsulfide minerals, was first detected in the open pit area in 1982, and from the on land waste rockdumps in 1985. Currently, all drainage from the mine area is directed to a water managementpond for recycling to the concentrator and discharge when all provincial effluent standards aremet. In comparison with other Canadian mines with acid rock drainage, effluent from IslandCopper’s on land dump has relatively low concentrations of contaminants.The objective of this study was to assist Island Copper in long term prediction of water qualityemanating from the North dump, the largest on land dump at the mine. The study involvedcharacterization of both the waste rock dump as a whole, and of the various waste rock typescomprising the dump.Waste rock dump characterization entailed examination of existing data coupled with fieldmeasurements. Results indicate that there is sufficient oxygen in almost all areas of the on landdumps for pyrite oxidation. There is also evidence of convective transport of air through thedump. In addition, elevated temperatures, indicative of increased sulfide oxidation rates, havebeen documented in several of the drill holes through the waste rock dumps. The limitedhistorical monitoring of one dump indicates that temperatures have increased over the last fiveyears, but may be stabilizing in the low 20° C range.111Waste rock characterization involved geological, mineralogical, geochemical and physicalassessment, as well as kinetic testing of samples from eight selected sites on the North dump.From this work, three categories of waste rock were derived: i) type I rocks, which areinterpreted to have sufficient excess alkalinity to do some degree of buffering on infiltratingacidic drainage, ii) type II rocks, which although possibly generating alkaline leachate atpresent, are not regarded to have sufficient excess alkalinity to adequately buffer infiltratingacidic drainage, but are not expected to significantly contribute to net acidity of the waste rockdump; and iii) type III rocks, which are presently producing leachate with high net acidity. TypeIII rocks are of variable lithology, strongly hydrothermally altered, and contain elevated levelsof fine grained disseminated pyrite. The dumps or dump areas documented to be producingacidic effluent contain at least 14 percent of type III and 21 percent of type II material.Comparison of leachate quality from laboratory kinetic tests and waste rock dump effluentindicates that the kinetic tests significantly overestimate actual contaminant loads, and only netacid load and molar calcium to sulfate can be confidently scaled from laboratory to fieldconditions.The model derived for prediction of future effluent quality indicates that when dumptemperatures stabilize, effluent quality will also stabilize and contaminant concentrations willgradually decrease over time.ivTABLE OF CONTENTSAbstract iiTable of Contents ivList of Figures viiList of Tables xiAcknowlegements xiii1.0 Introduction and Research Plan1.1 Introduction 11.2 Background 31.2.1 Acid Rock Drainage 31.2.2 Relevant History of Island Copper Mine 41.2.3 Other Relevant Research 71.3 Research Objectives 91.4 Research Plan 92.0 Site Characteristics2.1 Setting 112.1.1 Location and Access 112.1.2 Mine History 112.1.3 Local Geography and Climate 122.2 Geology 152.2.1 General 152.2.2 Bonanza Group Volcanic 152.2.3 Rhyodacite Porphyry 162.2.4 Hydrothermal Breccia 172.2.5 Hyrdrothermal Alteration 172.2.6 Sulphide Mineral Occurence 182.2.7 Acid Consuming Mineral Occurrence 202.2.8 Discussion 222.3 Waste Rock Dump Characterization 242.3.1 Objectives 242.3.2 Overall Effects of Development 242.3.3 Construction 252.3.3.1 Old North Dump 262.3.3.2 Eastern Most Outsiope 282.3.3.3 Cap 282.3.4 Hydrology 292.3.5 Water Quality 302.3.6 Drilling 302.3.7 Acid Base Accounting 322.3.8 Oxygen and Carbon Dioxide Monitoring 332.3.9 Temperature Monitoring 342.3.10 Summary 36V3.0 Waste Rock Characterization3.1 Objectives 403.2 Methods and Procedures 403.2.1 Sampling 403.2.2 Date of Mining 443.2.3 Rock Type and Mineralogy Assessment 443.2.4 Geochemistry 453.2.5 Physical Analysis 463.2.6 Replicate Analyses 463.3 Results 473.3.1 Overall Observations 473.3.2 Date of Mining 503.3.3 Rock Type and Mineralogy Assessment 503.3.4 Mineralogy 533.3.5 Elemental Analysis 553.3.6 Acid Base Accounting 573.3.7 Physical Analysis 603.4 Summary 624.0 Kinetic Test Work4.1 Introduction and Background 644.2 Column Tests 674.2.1 Objectives 684.2.2 Equipment and Procedure 684.2.3 Results 734.2.3.1 General Observations 734.2.3.2 Weekly Leachate Quality 744.2.3.3 Loads and Cumulative Loads 854.2.3.4 Pore Gas Analysis 884.2.3.5 Pre- and Post- Test Analysis of Column Material 904.3 Humidity Cell Tests 924.3.1 Background 924.3.2 Objectives 934.3.3 Equipment and Procedure 934.3.4 Results 954.3.4.1 General Observations 954.3.4.2 Weekly Leachate Quality 954.3.4.3 Loads and Cumulative Loads 1004.4 Discussion of Results 1004.4.1 Summary 1004.4.2 Kinetic Test Rate Constants 1084.4.3 Kinetic Test Neutralization Potential Depletion 1094.4.4 Kinetic Test ARD Potential Classification 1125.0 Prediction of Effluent Quality5.1 Introduction 1165.2 Characterization of ARD Potential Categories 117vi5.2.1 Lithology 1175.2.2 Alteration 1175.2.3 Pyrite 1175.2.4 Carbonate Minerals 1195.2.5 Acid Base Accounting 1205.2.6 Elemental Analyses 1235.2.7 Rock Competence 1245.2.8 Discussion 1245.3 Assigning ARD Potential Categories to Waste Rock Dumps 1265.4 Prediction of Present Effluent Quality from Dump Areas 1295.4.1 Method 1295.4.2 Leachate Quality of ARD Potential Categories 1315.4.3 Actual Effluent Quality of EMO and NWD Dumps 1315.4.3.1 Calculation of Actual Loads 1335.4.3.2 Calculation of Sulfide Oxidation Rate Constants 1345.4.4 Comparison of Estimated and Actual Effluent Quality 135from EMO and NWD5.4.5 Discussion of Results 1395.5 Temporal Modeling of EMO and NWD Dumps 1395.5.1 Introduction 1395.5.2 Limitations 1415.5.3 Method 1415.5.4 Results 1465.5.5 Validation and Calibration 1515.5.6 Discussion 1526.0 Conclusions and Recommendations6.1 Conclusions 1556.2 Recommendations 158References 160Appendix 1 Petrographic Report on Ten Polished Thin Sections from the 164Island Copper Deposit, B.C. for Acid Rock Drainage StudiesAppendix 2 List of Sample Numbers and Description 176Appendix 3 Elemental Analyses of Waste Rock and Till Samples 177Appendix 4 Calculation Method for APP and APPS2 179Appendix 5 Sieve Analysis of Waste Rock Samples 180Appendix 6 Moisture Contents, Sites 1 through 4 Sample Pits 190Appendix 7 Leachate Quality Analytical Techniques 191Appendix 8 Leachate Quality Analytical Replicates 193Appendix 9 Column and Humidity Cell Leachate Quality 199Appendix 10 Column Pore Gas Analyses 215Appendix 11 Beach Dump Characterization 216viiLIST OF FIGURESFigure 1.1 Location of Island Copper Mine 2Figure 1.2 Plan view of Island Copper Mine and waste rock dumps 5Figure 1.3 Regions of the North dump 6Figure 2.1 Normal monthly temperature and total precipitation, Port Hardy 13AirportFigure 2.2 Location of watersheds in Island Copper Mine area 14Figure 2.3 Geological cross section, Island Copper pit 19Figure 2.4 Location of perimeter ditch drainage sample sites and North 31dump drill holesFigure 2.5 Average dump temperature versus time for North West dump 35Figure 2.6 Down-hole temperatures for AMD #4 (east end of Old North 37Dump) and AMD #7 (upper Cap)Figure 2.7 Down-hole temperatures for AMD#1 and #2 (lower EMO), and 37AMD #3 (upper EMO)Figure 2.8 Down-hole temperatures for AMD#5 and #6 (west OND) 38Figure 3.1 Location of waste rock sample sites 42Figure 3.2 Sample pit profile, Site 4, lower EMO 48Figure 3.3 Indurated horizon below highly oxidized zone on upper Cap 49Figure 3.4 Sericite-chlorite-clay (SCC) altered volcanic? on Upper Cap 51Figure 3.5 Weakly altered volcanic on Upper Cap 51Figure 3.6 Acid consuming potential (ACP) versus acid-volatilized carbon 59dioxide for the waste rock samplesFigure 3.7 Range of particle size for waste rock samples 61Figure 3.8 Particle size distribution of till samples 61Figure 4.1 Column test apparatus 69Figure 4.2 Column test leachate pH 76Figure 4.3 Column test leachate Eh 76viiiFigure 4.4 Column test leachate conductivity 77Figure 4.5 Column test leachate sulfate 77Figure 4.6 Column test leachate alkalinity 78Figure 4.7 Column test leachate acidity 78Figure 4.8 Column test leachate dissolved metals: a) aluminum, b) calcium, 80c) cadmium, and d) copperFigure 4.9 Column test leachate dissolved metals: a) iron, 81b) magnesium, c) manganese, and d) molybdenumFigure 4.10 Column test leachate dissolved metals: a) sodium, 82b) nickel, c) phosphorus, and d) strontiumFigure 4.11 Column test leachate dissolved metals: a) titanium, and b) zinc 83Figure 4.12 Column test leachate sulfate loadings: a) column 1, b) column 2, 86c) column 3, and d) column 4Figure 4.13 Column test leachate alkalinity and acidity loadings: a) column 1, 87b) column 2, c) column 3, andd) column 4Figure 4.14 Oxygen content of column pore gas, week 39 89Figure 4.15 Carbon dioxide content of column pore gas, week 39 89Figure 4.16 Carbon dioxide content of column 4 pore gas, weeks 39 to 44, and 90July 28, 1993Figure 4.17 Pre- and post- test acid base accounting of column test material 91Figure 4.18 Humidity cell leachate pH 97Figure 4.19 Humidity cell leachate Eh 97Figure 4.20 Humidity cell leachate conductivity 98Figure 4.21 Humidity cell leachate sulfate 98Figure 4.22 Humidity cell leachate alkalinity 99Figure 4.23 Humidity cell leachate acidity 99ixFigure 4.24 Selected humidity cell loads: a) cell 1 sulfate, b)cell 6 sulfate, c) 101cell 1 alkalinity, and d) cell 6 acidityFigure 4.25 Leachate sulfate loads of humidity cell replicates: 102a) cell 2, b) cell 3, c) cell 4, and d) cell 6Figure 4.26 Leachate acidity loads of humidity cell replicates: 103a) cell 2, b) cell 3, c) cell 4, and d) cell 5Figure 4.27 Ranges of kinetic test molar calcium and magnesium, alkalinity, 105and acidity to sulfate load ratiosFigure 4.28 Comparison of replicate column and humidity cell sulfate, 107alkalinity and acidity loadsFigure 5.1 Lithological characteristics of ARD potential categories 118Figure 5.2 Visual pyrite estimates for each ARD potential category 119Figure 5.3 Acid base accounting parameter characteristics of ARD potential 121categories, a) total sulfur, b) sulfate, c) acid consuming potential(ACP), d) acid-volatilized carbon dioxideFigure 5.4 Acid base accounting parameter characteristics of ARD potential 122categories, a) net neutralizing potential using total sulfur(NNPS), b) net neutralizing potential using sulfide sulfur(NNPS2j,c) acid consuming potential to acid productionpotential (ACP:APP), d) paste pH (ppH)Figure 5.5 Estimated proportions of rock in each ARD potential category in 127the North dumpFigure 5.6 Estimated proportions of rock in each ARD potential category in 128the North West and Beach dumpsFigure 5.7 Flowchart for prediction of present effluent quality from dump 130areasFigure 5.8 EMO predicted sulfate and acidity concentrations, temperature 147scenario 1xFigure 5.9 EMO predicted sulfate and acidity concentrations, temperature 147scenario 2Figure 5.10 EMO predicted sulfate and acidity concentrations, temperature 148scenario 3Figure 5.11 Comparison of EMO average annual sulfate and acidity 148concentrations with predicted values using temperature scenario 2Figure 5.12 NWD predicted sulfate and acidity concentrations, temperature 149scenario 1Figure 5.13 NWD predicted sulfate and acidity concentrations, temperature 149scenario 2Figure 5.14 NWD predicted sulfate and acidity concentrations, temperature 150scenario 3Figure 5.15 Comparison ofNWD average annual sulfate and acidity 150concentrations with predicted values using temperature scenario 2xiLIST OF TABLESTable 1.1 Comparison of typical drainage quality between Island Copper and 8other selected mines in CanadaTable 2.1 Characteristics of the North dump and its major regions 27Table 2.2. Mean and standard deviations of acid base accounting analyses 33from the North dump and its various areasTable 3.1 Waste rock sample summary 41Table 3.2 Calculated precision of selected chemical analyses of waste rock 47Table 3.3 Estimated date of mining and in-pit source for waste rock sample 48sitesTable 3,4 Rock classification summary of the eight waste rock sample sites 52Table 3.5 X-Ray diffraction results from rock surface material 55Table 3.6 Acid-Base accounting and acid-volatiliized carbon dioxide analyses 58of the eight waste rock samples and two till compositesTable 4.1 Distilled water infiltration schedule for colunm tests 71Table 4.2 Waste rock conditions in column tests at start-up 74Table 4.3 Waste rock samples tested in humidity cells 94Table 4.4 Kinetic test periods used for data analysis 104Table 4.5 Minimum and maximum general leachate quality parameters from 104kinetic testsTable 4.6 Kinetic test rate constants and half-lives 110Table 4.7 Kinetic test estimated times to neutralization potential depletion 114Table 4.8 Delineating parameters for ARD Potential classification of kinetic 114testsTable 4.9 Classification of kinetic tests by ARD Potential category 115Table 5.1 Dominant alteration characteristics of ARD potential categories 119Table 5.2 Rock matrix reactivity to hydrochloric acid of ARD potential 120categoriesxliTable 5.3 Vein or fracture reactivity to hydrochloric acid of ARD potential 120categoriesTable 5.4 Rock competence characteristics of ARD potential categories 124Table 5.5 Tentative guidelines to field classification of Island Copper waste 125rock by ARD potential categoryTable 5.6 Tentative acid base accounting criteria for ARD Potential categories 126Table 5.7 Characteristics of kinetic test leachate chemistry by ARD Potential 132categoryTable 5.8 Characteristics of kinetic test sulfide oxidation rate constants by 133ARD Potential CategoryTable 5.9 Comparison of calculated versus actual effluent quality of EMO and 136NWD drainagesTable 5.10 Adopted scaling factors for calculating actual effluent conditions 138from estimated valuesTable 5.11 Estimated current effluent conditions in selected dumps and dump 138areas at Island Copper MineTable 5.12 Available alkalinity in EMO and NWD dump areas 143Table 5.13 Input parameters for temporal modeling of EMO and NWD dump 144effluentTable 5.14 Valid prediction periods for model trials 146xliiACKNOWLEDGEMENTSI would like most of all to thank my advisor Dr. George Poling for obtaining the necessarycooperation and funding for this project, and for his confidence and never-ending support in mywork. My committee members have been very flexible and have given me many helpfulsuggestions as to the direction of the study, and I am grateful to them as well.BHP Minerals Canada Ltd., Island Copper Mine provided funding and conducted some of theanalytical work for the project. In particular, Ian Home has done his best to accomodate theneeds of this project and his interest and unbounded enthusiasm has provided me with muchmotivation.I have also been given tremendous support from the Department of Mining and Mineral ProcessEngineering staff and fellow students. Sally Finora, Pius Lo, and Frank Schmidiger were alwaysable to help me with my technical problems, and Marina Lee and Gordie Lagore often went outof their way to deal with administrative issues. My fellow students seemed to have a knack ofbeing there to help me just when I really needed it, and I only hope that I can return thenumerous favours someday.My family and friends have been enthusiastic supporters of my work, and I am grateful to themas well.Finally, I would like to thank the Science Council of British Columbia for providing additionalfunding in the form of a G.R.E.A.T. scholarship.11.0 INTRODUCTION AND RESEARCH PLAN1.1 IntroductionIsland Copper Mine, owned by BHP Minerals Canada Ltd., is one of Canad&s largest open pit,low-grade copper mines. The mine is located on the north shore of Rupert Inlet, about sixteenkilometres south of the town of Port Hardy at the north end of Vancouver Island (Fig. 1.1).Mining commenced in 1971, and with current reserves is expected to continue until late 1995.In 1985, seepages from one of the on-land waste rock dumps were found to contain elevatedzinc levels and prompted the establishment of an extended monitoring network and the findingof a few areas of the dump where sulfide minerals in the waste rock were oxidizing andproducing acidic, metal-contaminated, drainage (termed “acid rock drainage”, or “ARD”).Currently, all seepage emanating from the on-land waste rock dumps is collected by a system ofdrainage ditches and culverts which direct the water to a water management pond where it canbe recycled through the concentrator as process water. Excess water in this pond can be releasedinto Rupert Inlet when all provincial water effluent standards of the permit are met.Although acid rock drainage is adequately managed at Island Copper Mine, long term waterquality trends must be predicted in order to plan for future mine decommissioning. This thesisdetails waste rock characterization of primarily the North dump, the largest on-land waste rockdump at Island Copper Mine. The study is one of a several conducted and/or funded by themine to provide the necessary data needed to plan for an appropriate and cost effectivedecommissioning of operations.Figure1.1Locationof IslandCopperMine3The project was funded jointly by BHP Minerals Canada Ltd. Island Copper Mine and a ScienceCouncil of British Columbia G.R.E.A.T. Award, with research conducted by Diane Lister,supervised by Dr. George W. Poling (UBC Department of Mining and Mineral ProcessEngineering), and in collaboration with Ian Home (co-ordinator, environmental closure plan,Island Copper Mine). Work was conducted from May 1992 to March 1994.1.2 Background1.2.1 Acid Rock DrainageThe prevention, control, and treatment of acid rock drainage (ARD) is a significantenvironmental challenge facing the mining industry today. In a 1987 questionnaire circulated toBritish Columbia’s operating metal mines, six of the sixteen respondants reported the presenceof ARD in varying degrees of severity at their site. In addition, at least five abandoned mines inBritish Columbia reportedly have ARD (Steffen, Robertson and Kirsten (SRK), 1989).Acid rock drainage results from the spontaneous weathering of certain sulfide minerals (mostcommonly pyrite due to its ubiquitous presence in the geological environment). Sulfideminerals are formed under reducing conditions and when exposed to both oxygen and water canbecome chemically unstable. The oxidation of pyrite by oxygen can be shown as:Fe52 +7/202+1120 —* Fe2+ 25042 + 2H (1.1)The dissolved ferrous, sulfate and hydrogen ions result in an increase in total dissolved solidsand, unless the surrounding solution is well-buffered, an increase in acidity and subsequentdecrease in pH. The reduction in pH can cause solubilization of heavy metals from either thesource rock or any medium along its seepage path. If sufficient acidity and heavy metals areintroduced into the effluent, the result is a low pH, metalliferous water that has potential toadversely impact aquatic life (SRK, 1989).4Mine waste rock piles and tailing impoundments may contain material with sufficient reactivesulfide and insufficient buffering capacity to produce net acidic and metal contaminated effluent.The impacts of ARD left unchecked in Scandanavia and eastern United States have been well-documented (SRK, 1989).Equation 1.1 represents just one of many possible reactions. A more rigourous discussion ofthe chemistry of ARD is presented in SRK (1989), Morin et. al (1991), and Li (1991).1.2.2 Relevant History of Island Copper MineAt Island Copper, waste rock has been placed in rock piles at various locations near the pit, bothon land and into the sea (Li, 1991). In the last decade, several small rock dumps have beendeveloped in the bottom pit area as well. Construction of the on land dumps started at thecommencement of mine operations and continued until 1987. The four on land dumps are: theNorth dump (76.4 x 106 tonnes), the North West dump (0.95 x 106 tonnes), the West dump (3.0x 106 tonnes), and the South dump (6.0 x 106 tonnes) (Figure 1.2). The Beach dump, locatedalong the north shoreline of, and extending into Rupert Inlet was also started in the early 70’s.Since 1987, all waste rock produced has been placed on this dump, making it by far the largestat the mine (540 x 106 tonnes),Despite pre-operational testing in 1968 for heap leach potential that indicated amenability ofboth ore and waste rock to bacterial leaching (BHP and Rescan, 1988), potential for ARD atIsland Copper was not fully realized until 1982. At this time it was observed that pyrite-richrocks on the west wall of the pit were iron-stained. Seeps from this area had a pH of 3.5.In 1985, seeps from the Old Marginal dump, forming the northwestern part of the North dump,began to show elevated zinc levels. This prompted the expansion of the on land dump drainage•t\)IC)IS—.0Cl)0097monitoring program and resulted in the delineation of two additional areas of the North dumpshowing evidence of acid production: the Cap and Eastern Most Outsiopes (EMO) (Figure 1.3).In addition, seepage from the North West dump (NWD) was also found to be net acidic. In1986, Island Copper commenced construction of perimeter ditches to collect seepage from theNorth and North West dumps. Currently, all drainage collected is directed to the watermanagement pond where water is contained, and either recycled to the mill, or released into anadjacent exfiltration pond when all effluent quality standards of the operating permit are met.In recognition of the potential for ARD from waste rock, two on land waste rock dumps (theSouth and West dumps) were constructed from 1986 to 1987 from waste rock designated fromproduction hole acid base accounting analyses to be potentially non-acid generating (BHP andRescan, 1988). Rock deemed net acid producing was placed in the Beach dump.Table 1.1 shows typical drainage quality from EMO station, considered to be the mostcontaminated effluent emanating from the waste rock dumps, and from station WME, which isthe cumulative drainage from North and North West dumps. Also shown are typical ARDdrainage quality values from selected Canadian mines.1.2.3 Other Relevant ResearchSince the onset of acid rock drainage at Island Copper, the mine has conducted and/or fundedconsiderable related studies including:i) over 300 static tests to determine acid generation potential of waste rock produced by the pitexpansion into the south wall (BHP and Rescan, 1988),ii) a drill program on the North and North West dumps to gather samples for static testing,install instrumentation gas monitoring, and allow ongoing temperature and water levelmonitoring of the core of the dumps (UBC MMPE 1990a,b,c, and Li (1991)),iii) ongoing assessment of leaching from pit walls (Morin, 1992),8Table 1.1 Comparision of typical drainage quality between Island Copper and otherselected mines in Canada (adopted from Rescan, 1992 and Steffen Robertson and Kirsten(1989))Island Copper Waste Rock UndergroundIsland Copper Overall Dump Tailings Pond Dump Seepage, Minewater,Parameter ARD Dump Drainage Seepage, British British(EMO) (WME) Ontario Columbia ColumbiapH 4.0 6.5 2.0 2.8 3.5Sulfate 1800 650 7440 4650 1500(mg/I)Acidity 600 40 14600 43000 Not Available(mg CaCO3/l)Al 100000 200 588 359 Not Available(jig/I)Cu 2000 60 3600 89800 16500(jig/i)Cd 90 50 50 500 143(jig/i)Fe 1000 Not Available 3200 1190 10.6(mg/I)Zn 18000 2500 11400 53200 28500(jig/i)9iv) hydrological and metal loadings study of North and North West dump drainages (Rescan,1992), andv) prediction of minewater chemistry from the on-land waste rock dumps (Morin, 1994)1.3 Research ObjectivesThe primary objective of this work is to assist Island Copper Mine in long term prediction ofwater quality emanating from the North Dump by:i) determining weathering characteristics of the various dump rock types using mineralogy,geochemistry, physical characterization, and controlled laboratory weathering (kinetictesting),ii) correlating waste rock characterization fmdings with current and historic waste rockdump conditions, andiii) assisting in evaluating alternative control and treatment strategies for decommissioning.Data derived from this study will be used by Morin (1994), in prediction of metal concentrationsfrom the on-land waste rock dumps.1.4 Research PlanIn order to achieve the research objectives, work was divided into the following twocomponents:i) waste rock characterization, andii) dump characterization.Waste rock characterization comprised first obtaining a suite of samples from eight sites in theNorth dump deemed representative of the various waste rock units, or mixtures of rock units.10Samples were first classified geologically, mineralogically, geochemically (including multi-element and acid base accounting analyses) and physically (Chapter 3.0). Laboratory controlledweathering experiments in the form of column leach and humidity cell tests were conducted todetermine resultant effluent quality from each sample (Chapter 4.0).Much of the dump characterization was based on measurements and work conducted byprevious graduate student M.G. Li (UBC MMPE 1990a, 1990c, and Li, 1991), but also includedrecent measurements and observations of the North and other dumps at Island Copper Mine(Chapter 2.0).Findings from the waste rock characterization study were then related to present and historicalconditions mainly in the North dump, but with expansions to other dumps as data and relevanceallowed (Chapter 5.0). Implications of the study’s findings for future water quality trends arealso presented.Finally, conclusions of this study, and recommended additional work are discussed in Chapter6.0.112.0 SITE CHARACTERISTICS2.1 Setting2.1.1 Location and AccessIsland Copper Mine is located at latitude 50°32’N and longitude 127°37’W on the north shore ofRupert Inlet, a marine fjord. Access to the mine is by paved road from Port Hardy. Separatebarge and ship docks at the mine provide moorage for incoming freight and outgoing concentrate(Perelló et al., 1994).2.1.2 Mine HistoryIsland Copper is a calc-alkaline copper-molybdenum-gold porphyry deposit (Cargill et al., 1976).The initial discovery in the area was made in the mid- 1960’s when prospector Gordon Milboumelocated minor amounts of native copper and chalcopyrite on roads, outcrops and test pits north ofwhat is now Island Copper. In 1966 Utah Construction and Mining Co. entered into an optionagreement with Mr. Milboume and commenced an aggressive exploration program consisting ofdrilling, geological mapping, soil sampling and geophysics, Drilling in February 1967 testing alarge soil copper anomaly several kilometres southeast of the original showings intersected 88metres of 0.88 percent copper - the Island Copper deposit had been discovered. Drillingcontinued and by 1969 reserves of 257 million tons (233 million tonnes) of 0.52 percent copperand 0.0 17 percent molybdenum had been delineated (Perelló et al., 1994).Project approval was given later in 1969, and construction completed in 1971. Major facilitiesconsisted of: a 30,000 tonne per day concentrator including tailings thickeners and outfallpipeline to Rupert Inlet, docking facilities for concentrate shipment, a 19 kilometre water supplypipeline and pump station from Alice Lake (east of the mine), a 194 kilometre 138 kVtransmission line from Strathcona generating station, assay and environmental lab facilities, andadministration, warehouse and shop buildings.12Contingent upon obtaining a permit to discharge tailing effluent into Rupert Inlet, Island Coppercommitted to conducting an extensive, continuous marine monitoring program covering RupertInlet and adjoining fjords. The various surveys, performed on seawater, bottom sediments andmarine organisms are conducted on a monthly, quarterly or yearly basis to determine tailingsdeposit depths and migration, seawater turbidity and metal content, and heavy metal uptakes inmarine organisms. In addition, monitoring of freshwater quality of drainages in and adjacent tothe mine area is regularly conducted. As a result of this intensive program, the mine operatedwith five full-time environmental employees and full laboratory facilities. In 1971, this was verymuch a precedent, and even today the number of staff and facilities at Island Copper’senvironmental department are unmatched by any British Columbia mine.2.1.3 Local Geography and ClimateThe area is characterized by low hills up to 150 metres elevation which are overlain by 1 to 20metres (locally up to 75 metres) of overburden composed of glacial till, colluvium, peat andmoss. Outcrops are sparse with exposures limited to road cuts, streams, shorelines, and rarecliffs (Cargill, 1975). A dense growth of timber and undergrowth covers most areas.Although climate data at the mine site have been collected since commencement of operations,the data, unlike Port Hardy airport’s (17 km northeast of the mine), have not been statisticallycompiled. Comparisons between Island Copper’s and Port Hardy airport’s precipitation recordsindicate that the two are sufficiently correlated to be used interchangeably.Island Copper and the Port Hardy area have a normal annual precipitation of about 1780millimetres with over 50 percent of this precipitation occurring from October through January,where on average 244 millimetres precipitation occurs per month. Snowfall makes up only about76 millimetres (4.3 percent) of the annual precipitation, and typically does not accumulate formore than a few weeks during the year. Climatic records for Port Hardy airport indicate that the13C)0a? ESI- C0) oS CU.1—iI—C,CU a?0o -zI—CUEI0zFigure 2.1 Normal monthly temperature and total precipitation, Port Hardy Airport (adaptedfrom BHP, 1988)Most of the Island Copper Mine and its associated workings are located within two smallhydrological basins: the historic End Creek (approximately 3 km2), and Trey Creek(approximately 1.5 km2) watersheds (Figure 2.2). A portion of the on-land waste rock dumpsnorthwest of the current open pit are located within the much larger Stephens Creek watershedwhich flows westward into Francis Bay and contains productive fish habitat and a salmonhatchery (Island Copper Mine, 1 988a).maximum precipitation recorded in a 24 hour period is 153.8 millimetres which occurred onDecember 10, 1980. The driest months in the area are May through August with about 65millimetres monthly precipitation.Temperatures at the site range from -7°C to 27°C. The mean normal annual temperature, takenfrom Port Hardy airport meteorological records, is 8°C. Figure 2.1 shows monthly normaltemperature and precipitation values for Port Hardy airport.20151050._ temperature •precipitation14CUII..()0r4• —15Monitoring of freshwater quality began in 1970, one year prior to mine production, and primarilyfocussed on End Creek, Trey Creek and Bay Lake (located at the headwaters of Stephens Creek).No natural acid rock drainage prior to operations is documented.2.2 Geology2.2.1 GeneralThe Island Copper deposit is part of the Island Copper Cluster, a series of five calc-alkalineporphyry copper-molybdenum-gold systems genetically associated with Jurassic rhyodaciticporphyry stocks (approximately 180 Ma) that intruded calc-alkaline basalts, andesites, andpyroclastic rocks of the comagmatic Bonanza Group (Perelló et a!., 1994). Ore minerals(chalcopyrite and molybdenite) occur with pyrite in breccia and fracture stockworks immediatelyadjacent to an approximately 200 metre wide steeply dipping rhyodacitic dyke intruding thevolcanics. As is typical of porphyry deposits, rock units have been altered by several stages ofhydrothennal fluid intrusions both during and after emplacement of economic minerals (Lister etal., 1993, Perelló et al., 1994).The three main lithological units recognized in the Island Copper pit area are:i) upper member Bonanza Group Volcanic,ii) Rhyodacite Porphyry, andiii) Hydrothermal Breccia.2.2.2 Bonanza Group VolcanicBonanza Group Volcanics are the most common lithology in the pit area and are comprised oflithic tuffs, breccias and interbedded andesitic and basaltic flows, and form a belt strikingapproximately N70°W and dipping 25° to 30° to the southwest (Cargill, 1975).16Tuffs are massive to finely bedded, are of variable grain size, and contain lithic and volcanicfragments as well as plagioclase and quartz crystals. Other features of the tuffs include gradedbedding, fine layering and the occasional presence of bivalve fossils (Perelló et al., 1994).Flows tend to be massive and have aphanitic to medium-grained porphyritic and brecciatedtextures. Primary mineralogy includes plagioclase (labradorite to bytownite composition),augite, hypersthene and amphibole (Perelló et al., 1994).2.2.3 Rhyodacite PorphyryThe Rhyodacite Porphyry is subdivided into: i) the Main Porphyry which is associated witheconomic mineralization, and ii) Intermineral and Late Mineral phases which crosscut the mainporphyry and are not associated with economic mineralization.The Main porphyry forms an elongate dyke intruding the Bonanza Volcanics along a strike ofN70°W and a dip of 60° to the northeast. It is over 1200 metres in length, has an average widthof 200 metres and extends at least 350 metres below sea level. Much of the dyke has beenintensely altered and thus its original composition is difficult to interpret (Cargill, 1975). Theminimally altered dyke core consists of a fine-grained predominantly quartz and feldspargroundmass with 15 to 30 percent of 0.4 to 1.0 centimetre subrounded quartz phenociysts, 15 to30 percent 0.2 to 0.5 centimetre plagioclase (oligoclase to andesine composition) phenocrysts,and 5 percent or less chloritized biotite phenocrysts up to 0.5 centimetres across (Cargill, 1975,Perelló et al., 1994).Intermineral and Late Mineral phase porphyry units tend to be less hydrothermally altered, areoften coarser grained, and tend to have more quartz phenocrysts than the Main porphyry (PerellóCt al., 1994).172.2.4 Hydrothermal BrecciaA substantial volume of Hydrothermal Breccias were formed along the Main porphyry andBonanza Volcanic contact. Two main types of breccias are recognized in the pit area: i)Marginal Breccia, and ii) Pyrophyllite Breccia.Most of the Marginal Breccias are classified as either i) crackle breccias usually composed ofeither porphyry or volcanic unrotated fragments in a stockwork of quartz-amphibole-magnetiteveinlets, and ii) rotational breccias composed of mineralized rotated fragments of volcanic and/orporphyry in a rhyodacitic, locally quartz-flooded matrix (Perelló et al., 1994).In the pit, Pyrophyllite Breccia occurs as a tabular body capping the northwest end of theporphyry dyke where it is more than 100 metres wide and gradually tapers off, wedge-like, to thenorthwest (Cargill, 1975). Poorly sorted, angular to subrounded fragments of volcanic, porphyryand vein quartz are supported by a matrix thought to have been derived from intensely brecciated“rock flour” (Perelló et al., 1994). Subsequent hydrothermal alteration then later transformed theflour to an assemblage of pyrophyllite, kaolinite, sericite, and dumortierite, with variableamounts of pyrite.2.2.5 Hydrothermal AlterationThe three lithological rock units at Island Copper have been subsequently subjected tohydrothermal alteration, causing modification of original, or primary mineralogy, and in extremecases, destruction of original textures to the point that the primary rock type is indistinguishable.The current conception of Island Copper geology identifies three distinct phases of alteration:i) early stage,ii) intermediate stage, andiii) late stage (Perelló et al., 1994).18Early stage alteration occurred upon and just after intrusion of the porphyry dyke is andconsidered by Cargill (1975) to be mainly a contact, or thermal, metamorphism phenomena.Perelló et al. (1994) however believe it to be hydrothermal, and divide the effects of early stagealteration into four outwardly-progressing zones: i) a stockwork core of quartz-amphibolemagnetite, ii) a biotite-magnetite zone, and iv) an epidote zone. The economic mineralization,thought to be emplaced mainly during this phase, tends to be contained within the biotitemagnetite zone.Additional economic mineralization is thought to have been emplaced during the intermediatestage of alteration. This stage is mineralogically characterized by secondary quartz, sericite,kaolinite, illitic clays, and chlorite, accompanied by pyrite, molybdenite and minor chalcopyrite.The two types of intermediate alteration distinguished are: i) quartz-sericite-pyrite, affecting arelatively small volume of rock, and ii) pervasive sericite-clay-chiorite-pyrite (SCC) which hasaffected large volumes of both ore and waste rock. The SCC alteration caused total or partialdestruction of feldspars, biotite and amphiboles, although original rock texture was retained. Theintroduction of fine-grained, disseminated pyrite is also a significant effect of the SCC alteration.Emplacement of the Pyrophyllite Breccia and later episodes of calcite, ankerite and zeoliteveining mark the late stage alteration phase at Island Copper.Figure 2.3, a typical geological cross section through the deposit, illustrates the complexity ofIsland Copper geology.2.2.6 Sulfide Mineral OccurrenceThe major sulfide minerals at Island Copper are chalcopyrite, molybdenite, sphalerite and pyrite.Only chalcopyrite and molybdenite are recovered for economic purposes.-240Bench(1240’belowsealevel)400Feet---120M)level) F’560Bench480BenchU.’v0Bench7PROPOSEDULTIMATEPIT//auartzMagnetiteStockworkIIQuartz-’SerlciteStockwork1*‘1MarginalBreccias1++1flhyodacitePorphyrles[AL-IBonanzaVolcanicsFigure2.3Geologicalcrosssection,IslandCopperpit(PerellOetal.,1992)20Chalcopyrite occurs as veinlets (0.1 mm thick) and disseminations on fractures and slip surfaces.Minor amounts occur with molybdenite on slip surfaces and with sphalerite in late stagecarbonate-zeolite veins (Cargill, 1975).Molybdenite occurs in quartz veins and on fractures and slip surfaces. The molybdeniterecovered at Island Copper has economically significant rhenium content.Iron-rich dark brown to black sphalerite occurs as one millimetre crystals with pyrite incarbonate-zeolite veins, both within and adjacent to the ore zone. Trace amounts of galena havealso been reported with the sphalerite (Cargill, 1975).Pyrite is the most common sulfide mineral at Island Copper and occurs both in and adjacent tothe ore zone, with modal estimates generally ranging from 2 to 5 and locally up to 15 percent(Cargill, 1975). Within the ore zone, pyrite is associated with chalcopyrite and molybdenite inveinlets, and within chioritized mafic minerals (SCC alteration). In waste rock, fine-grained (1mm or less) pyrite is disseminated in the porphyry dyke, and also occurs as a disseminatedsecondary alteration mineral with chlorite in both the early stage chlorite-magnetite andintermediate stage sericite-chlorite-clay (SCC) alteration in all lithological units (Cargill, 1975).Relatively coarse-grained (2 mm) pyrite also occurs with sphalerite in late stage carbonate-zeoliteveins.2.2.7 Acid Consuming Mineral OccurrenceAlthough calcite, aragonite and dolomite are the most well known acid consuming minerals,Kwong (1994), quoting a study of acid neutralizing capacity of various silicates, proposes thatfast and intermediate weathering silicate minerals, if occurring in excess of approximately 10 and15 percent respectively, may also contribute to acid neutralization. Minerals on Kwong’s listoccurring in significant amounts at Island Copper are anorthite (fast weathering), and epidote,pyroxene group minerals, chlorite, and biotite (intermediate weathering). Not mentioned on the21list but relatively common at Island Copper are zeolite minerals, which although not acidconsuming, can be effective in heavy metal removal (Vos and O’Hearn, 1993).Calcite is the most common carbonate mineral at Island Copper, but brown-weathering dolomiteor ankerite are also observed (Leitch, 1988). Calcite most commonly occurs in veins up to one ortwo centimetres across, down to tiny veinlets less than 0.5 millimetres wide, and occasionally asirregular alteration patches with sericite. Modal composition is highly variable from virtuallynone to 5 percent (BHP-Utah and Rescan, 1988). Although not a rule, calcite tends to be moreprevalent in the less altered rocks.Anorthite, a calcium-rich feldspar, has not been identified at Island Copper, but slightly moresodic feldspars, labradorite and bytownite, are present in weakly or unaltered Bonanza Volcanics.Petrographic reports from BHP-Utah and Rescan (1988), however report that although originalfeldspar contents in the rock are estimated to be 45 to 55 percent in Bonanza Volcanic units and25 to 45 percent in Rhyodacite Porphyry units, in many samples examined, primary plagioclasehas been completely replaced by sericite or sericite-clay (Leitch, 1988). Overall, feldsparminerals, because of their replacement by secondary minerals, are not considered significant inacid neutralization.Epidote and pyroxene minerals, though fairly common in weakly altered Bonanza Volcanic,generally account for less than 10 modal percent of the rock, and are thus not considered to besignificant contributors to acid neutralization. Similarly, biotite, though readily recognized by itsdistinctive purple-brown colour in hand specimens of volcanic, rarely accounts for more than 10percent of the rock, and thus does not likely play a significant buffering role.Chlorite minerals are ubiquitous at Island Copper as a replacement of most primary maficminerals, and are present in most alteration zones (Cargill, 1975). Leitch (1988) identified twovarieties of chlorite present at Island Copper: i) a possibly higher magnesium variety found only22in Bonanza Volcanics, and ii) a possibly lower magnesium variety found only in the rhyodaciteporphyry. Most petrographic reports reviewed indicate that significant amounts of chlorite(greater than 15 percent) occur only in Bonanza Volcanic units. Estimates of chlorite content involcanics ranges from 10 to 20 percent in highly altered sericite-chiorite-clay zones, to between35 and 50 percent in weakly altered chiorite-magnetite and epidote zones. Based on Kwong’s(1994) criteria, chlorite may be a significant buffering mineral at Island Copper.Although zeolite minerals, occurring as late stage veins with calcite may be of local significancein heavy metal attenuation, they are not considered to be sufficiently abundant to effect overallrock dump water quality.In summary, calcite and possibly chlorite are the two minerals considered to be present insufficient quantity and occurring in a variety of rock types to be significant acid neutralizers atIsland Copper. However, because of the lack of substantiated data on the role of chloriteminerals as ARD neutralizers, for this study only calcite will be considered as the activeneutralizing mineral at Island Copper. Dolomite or ankerite, calcium-sodium feldspars, andzeolite minerals though possibly of sufficient quantity in localized areas, likely play aninsignificant buffering role.2.2.8 DiscussionIn assessing acid rock drainage potential of Island Copper waste rock, it is of relevance toconsider: i) the nature of the circulating hydrothermal fluids during the various alteration phases,ii) the type, habit and reactivity of sulfide minerals, and iii) the type, habit and reactivity of acidconsuming minerals.Early stage alteration is thought to be in large part a “thermal’ phenomena with limitedcirculation of fluids only where stockwork can be observed in the rock.23The intermediate stage pervasive alteration of primary biotite, feldspars and amphiboles tosericite, clay, and chlorite with pyrite is considered to be due to acidic, reducing, sulfur-richwater (Cargill, 1975). Ostatenko and Jones (1976) postulate that the presence of the sericitepyrite assemblage implies a sulfur rich, reducing solution with an estimated pH and temperatureof 1.7 and 260°C, respectively. These fluids, in addition to depositing pyrite, also weresufficiently acidic to leach strongly the original rock, leaving it with virtually no neutralizingcapacity. This concurs with Kwong (1994), which ranks caic-alkaline suite porphyry deposits asmore susceptible to ARD than the alkaline suite due to the much more intensive hydrothermalalteration.Fluids causing late stage pyrophyllite alteration were likely similarly acidic, but with less sulfur,since Pyrophyllite Breccias tend to be low in pyrite. Kwong (1994) notes that pyrophyllite is arelatively unstable mineral under atmospheric conditions and rapidly weathers to clay minerals,releasing aluminum and exposing fresh sulfides.A substantial change in thermal gradients occurred before fmal stage alteration (Cargill, 1975)since the zeolite-carbonate mineral assemblage is indicative of low temperature, alkalineconditions.Sulfides present in waste rock include 2 to 5 percent pyrite with rare sphalerite, chalcopyrite, andmolybdenite. Pyrite can occur both finely disseminated throughout the three lithological units,and as fracture fillings with chalcopyrite and molybdenite, or with quartz, calcite ± sphalerite.Pyrite contents of up to 15 percent have been observed in occasional wide veins and stockwork.For this study, calcite is the only mineral considered to have a potential significant contributionto acid neutralization.24In summary, the original textures and mineralogy of the three main lithological units at IslandCopper proximal to the ore zone have in many cases been totally or partially destroyed by laterhydrothermal alteration. In terms of acid rock drainage, the most significant alteration occurredduring the intermediate stage when high temperature, reducing, sulfur rich, and acidic solutionsinfiltrated through the rock mass causing both: i) pervasive leaching of primary feldspar andmafic minerals and replacement with a sericite-chlorite-clay (SCC) assemblage, and ii)emplacement of fine-grained disseminated pyrite. Final phases of late stage alteration emplacedpotentially acid-buffering carbonate with zeolite minerals along fractures.2.3 Waste Rock Dump Characterization2.3.1 ObjectivesThe primary objective of the waste rock dump characterization was to assess the macroscopicARD-controlling features, including:i) flow of water through and out of the waste rock dump,ii) amount of sulfide and acid consuming potential in the waste rock dump, andiii) supply of oxygen to the interior of the waste rock dump.In addition, current and historic conditions of water quality and waste rock dump temperature arediscussed as they apply to prediction of future conditions.2.3.2 Overall Effects of DevelopmentLocal on-land conditions at Island Copper have been affected both by excavation of the open pit,and construction of the waste rock dumps.Although there is very limited knowledge of pre-mining groundwater conditions, excavation ofthe open pit created a discharge area, and likely resulted in a lowering of the groundwater table inareas upgradient, or north of the pit. Because the pit and most of the North Dump are within the25End and Trey Creek wastersheds, and also that the underlying Bonanza Volcanics dip south, itlogically follows that if drainage from the North dump enters the groundwater system, themajority will ultimately seep into the pit.2.3.3 ConstructionBased on observations of current dumping practice and analysis of annual aerial photography,waste rock dumps at Island Copper were constructed using both the push dumping and freedumping methods described in Morin et al. (1991). In push dumping, waste rock is dumped nearthe dump crest, and a bulldozer is used to push material over the crest. In free dumping, wasterock is deposited in closely spaced truckload-sized piles approximately three metres in heightacross the level surface of the dump. The material is then leveled using a bulldozer before thenext level of dumping proceeds.The Beach dump is currently the only active waste rock dumping area at the mine and is mainlyconstructed using the push dumping method. Marginal ore was also deposited on the top of theBeach dump prior to 1985 using both push and free dumping, and is currently being re-handledand processed with freshly mined ore (Perelló et al., 1994).Similar construction techniques were used in the North, North West, South and West dumps.However, it appears from airphotos that the accumulation of too many truckload piles adjacent tothe dump crest resulted in most of the waste rock being pushed over the crest into lifts up to 20metres high. The remaining waste rock, deposited some distance from the crest was smoothedover the top of the dump, free-dumping style, creating a very short lift.The overall technique of dumping has had a profound effect on the mixing of the pile materialand the distance between subsequent lifts. Dump scarps on the marginal ore beach dumpillustrate the various patterns that have arisen. Push dumping has resulted in an approximately 8to 15 metre high lift with a cross section showing the individual truck load piles distributed in a26series of moderately steeply dipping bands up to two metres wide. Free dumping has resulted ina much shorter lift height of about two and a half metres, and the waste rock relatively wellmixed. Although push dumping appears to have been most frequently used in dumpconstruction, the intermittent use of free dumping makes it difficult to predict lift height, andhence water flow paths, in the dump.Table 2.1 summarizes some important characteristics of the North dump. The table, and much ofthe following information on the North dump construction was taken from UBC MMPE (1990c).For this study, the North dump consists of three distinct regions: the Old North dump (OND),the Eastern Most Outslopes (EMO), and the Cap.Prior to dumping, the area north of the pit was logged. During initial years of mining,considerable till from overburden stripping in addition to waste rock was deposited on the dump.The till by nature contains significantly more sand to silt sized particles than does waste rock andhas net acid consuming properties (Section 3.4). As a result the basal ten to twenty metres ofalmost all of the North dump forms a relatively low permeability, acid consuming horizon. TheEMO and Cap areas constructed later in the mine’s life contain little or no till and this factor is alikely contributor not only to their high permeability, but also to their current net acid-generatingcharacter.2.3.3.1 Old North DumpThe Old North dump was constructed from 1971 to approximately 1981 and is a mixture of about44 percent till and 56 percent waste rock (UBC MMPE, 1990c). Some previous studies (UBCMMPE 1 990c and Li, 1991) have defined the Old North as being only the westernmost region ofthe North dump, however for this study OND is defined as the lower bench of waste rockTable2.1CharacteristicsoftheNorthdumpanditsmajorregions(fromUBCMMPE,1990c)DumpConstructionPeriodTonnageAreaTillEstimatedEstimated(x106tonnes)(Ha)(wt.%)PorosityBulkDensity(kg/rn3)FromToONDApril1971<June1984?62.112544.40.191981EMOApril1981Dec.19815.0152.40.301840CAPJune1984Aug.19859.3400.00.271928NorthApril1971Aug.198576.414036.50.21196528covering an area extending from the western limit of the North dump east to the Eastern MostOutsiope dump. From 1972 to 1975, approximately 830,000 tonnes of marginal ore wasstockpiled on the west end of the North dump. About 440,000 tonnes of till were later dumpedin the same area (now known as the Old Marginal dump) when it was apparently decided to notprocess the marginal ore. Since the exact location of the Old Marginal dump is not clear fromprevious reports, for this study the Old Marginal dump is referred to as being part of the OldNorth dump. Initial reclamation of most of the Old North dump was conducted in 1984, andtrees planted in 1987. Numerous truckloads of till were deposited on the top of the eastern endof OND during the late 1980’s for later reclamation work.2.3.3.2 Eastern Most OutsiopeThe Eastern Most Outsiope was built off of the outer southeast margin of OND from April toDecember 1981. The dump has two levels; the lower EMO (12.08 Ha) and upper EMO (3.16Ha). EMO material is estimated to contain less than three percent till. A water quality seepagesurvey during the summer of 1987 showed several low-pH seepages, and a ditch wasimmediately constructed to collect drainage and direct it to the existing Eastern Drainage ditch(or EDD) (BHP-Utah, 1988). Reclamation activities included seeding with a grass and legumemixture and planting alders in 1987.2.3.3.3 CapMaterial placed on the central portion of the Old North dump from June 1984 to August 1985forms what is known as the Cap. The Cap covers 40 hectares and is comprised of the westerlyLower Cap, and the easterly Upper Cap. The Cap is composed exclusively of waste rock. Itssurface has numerous oxidized patches up to twenty metres across, and some seepages from thebase of the Cap are acidic. The mine currently has a permit to dump wood and scrap metal intoa pit near the eastern end of the Upper Cap. Heavy grease products are disposed in a small soillined pit a short distance to the west. Reclamation work on the Cap has been limited due touncertainty of decommissioning strategies. Till from South Wall Pushback pit extension29stripping was deposited in the late 1980’s along the south margins of both the Upper and LowerCap in 1988. The spreading of this material across the southern slope of the Cap commenced inearly 1993.2.3.4 HydrologyAs previously mentioned, most of the North dump area (and almost the entire pit) are locatedwithin the historic End and Trey Creek watersheds (Li, 1991, Fig. 2.2). A portion of the westernend of the Old North dump, and the entire North West dump are within the Stephens Creekwatershed.The development of the North dump has most significantly affected the End Creek watershed byrestricting flow down the historic drainages. Although subterranean flows thought to be EndCreek and Trey Creek are observed on the south margin of the North dump, the development ofthe dump has resulted in the formation of several ponds along its northeast margin.Construction of the perimeter ditch system around much of the North and North West dumpsfrom 1986 through to the present has directed all drainage southeastward. Drainage from theNorth West dump, situated at slightly lower elevation than the North dump, is pumpedapproximately 500 metres east and fed into the North dump drainage ditch. Currently, alldrainage flows to a sump southeast of the North dump, which is drained by a culvert leading tothe synthetic membrane-lined Water Management Pond situated on the Beach dump. WaterManagement Pond’s water is pumped to the mill for use as process water. If necessary, excesswater may be released into the adjacent Exfiltration Pond when all water quality objectives ofthe operating permit are met. Tidal action allows gradual mixing of sea water and effluent as thewater exfiltrates through the Beach dump.The total basin area drained by the perimeter ditch system (not including the North West dump),is estimated at 279 hectares (Rescan, 1992), twice the area of the North dump.302.3.5 Water QualityDetailed water quality monitoring results of potentially impacted sites and waste rock dumpperimeter stations are given in annual environmental assessment reports. These reports,compiled by Island Copper Mine, are reviewed by the Island Copper Mine environmentaltechnical advisory committee.The location of current perimeter ditch sample sites are given in Figure 2.4. Acidic effluentcomparable in magnitude with typical drainage from station EMO (Table 1.1) occurs at stationsNWD, NDD, EMO, EDD, and EDT.Water samples are routinely measured for pH, total dissolved, fixed and volatile solids,alkalinity, acidity, turbidity, sulfate nitrate, calcium and magnesium. Metals determinedinclude dissolved cadmium, copper, iron, lead, manganese, molybdenum, and zinc. Theseparameters were short-listed to pH, alkalinity, acidity, sulfate, calcium, magnesium, anddissolved aluminum, cadmium, copper, and zinc for the recent hydrology and metal loadingsstudy (Rescan, 1992). Detailed analytical procedures are given in BHP (1986).2.3.6 DrillingIn 1988, a total of ten drill holes were completed on the North (7 holes) and Beach (3 holes)dumps using a Becker 505 percussion drill (UBC MMPE, 1990c).Eight foot composites of drill cutting splits were analyzed for acid base accounting parametersof total sulfur and acid consuming potential. No sulfate or paste pH analyses were performed.Following completion of each hole, a slotted PVC pipe was installed to maintain the opening forfuture monitoring (UBC MMPE, 1990c).Figure2.4Locationof perimeterditchdrainagesamplesitesandNorthdumpdrillholes32In 1989, seven Becker percussion drill holes were completed on the North West dump. Inaddition to performing acid base accounting on drill cuttings and installing slotted PVC pipe, abasal piezometer and gas monitoring tubes at 2 metre intervals were installed down each hole.The locations of the seven North dump drill holes are shown in Figure 2.4. AMD #1 through #3are located on the EMO dump area, AMD #4 at the eastern end of OND was intended tointersect the old Trey Creek streambed, holes AMD #5 and #6 tested the Old Marginal dumparea and western end of OND respectively; and hole AMD #7 was intended to test the Cap andpossibly intersect a stream bed in the End Creek watershed (UBC MMPE, 1990c).2.3.7 Acid Base AccountingA total of 188 acid base accounting analyses were performed on drill cuttings from the North(68 samples), North West (66 samples), and Beach (54 samples) dump drill holes. Detailedresults are given in UBC MMPE (1990a, 1990c) and Li (1991).Assuming normal distributions, mean and standard deviations of acid base accounting results aregiven in Table 2.2 for both the North dump and its various areas.The high standard deviations with respect to the means illustrate the heterogeneity of the dumpmaterial. Based on the significant variability, it is questionable whether the amount of samplingis adequate for an 84 million tonne, 140 hectare waste rock dump. The lack of adequate data ismost obvious in the Cap area (7 samples from one drill hole). Nevertheless, the drill holesrepresent the only direct information on dump composition (UBC MMPE, 1 990c).Overall, the acid base accounting analyses do confirm:i) the net acid generating potential of the EMO and Cap areas, andii) the net (albeit marginal) acid consuming character of OND.33Table 2.2 Mean and standard deviations of acid base accounting analyses from the Northdump and its various areasAPP ACP NNP ACP:APP(kg CaCO3/t) (kg CaCO3/t) (kg CaCO3/t)Area Mean Std.Dev. Mean Std.Dev. Mean Std.Dev. Mean Std.Dev.OND 22.6 14.0 30.5 17.0 +7.9 15.4 1.72 1.65(n = 42)EMO 51.1 23.5 18.7 11.7 -32.5 29.1 0.48 0.46(n=19)CAP 52.3 15.3 43.5 10.4 -8.8 19.5 0.91 0.41(n = 7)North Dump 33.6 22.1 28.5 16.6 -5.1 27.0 1.29 1.43(n = 68)2.3.8 Oxygen and Carbon Dioxide MonitoringMonitoring of oxygen and carbon dioxide levels in the seven North West dump drill holes wasconducted in October and November 1989, and February 1990 (UBC MMPE, 1990a). Thetubing leading out of the holes, exposed to light and variations in temperature, has sincedisintegrated and cracked, and the system will require some refurbishing for future monitoring.Detailed monitoring results are given in UBC MMPE (1990a). Decreased oxygen and elevatedcarbon dioxide levels were encountered down a number of drill holes. Very low (less than 1%)oxygen levels were consistently encountered only in one six metre interval down NWD #4; theoxygen levels in the remaining areas generally ranged from 10 to 21 percent.Morin (1990), quoting work from Ohio State University, indicates that pyrite oxidation byoxygen is limited by oxygen levels below 2 percent. Based on the North West dump monitoringresults, it is concluded that although there are occasional pockets within the dump that haveoxidation rate-limiting levels, the majority of the dump contains oxygen levels that are not34sufficiently low to limit the rate of pyrite oxidation. Since similar waste rock and constructionmethods were used, the same conclusion is reached for the North dump.2.3.9 Temperature MonitoringHarries and Ritchie (1981) justify the use of waste rock dump temperature as an ideal method ofdetermining pyrite oxidation rate because:i) temperatures are easily and accurately measured with relatively simple instrumentation,ii) temperatures are a measure of average heat production over a large volume of surroundingdump material, andiii) waste rock dump temperatures respond quickly (within a few weeks) to changes in oxidationrates.Down hole temperatures were monitored using multi-thermistor strings and a portable readoutdevice (UBC MMPE, 1 990a). Temperature monitoring was conducted on the North West dumpconcurrent with oxygen and carbon dioxide monitoring. At time of writing, Island Copper Minehas commenced routine temperature monitoring down the fourteen on land dump drill holes.Recent results from this dump allow the construction of a temperature - time gradient to assist inprediction of future temperature trends.Temperature monitoring at both the Rum Jungle site, Australia, (Harries and Ritchie, 1981) andMine Doyon, Quebec (Université Laval, 1991) showed that at least the top four metres of thewaste rock dump is subject to temperature variations caused by seasonal climatic changes.Therefore, to eliminate the effect of seasonal variation, only temperatures below four metresdepth were used to calculate average down hole temperatures on Island Copper waste rockdumps.Solely for the purpose of determining overall temperature change with time, temperaturemeasurements below four metres depth from all seven North West dump drill holes were35averaged to give a single value for the monitoring period. Because they showed negligiblevariation, readings from October 1989 to February 1990 were taken as a single reading taken onDecember 1, 1989. Assuming that the rock temperature at time of dumping (January 1, 1983)was equal to the average annual temperature of 8°C, a temperature versus time relationship canbe estimated (Figure 2.5). The results show a time of accelerated temperature increase between1983 and 1989, and a relatively lower rate of increase from 1989 to 1994.2520E 15a,IC,a,105—Jan-82DateFigure 2.5 Average dump temperature versus time for North West dumpFrom the measurements, the North West dump calculated temperature gradient from December1983 to December 1989 is +1.54°C per year, and from December 1989 to February 1994 is+0.37°C per year.Although temperature measurements down North dump drill holes were reportedly taken in late1989 or early 1990 (Ian Home, pers. comm.), results have not been located to date. Results ofFebruary 1993 monitoring are given in figures 2.6 to 2.8.Jan-85 Jan-88 Jan-91 Jan-9436Significantly elevated temperatures were found in holes through the Cap and EMO areas, andwarm moist air could be easily felt moving out of the holes. Hole AMD #7 through the Capshowed the highest temperature of 24.3°C, similar to elevated temperatures recorded in NWD #2during the 1989 and 1990 monitoring. Holes through the OND areas showed the least elevatedtemperatures.Assuming an initial dump temperature of 8°C and using an average temperature of 17.0°Cobtained in March 1993, the temperature gradient for EMO from January 1981 to March 1993 is+0.74°C per year.2.3.10 SummaryThe development of the Island Copper Mine has affected local hydrology by:i) creating a discharge area by excavating the open pit,ii) impeding flow of End and Trey Creek drainages, thus creating several ponds along thenorthern boundary of the dump, andiii) directing surface water from the End and part of the Trey Creek drainage basins into theperimeter ditch system.Waste rock dump construction used mainly push dumping with occasional use of free dumpingmethods (Morin et a!., 1991). The intermittent use of free dumping makes it difficult to predictwater flow paths in the waste rock dumps.37300ci)0.El100-- AMD#4 (east OND) -- AMD#7 (upper Cap)IDown-hole temperatures for AMD #4 (east end of Old North Dump) and AMD0 5 10 15 20Depth (m)-- AMD#1 (lower EMO)—_ AMD#2 (lower EMO)-E-. AMD#3 (upper EMO)Figure 2.7 Down-hole temperatures for AMD#1 and #2 (lower EMO), and AMD #3 (upperEMO)300ci)a.E(1) 10I—0Figure 2.6#7 (upper Cap)0 5 10 15 20 25 30 35Depth (m)25 30 353830C)o 200-• I I I I0 5 10 15 20 25 30 35Depth (m)- AMD#5 (west OND) -- AMD#6 (west OND)Figure 2.8 Down-hole temperatures for AMD#5 and #6 (west OND)Perimeter ditch water quality stations consistently returning contaminated effluent are:i) NWD (draining the North West dump),ii) NDD (likely draining the Old Marginal dump),iii) EMO (draining the EMO dump area),iv) EDD (draining EMO and the eastern flank of OND and the Cap dump areas), andv) EDT (combination of EDD and Trey Creek subterranean flow).Acid base accounting results indicate that the OND dump area has the lowest potential for netacid generation. This region contains significant till, thus creating a potentially acid consuming,and relatively low permeability horizon in the basal ten metres of the North dump. The EMOdump area has virtually no till and acid base accounting analyses show it to have net acidgeneration potential. The Cap region apparently has less net acid generation potential, butlimited data are available for this area.39It is concluded that, based on oxygen measurements from North West dump montioring, thatthere is sufficient oxygen in almost all areas of the dump for pyrite oxidation. There is alsoevidence of convective transport of air through the dump.Elevated temperatures (indicative of enhanced pyrite oxidation rates) have been documenteddown several North and North West dump drill holes. Calculations of North West dumpmonitoring data spanning five years indicates that the temperature gradient is decreasing. Dueto lack of historic monitoring data, it is uncertain whether this gradient can be applied to the Capand EMO regions of the North dump. Future temperature monitoring of the waste rock dumpswill provide valuable data for modeling of future effluent quality trends.403.0 WASTE ROCK CHARACTERIZATION3.1 ObjectivesThe objectives the waste rock characterization study were:i) to characterize waste rock material with respect to rock type and alteration, geochemistry,and physical characteristics such as grain size distribution,ii) to determine degree of weathering that had already occurred in the rock after 8 to 12 years inthe dump, andiii) to determine effluent quality from various rock units under controlled laboratory weatheringconditions.3.2 Methods and Procedures3.2.1 SamplingA total of eight waste rock and two till samples were taken from the North dump in 1992.Details of each sample site are given in Table 3.1, and site locations are shown in Figure 3.1.During phase 1 sampling in April 1992, four 100 to 140 kilogram samples were collected forcolumn test work. The Cap and EMO dump areas were selected as source areas because basedon dump seepage monitoring, these areas were currently generating the most significant ARD.Three out of four sites were located adjacent to existing drill holes, as the drill holes providedacid base accounting values to guide in selection of a sample each of material currently acidgenerating, and material with some acid-generating potential from the two dumps.Table3.1WasterocksamplesummaryAbbreviations:EMOCAP-LCAP-UEasternmostOutsiopeLowerCapUpperCapIslandCopperGridCoordinatesApprox.SiteDumpAreaNorthingEastingDateSampledSampleMassComments(feet)(feet)(kg)1CAP-U770030100April1992100-1401-1.5mpits;columntesting2CAP-U780029700April1992100-1401-1.5mpits;columnandhumiditycelltesting3EMO610031600April1992100-1401-1.5mpits;columntesting4EMO610032500April1992100-1401-1.5mpits;columnandhumiditycelltesting5OND-W860025200Sept.19925-100.30mpits;humiditycelltesting6OND-W830026300Sept.19925-100.30mpits;humiditycelltesting7CAP-L830028300Sept.19925-100.30mpits;humiditycelltesting8OND-E710030000Sept.19925-100.30mpits;humiditycelltestingTiCAP-UNA;compositeNA;compositeApril199210compositeof>10tillpilessamplesampleondump;chem. &phys.characterizationT2OND-ENA;compositeNA;compositeApril199210compositeof>10tillpilessamplesampleondump;chem.&phys.characterizationOND-EOldnorthdump,eastendOND-WOldnorthdump,westendNANotApplicableFigure3.1Locationofwasterocksamplesites43A “grade-all” excavator was used to obtain the four samples and place them in barrels. Depthsof sites 1, 3, and 4 sampling pits were about ito 1.5 metres, and only 0.3 metres for site 2.The material was placed into barrels double-lined with heavy duty plastic bags, sealed andimmediately shipped to the UBC Department of Mining and Mineral Process Engineering.Photographs were taken of each excavation and of the waste rock profile in each pit. Continuouschannel samples were taken down one or more profiles in the pit and samples were immediatelysealed in plastic for subsequent moisture content determination. Three to four hand specimensof the rock types at each site were taken for identification and further study.Two ten kilogram composite till samples were also taken in April 1992 from 10 to 15 piles eachon the Upper Caps (sample Ti) and east end of Old North dump (sample T2).The second phase of sampling consisted of four additional waste rock samples (sites 5 through8) for humidity cell testing, and were obtained in September 1992 after material from the firstfour sites had been examined and column testing had commenced. Selection criteria was basedon both obtaining better representation of the various Island Copper waste rock units, and betterspatial representation of the dump as a whole. Samples were generally taken from the top 0.3metres of the dump surface on sideslope areas where there was minimal vegetation.Selected samples from sites 1 through 4 and site 6, and from waste rock taken from thesoutheast area of the 640 bench in the open pit were used in a study relating field weathering andARD prediction by acid-base accounting (Lister et a!,, 1993).443.2.2 Date of MiningThe date of mining was determined by referring to waste rock dumping records compiled by Li(1988). The compilation consists of a map of the dump and pit area for every month sincecommencement of operations, and based on availability of information, shows both source areasin the pit, and destination areas in the dump. For some months, poor records were kept, and thesource and/or destination information is missing.3.2.3 Rock Type and Mineralogy AssessmentThe rock type and mineralogy of the sample was assessed through hand sample and limited thinsection and x-ray diffraction (XRD) analysis on selected samples.Hand specimens taken from sites 1 through 4 at time of sampling were examined and described.A selection of these rocks were also examined for confirmation purposes by J. Fleming, chiefgeologist at Island Copper. In addition, a number of rocks were randomly selected from eachsite’s sample upon its arrival at UBC (10 samples each for sites 1 through 4, and 5 samples eachfor sites 5 through 8). Each sample was classified as to rock type and alteration, amount andmode of occurrence of sulfide minerals, amount and occurrence of calcite, colour of weatheredproducts, rock competence, and presence of zeolite, gypsum, feldspar, or other accessoryminerals of interest.Ten polished thin sections were made from a suite of mainly highly oxidized samples selectedfrom the various sites. These were microscopically examined by Dr. C. Leitch (an orepetrologist with extensive experience in Island Copper geology) for similar characteristics as thehand sample classification. In addition, modal estimates of each sample’s mineral assemblageand an estimate of degree of pyrite oxidation were compiled. The interaction with both Mr.Fleming and Dr. Leitch provided a solid basis for the author’s own interpretation of thesomewhat complex alterations observed in many of the hand samples.45Limited XRD analysis (four samples) were conducted on weathered products from surfaces ofthe hand samples. Analyses were done at the UBC Department of Geological Sciences using aSiemens D5000 x-ray powder diffractometer.3.2.4 GeochemistryGeochemical analyses consisted of 30-element inductively coupled plasma (ICP), acid-baseaccounting (ABA), and acid-volatilized carbon dioxide.Samples for ICP, ABA, and acid-volatilized CO2 analyses were initially crushed, split ifrequired, and pulverized using UBC MMPE facilities. Pulverized samples were stored in eitherkraft or plastic bags.A 10 to 20 gram pulp of each sample was submitted to Acme Analytical Laboratories inVancouver who conducted a thirty-element ICP scan on a 0.500 gram sample digested in aquaregia. The aqua regia leach is considered partial for Mn, Fe, Sr, Ca, P, La, Cr, Mg, Ba, Ti, B, W,and limited for Na, K, and Al.Acid-base accounting was conducted at the UBC MMPE department. Acid consuming potential(ACP) was conducted according to BHP (1986) procedures, which are an adapted version of theSobek et al. (1978) procedure. Total sulfur was gravimetrically determined by oxidation tosulfuric acid using nitric and hydrochloric acid digestion, followed by precipitation with bariumchloride. Sulfate was similarly determined, with the exception that a weak acid (10 percentHC1) digest solution was used to extract soluble sulfate for barium chloride precipitation.46Paste pH was determined using a 2:1 soil to water mixture.Acid-volatilized CO2 (as carbonate minerals) was determined using a Coulometrics Coulometer.This instrument measured the quantity of CO2 gas released when 2N perchioric acid was addedto a pre-weighed mass of sample.3.2.5 Physical AnalysisAir-dried moisture content was determined for profile samples taken from sites 1 through 4 byrecording initial mass, air-drying the sample for 36 hours at approximately 30°C, and reweighing.Dry sieve analysis was conducted on samples from all sites using a .ñ series of sieves.3.2.6 Replicate AnalysesReplicate geochemical and physical analyses were conducted on the waste rock samples todetermine variability due to sampling and laboratory technique. Where possible, estimates ofprecision were made on the replicate data set. The method adopted involved first calculating theabsolute value of the difference in result between each replicate set replicates (Lix), and thencalculating the standard deviation of the replicate data set. The precision values presented inTable 3.2 are two standard deviations of the summed Lx values; thus, nineteen times out oftwenty (or 95 percent of the time), a duplicate analysis will yield a value similar to the originalresult within plus or minus the precision indicated.47Table 3.2 Calculated precision of selected chemical analyses of waste rockParameter # Replicates Calculated PrecisionTotal Sulfur 2 ±O.4wt%Sulfate 2 ±O.lwt%Paste pH 11 ± 0.22 pH unitsAcid Consuming Potential 7 ± 10 kg CaCO3/tAcid-Volatilized CO2 5 ± 0.03 wt% CO23.3 Results3.3.1 Overall ObservationsFigure 3.2 shows the profile of the 1.2 metre deep sample pit at Site 4 on lower EMO.Evidence of sulfide oxidation is indicated by yellow and dark rusty brown staining. At mostsample sites, a considerable amount of fines were agglomerated onto the surfaces of the largerrock particles.Figure 3.3 shows an attempt at obtaining a sample in an obviously highly oxidized zone on theUpper Cap. The excavator encountered an indurated horizon approximately 15 centimetresbelow the surface. The horizon could be seen on a dump scarp about ten metres from the site asa distinct oxidation “front” into the pile, with relatively fresh, unoxidized material below. Asecond attempt in another oxidized area on the Upper Cap produced similar results, only theindurated horizon was 30 centimetres below the surface. As the excavator was unable topenetrate further, the site 2 sample was taken from the upper oxidized horizon.Q00‘1-0Q-4-.E00a)I)da)a)——a)0:.-c.4.--4-.a)II49Figure 3.3 Indurated horizon below highly oxidized zone on upper Cap50Reconnaissance on the Cap area during sampling revealed that the most of the acid-generatingrocks were highly altered with fine-grained disseminated pyrite. In contrast, rocks with lesspervasive hydrothermal alteration, but still with significant pyrite content, showed relativelylittle evidence of pyrite oxidation (Figures 3.4 and 3.5). In addition, the acid-generating rocktypes were frequently found intermingled with Pyrophyllite Breccia, which tends to contain littlepyrite, but has negligible acid-neutralizing capabilities (BHP and Rescan, 1988).3.3.2 Date of MiningEstimated dates of mining, and in-pit source for the eight sites are given in Table 3.3.Table 3.3 Estimated date of mining and in-pit source for waste rock sample sitesSite Estimated Date of Estimated In-PitNumber Mining Source(s)1 August 1984 - April 1985 Northwest 1040,1080,1120 benches2 August 1984 Northwest 1120 bench3 Sept 1981 West 600,800,840,1280,1320 benchesEast 600, 1080, 1120 benches4 Sept 1981 West 600,800,840,1280,1320 benchesEast 600, 1080, 1120 benches5 Sept 1983 Northwest 1160 bench6 Oct 1983 Northwest 1160, 1200 benches7 Jan - May 1984 Northwest and West 1160 bench8 June - August 1985 West 1040 and 1080 benches51Figure 3.4 Sericite-chiorite-clay (SCC) altered volcanic? on Upper Cap, with finelydisseminated pyrite that is obviously oxidizing.Figure 3.5 Weakly altered volcanic on Upper Cap, with medium-grained , fracturecontrolled pyrite showing little evidence of oxidation.Table3.4RockclassificationsummaryoftheeightwasterocksamplesLithologyMineralsBVANBonanzaVoic.,Undiff.blobiotiteBVATBonanzaVoic.,TuffchichloriteBXBVBonanzaVoIc.,BrecciaepchalcopyriteBXPYPyrophylliteBrecciadumortdumortieritePPQFRhyodacitePorphyryepepidoteVEINVeinmaterialhehematitepyrophpyrophylliteqzquartzAlterationbio-mtbiotite-magnetitepyrophpyrophylliteqz-serquartz-sericiteSCCsericite-chl-clayHCIReactionSiteWeatheredDominantOtherDominantOtherVisualPrimaryOtherMatrixVeinOtherPhysicalSurfaceLithologyLithologiesAlterationAlterationPyritePyriteSulfidesMineralsCompetenceColourAvg. %HabitNotedIwhiteBVAN-BVAT-100%epidoteqz-sertrdissmodstrzeo-veinscomp>100%bio,he,ep,v.compchl2yellowBVAN-60%BVAT-20%SCCqz-ser3disscp-traceweaknilgypsummod>BXBV-10%pyrophsoftBXPY-10%3whiteBXPY-70%PPQF-30%pyrophqz-sertrdissnilnilmod4white,BVAN-80%PPQF-20%bio-mtSCC1.5diss>cp-tracemodweakzeo-veinsmod>yellowqz-serveinep,pyrp,biocomp5whiteBVAN-ser-clay0.5vein>cp-tracemodweakzeo-veinsv.comp100%disssp-0.5%6yellowVEIN-40%BVAT-20%SCC12diss>nilnilsoft>PPQF-40%veinmod7rust,BVAN-SCCqz-ser1.0diss>nilnil>gypsumcompyellow100%veinweakep8white,BVPY-60%PPQF-20%pyrophSCC2.0dissnilnildumortmodyellowBVAN-20%sersericitespsphaleritezeozeoliteCompetencev.compverycompetentcampmoderatemod.moderatelycompetentSulfidehabitlabundancetrtracedissdisseminated>morecommonthanHCIReactionstrstrongmodmoderateweakweaksoftsoftnilnoreaction533.3.3 Rock Type and Mineralogy AssessmentTable 3.4 summarizes rock characteristics obtained from hand specimen examination of severalrandomly selected samples from each site.As mentioned, all specimens had a considerable amount of fine-grained particles agglomeratedto their surfaces. Colours of both the agglomerated fines and the actual weathered samplesurface were either white-gray, yellow, or dark brown rust. Numerous specimens, especiallythose from sites 4 and 8 had both white and yellow mottled surfaces. Specimens from sites 2, 6,and 7 had entirely yellow or dark brown rust surfaces, indicative of significant sulfide oxidation.It can be seen that Bonanza Volcanic lithologies predominate the sample suite, followed byHydrothermal Breccias, and finally, Rhyodacite Porphyry material. The specimens examinedwere variably altered. Pyrite occured mainly in disseminated form while chalcopyrite andmolybdenite were rarely observed. Significant quantities of vein-occurring sphalerite werefound in two of the five hand specimens from site 5. The highest amount of pyrite (12 percenton average) was observed in specimens from site 6.With the exception of sites 1, 4, and 5, the specimens examined generally showed weak to nileffervescence with ten percent hydrochloric acid. Accessory minerals observed included zeolitein veins in site 1, 4 and 5 material, and two millimetre long gypsum needles on highly oxidizedsurfaces of sites 2 and 7 specimens.Competence of the rock, qualitatively assessed by its hardness and ease of breaking, variedconsiderably.3.3.4 MineralogyPetrographic descriptions of a suite of mainly highly oxidized samples is given in Appendix 1.54The study confirmed the primary habit of pyrite in waste rock as disseminated subhedral toeuhedral one to two millimetre crystals. Modal estimates of pyrite varied from zero (in one site8 specimen) to 75 percent (in a specimen of site 6 vein material), but generally ranged from twoto ten percent.The most common mineral in the highly oxidized suite was sericite, followed by chlorite, clayminerals, and quartz. Traces of rutile occurred in many samples, and occasional dumortierite,apatite, magnetite, zeolite and carbonate were observed in one or two samples. Significantquantities of feldspar were only found in a sample from site 8; in all others primary feldspar wastotally replaced by sericite.Samples of agglomerated fines adhering to outer surfaces of four samples were analysed by xray diffraction. Results are given in Table 3.5.Unexpectedly, no jarosite (iron sulfate hydroxide) minerals were found in the yellow to brownweathering material. It is possible that amorphous iron hydroxide minerals (undetectable by xray diffraction) are instead the main product of sulfide oxidation. With the exception ofgypsum, the suite of minerals adhering to the rock surfaces are identical to those found in therock mass. Therefore, the agglomerated fines appear to be mainly derived from eithermechanical breakdown of rock due to mining or physical weathering, and are not chemicalweathering products.Both petrographic and x-ray diffraction studies indicate that although some samples showconsiderable surface oxidation, negligible pyrite and other mineral weathering has occurredwithin the rock mass.55Table 3.5 X-ray diffraction results from rock surface materialSample Site Appearance Minerals IdentifiedX3-1A 3 gray-white quartzpyrophyllitenacrite (clay mineral)X4-2A 4 medium brown quartzmuscovite (sericite)gypsumclinochlore (chlorite)X4-3A2 4 white muscovite (sericite)quartzlaumonite (zeolite)nimite (chlorite)gypsumX4-2C2 4 yellow quartzgypsummuscovite (sericite)clinochiore (chlorite)3.3.5 Elemental AnalysisResults of thirty-element analyses performed on samples from the eight waste rock sites and twotill composites are given in Appendix 3.The major mineral-forming elements analysed included aluminum, calcium, magnesium,potassium, and sodium. The highest aluminum values were from sites 1 and 7 (3.5 to 4.2percent), with the lowest, site 8 at 0.8 percent. Pyrophyllite, the primary mineral in site 8 rock,is an aluminum-poor mineral relative to feldspar and sericite, which are primary constituents ofsite 1 and 7 rock.Highest calcium values were found in sites with little or no evidence of sulfide oxidation (sites 1and 5, till composites), and were in the range of 2.1 to 3.5 percent. Lowest values, less than 0.756percent occurred in site 2, 6 and 8 samples. These results correlate well with the dilutehydrochloric acid reactivity of each site (Table 3.3), and indicate that most calcium probablyoccurs as calcite or dolomite. Magnesium values follow a similar trend as calcium, except thatsite 7 returned high magnesium values. This may be attributable to the presence offerromagnesium minerals.Highest potassium values (0.12 to 0.2 1%) tended to occur in the obviously acid generating sites2 and 6. Lowest values (0.04 to 0.06%) were from sites 3, 5 and 8 samples. The oppositeappeared to be true for sodium; slightly higher sodium values (greater than 0.1%) occurred insites 1 and 5, and the till composites, while the highly oxidized sites 2, 6 and 7 were relativelydepleted of sodium. High potassium values can be attributed to the presence of considerablesericite, while sodium values may be due to the presence of plagioclase feldspar.Heavy metals of significance to Island Copper include copper, iron, manganese, molybdenum,nickel, cobalt, zinc, and cadmium. Highest copper concentrations (427 to 847 ppm) wereencountered in sites 3, 4 and 6; site 8 contained the lowest amount of copper (65 ppm). Highestiron values (13.14 to 13.87%) were found in the highly pyritic sites 6 and 7, with the lowest insites 3 and 8 (1.56 to 1.59%). High manganese, probably indicative of mafic minerals, occurredin sites 1, 5 and 7 (3192 to 6709 ppm). The lowest manganese levels (401 to 694 ppm) occurredin sites 3, 4 and 8. Molybdenum values were low in all samples, ranging from 3 to 32 parts permillion. High nickel (85 ppm) concentrations were found in site 5 material, with the remainingsites ranging from 9 to 30 parts per million. Cobalt levels were greater than 20 parts per millionin sites 1, 2, 5, 6 and 7. Highest zinc (5225 ppm) occurred in sphalerite-rich site 5 material, andsite 1 also returned anomalous values of 740 to 1125 parts per million. Lowest values (83 to180 ppm) were found in the till composites and site 4 material. Cadmium, occurring as a traceelement in sphalerite, had a similar pattern as zinc, but with concentrations ranging from 0.2 to32.3 parts per million.57Scatter plots of the various heavy metals indicate strong positive correlations between cadmiumand zinc, iron and cobalt, iron and nickel, and nickel and cobalt. This suggests that i) asmentioned above, cadmium occurs as a trace element in sphalerite, and ii) pyrite contains tracesof nickel and cobalt as either inclusions or in solid solution.3.3.6 Acid Base AccountingAcid base accounting parameters analysed for included total sulfur, sulfate, acid consumingpotential, and paste pH, and acid-volatilized carbon dioxide. Results are given in Table 3.6.Anomalously high total sulfur values occurred in site 6 material, and the remainder of the wasterock samples sites had total sulfur contents ranging from 0.59 (site 3) to 4.3 (site 7) percent. Nodetectable sulfate was found in samples from sites I and 3; sites 6 and 7 had significant sulfatecontents (over 1%). Two types of acid producing potential (APP) were determined: i) from totalsulfur (APPS), and ii) from total sulfur minus sulfate (APPS2). The calculation methods forAPPS and APPS2 are given in Appendix 4.Acid consuming potential (ACP) varied considerably. Negative values were encountered in asample from site 6, indicating accumulation of considerable acidic products on the material.The highest ACP value, found in siteS material, was 110.2 kg CaCO3/tonne.Net neutralization potential (NNP, the difference between ACP and APP) of the samples tendedto be low. The NNP values obtained for samples with low paste pH may be slightly inaccurate,since the oxidation products contain sulfate and are accounted for in the APPS calculation, andalso cause a decrease in the ACP value due to their acidic nature. Only two of the eight wasterock sites and the two till composites had positive NNP values. The lowest NNPS2 (- 261.4kg CaCO3/tonne) was obtained from site 6 material.Table3.6Acidbaseaccountingandacid-volatilizedcarbondioxideanalysesoftheeightwasterocksamplesandtwotillcompositesSamp#Site#TotalSSO4APPSAPPS2ACPNNPSNNPS2ACP:PasteCO2(wt%)(wt%asS)(kgCaCO3/t)(kgCaCO3It)(kgCaCO3It)(kgCaCO3/t)(kgCaCO3/t)APPS2pH(wt%)111.45<0.0245345374729.429.41.657.911.95211.25<0.0239.139.162.523.423.41.607.760.96311.30<0.0240.640.657917.317.31.437.961.39423.250.26101.693.33.6-98.0-89.70.043.380.06522.650.2082.876.68.2-74.6-68.40.113.730.1622.700.2184.477.96.7-77.6-71.20.193.460.08730.59<0.0218.418.421.81.186.990.12830.94<0.0229.429.417.8-11.6-11.60.616.760.06930.72<0.0222.522.520.7-1.8-1.80.927.080.121041.300.1140.637.321.9-18.7-15.40.596.820.431142.300.1771.966.529.1-42.8-37.40.446.380.411241.600.1450.045.522.9-27.1-22.70.506.620.382222.950.2292.285.28.0-84.2-77.20.093.500.042341.900.2359.452.332.8-26.5-19.50.636.600.562451.750.0454.753.5110.255.556.62.067.773.542568.900.92278.1249.5-11.9-290.0-261.4-0.052.380.022674.300.45134.4120.39.5-124.9-110.80.082.870.012781.000.0631.329.410.5-20.8-18.90.364.840.0428Till0.300.039.48.544.635.236.15.257.851.18U.Cáp29Till0.480.0215.014.444.129.129.73.068.070.79ONDCo59On average, 93 percent of total sulfur is estimated to be in sulfide form with the remainder assulfate. Carrying this to NNP values, the mean NNPS2 is about 85 percent of the mean NNPS.Paste pH is considered to be indicative of current acid generating conditions in the sample, andif a sample has a paste pH of less than 4.5, it is considered to be generating net acidity. Paste pHvalues were below 4.5 in sites 2, 6, 7 samples, and a marginally acid generating pH value of 4.8was obtained from site 8 material. The highest paste pH was from site 1 material (7.98 pH).Acid-volatilized carbon dioxide analyses were highest in sites 5 (3.54 wt%C02),and 1 (0.96 to1.95 wt%C02). Low, but detectable values were encountered in the strongly oxidized sites 2, 6and 7 samples (0.01 to 0.10 wt%C02). There is a reasonable correlation between acid-volatilized carbon dioxide and acid consuming potential (Figure 3.6). Linear regression of thisrelationship gives the following equation:C02(mol/kg) = 0.0066[ACP(kg CaCO3/t)} - 0.055 (3.1)•,-20 0 20 40 60 80 100 120ACP (kg CaCO3It)• ACP vs. C02 — (Linear Fit)Figure 3.6 Acid consuming potential (ACP) versus acid-volatilized carbon dioxide for thewaste rock samples603.3.7 Physical AnalysisPhysical characterization included particle size analysis, moisture content, and surface area.Sampling of sites 1 through 4 was constrained to take that portion of the dump material thatcould easily be placed in the sample barrels, and the material obtained contained fragments up to5 inches (12.70 cm) in size. During sample preparation for column testing, the minus one inchfraction was segregated from the rest of the waste rock sample. The amount of material betweenone and five inches (2.54 and 12.70 cm) in size was measured to range from 42.0 to 50.6 percentof the total sample mass. Extrapolating this to the entire size range of particles in the waste rockdump, it is conservatively estimated that 50 weight percent of the dump is comprised offragments coarser than the one inch (2.54 cm) and less fraction used in kinetic testing.Detailed particle size analysis results for the eight waste rock sites and two till compositesamples are given in Appendix 5. Only the minus one inch (2.54 cm) portion of the waste rocksample was used in sites 1 through 4 analysis, the minus one half inch (1.27 cm) portion wasused for sites 5 through 8, and the entire sample (up to 2 inch or 5.08 cm particles) was used forthe till composites. Problems of static agglomeration of fines and blinding of mesh openingswere encountered during dry sieving of the till composite samples for mesh sizes of 70# (0.212mm) and below. Figure 3.7 and 3.8 show the range of particle sizes obtained from the wasterock and till composites, respectively.Comparisons between Figures 3.7 and 3.8 indicates that the till samples have significantly morematerial finer than 0.5 millimetres than do the waste rock samples. Wet sieving, or anotherappropriate method, is required to obtain the lower portion of the till particle size distributioncurve.II IIIIIIllII111111111111111IIlIttJ 11%Ililill11111liltliltIIlIltIliltIIIttIIllillII11111II11111II11111II11111II11111II11111II11111II11111II11111II11111II11111II11111IIItIIIII11111IIltIllIIthu—I-—1—4-4-1-14-i———4II11111IlullI111111I111111II11111II11111I111111I111111II11111I111111I111111I111111-a 0 011111IIII11111I1I111111111111I111111111111111I1111111I11111III11111I11111III1111111111111I1111111I11111tII11111I111111111111111I1111111III11111I...J_iJi_J_J_I_lJLllIllIII111111IIliltIIIIIIIllIlllliII111111llttIlIII1111111IIIIIIII11111I111111I11111I11111I‘I11111II11111I11111Stlilt1111111111tlIl__tL1!11111IIIIlliCit1—I411111II>II11111ItCD)IItlllItlIIIIllII0IIIIlIllti3IIIII()CDtItIij3IIttIlIIIIltlItIIIItlII1111111ItIIIItlt111111III14111111III-IIII1111111IIIllIIIIllllIIIllII111111IIIllIIIIttiiltililt1111111II1111ll11111IIIIll111111IIliii111111IIIIIll11111)I1111111111III1111111111II11111111111IIII1111Wt.%PassingllIIj1111111IIlltIllI11111111111111I1111111I1111111I111thIt1111111IIlilItlI11111111111111ItitttitlI1111111I1111111I11111111111111IIhullItl’I4.tII’l111111I1111111IlilitI.4,tthuI1111111lllltt5Il%lhhttII11111111111111%It\lltIlI1111111IIlIltI51141111I1111111—t—-ti-t-I1-———Ss—_4l1—I4-IH4-111111lSllltItI11111111111111i\lIlIljI111111111111111411lt,I11111111111111It\llttl\I11111111111111I15111!I11111111111111IItllII11111111111111II151111St1111111IIIitItl1111111IIttliltItISIlItISI11111111111111IIlt5lll41111111II1111111h151111111IttttitIItliI\tll\l111111_ii_l_II.I_tJ.1111111IIlIill!uftltltIl1111111t1111111%IIllIllIl1111111IIttltli!I14111111IIltlttIIlltIt!SI5111111111111I11111111kI14111111111111I1111111SII151111IIttitII1111111tIlillillItIllIltSI15111IIttiltII11111t\tttt4titIttlItIIItltltt.ISlI15111111111IIlllIlljI•It5tt1111111I11111111Il’4tlr.I_LLL1LlJL___l_J_I_I_tiLt__J_LJ4JJ.l1111111I1111111IIliltIIIltIllI1111111,IIlt\lltIIllIllIIllthllII111511111111IIttlIltIttll!,jIhullItl!lIllIItiltiS111111IItIllIllI11111111111111IIl1llllI11111111111111I1111111II111111II111111I1111111II111111III111111IIIllutIIII11111I1111111I1111111IIIIIIItI•00Wt.%Passing-.-0p-a-a 0p0---p -a 0-a 0 0T1-4 CD I I-I 0 z C CD -5 C) •00 CDCD C CD -5 0) I- 0 CD -5 I- 3-0 CD0—-a p -a -a 0 -a 0 0IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII4--I0 0062Moisture contents from sites 1 through 4 sample pit profiles are given in Appendix 6. Site 2material had the highest moisture content of 6.9 weight percent in the top oxidized 30centimetres, and 9.3 weight percent from the underlying indurated horizon. High moisturecontents in the top 8 centimetres of the two site 3 profiles (7.9 and 9.8 wt%) are likely a result ofhigh water retention by organic soil and root matter on the EMO dump. Below this horizon, andin sites 1 and 4 profiles, moisture contents ranged from 1.5 to 4.1 weight percent. Norelationship between moisture content and depth was observed.3.4 SummaryBased on paste pH analysis results, sites 2, 6, and 7 are deemed to be currently net acidgenerating. Site 8, at pH 4.8, is classified as marginally acid generating. The three acidgenerating sites all have obvious yellow to rust brown iron oxide staining completely coveringexposed surfaces. Sulfur content of site 6 and 7 material is high in comparison with the rest ofthe waste rock sample suite, however sulfur content of site 2 material is only marginallyanomalous. Samples from all of the acid generating sites appear to be strongly hydrothermallyaltered, and based on acid-volatilized carbon dioxide analysis, contain very low levels ofcarbonate minerals.Sites not currently acid generating vary greatly in mineralogy and geochemistry. Sites 3 and 8have acid-volatilized carbon dioxide contents comparable to the low levels found in the acidgenerating sites, and are interpreted to have little excess buffering capacity.Petrographic analysis of selected samples indicates that sulfide oxidation is restricted to exposedrock surfaces and is rarely present in fractures. Therefore, a very small proportion of the totalcontained pyrite is presently oxidizing.63Variable levels of heavy metals are present in each of the eight sites’ samples. Based oncorrelations from elemental analysis, traces of cadmium are present in sphalerite, and traces ofcobalt and nickel are occurring in pyrite.Geochemical analysis of the two till composites indicates that they are low in sulfur (0.30 to0.48 wt %), have moderate acid consuming potential (44 kg CaCO3/tonne), and moderate tohigh carbonate mineral content (0.70 to 1.18 wt% C02). In comparison with the eight wasterock sites, the till is considered to have sufficient excess alkalinity to some degree of bufferinfiltrating acidic drainage.644.0 KINETIC TEST WORK4.1 Introduction and BackgroundUnlike static tests which attempt to predict ultimate acid generation potential, kinetic testsattempt to predict the longer term weathering characteristics of a waste material and leachatewater quality as a function of time (Lawrence, 1990b).The objectives of the Island Copper waste rock kinetic test program were:i) to quantify aqueous chemical loads of eight waste rock samples from the North dump,ii) to give indication of variation of water quality with infiltration rate, andiii) to document temporal variation of leachate quality over the test duration.Waste rock from the eight sample sites described in section 3.0 were weathered in four columntest and eight humidity cell experiments. The experiments produced a significant amount ofdata, some of which are extraneous to the specific goals of this study. All data obtained fromkinetic testing is presented in this report, making this particular chapter a considerable length.However, the kinetic test results are considered to be a major contribution to the overallunderstanding of acid rock drainage at Island Copper, and will likely be used in subsequentstudies.The overall objectives of ARD kinetic tests are (Steffen Roberston and Kirsten, 1989):i) to establish rate and temporal variation of acid generation and water quality of a sampleon a continuous basis,ii) to confirm static test results, andiii) to test treatment and mitigation option options.65Because acid generation is a reaction which often takes years to evolve in the field, workersconducting laboratory kinetic tests attempt to accelerate the process in order to collect themaximum data on long term weathering in the shortest amount of time. Several enhancementmethods can be considered:i) exposing higher surface area (such as crushing sample),ii) increasing infiltration rate (Ritcey and Silver, 1982),iii) pre-acidification of test (Lawrence, 1990),iv) inoculation of test with T.ferrooxidans (Lawrence, 1990),v) increasing temperature of test,vi) increasing oxygen concentration in surrounding atmosphere, andvii) supplementing test with humidified air.While most of the above mentioned implementations do appear to increase the rate of acidproduction, it is difficult to quantify exactly how much or how uniformly the oxidation reactionhas been accelerated. Ritcey and Silver (1982) contend that their lysimeter test work onuranium tailings was accelerated ninefold by infiltrating the tests at nine times the averagerainfall rate, thus implying that in their case, removal of oxidation products is the controllingfactor in the rate of acid production. Caruccio and Geidel (1981) performed small scale (300-500 gram samples) leaching tests subjecting the sample to humidified air and rinsing withdeionized water every 3 to 5 days. No estimate of temporal acceleration was given.Other workers in the field of dump leach modeling contend that the rate determining factor inacid generation is oxygen availability (Davis and Ritchie, 1986). The presence ofT.ferrooxidans also appears to have a direct effect on oxidation of pyrite. Based on thesecontentions it seems that predictable test acceleration is complex and at the present timeincompletely understood.66Perry (1985) is skeptical of accurate interpretation of leaching tests for several reasons:i) test conditions are generally designed to promote maximum rates and amounts of pyriteweathering, thus giving “worst case” results,ii) actual period of weathering simulated is uncertain and might only be simulating shortterm conditions,iii) results are method specific and cannot be compared directly with other leaching tests,iv) scaling factors (method and site specific) must be applied to correlate lab results withfield conditions, andv) leaching tests were originally designed for studies of solid and hazardous waste landfillsand as such are not necessarily applicable to waste rock studies.Lapakko (1990) recognized that due to the expense and time required for kinetic test work, testsmay be run for durations that fall short of the time required for depletion of acid neutralizationpotential. Nonetheless, he showed that once leachate concentrations reached steady state, thetest time to depletion of acid neutralization potential can be calculated. However, Lapakko didnot predict actual field weathering rates from the kinetic test rates. Ferguson and Morin (1992)presented a similar method of calculating time to sulfide and neutralization potential depletion.In addition, they compared results from a 30 tonne waste rock test pile with humidity cell testresults from the same material and found that the time to peak sulfate concentration was muchshorter for the humidity cell, and that the humidity cell released sulfur at a much higher rate.However, results suggested that the test pile would ultimately produce more sulfate, possiblydue to field conditions causing more physical breakdown of particles than occurs in humiditycells.Morwijk (1993) compared results from Bell Copper’s humidity cells, 4 inch diameter columns,24 inch diameter columns and 10 tonne on-site waste rock pads, and found that chemical loadingrates for the different types of tests were comparable. Renton et al. (1988) found that thereverse of laboratory acceleration occurred; their field tests weathered almost 9 times faster than67their bench scale tests. These two examples illustrate the variety of results that can be obtainedand the potential difficulties in extrapolating kinetic test results to waste rock dumps.As waste rock material weathers in the field, individual rock particles slake, or break down,exposing more surface to oxidizing conditions, and thermodynamically unstable mineralsdissolve or alter to more stable compounds. This process occurs at widely varying rates fordifferent rock types and is an inherent part of the soil forming mechanism, taking tens of years,or even centuries to occur to any appreciable extent. As the residual mineral composition of therock changes, leachate from the waste rock changes as well. From the literature reviewed andconsulting various workers in the ARD field, insignificant physical weathering has beenobserved during kinetic tests, and thus it appears that the tests do not simulate this long termaspect of weathering. Given this, one should bear in mind that at best ARD kinetic tests canoptimistically simulate only the initial stages of waste rock weathering.The limitations of unknown acceleration of field conditions by kinetic tests, and the short termweathering simulated must be kept in mind when considering the design, results, andinterpretation of Island Copper waste rock kinetic tests.4.2 Column TestsColumn testing was conducted on the four large scale waste rock samples from the Caps andEMO dumps (sites 1 through 4). The experiment was initiated on September 4, 1992 and wasterminated on June 11, 1993 for three of the four columns, and on July 9,1993 for the finalcolumn.684.2.1 ObjectivesThe objectives of the Island Copper Mine column test work were:i) to quantify aqueous chemical loads of four waste rock samples from the Caps and EMOareas of the North Dump, andii) to give indication of variation of water quality with infiltration rate, andiii) to document temporal variation of leachate quality over the test duration.4.2.2 Equipment and ProcedureClear plexiglass columns 1.9 metres high and 15 centimetres outside diameter (14 cm insidediameter) (Fig. 4.1) were constructed for the tests. The rock was supported at the base with aperforated PVC plate lying across stainless steel rods. The entire column was suspended fromthe top from two additional stainless steel rods. One half inch (12.5 mm ) diameter ports wereinstalled at 30 centimetre intervals, with rubber septums sealing the ports.Distilled water was dripped into each of the columns at a slow rate (0.36-1.13 mI/mm) using aMasterfiex low rpm multi-channel peristaltic pump. Each of the four columns had its ownsource container in order to monitor accurately water influx to each sample. Leachate wascollected in plastic pails placed at the base of each column.The experiment was intended to be run for approximately 40 weeks. At the end of 40 weeks,column tests 1 through 3 were terminated, while column test 4 was continued for another fourweeks.Since the experiment was designed to determine present effluent emanating from the waste rocksamples, no additional crushing was performed. To reduce channeling due to large particles(Van Zyl et al., 1988), only the minus one inch (2.5 cm) portion of each waste rock sample wasplaced in the columns. Approximately 50 percent of the waste rock dump’s mass is estimated to69Distilled______________1/32” LD. Tygon tubingWater____rods6” l.D. 1/411 wall X 6’plexiglass tubingWaste rock materialK — Septums for gas samplingGlass wool___Plexiglass I PVC perforated plate2 X 1/211 stainless steel rodsV Collection vesselApprox. Scale: 1” = 10”Figure 4.1 Column test apparatus70be above 1 inch in size (Section 3.3.6), however, due to their relative surface areas, the amountof weathering products produced by the coarse fraction is negligible compared with the finerfraction. Therefore, barring any other scaling and laboratory factors, the calculated weeklyloads per unit mass from the column (and humidity cell) tests will approximately double theamounts obtained on a sample of the entire grain size distribution of the waste rock.Prior to testing, samples were characterized chemically, and physically, using threerepresentative two to four kilogram splits from each of the pre-test samples. A fourth split ofsimilar size was sealed in plastic and archived for possible future reference. Detailed proceduresand results of the pre-test characterization are given in chapter 3.0.Water infiltration rates for the column tests were determined through literature surveys, analysisof Island Copper and Port Hardy airport precipitation data, and consultation with UBC facultyand Island Copper Mine staff.The waste dumps are subject to varied intensities of rainfall (see Section 2.1.3), but due to thesite’s latitude and elevation, no snowpack accumulation occurs during winter months. Therainfall “seasons” were simulated in the column test with periods of intense, moderate, and lowinfiltration rates. This ensured that both maximum flushing of oxidation products occurredoccasionally through all possible flow paths in the column, and that accumulation of oxidationproducts was possible during moderate and low infiltration intervals. At the same time,infiltration rates were not varied so much as to make results difficult to interpret.Examination of the annual precipitation patterns in the Island Copper area showed that the yearcan be, without excessive distortion, divided up into time periods of moderate (January to June),light (July to September), and heavy (October to December) rainfall (see Fig. 2.1). Infiltrationinto the colunms was varied in this manner as well, compressing one year’s precipitation into afour week cycle. This enabled the experiment to run through at least ten yearly precipitation71cycles in the 40 week test period. The infiltration schedule is shown in Table 4.1. As discussedin Section 4.1, it is difficult to quantify the amount of reaction acceleration, if any, as a result ofthe tenfold flow rate increase over natural conditions. The high flow rate does however, reducethe chance of reactions being limited due to solubility constraints.Table 4.1 Distilled water infiltration schedule for colunm testsWeekly Cycle # Infiltration Level Monthly Field Column Total InfiltrationRainfall Simulated Infiltration Rate Volume(mm) (mI/mill) (I)1 Moderate 140.2 0.58 5.82 Moderate 140.2 0.58 5.83 Low 65.1 0.36 3.64 Heavy 248.2 1.13 11.4Using an average porosity of 0.32 (see Table 4.2) and knowing that the rock in each columnoccupied a volume of 0.028 cubic metres, each four-week cycle infiltrated almost three porevolumes of water through the column.Pore gas samples were extracted in 60 cubic centimetre plastic syringes via the sampling portsduring the final weeks of testing (weeks 39 and 40 for columns 1 through 3, and weeks 39through 44 and July 28, 1993 for column 4). Oxygen analysis was conducted on the samplesusing a PE Series 104 gas chromatograph, and a Coulometrics Coulometer was used todetermine carbon dioxide content of the sample.Average moisture content was determined by weighing each column using a heavy dutyoverhead spring balance at leachate sampling times. Weighing was initially conducted on a72weekly basis up to week 26, after which the frequency was reduced to approximately every fourweeks.The experimental work was conducted at the ambient temperature in the Centre for Coal andMineral Processing (CMP) building (average 21°C). Due to the relatively small diameter of thecolumn, core temperatures were not expected to be significantly elevated, and were notmonitored.Before filling, the columns were thoroughly cleaned first using laboratory detergent, followedby distilled water rinsing, rinsing with a ten percent nitric acid solution, and final distilled waterrinsing. Once dry, the columns were weighed. Waste rock was then placed in columns using a4” PVC pipe insert to minimize damage to the inside of the columns. The columns were filledin about one foot lifts, and the outside of the columns pounded with a rubber mallet to helpsettle the material.Glass wool mats were placed above and below the waste rock. The lower mat acted as a finesfilter for the infiltrating water, and the upper mat helped to disperse the distilled water as itdripped into the column.The dry weight of each column’s material was determined by re-weighing the column afterfilling. Water infiltration at 0.58 ml/min began on September 4, 1992. Initial wetting of thecolumns was closely monitored by taking periodic photographs and measurements during thefirst 72 hours of infiltration.Columns were monitored at least every other day and the volume of water pumped recorded. Atthe end of each week (infiltration cycle), the columns were weighed and the leachate collectedand its volume recorded.73Less than two litres of leachate were required for all analytical work. Approximately 1.5 litreswas filtered through 0.45pm cellulose nitrate, transferred to 1 litre bottles, preserved withconcentrated nitric acid, and shipped to either Island Copper Mine or Analytical ServicesLaboratory, Vancouver for dissolved metals analysis. The remaining 0.5 litres of the samplewas analyzed at the UBC Department of Mining and Mineral Process Engineering laboratoryfacilities for sulfate, alkalinity, acidity, conductivity, pH, and Eh. Details of analytical methodsand estimated precisions are given in Appendices 7 and 8, respectively.Leaching of columns 1 through 3 was terminated on June 11, 1993 and on July 9 for column 4.The columns were allowed to stand in place for approximately 2 weeks to allow accumulatedwater to drain. Contents of each colunm were then emptied into semicircular troughsconstructed of 10 inch (25 cm) PVC pipe cut in half lengthwise, and markers put in every 25centimetres. The material in the troughs was photographed immediately following placement.Three two kilogram post-test composite samples were collected over the entire length of eachcolumn. The material was split twice using a Jones riffle, one fraction pulverized for chemicalanalysis, and one fraction stored in plastic for future reference. Post-test chemical analysesincluded acid-base accounting, and 30-element ICP,4.2.3 Results4.2.3.1 General ObservationsInitial conditions of the material each colunm are given in Table 4.2.Overall, the experiment was relatively simple to run and maintain. There were problems incalibrating the peristaltic pump precisely to the design flow rate, but frequent monitoringallowed adjustments in flow to be made throughout the week.74At an initial flow rate of 0.58 millilitres per minute, columns I and 4 took approximately 90hours for effluent “breakthrough” at the bottom of the column. Columns 3 and 2 tooksignificantly longer (120 and 140 hours, respectively).Table 4.2 Waste rock conditions in column tests at start-upColumn 1 Column 2 Column 3 Column 4Mass Dry Waste 53.3 55.8 48.9 49.4Rock (kg)Waste Rock 2785 2750 2725 2730Density (kg/rn3)CaIc. Waste Rock 0.019 0.020 0.018 0.018Volume (m3)Volume Occupied 0.028 0.028 0.028 0.028in Column (m3)CaIc. Porosity 0.32 0.29 0.36 0.36Logically, the time to effluent breakthrough for each of the columns is directly related to theirrespective moisture contents during the experiment. Columns I and 4 had the lower moisturecontents ranging from 6.0 to 8.5 weight percent (column 1), and from 6.4 to 8.2 weight percent(column 4). Moisture contents for column 2 ranged from 9.5 to 11.0 weight percent, and forcolumn 3 from 13.0 to 15.1 weight percent. All columns showed an increase in moisturecontent as the experiment progressed.754.2.3.2 Weekly Leachate QualityTabulated leachate quality results for the column tests are given in Appendix 9.Leachate pH conditions of each column remained approximately constant throughout theduration of testing (Fig. 4.2). Leachate from columns 1, 3 and 4 returned near- or above neutral(6.91 to 8.76) pH levels, while column 2 leachate remained acidic (2.13 to 2.82). Although pHvalues for each column appeared to fluctuate, no pattern of variation with infiltration rate wasobserved.Measurement of leachate Eh did not commence until week 5 due to equipment availability.Similar to pH, leachate Eh remained approximately constant for each column during the courseof the experiment, with column 2 returning consistently high values (767 to 921 mV H°), andcolumns 1, 3 and 4 remaining in the more moderate range (413 to 640 mV H°) (Fig. 4.3). Theconsiderable variation in the values is likely more reflective of the difficulty in measuring Ehconsistently, rather than an actual change in leachate quality.Leachate conductivity values for each column varied from the beginning to end of the testing(Fig. 4.4), with values initially high, then plateauing as the experiment progressed. Levels incolumns 1 through 3 leachate became more consistent by week 12, while column 4 levelsremained high until week 25 before sharply dropping. All column leachate showed highestconductivity values during low infiltration periods in the four week cycle. Lowest values wereobserved from leachate collected the week after the high infiltration period.Leachate sulfate concentrations appear to mirror conductivity trends for the columns (Fig. 4.4and 4.5). Sample conductivity was used to determine the appropriate dilution for sulfateanalyses which considerably reduced lab work. As with conductivity, sulfate concentrationswere highest during low infiltration periods, and lowest in the week following high infiltration.Sulfate concentration values for all four columns show a decreasing trend during the experiment.7610 508 406 304 - 20WeekI0h1 _+_coI2_’i._coI3__CoI4Figure 4.2 Colunm test leachate pH1000 50Z 700J I 2600 - ___ 020.LU500 _400 -- ——10j1’1’12Week--coI1 ._.—coI2 ——coI3 .-—co(4Figure 4.3 Column test leachate EhConductivity(mS/cm)p—--00‘I’miii,,IHII-I1mwiiitItillliiiIIIIliiiIiiiiiiIIIIII11111I111111111II11111IIliii1111IIIi11111IhIll11THII111111111111liii1111III11111111111111HuhS.1111111I.HililiI111111_________HIllIIIIIIIIllIllI11111111111111111I1111111111111111111I111111I11111111111111iiIIIhlI11111I1111111I1111111111111I11111111111111111111I111111I1111111IIIliiiIliiIIII1111111111111111111II11111I1111111IIIlIluuiI111111II1111111111111411111111111111I1111111CDSwSIIulIIIl1111111I111111I1111111CD111111111111111I.11111I1111111‘H.i1111111I111111II111111(.11111111111111111111111II111111111111111111111I111111I11111111111111111111Ii11111I1111111is.)h%’111111111111lIIlullI1111111HIIIiiII11111I1111111•I1111111111itiI4IIillIIIII1)1111IIIIIIII11111II111111IIIllII11111I11111111111111IIIilII111111111111111111111IIl_lII111111II11111111111111iuffIit1111I1111111C.)IlIlIIIilII11111I1111111IfiuiIIHillII111111111111Ii1DjiiiII111111II11111IIIlII111111I1111111••III:II_JIIiiII111111II1111111111111IIIJIIIII1111111II1111111111111IIIIIIII11111111I1111111InfiltrationVolume(I)CD UImm0—Sulfate(mgIl)mmmmr’3CO.H.Cfl0 0CD - (Th 0 CD CD CD C.) 0 C.)8 IC, IC C. 1%)CD CD7’)0 7’)IC C.)C.)C.)-4;:11111I111111•II IIII11111I111111111111111111II1)11111I111111 IIIII111111111111I1111111IIlIlt1111111IllIItill111111I11111I111111IH’’I11111IlillilI11111•ThiV C’ Cl11111111II1111111IIIIIIIIIIII111111IIIIIIIIIIIlI.II 1111II1111111I11111II1111111I11111I1111111lIltIIIIIIIIII111111IIIIIIIIIlIIIIIIlIIIIIIIIIIIIIIIIlIIIIIIlIIlIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIllIIIiiiti%11IllIIIIIIIIIIIHItllIlIIIllllIlIlIllilIIlIlIiiIIdr1IlIIIllII4IhullhlIIl6IillllIII1i),iiiiiitii.iiiIlIIIIIIIii11lIIlIIIlIIIIIlIIIIIIlIllIIIIliiiIIlIllIllIIIlIIlIIIIIIIIIIIhIlltIIIIIIIIIi)IIIIIIIIIIhillIIIllIIIl.,.—TiIIlillIII’IIIIIIhIllIIIIIlIltIIIllIllIIIIIhlIlIlIIIlIhillIIIIIIliltIIIIIlIltIIIIIllIIIIIhIllIIIiiliiiIIIItillIIIIIIIIII11111IhillII11111IIII111111I111111IIIliiiIIIllliltII111111I111111III11111I111111IIIIllillIIIiililtII111111III11111I111111II111111I111111II111111II1111111111111IIII111111II111111IIIhiltII1111111111111II1111111111111II111111II111111II1111111111111II111111I1111111II111111I1111111II1111111II111111IIllIlhIIII1111111II111111II1111111IIIIhIlhIllII111111c3 8 80—7’)C.)000InfiltrationVolume(I)0C,’078250200 — — .40c)o ci)C-) E(0 150 .30C_) -0) >E100 -_____-- - ___ -.20.250 — 100 021 22’337’’41WeekIFigure 4.6 Column test leachate alkalinityWeek21Figure 4.7 Column test leachate acidity79Leachate alkalinity analyses were performed on columns 1, 3 and 4, are shown in Figure 4.6.Values varied considerably during the course of the experiment, with a general trend towardsdecreasing alkalinity for each of the three columns. Column 4 leachate showed the largest dropin alkalinity, starting at 240 mg CaCO3/l, then leveling off towards the end of the test tobetween about 70 to 110 mg CaCO3I1. Leachate alkalinity for each column had a distinct trendwith the four week infiltration cycle. Columns 1 and 4 leachate showed a similar pattern of peakalkalinity during high infiltration, followed by a drop during the first week of moderateinfiltration, followed in the next week by a slight increase, and finally sharply dropping to itsfour-week trough during low infiltration. Column 3 leachate showed a different and much moresubtle pattern with the infiltration cycle. Peak levels of alkalinity consistently occurred duringthe low infiltration week, and the lowest alkalinity concentrations usually occurred in leachatefrom the week following the high infiltration period.Leachate acidity was determined only for column 2 leachate, due to the high pH levels of theother three columns. Initial acidity levels were extremely high (26,000 mg CaCO3/l) for the firstfour weeks of testing (Fig. 4.7). Leachate acidity concentrations were highest during lowinfiltration periods and lowest in the week following high infiltration periods. Acidity valuesappear to gradually decrease from about week 25 to the end of the experiment.Leachate dissolved metal concentrations for fourteen selected metals are shown in Figures 4.8 to4.10. Leachate from the first 12 weeks of testing was analysed by atomic absorption at 1CMenvironmental laboratory, and subsequent weeks by 30-element ICP at Analytical ServiceLaboratory (ASL) in Vancouver. The initial analyses, though a smaller metal suite, hadconsiderably lower detection limits than the subsequent ICP analyses.048121620242832364044WeekFigure4.8Columntestleachatedissolvedmetals:a)aluminum,b)calcium,c)cadmium, andd)copper00 Ca) c)1000 800600C) ‘: 0048121620242632364044Weekb) d)0.3048121620242832364044600500400E300200100 010 8—6C) E 04 2 0Week0.2C) E •0 00.1T48121620242832364044WeekI_-co1__CoI2YCoI3..x_CoI4Ic)600480360C) E a, U..24012048121620242832364044Week32.240) E C16 0i.1A.__._EIETIEII]IEIE1EXI...048121620242832364044Week048121620242832364044Weeka)b) d)400) E 0)20 10x aIIIT0.1 0.080) E0.060.040.020•Week-.-Coil—Col2Col3-x-Ccl4Figure4.9Columntestleachatedissolvedmetals:a)iron,b)magnesium,c)manganese,andd)molybdenum00a)___b)0.4WeekWeekc)d)I________0.048121620242832364044046121620242832364044WeekWeekIulFigure4.10Columntestleachatedissolvedmetals:a)sodium, b)nickel,c)phosphorus, andd)strontium40 300) E N20 100.030.0250.02I-500.015a)b)0.01Figure4.11Co1unintestleachatedissolvedmetals:a)titanium,andb)zinc048121620242832364044Week048121620242832364044Weekj...-CoIl_i_CoI2.._CoI3x..CoI4jCo84Relative to columns 1, 3 and 4, column 2 leachate consistently returned anomalousconcentrations of dissolved aluminum, copper, cadmium, iron, nickel, and zinc. Concentrationsgradually decreased over the course of the experiment. Additional anomalous metalconcentrations for column 2 leachate not shown in the figures include cobalt, chromium andlithium. With the exception of dissolved zinc, column 1, 3 and 4 leachate tended to haveconcentrations of these nine metals below the ICP detection limit. Of these three columns,dissolved zinc concentrations were highest in column 3 (0.03 to 0.05 mg/l range), followed bycolumn 1 (<0.005 to 0.045 mg/i). Dissolved zinc levels in column 4 leachate were low;dropping below the detection limit from week 31 to the termination of the experiment. Incontrast to column 2, column 1, 3 and 4 leachate contained measurable, though still low,concentrations of molybdenum (up to 0.109 mg/i).Other dissolved metals of interest include calcium, magnesium, manganese, sodium,phosphorus, strontium, and titanium.Column 2 and 4 leachate calcium levels were initially high, corresponding with high sulfateconcentration. These levels are likely reflective of dissolution of accumulated gypsum and othersoluble sulfate minerals. Towards the end of the test, calcium concentrations reduced to levelsin the same order of magnitude as columns 1 and 3.Similar initial trends can be seen for dissolved magnesium concentration in the column leachate,however column 2 leachate concentrations began to rise again after week 18, and continuallyincreased until the end of the experiment. Concentrations of dissolved titanium in colunm 2 alsoshow a corresponding dramatic increase after week 18.Dissolved manganese was only present in consistently detectable quantities in column 2leachate, and showed a slight increasing trend towards the end of the experiment.85Detectable levels of dissolved phosphorus were present only in column 2 leachate, showedmaximum concentrations during the middle period of testing, and again had reducedconcentrations from week 36 to 40.Dissolved strontium concentrations remained below 1 mg/i for column 1 through 3 leachate.Only column 4 leachate had high initial levels of dissolved strontium.Dissolved sodium was one of the few parameters that showed near equal concentrations in eachcolumn’s leachate. Bonn et. al (1985) note that during initial silicate weathering processes,alkali and alkaline earth ions are released into the soil solution. Providing that there issufficient water influx, both sodium and potassium tend to not re-precipitate as secondaryminerals and thus may be detectable in the resulting leachate. In the case of the column tests,the resulting concentrations of these two metals is considered to be reflective of the weatheringrates of the primary silicate minerals, namely feldspars. Although dissolved sodiumconcentrations were consistently above the ICP detection limit of 2.0 mg/i, potassium valueswere not. Leachate analyses using atomic absorption methods from weeks 10 through 12returned dissolved potassium concentrations between 0.1 and 0.5 mg/i for the four columns.4.2.3.3 Loads and Cumulative LoadsCalculated loading and cumulative loading for sulfate and alkalinity or acidity are plotted inFigures 4.12 and 4.13.Columns 1 and 3 both produced low sulfate loading rates and cumulative loads (less than 10mg/kg/week, and less than 600 mg/kg over 40 weeks). Column 2 consistently produced highsulfate loading (more than 200 mg/kg/week). Column 4 was transitional, and normallyproduced from 100 to 350 mg/kg/week up to week 23. After this time, sulfate productionsharply declined, and in the final four week cycle, only 16 to 37 mg/kg/week was produced.1508)100C a, U)04000 I 200w E E 100 0100008000-J a)6000U,4000a) (2000U)02000a,1500a,a,10000 a’500C/)05000D a, 04000a)a,3000C/)2000E E1000C)a) c)“WI”2:2’2”3h’Weekb) d)048121620242832364044Week0 a,o150-J a) a)1000 a, 50C/)RflC)fl048121620242832364044WeekWeekSulfate(mg/I)SulfateLoad(mg/kg/wk)-v-.Cumm. SulfateLoad(mg!kg)Figure4.12Columntestleachatesulfateloads:a)column1,b)column2,c)column3,andd)column4008000Cu 0-J6000•0 C)4000>.02000 00 Cu 0 -J .1500 >. t100Cua) c)100000500-J‘S C Cu300< E200C)b) d)048121620242632364044Week048121620242832364044Week1400012000t Cuioooo3 ‘S800060004000‘AnD0 cu 0-J‘S C cu E E z C-)LQVIVY600200.35003150400EWeek250V cu2000-J1500‘100C Cu50IC0.Concentration(mg CaCO3II)-WeeklyLoad(mgCaCO3IkgIwk)-,-Cumm.Load(mg CaCO3Ikg)00 —aFigure4.13Columntestleachatealkalinityandacidityloads:a)colunm1,b)colunm2,c)column3,andd)column488Column 2 weekly acidity loads were in the 150 to 350 mg CaCO3/kg/week range. Thealkalinity loading plots (Fig. 4.13a, 4.13b, and 4.13d) for columns 1, 3 and 4 are plotted onidentical scales. Weekly loads were similar for columns 1 and 4 (5 to 25 mg CaCOIkg/week),while column 3 had a significantly lower alkalinity loading rate of 3 to 10 mg CaCO3/kg/week.The contrast between acidity and alkalinity loads illustrates the low buffering potential of thenon-acid generating waste rock.4.2.3.4 Pore Gas AnalysisSelected results of pore gas analysis are shown in Figures 4.14 and 4.15, and tabulated resultsare given in Appendix 10. Measured oxygen levels between weeks were similar for eachcolumn. Oxygen levels decreased with depth in the top half of all columns, and with theexception of column 4, values leveled off or increased towards the bottom of each column.Column 2 had markedly decreased oxygen levels (approximately 10 mol %) within 0.2 metresfrom the top, and decreased to below detection limit (approximately 0.5 mol %) at 0.5 metres.Oxygen levels gradually increased down the column to about 18 percent at 1.6 metres depth.Columns 1 and 3 had only slightly reduced oxygen levels (approximately 19.5 mol %) in thecentre region of each column. Column 4 had steadily decreasing oxygen levels down thecolumn, with the minimum value of 13.6 mole percent measured at the bottom sampling port.Carbon dioxide levels in cells were highest during initial sampling in week 39 (especially inColumns 3 and 4), and subsequently declined. Column 4 pore gas was sampled on July 28 (19days after previous sampling) to determine whether or not carbon dioxide levels were depletingas a result of sampling, or by reasons related to weathering reactions within the column. Carbondioxide levels on July 28 were significantly higher than those measured in weeks 40 through 44,but were lower than the initial levels in week 39 (Figure 4.16). This indicates that levels wereprobably depleting as a result of sampling, and that four to six weeks is likely the maximumsampling frequency for meaningful carbon dioxide pore gas measurement.89252O!15._Distance from Column Top (m)--CoIl _-1--Co12 -—CoI3 -—CoI4Figure 4.14 Oxygen content of colunm pore gas, week 394,0Eci)0x2,00.0Ia)C-)---0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8Distance from Column Top (m)--CoIl __CoI2 --CoI3 -—CoI4Figure 4.15 Carbon dioxide content of column pore gas, week 39902.520E1.5x0121C0.01Cu() 0.500.2__Week 39 -+— Week 40 -—Week41 -*-Week42 —*—Week43 -x_Week44Figure 4.16 Carbon dioxide content of column 4 pore gas, weeks 39 to 44, and July 28, 19934.2.3.5 Pre- and Post- Test Analysis of Column MaterialComparisons between pre- and post- test acid-base accounting analyses are shown in Figure4.17. Obvious visual differences between pre- and post- test results are apparent for sulfate,paste pH, and acid consuming potential (ACP).Sulfate content of column 2 waste rock appears to have increased as a result of kinetic testing,however the reverse appears true for column 4 material. Column 1 and 3 pre- and post-testsamples had sulfate levels below the detection limit.Sulfate content of the three pre-test samples of column 2 waste rock appear to be significantlyless than the post-test samples. Conversely, column 4 waste rock pre-test samples aresignificantly higher in sulfate than the post-test samples. Neither pre- nor post- test samples ofcolumns 1 and 3 contained detectable levels of sulfate.0.5 0.8 1.1 1.4 1.7Distance from Column Top (m)a)b)3.2.0.21’4I——Cl)0.10IIIIIvIIIIPrePostPrePostPrePostPrePostPrePostPrePostPrePostPrePostCo!ICol 2Col 3Col4ColICol2Col3Col4c)d)808.III60II01()(1)_6.C.)()CU0)a-•C.)I<20iiPre1ost0Pre1ost’PreostCotICot2Col3Cot4ColICol2Col3Cot4Figure4.17Pre-andpost-testacidbaseaccountingofcolumntestmaterial92Post-test paste pH values for column 4 are significantly higher than corresponding pre-testresults. Column 2 shows a similar trend, however a replicate reading of a pre-test sample (doneconcurrent with the post-test analyses) returned a higher pH value than previously recorded. Nosignificant change in paste pH was noted for columns 1 and 3.Column 4 post-test acid consuming potential (ACP) values were slightly higher than pre-testvalues. In view of the higher paste pH and lower sulfate content in the post- test samples thisindicates that low pre-test ACP values are due to considerable accumulated acidic products onthe samples before column testing.4.3 Humidity Cell TestsHumidity cell testing was conducted on eight samples of waste rock from six different sites.Testing was initiated on August 3, 1993 and terminated on September 14 after 42 days ofcontinuous operation.4.3.1 BackgroundHumidity cells are an industry-accepted method of determining acid generation potential ofwaste rock. Although cell design varies considerably, the underlying principle of the test is thesame; waste rock is subjected to three different conditions, usually over a 7 day period: i) dryair passed through the sample for 3 days, ii) humid air passed through the sample for 3 days, andii) leaching of the sample in the cell on the final day of the cycle (Lawrence, 1990).Previous humidity cell testing on Island Copper waste rock includes five samples of cuttingsfrom drill holes from the North West dump which were tested for 10 weeks in 1990. Results ofthis work are documented in UBC MMPE (1990a).934.3.2 ObjectivesThe objectives of the humidity cell tests were:i) to indicate leachate quality currently being produced by various Island Copper waste rocktypes, andii) to document temporal variation of leachate quality over the test duration.4.3.3 Equipment and ProcedureEquipment for the testing included the humidity cell, an air humidifier, and a compressed airsource. Both cells and humidifier were constructed according to specifications described inLawrence (1990).The humidity cells used were constructed using an 8 inch length of 4 inch diameter plexiglasstubing. The cell had a fixed base plate with a leachate drainage hole fitted with a tubing nipple.The waste rock sample was placed inside the tubing on a perforated support plate about 1 inchabove the base plate. Air entered the cell via a side port located between the base and supportplates, and exited via a hole in the top cover of the cell. Several layers of screen cloth wereplaced on the support plate prior to putting the waste rock sample in the cell to impede themigration of fmes into the leachate.The air humidifier used was an approximately 3 foot length of 4 inch diameter plexiglass tubingsealed at both ends, and operated in the horizontal position. The tube was filled approximatelyhalf full of water and contained two 15 centimetre long aeration stones connected via tubing tothe air source and a submersible aquarium water heater laying along the length of the humidifier.Air outlets to the humidity cells were spaced equidistantly along the top surface of thehumidifier and were fitted with tubing nipples. Air temperature in the cells was 23°C.A Perkin-Elmer oil free air compressor was used to deliver air to the humidity cells.94One (±0.004) kilograms of minus one half inch waste rock was placed in each cell. About 0.75kilograms of additional sample was also prepared for physical and geochemical analysispurposes. Samples tested are given in Table 4.3.Table 4.3 Waste rock samples tested in humidity cellsCell Number Site NumberHC1 5HC2 8HC3 8HC4 7HC5 7HC6 6HC7 2HC8 4Descriptions of the samples are given in Chapter 3.0. Cells 3 and 5 were duplicates of cells 2and 4 and were intended to qualitatively indicate variance due to sampling and testing. Cells 7and 8 contained samples from sites 2 and 4, which were column-tested, and were intended toassist in correlation between column and humidity cell test results.Testing was conducted for six weeks, thus completing six weekly cycles of alternating dry andwet air, and sample leaching. The leaching phase consisted of adding 500 millilitres of distilledwater to the cell and allowing it to stand for one hour with the leachate drain closed. Theleachate was then drained into a tared sample bottle which was then weighed to determineleachate volume.95An intense pre-flushing of each sample was conducted prior to starting the first humidity cellcycle. This was done in order to remove accumulated soluble weathering products on thesample. After samples were placed in the cells, the procedure consisted of adding a total of1500 millilitres of distilled water to the cells in 500 millilitre increments. The water wasallowed to stand for a minimum of one hour before draining and repeating the cycle a secondand third time.Pre-flushing leachate was analysed for pH, conductivity, and sulfate. The weekly leachate wasanalysed identically to the column tests for pH, Eh, conductivity, acidity and/or alkalinity, andsulfate using the UBC Department of Mining and Mineral Process Engineering facilities.Thirty element dissolved metals analyses (via ICP) was performed on two-week composites byAnalytical Service Laboratory, Vancouver.Testing commenced on August 3, 1993 and was terminated on September 14 after 42 days ofcontinuous operation, with leachate samples being taken weekly.4.3.4 Results4.3.4.1 General ObservationsOverall, it was found that air flow conditions in the humidity cell were difficult to control,possibly causing varying concentrations of soluble salts to occur. Each sample in its cell had adistinct air permeability, and thus different air flow rates were required to sufficiently supplyeach cell. Varying amounts of water (up to 75 ml) often condensed in the base of the cell duringthe humidified air cycle, thus causing dilution of the leachate. Mechanical problems were alsoencountered with the compressor, however these were resolved early in the testing.964.3.4.2 Weekly Leachate QualityTabulated leachate quality results for the humidity cell tests are given in Appendix 9.Similar to the column tests, leachate pH conditions for each cell remained approximatelyconstant throughout the duration of testing (Fig. 4.18). Only cells 1 and 8 had pH-neutralleachate, cell 2 and 3 leachate had weakly acidic (jH 4 to 5 range) values, and cell 4 through 7leachate was less than pH 3.4.Leachate Eh values (Fig. 4.19) did not show any trend over the course of the experiment. Cell 1leachate returned low Eh values consistent with non-acidic leachate, and cell 5 through 7leachate Eh values were high (over +700 mV H°). Leachate Eh from cells 2, 3, and 8 wereintermediate (+550 to +675 mV H°).Leachate conductivity was initially high for all cells during the pre-flushing phase, but tended toplateau out once weekly leaching commenced. Some erratic values were observed (Fig. 4.20).Leachate from all eight cells had elevated sulfate levels in the pre-flushing phase. The mostacidic cells (4 through 6) produced extremely high (48,500 to 190,000 mg/I) concentrations (Fig.4.2 1). Cells 2 and 6 had considerable variance in sulfate concentrations following the preflushing phase, while the other six cells had relatively consistent concentrations.Leachate alkalinity, measured only for cells 1 and 8, is shown in Figure 4.22. Cell 1 leachatewas consistently higher in alkalinity (14.5 to 26.5 mg CaCO3/l) than cell 8 (5.5 to 16.0 mgCaCO3/l). No obvious temporal trends were observed for either cell.Acidity values for cell 4 and 5 leachate were both relatively high in week 1 before leveling offfor the rest of the test (Fig. 4.23). Cell 6 leachate acidity appeared to be taking off in the finaltwo weeks, increasing by 1000 mg CaCO3/Ifor both weeks 5 and 6.9797C E3 - -6 -0— — ___——4 _-__- =2 I I I I0 1 2 3 4 5 6WeekHC2 ....HC3 - HC4 HC5 -HC6 --HC7 ...-HC8Figure 4.18 Humidity cell leachate pH1000900IWeekI— -.HC2-..HC3.,1,Figure 4.19 Humidity cell leachate EhSulfate(mg/I)I C) CD — I!0 -CD C C.) CD CD C)- 0 0* C) •1’ z C) r%3 a C) :r C) = C) ICDC CD c.I I C) I C) a I C) C) 2: C) I C) I0 CD 01. 0)Conductivity(mS/cm)p- 0II.14iu.LIr::::::1::I!IIILIIIlIlIlilI111111Iiijii\i/41!111111I1111111IIIIiiiiS(i11111111iIIII14111Iji1111111IIIIIiij\I14111111IIIIIiki$i1111111IIigiiiiliI11111111I1111111IIIII1111IIIII11111IIIIliiiIIIII111111IIIIIliiiIIIIliiiIIIIII)IIIIIIIliltIIIIIIlI1(1IIIIIIIISillIIIIIIllIiII(titiii1111111IIIillliiiPI_IIllllII1111111•iiirtI1111111I111111111111111,I11111111I1111111I1/IIIIIIfII’I11111111IIfIIIIIlI4”l1111111II111111II)III_I’IlI1111111II111111IfII,).IIIIIIIIIIIIIIIIliiiiftiiiiIpiI1111111IIIIlIIIIIIII1111111II111111ViIi1iiI1111WIIIlIIIIIIii1111111II111111IIIiIIllIIIII1111III11111IIit’IIiII’1111111III.I’III’I.IIIII1111111IIIIIIIl•IIIIII11111III1111IIIIIIl,4I1111111I1111111I111111II111111III11111IIIIjJIIPi1111111II111111I11111111‘1111111111II111111II?lIlIlIIlIIlllIlII111111IIIIIIIII111111111111I1111111IISII11)11I1lI11111IIII1111IjIIIIIlIlIIiIIII1111IIIIIIIIilIllIllIllII11,111111IlI_IlIlillII‘i)IIIIIII1111111)IISj4IIIILI.iIIIIIIIIIIIIIIIIIifilIIIIIII111111IIIIIIIIIjIIIII4111111II111111111111111411lI’I11111111II111111IIIIIIIIJIIjIifI11111IIII1/IIIUIIIIIJIIfI11111IIIIIIiiIIIIIiiiliIIIIji11111IIIIIIIIIJIJIIIII.1LIifi11111III111110i 0)009950— 40 -c)0C-) 30 -WeekHC1 -,-HC2 -..HC3Figure 4.22 Humidity cell leachate alkalinity3500Week--HC2-..HC3-. HC4.HC5HC6HC7.HC8IFigure 4.23 Humidity cell leachate acidity100Leachate dissolved metals concentrations are given in Appendix 9. Because only three biweekly composites were analysed for each cell, results are not presented in graphical form.Similar to the column tests, leachate from the highly acidic cells (HC4 through HC7) returnedconsistently anomalous concentrations of dissolved aluminum, copper, cadmium, cobalt, iron,nickel and zinc. The two weakly acidic cells (HC2 and HC3) produced concentrations ofcadmium, nickel, cobalt and zinc comparable to the highly acidic cells, but relatively reducedlevels of copper, and significantly less iron and aluminum. The non-acidic cells (HC 1 and HC8)produced very low levels of heavy metals.4.3.3.3 Loads and Cumulative LoadsFigure 4.24 shows the range of sulfate, alkalinity and acidity loads obtained from the humiditycell tests. Cell 1 had the lowest sulfate and highest alkalinity loads, and cell 6 had the highestsulfate and acidity loads.Results of the two replicate cell pairs are given in Figure 4.25 and 4.26. Similar average weeklyloads were obtained for each pair, however cumulative loads between each replicate variedconsiderably. This is attributable to the large initial concentrations obtained during pre-flushingand the first week of the regular humidity cell cycle.4.4 Discussion of Results4.4.1 SummaryTwelve kinetic tests consisting of four column leach and eight humidity cells tested theweathering behavior of eight samples from various areas of the North dump.c)500400-J a).300C’)I- o200a) (0 51001Cl)•0 (0 0300a) 4!250a)200E150E C.)*Sulfate(mg/I)—SulfateLoad(mg/kg/week)-Cumm.SulfateLoad(mg/kg)Alkalinity(mgCaCO3/l)._AlkalinityLoad(mgCaCO3/kglwkCumm.PJk.Load(mgCaCO3Ikg)d)(0 0-J a) 4! C,, 0 a) 4! Cl)•Sulfate(mg/I)—xSulfateLoad(mglkg!wk).Cumm.SulfateLoad(mg/kg)•Acidity(mgCaCO3/l)—xAcidityLoad(mgCaCO3IkgIwk).Cumm.Acid.Load(mgCaCOSikg)Figure4.24Selectedhumiditycellloads:a)cell1sulfate,b)cell6sulfate,c)cell1alkalinity, andd)cell6aciditya)b)023456Week234Week6070.0Weeknnngnnn•0 a)•5000-5000..4000-4000C03Week56a)b)1500140015001400WeekWeekc)d)5000________________5000______________4000560OQ4000580005600X006000000-:;:-.:5400•200054000E..--..Ec1000’-----==----=52000E1000=2000EaIIIoooo0IIIII5000001234560123456WeekWeek•Sulfate(mg/I)._SulfateLoad(mg/kgtwk)Cumm.SulfateLoad(mg/kg)Figure4.25Leachatesulfateloadsofhumiditycellreplicates:a)cell2,b)cell3,c)cell4,andd)cell5•Acidity(mg CaCO3/I)—xAcidityLoad(mgCaCO3lkglwk)-Cumm.Acid.Load(mgCaCO3Ikg)Figure4.26Leachateacidityloadsofhumiditycellreplicates:a)cell2,b)cell3,c)cell4,andd)cell5a) c)1001003 ::Innb) d)(0 3750SoI 0 D25 A6AnnA012345Week40003000———0IIIIIWeek4000to 33000•0 <200021000Week0 (080340EF°E:°A 40000-J3°00’20000) (0(0 0-J300°•020000) (0 !0123456Week456104As expected, the pre-oxidized nature of the samples produced initially high ionic strengthsolutions in the first stages of testing. This is most obviously reflected in conductivity, sulfate,acidity, alkalinity and metal levels. In order to best analyse results, only leachate quality fromthe period after each test reached “pseudo-steady state” is considered in the followingdiscussion. The periods used in analysis are shown in Table 4.4.Table 4.4 Kinetic test periods used for data analysisTest Weeks Used for Data AnalysisCoil 21-40Co12 17-40Coi3 21-40Co14 37-44Eight humidity cell tests conducted 1 - 6August -_September_1993Leachate from sites 1, 3, 4, and 5 were pH neutral or above. Leachate from site 8 was weaklyacidic (greater than pH 4.0), and the remaining three sites (2, 6, and 7) produced strongly acidic(less than pH 4.0) leachate. Table 4.5 shows the range of pH, Eh, conductivity, and sulfate,alkalinity and acidity loads produced from the twelve tests after they reached pseudo-steadystate.Table 4.5 Minimum and maximum general leachate quality parameters from kinetic testspH Eh Cond Alkalinity Acidity Sulfate(mV HO) (mS/cm) (mgCaCO3/k /wk) (mgCaCO3/k /wk) (mg/kg/wk)Iinimum 2.13 384 0.11 0 0 3Iaximum 8.51 860 4.79 23 1737 2458105The molar ratios of alkalinity, calcium and magnesium and acidity to sulfate loads can giveconsiderable insight on the acid generation and neutralizing reactions taking place within thesample (Ferguson and Morin, 1992, UBC MMPE, 1 990a). Molar alkalinity or calcium andmagnesium to sulfate ratios indicate the amount of excess alkalinity in leachate. The decline ofthis ratio to unity during kinetic testing is often used as an early warning to imminent net acidityproduction. Molar acidity to sulfate ratios indicate the amount of acidity not internally bufferedin the sample. Assuming sulfate load is reflective of the total acidity released by the rocksample, a ratio of unity indicates no internal buffering, while a near zero ratio indicatessignificant buffering. Ranges of these ratios obtained in the kinetic tests are shown in Figure4.27.Figure 4.27 Ranges of kinetic test molar calcium and magnesium, alkalinity, and acidity tosulfate load ratiosHigh (greater than two) molar calcium and magnesium to sulfate load ratios consistently occuredin column 1 leachate, and occasionally from column 3 and HC 8. Lowest ratios (less than 0.5)were found in column 2, HC 4, HC 5, and HC 6 leachate.32.521.5I0.50mol((Ca+Mg)1S04) mol(AIK1SO4) mol(AcIdISO4)106Molar alkalinity to sulfate load ratios were calculated only for leachate samples with measurablealkalinity. Highest ratios (above 1.5) were found only in column 1 leachate samples. Aconsiderable number of leachate samples with net neutral pH from columns 3 and 4 and HC 8had calculated molar ratios of less than one. This may be indicative of soluble sulfatedissolution contributing to total measured sulfate in solution.Molar acidity to sulfate load ratios were calculated only for leachate samples with measurableacidity. The highest ratio was 1.08 and was obtained from the first week’s leachate from HC 4;this greater than unity value may be due to stored soluble acid products still being released fromthe sample despite the pre-flushing. Subsequent weekly leachate from HC 4 had calculatedratios of 0.75 or less. Leachate from column 2, HC 4, HC 5, and HC 6 consistently had ratios ofover 0.50, illustrating the negligible remaining neutralizing capacity of the samples. On theother hand, the very low ratios (less than 0.10) from HC 2, HC 3, and HC 8 indicate that mostacidity produced by these samples is internally buffered.Samples from sites 2 and 4 were tested both in column and humidity cells. Figure 4.28 depictsthe ranges and means of alkalinity, acidity and sulfate loads for the two replicates. Overall,acidity and alkalinity loading in leachate from both column tests was higher than in theircorresponding humidity cells. Conversely, sulfate loading was higher for the humidity cells.The difference in alkalinity loading may be in part attributable to the high aeration conditions inhumidity cell tests which rapidly remove carbon dioxide volatilized during acid neutralization.This favors the following reaction to proceed:H2C03° —* CO2 (g) + H20rather thanH2C03° —> H + HCO3-which would tend to dominate in a closed system and slow the rise of pH to levels above 6.0(Ferguson and Morin, 1992). Since leachate alkalinity is a measure of bicarbonate ion in250___________________________________________________250200200—150,150CaCa____o0—I100—‘100-—505000Co12HC7Co14HC8500____________25maximum400200)0)0300015________mean.200V10>.0<10::minimumCo12HC7Co14HC8Figure4.28Comparisonofreplicatecolumnandhumiditycellsulfate,alkalinityandacidityloads108solution, the resulting alkalinity values for humidity cell would be less than for a column test onsimilar material. The open, aerated system of the humidity cell also results in a more efficientneutralization of hydrogen ion by calcite (close to 2:1 molar ratio), whereas in a more closedsystem such as the columns, a 1:1 acid to carbonate molar ratio is dominant. This may alsoexplain the comparatively lower acidity loads produced in site 2 humidity cell test; the humiditycell allows available neutralizing capacity to be used in close to a 2:1 acid to carbonate ratio,thus the resulting humidity cell leachate should of lower net acidity than a column test.The higher sulfate loading in humidity cells of both replicates may indicate that either moreaggressive oxidation occurred in the aerated humidity cell tests, or that significant solublesulfate was still leaching from the material despite the pre-flushing.Pore gas analysis of column 2 indicates that highly acid generating material may have oxygendepletion within the top 30 centimetres of the waste rock dump. This explains the occurrence offresh, unoxidized material beneath a 15 to 30 centimetre layer of highly oxidized material on thedump surface (Fig. 3.3). Oxygen availability in such rapidly oxidizing waste rock is obviouslylimited both by diffusion and consumption by pyrite oxidation.4.4.2 Kinetic Test Rate ConstantsRenton et al. (1988) noted that plots of unreacted sulfide versus time for coal refuse kinetic testsresembled a first order decay curve, in which the rate of sulfide oxidation is assumed to bedirectly related to the amount of unreacted sulfide remaining. By applying the relatively simplefirst order equation to laboratory bench scale tests, they were able to successfully model sulfideoxidation of a 350 ton waste rock kinetic test. Steffen, Robertson and Kirsten (1992) also usedthe first order equation to predict not only sulfate, but also various metal loads.109The first order equation can be expressed as:(4.1)where dS/dt = rate decrease of solid phase sulfide, k2 = initial oxidation rate (mollkg/wk), and k1= sulfide oxidation rate constant (wlcl).For a first order reaction, the rate constant k1 is equal to:k1= -2.303(dlog[S1/dt) (Russell, 1980) (4.2)This is simply 2.3 03 times the slope of the log of sulfide remaining versus time plot, and caneasily be calculated for all the kinetic tests using only the weeks after pseudo-steady state wasobtained (Table 4.6).Problems arise in applying equation (4.1) to the kinetic tests because the material had weatheredat least eight years before sampling (Table 3.3). Therefore, the initial oxidation rate (k2), and thetime of commencement of reaction, or time of ARD onset, are unknown. Numerous attemptswere made to apply the model to this study’s kinetic tests, but through sensitivity analysis it wasfound that the assumptions that had to made resulted in significant variation of results.Although k2 and the time of ARD onset are unknown, the sulfide oxidation rate constant (k1) canbe calculated, and are presented in Table 4.6. For clarity, the half-life, or amount of timerequired for half of the material to oxidize (equal to [2.3031og(2)/kj] ), is also given.110Table 4.6 Kinetic test rate constants and half-livesKinetic Test Site # Rate Half-LifeConstant* (years)(wk- 1)Col 1 1 0.00005 245.1Co12 2 0.00158 8.4Col 3 3 0.00009 154.3Col 4 4 0.00027 50.3HC 1 5 0.00013 100.8HC 2 8 0.00057 23.6HC 3 8 0.00076 17.5HC4 7 0.00184 7.2HC5 7 0.00131 10.2HC 6 6 0.00168 7.9HC 7 2 0.00065 20.6HC8 4 0.00051 26.1* rate constants temperature-adjusted to 8°C4.4.3 Kinetic Test Neutralization Potential DepletionIn order to classifSr samples as to their long term acid buffering ability, times to depletion ofavailable neutralization potential (NP) were calculated for each kinetic test. The time to NPdepletion uses weekly sulfate loads coupled with either weekly alkalinity or calcium andmagnesium loads to determine both the rate of sulfide depletion and the rate of consumption ofalkalinity. If the available NP in the sample is known either through acid base accounting, acidvolatilized carbon dioxide, or elemental analysis, the time to NP depletion can be calculated.Although Lapakko (1990) showed that the time of alkalinity depletion could be predicted in111short term kinetic tests, in this study, the times estimated by these calculations are used strictlyto classify samples as to their long term buffering capacity. Because the calculation uses a linearextrapolation of short term kinetic test results, the times yielded by the calculation, especially ifgreater than two years, are not considered to accurately indicate true depletion times.As mentioned, NP depletion can be calculated in two ways: i) using molar sulfate to alkalinity(as HCO3j(S04/Alk) (Ferguson and Morin, 1992), or ii) using molar sulfate to calcium andmagnesium ratios (S04/(Ca+Mg)) (Lapakko, 1990). Both methods were used and compared onIsland Copper kinetic tests.It was found that for the columns, SO4IA1k ratios and S04/(Ca+Mg) ratios were comparable.However for the humidity cells, measured leachate alkalinity was significantly lower than thoseobtained from column tests, and as a result, extremely high S04/Alk ratios were obtained.Reasons for this are related to the low alkalinity loading observed in humidity cell leachate andare discussed in section 4.4.1.For this study, the method of Lappakko (1990) was used to calculate time to NP depletion. Theassumptions used in the calculations are that:i) all acid neutralization will be done by carbonate minerals (calcite and/or dolomite);ii) all carbonate is available for neutralization;iii) all sulfide sulfur is available for oxidation;iv) all sulfate released to solution is from iron sulfide oxidation;v) all of this sulfate remains in solution; andvi) the rates of carbonate and sulfide depletion is constant.To test assumption v), actual molar sulfate to calcium ratios were compared with theoreticalvalues derived from the formula for gypsum equilibrium given in Ferguson and Morin (1992).All leachate samples from the data analysis periods specified in Table 4.4 had much higher112molar sulfate to calcium ratios than the theoretical level, indicating that they were unsaturatedwith respect to gypsum; thus, assumption v) is valid.The equation used for NP depletion calculation is:Cc0 43Cd[Ca2++Mg2+1dtwhere t, = time to carbonate depletion (weeks), Cc0 = amount carbonate in sample at test start(mol/kg), and d[Ca2 + Mg2]/dt = leachate calcium and magnesium load (mol/kg/week).The total available carbonate in each sample expressed in mol/kg units was determined throughacid-volatilized carbon dioxide analyses. In the case of the columns where three separateanalyses were performed on each sample, the geometric mean was used.NP depletion calculations were performed on data from each week of the humidity cell tests, andfor the columns, weekly loads were summed into a four-week load.The resulting ranges of estimated time to NP depletion for each kinetic test are given in Table4.7.4.4.4 Kinetic Test ARD Potential ClassificationIn examination of a few key water quality parameters from all kinetic tests, certain groupingsbecame apparent. These, combined with time to neutralization depletion calculations, served toc1assifr the twelve kinetic tests into one of three categories:i) Type I rocks, which are interpreted to have sufficient excess alkalinity to do some degree ofbuffering of infiltrating acidic drainage,113ii) Type II rocks, which although possibly generating alkaline leachate at present, are notregarded to have sufficient excess alkalinity to adequately buffer infiltrating acidic drainage,and are also not expected to significantly contribute to net acidity of the waste rock dump;andiii) Type III rocks, which are presently producing leachate with high net acidity.The delineating parameters for each category are given in Table 4.8.The category assigned each kinetic test is shown in Table 4.9.114Table 4.7 Kinetic test estimated times to neutralization potential depletionKinetic Test Predicted Time toNeutralizationPotential Depletion*(years)Coil 38-44Co12 <1Co13 4-5Co14 5-6HC1 40-53HC2 <1HC3 <1HC4 <1HC5 <1HC6 <1HC7 <1HC8 1-3*assuming laboratory temperatures (21 to 23°C)Table 4.8 Delineating parameters for ARD Potential classification of kinetic testsType I Type II Type IIITime to Alkalinity >25 years <1 to 25 years <1 yearDepletionpH >7.0 >4.3 4.3Sulfate Load <30 mg/kg 160 mg/kg > 160 mg/kgTable 4.9 Classification of kinetic tests by ARD Potential categoryARD Potential CategorySite Test Type I Type II Type III1 Coil .72 Co12 .72 HC7 .73 Co13 .74 Co14 .74 HC8 .75 HC1 .76 HC6 .77 HC4 .77 HC5 .78 HC2 .78 HC3 .71151165.0 PREDICTION OF EFFLUENT QUALITY5.1 IntroductionThis chapter links results of laboratory scale waste rock characterization studies with measuredcharacteristics of the North dump. At the conclusion of Chapter 4.0, the eight sites sampledwere categorized into one of three ARD potential categories on the basis of their kinetic testperformance:i) Type I rocks, which are interpreted to have sufficient excess alkalinity to do some degree ofbuffering on infiltrating acidic drainage,ii) Type II rocks, which although possibly generating alkaline leachate at present, are notregarded to have sufficient excess alkalinity to adequately buffer infiltrating acidic drainage,but are also not expected to significantly contribute to net acidity of the waste rock dump;andiii) Type III rocks, which are presently producing leachate with high net acidity.In section 5.2, rock type, alteration, mineralogy, geochemical and water quality data from theeight sites are re-examined to determine if there are any delineating characteristics for eachcategory.In section 5.3, selected dumps and dump areas are quantified with respect to the amount ofmaterial in each ARD potential category.In section 5.4, characteristics of present effluent quality in various dump areas are predictedusing relationships between ARD potential categories and dump characteristics.117In section 5.5, a simple, temporal model is used to predict future effluent quality from EMO andNorth West dumps.5.2 Characterization of ARD Potential Categories5.2.1 LithologyEstimated proportions of each lithology found in samples from the three ARD potentialcategories are shown in Figure 5.1. Data from Table 3.4 was used to arrive at these estimates.Type II and III samples are composed of a variety of lithologies, however type I samples containonly Bonanza Volcanic rocks. Type II samples contain a significant amount of pyrophyllitebreccia.5.2.2 AlterationTable 5.1 depicts the dominant alteration of the samples from each ARD potential category.Although type I and II samples have overlapping alteration characteristics, type III samples areall dominantly SCC (sericite-chlorite-clay-pyrite) altered. Type II samples contain dominantlypyrophyllite-altered material.5.2.3 PyriteVisual estimates of pyrite for each ARD potential category are shown in Figure 5.2. There issignificant overlap in the visual pyrite estimates in each category.100CI)75.0. E a) 50.25.0.________100w75.a. E (U 50.__25.0._____________________Figure5.1LithologicalcharacteristicsofARDpotential categories00TypeIonanzaV100.75a. E (U Cl) 50250TypeIIrj•I._nanzaVolcanicBrecciaVeinRhyodacitePocptHydrothermalBrecciaP,ropliytliteBreccaVein,..hyodacitePorphyryHydrothermalBrecciaTypeIIIonanzaVoIcaP1,rophyfliteBreJiaI-—RhyodacitePorphyryHydrothermalBrecciaDominant alteration characteristics of ARD potential categoriesARD Potential CategoryAlteration I II IIIsericite- V’1 ‘V 1chlorite-clayquartz-sericite ‘Vpyrophyllite ‘/‘ •1biotite- ‘/‘magnetiteepidotechlorite1210 I -I8 I ]64I I —2.1 -lI I0 I I IType I Type II Type flI.pyrite (°“)Figure 5.2 Visual pyrite estimates for each ARD potential categoryTable 5.11191205.2.4 Carbonate MineralsTables 5.2 and 5.3 illustrate degree of effervescence from dilute hydrochloric acid for rockmatrix and veins or fractures for each ARD potential category. While type I samples generallyshow greater effervescense to dilute acid, no one ARD potential category is distinguishable fromthe other based on effervescence alone.Table 5.2 Rock matrix reactivity to hydrochloric acid of ARD potential categoriesARD Potential CategoryReactivity I II IIIStrongModerate 4/ 4/ 4/Weak 4/Nil 4/ 4/ 4/ 4/Table 5.3 Vein or fracture reactivity to hydrochloric acid of ARD potential categoriesARD Potential CategoryReactivity I II IIIStrong 4/ModerateWeak 4/ 4/ 7Nil 4/ 4/ 4/ 4/5.2.5 Acid Base AccountingType III samples are distinctly higher in total sulfur than the type I or II samples (Fig. 5.3a).Based on this relatively small dataset, it appears that samples with greater than 2 percent totalsulfur tend to be in the strongly acid generating category.120100 80 60 40 20 0-208 6 4 2 0a)b)10IIIIII[LI-1----.I•I.J—I-TypeITypeIITypeIllTotalSulfur (wt%)c)d)0.80.60.40.2 0 4 3 2 1 0TypeITypeIITypeIllSulfate(wt%asSulfur)“rI.’.II—FF•IIITypeIITypeIllTypeITypeIITypeliiTypeI•ACP(kgCaCO3It)I—Acid-volatilizedC02(wt%)Figure5.3AcidbaseaccountingparametercharacteristicsofARDpotentialcategories,a)total sulfur,b)sulfate, c)acidconsumingpotential(ACP),d)acid-volatilizedcarbondioxide100 50 0-50-100-150-200-250-300100 50 0-50-100-150-200-250-300Figure5.4AcidbaseaccountingparametercharacteristicsofARDpotentialcategories,a)netneutralizingpotentialusingtotalsulfur(NNPS),b)netneutralizingpotentialusingsulfidesulfur(NNPS2j,c)acidconsumingpotentialtoacidproductionpotential(ACP:APP),d)pastepH(ppH)a).—b)TypeITypeIITypeIIINNPS(kgCaCO3It)c)2.5 2 1.5 10.5 0-0.5d)TypeITypeIITypeIIINNPS2-(kgCaCO3It)II—--H •1----a--------------.----_8 7 6 5 4 3 2TypeITypeIITypeIIITypeITypeIITypeIIIIACP:APPII.PasteP’I123Type III samples are also significantly higher in sulfate than types I or II (Fig. 5.3b). Samplesshow distinct acid consuming potential (ACP) characteristics for each ARD potential category(Fig. 5.3c). Acid-volatilized carbon dioxide levels are distinct between type I and II samples,but there is overlap between types II and III (Fig. 5.3d).Similar trends for net neutralization potential using total sulfur (NNPS) and sulfide sulfur(NNPS2j(Fig. 5.4a and 5.4b).Samples in each ARD potential category also have distinct acid consuming potential to acidproducing potential (ACP:APP) ratios (Fig. 5.4c). Paste pH of the samples also shows adecreasing trend from type Ito type III category rocks (Fig. 5.4d).5.2.6 Elemental AnalysesOverall, only a few distinguishing elemental characteristics of the ARD potential categorieswere delineated. This is in part due to the small sample size.Type II samples are distinct in that they are relatively low in manganese, iron, magnesium andaluminum. As mentioned in Section 3.3.3, this is reflective of the considerable amount ofpyrophyllite-rich rocks in the type II samples.Calcium is the only element with relatively distinct groupings for each ARD potential categorywhich closely resemble that of acid-volatilized carbon dioxide (Fig.5.3d). The two type Isamples are over 2.5 percent calcium, the three type II samples are between 0.5 and 1.5 percentcalcium, and the three type III samples form a tight grouping between 0.5 and 0.75 percent.Type I samples were relatively high in zinc and cadmium. This is likely due to the associationof sphalerite with carbonate minerals.1245.2.7 Rock CompetenceThe sample’s rock competence, qualitatively determined by the number of hammer blowsrequired to fracture a given specimen are shown in Table 5.4. Type I samples tend to be morecompetent than type II and III samples.Table 5.4 Rock competence characteristics of ARD potential categoriesARD Potential CategoryCompetence I II IIIVery Competent 7Competent ../ 1Moderate ..7 v_FSoft5.2.7 DiscussionBased on observations of lithology, alteration, pyrite content, reaction to dilute hydrochloricacid, and rock competence, tentative guidelines to field classification of Island Copper wasterock into ARD potential category are given in Table 5.5.Table 5.5 also indicates the rank, or weighting that each parameter should be given whenclassifying a given rock. For example, if considering an SCC-altered rock with less than 1percent estimated pyrite, it would be classified as type III because of the higher weighting givento alteration.More sampling in the form of reconnaissance work on the dumps would further improve thisclassification.125Table 5.5 Tentative guidelines to field classification of Island Copper waste rock by ARDpotential categoryARD Potential CategoryDharacteristic Rank Type I Type II Type III.ithology 4 Bonanza Volcanic All Lithologies, but All Lithologiespredominantlypyrophyllite)ominant Alteration 1 non-SCC non-SCC, usually SCCnon-pyrophyllite pyrophyllite orquartz-sericitePyrite 2 <1% <2% >1%visual estimate)Reactivity to 10% 3 moderate to strong nil to weak nil to weakRydrochioric AcidRock Competence 5 very competent moderate variableThe analysis of acid base accounting characteristics of the ARD potential categories hasdemonstrated that samples indicated by acid base accounting to be potential acid generators arenot doing so despite up to twelve years of weathering on the dump surface. The criteria in Table5.6 are based on results presented in Tables 5.3 and 5.4.Worthwhile to note is that based on this work, an ACP:APP ratio of greater than 1.3 isconsidered indicative of type I, or acid consuming waste rock. This is in contrast to recentguidelines suggesting minimum ratios of 4:1 (Ministry of Energy, Mines and PetroleumResources, 1993) for initial screening of potentially non-acid generating samples. Furthersampling on the waste rock dumps and integration of existing data (for example BHP andRescan, 1988) may further refine the ABA criteria given in Table 5.6.126Table 5.6 Tentative acid base accounting criteria for ARD Potential categoriesARD Potential CategoryType I Type II Type IIINNP(total sulfur) NNP> 10 -25< NNP 10 NNP -25(kg CaCO3It)ACP ACP> 50 15 < ACP 50 ACP 15(kg CaCO3It)ACP:APP ACP:APP >1.3 0.3 < ACP:APP 1.3 ACP:APP 0.3(using total sulfurNNP)5.3 Assigning ARD Potential Categories to Waste Rock DumpsBased on the acid base accounting (ABA) criteria in Table 5.6 and using the drill hole ABAanalyses, the amount of waste rock in each ARD potential category was calculated for the OldNorth, EMO, and Cap regions of the North dump, as well as the North West and Beach dump.Each ABA analysis was designated to the appropriate ARD Potential category using criteria forNNP(total sulfur). Assuming equal weighting to each analysis, the percent of waste rock in eachARD potential category was calculated. For example, out of a total of 19 samples from EMO, 8were categorized to be marginal. Therefore, 42 percent of waste rock in EMO is estimated to bein this category.The results of the waste rock dump classification are shown for the North (Figure 5.5), NorthWest (Figure 5.6), and Beach (Figure 5.6) dumps. It can be seen that the waste rock regions orEMO(n=19)CAP(n=7)TypeIII(52.60%)—i1(5.30%)—Type11(42.10%)TypeIII(14.30%)—\,.—.-Typel(14.30%)TypeII(50.00%)___IOND(n=42)TypeIII(2.40%).1—Type1(47.60%)EntireNorthDumpTypeIIIType11(50.44%)—’Type1(40.27%)L’JL_Type11(71.40%)Figure5.5EstimatedproportionsofrockineachARDpotentialcategoryintheNorthdumpNWD(n66)TypeIII(42.60%)___1BCH(n=54)Type1(53.00%)[.Type11(53.70%)Figure5.6EstimatedproportionsofrockineachARDpotentialcategoryinthe NorthWest andBeachdumps00129dumps known to be net acid generating are estimated to contain from 14 to 56 percent of type IIIwaste rock. In contrast, the Old North dump is estimated to contain just over 2 percent (1sample) of strongly acid generating material. There is also a problem of adequate sampling insome areas, particularly from the Cap region (7 samples). The entire North dump is estimated tocontain about 9 percent of type III material.5.4 Prediction of Present Effluent Quality from Dump Areas5.4.1 MethodA simplified flow chart of the prediction process is shown in Figure 5.7.The kinetic test leachate loads are first examined according to their assigned ARD potentialcategory (box 10 on Figure 5.7), and simple statistics were performed to arrive at mean values ofalkalinity, acidity, molar calcium and magnesium, and sulfate loads (box 9). In addition, the“net acid load” for each category is also calculated. The net acid load is equal to the differencebetween molar sulfate and calcium and magnesium loads, and is indicative of the amount of acidproduced that is not neutralized by available carbonate minerals. The assumptions in thecalculation are that: i) sulfate production is representative of acid generation, ii) calcium andmagnesium in effluent is most reflective of carbonate mineral dissolution, and iii) carbonateminerals play the major role in acid neutralization.For each dump or region of dump quantified with respect to ARD potential, typical acidity oralkalinity, sulfate, molar calcium and magnesium, and net acid load values are assigned based onthe percent of material in each ARD potential category (box 11 on Figure 5.7).130CompareEstimated andActual EffluentQuality13 (Table 5.9)ERockI Samples1Waste RockDumps2Kinetic testleachate quality3 (Ch.4.O)Derive ARDPotentialCategories4 (Table 4.8)acid baseaccountingABA Criteriafor ARDARD PotentialCategories6 (Table 5.6)5 (Table 3.6)acid baseaccountingAmt. of EachARD PotentialCat. in WasteRock Dumps7 (Fig.5.5,5.6)Kinetic testleachate quality8 (Li,1 991)9 (Ch.4.O)EstimatedEffluent Qualityfor EMO andNW dumpsii (Table 5.9)Actual EffluentQuality fromEMO and NWdumps12 (Table 5.9)flow of predictionprocesssource of dataEstimate EffluelQuality for ONDCap, and Beachdump areas14 (Table 5.11)Figure 5.7 Flowchart for prediction of present effluent quality from dump areas131Actual effluent quality loads from the EMO and NWD dumps are calculated so that comparisonsbetween kinetic test and field-derived data can be made (box 12 on Figure 5.7)Estimated results are then compared with field water quality measurements. Factorscontributing to discrepancies and agreement in the results are then discussed.5.4.2 Leachate Quality of ARD Potential CategoriesFor the purposes of effluent quality prediction, only selected leachate quality parameters will bediscussed in detail. Gaussian statistics for these selected parameters by ARD Potential Categoryare given in Table 5.7. As shown, types I and II leachate have negative net acid loads (or netalkalinity). Although the net acid load values for the two categories are similar in magnitude,alkalinity depletion calculations (section 4.4.4) demonstrates the lower ultimate bufferingcapacity of the category II material.Sulfide oxidation rate constants for the kinetic tests are tabulated by ARD potential category inTable 5.8. Because only one rate constant was calculated per kinetic test, standard deviationsare not indicated for category I due to its small sample size.5.4.3 Actual Effluent Quality of EMO and NWD DumpsThe EMO and NWD dumps were selected to compare loads predicted from kinetic tests withfield conditions because: i) water quality data is available from ditches exclusively drainingeach of these dump areas, and ii) there is sufficient acid base accounting information on each ofthese dump areas.Table5.7CharacteristicsofkinetictestleachatechemistrybyARDPotentialcategoryARDAlkalinityLoadAcidityLoadMolar(Ca+Mg)LoadPotential(mgCaCO3/kg/wk)(mgCaCO3/kg/wk)(mollkg/wk)CategoryMiMax.MeanStandardMm.Max.MeanStandardMm.Max.MeanStandardDeviationDeviationDeviationI4.019.09.84.0----0.0000800.0003850.0001920.000110II023.05.05.00533.49.00.0000540.0028700.0005670.000708III----17373863293290.0003470.0054400.0019410.001506ARDSulfateLoadNetAcidLoadPotential(mg/kglwk)(=meanmolar(sulfate-(Ca+Mg)])CategoryMm.Max.MeanStandard(mgCaCO3equivJkg/wk)DeviationI4.032.010.58.1-8.2II3.0436.046.373.6-8.7III1552458574452404.0133Table 5.8 Characteristics of kinetic test sulfide oxidation rate constants by ARD PotentialCategoryARD Sulfide Oxidation Rate Constant (k1)Potential (wk-’)Category Mm. Max. Mean StandardDeviationI 0.00005 0.00013 0.00093(n=2)II 0.00009 0.00076 0.000438 0.000264(n=5)III 0.00065 0.00184 0.001411 0.000469(n=5)To best compare kinetic test and field-derived data, effluent quality for both dumps wascalculated using data for one year from September 1992 to August 1993, as during this periodthe majority of kinetic testing was conducted.5.4.3.1 Calculation of Actual LoadsThe method of calculation of actual dump loads used total precipitation minus losses toevaporation and groundwater to estimate the volume of water reporting to the drainage ditches.An evaporation loss of 15 percent of total precipitation was used. Li (1991) calculated a 21.7percent evaporation loss based on pit dewatering data; it was believed, however, that thisestimate was too high. Assuming this evaporation loss, Li also calculated losses to groundwaterin two areas of the North dump to be 7 and 17 percent respectively. A loss to groundwater of 10percent of total precipitation has been adopted for this study.The total annual precipitation was broken down into monthly values, and based on horizontaldump area and accounting for losses to evaporation and groundwater infiltration, monthlyvolumes of water reporting to the drainage ditch were calculated, These volumes weremultiplied by corresponding average monthly sulfate, acidity, calcium and magnesiumconcentrations to get the monthly mass of each parameter reporting to the drainage ditch. The134amount calculated to be lost to groundwater was then added to these values. The twelvemonthly loads were then summed to yield the annual mass of each parameter released from thedump.To best compare kinetic test and field data, the “active” dump mass was considered to be theportion of material in the dump of similar particle size distribution to the kinetic test material.As discussed in Section 3.3.5, about 50 weight percent of the dump is estimated to be greaterthan the size fraction used in the tests, therefore, the active dump mass is assumed to be 50percent of the total dump mass.Calculation of load per unit active mass of the dump was then obtained by dividing the annualmass of sulfate, acidity, calcium and magnesium released by each dump by its active dumpmass.The loads for EMO and NWD are presented in Table 5.9.5.4.3.2 Calculation of Sulfide Oxidation Rate ConstantsSulfide oxidation rate constants from September 1992 to August 1993 for EMO and NWD werecalculated using: i) the annual total sulfur oxidized and released as sulfate (derived according tothe method given in section 5.4.3.1), and ii) the total available sulfur in. each dump as calculatedfrom drill hole acid base accounting values.Total sulfur available in each dump was calculated by using the average APP value expressed askilograms sulfur per tonne, and multiplying this by the dump’s active mass (one half of its total135tonnage). The estimated percent sulfur released from the dump during the one year period wascalculated using:%S Released [STR(92.93)] / [ST] x 100 (5.1)where STR(92..93) is the total amount of sulfur released as sulfate from the dump from September1992 to October 1993 (mol/kg), and ST is the estimated total sulfur contained in the waste rockdump.Using the percent sulfur released from 1992 to 1993 and knowing the year of the collection ofthe acid base accounting samples from the dump, the approximate sulfur content of the dump inSeptember 1992 was calculated. The sulfur content of the dump in August 1993 was thendetermined by subtracting the annual percent sulfur released determined from equation 5.1. Theannual sulfide oxidation rate constant, k1 (in year1)w s calculated using:k1 = [log(ST(92)) - log (ST(93))] / [1 year] (5.2)Rate constants for EMO and NWD are given in table 5.9.5.4.4 Comparison of Estimated and Actual Effluent Quality from EMO and NWDUsing the mean leachate quality parameters given in Tables 5.7 and 5.8, coupled with theproportion of each ARD potential category in the EMO and NWD dumps, an estimate of dumpeffluent quality was calculated for each parameter.A comparison of estimated and actual effluent quality for the selected parameters is given intable 5.9. Overall, loads predicted by kinetic testing and ARD potential category weresignificantly higher than actual field conditions. Net acid load gave the largest differences136between actual and estimated values, while the smallest differences were obtained for thedimensionless molar calcium and magnesium to sulfate and net acid load to sulfate ratios.Table 5.9 Comparison of calculated versus actual effluent quality of EMO and NWDdrainagesEMO NWD %DifferenceEstimated Actual Scale Estimated Actual Scale in ScaleFactor Factor FactorsRate Constant 0.00093 15 0.0000368 0.038 0.0005060 0.0000637 0.125 70(wk1)Mo! (Ca+Mg) 0.001271 0.000026 0.020 0.000723 0.000049 0.067 70(mo!Ikglwk)Net Acid Load 208.4 1.8 0.0086 98.0 0.8 0.0082 5(mg CaCO3equivikglwk)Sulfate Load 322.1 4.2 0.013 163.6 5.5 0.033 60(mg/kglwk)molar 0.38 0.59 1.67 0.42 0.86 2.00 15[(Ca+Mg):Sulfate]molar 0.62 0.41 0.67 0.58 0.14 0.24 60[Net Acid:SulfatelThe discrepancies between actual and estimated effluent quality may be attributable to thefollowing factors:1) the kinetic tests significantly accelerating weathering reactions,ii) a significant error made in the estimate of actual active leaching mass of each dump, andiii) precipitation of gypsum and other sulfate minerals within dump, thus reducing effluentsulfate values.The acceleration of weathering reactions within kinetic tests may have occurred because of thecomparatively higher temperatures and the aggressive flushing regime used in the experiments.However, as discussed in Section 4.1, kinetic test acceleration of field behavior is poorly137understood. Nonetheless, the estimates of the existing acceleration of field weathering are lessthan an order of magnitude, thus not entirely accounting for the discrepancies observed.The actual active leaching mass of each of the dumps is probably the least known factor in theprediction calculation. As discussed in Section 2.3.4, flow of water through the Island Copperand other mine dumps is at present poorly understood. However, even if the 50 percent activeleaching mass assumed for the Island Copper waste rock dumps has overestimated the actualvalue by 100 or 200 percent, the large discrepancy in loads is still unexplained.Although occasional gypsum crystals were observed on surfaces and fractures of strongly acidgenerating samples, no other sulfate minerals were noted on rock surface coating analysed by xray diffraction (Section 3.3.4). Li (1991) concluded from analysis of EMO drainage chemistrythat conditions indicative of gypsum precipitation only occurred occasionally in the data.Although the precipitation of gypsum and other sulfate minerals may be occurring in localizedareas of the dumps, it cannot by itself account for the large discrepancy between estimated andactual sulfate loading.Overall, the significant discrepancies between estimated and actual effluent loads of the EMOand NWD drainages remain largely unexplained. This is likely due to our limited knowledge ofdump hydrology, the chemistry of rock-water interactions, and the design of laboratory scalesimulations. A better understanding of speciation and precipitation reactions within the dumpswould no doubt make correlations between laboratory and field-derived data better. The studyof the on-land dump effluent chemistry being conducted by Morin (1994) may provide someinsight into this phenomonen.Despite these discrepancies, if the ratio between actual and estimated conditions is known, theestimates can be scaled with reasonable confidence. By comparing actual and estimated scalefactors for the two dump areas, an indication of the reliability of the factor can be obtained. The138far right column of Table 5.9 shows the percent difference between the scale factors obtained forthe EMO and NWD drainages. It can be seen that reasonable agreement (within 5 and 15 %,respectively) was obtained from both the net acid load and molar calcium and magnesium tosulfate ratio scale factors. Adopted scale factors for these two parameters were obtained bytaking the mean of the values from EMO and NWD, and are shown in Table 5.10. Reliablescaling of the other parameters shown in Table 5.9 is not considered feasible.Table 5.10valuesAdopted scaling factors for calculating actual effluent conditions from estimatedParameter Adopted Scaling FactorEstimated —* ActualNet Acid Load 0.0084(mg CaCO3 equiv./kg/wk)molar [(Ca + Mg):Sulfate] 1.8Using these scale factors, estimated current effluent conditions for the OND, Cap, and Beachdumps are given in table 5.11. Actual effluent conditions for EMO and NWD are also given.Dump or Dump Area Net Acid Load molar [(Ca +(mg CaCO3equiv.Ikglwk) Mg):Sulfate]OND <0.1 5.0EMO* 1.8 0.6Cap 0.4 1.0NWD* 0.8 0.9Beach 1.4 0.7Table 5.11Copper MineEstimated current effluent conditions in selected dumps and dump areas at Island* actual values based on measured effluent quality1395.4.5 Discussion of ResultsThe net acid consuming potential of the OND dump area is reflected in its estimated low netacid load and high molar calcium and magnesium to sulfate ratio (Table 5.11).There is inadequate waste rock data on the Cap (only 7 samples from one hole), and thecalculated amount of material in the strongly acid generating category (type III) is considered tounderestimate actual amounts. This is reflected in the low net acid load and the high molarcalcium and magnesium to sulfate ratios estimated for Cap effluent. However, this result isbelied by field evidence indicating significant acid generation in the Cap, including: 1) thepresence of low pH effluent from several seepages from the toe of the Cap, ii) the numeroussurface patches of highly oxidized material on the dump, and iii) elevated down-holetemperatures greater than those obtained in the EMO dump holes. Based on this evidence, thedegree of acid generation presently occurring in the Cap is considered to be equal in magnitudeto the EMO or Beach dump areas, despite the above estimates to the contrary.EMO and Beach dump areas have similar predicted effluent quality characteristics. However,the Beach dump, being partially submerged in tidewater, has oxygen availability andtemperature distributions different from the on land dumps. Since the predictions are based onon-land dump scale factors, the accuracy of the Beach dump predictions are the least certain ofall the dump areas. Further discussion of the Beach dump predictions is given in Appendix 11.5.5 Temporal Modeling of EMO and NWD Dumps5.5.1 IntroductionGiven that ARD is already occurring within some regions of the Island Copper on-land wasterock dumps, the purpose of temporal modeling of the dumps is to help answer the followingquestions:140i) will the ARD problem get better or worse?ii) what concentrations of contaminants are expected from the dumps in the future?Some previous studies have also focused on the question of time to sulfide depletion (Morwijk,1993). However, in terms of bond-setting and design, the question of exactly how long tosulfide depletion becomes purely academic if our current unrefined estimates give times in theorder of several hundred years or longer, for example the 610 years calculated by Li (1991) forthe EMO dump. Indeed, the actual existence of a sulfide-depleted waste rock dump isdebatable; to the writer’s knowledge, there are no waste rock piles in existence whose sulfidereserves are depleted and are no longer producing acidic leachate. This includes the severalhundred year old ARD sites in Sweden.As discussed in Section 2.2.7, field observations on waste rock dumps at Island Copper Mineindicate that oxygen unavailability, though occurring in localized zones in the dumps, is likelynot controlling the rate of acid generation. However, the documented temperature increaseswithin the dump do have the potential to significantly increase sulfide oxidation, and hence acidgeneration rates (Marries and Ritchie, 1981).The temporal model assumes that acid generation kinetics can be approximated using a firstorder reaction. This method, as discussed in Section 4.4.2, has been used by Renton et. al.,(1988) and Steffen Robertson and Kirsten (SRK)(1993) for bench and field scale kinetic tests.In modeling copper dump leaching, Cathies and Apps (1975) also assumes that pyrite oxidationby ferric ion is a first order reaction. In addition, similar decay curve equations have been usedin other studies (Norecol, 1988, and the Dominique-Janine extension mentioned in SRK, 1993).The model allows for increased oxidation rate due to temperature rises by using the Arrheniusequation (Russell, 1980) to recalculate rate constants for each time step.1415.5.2 LimitationsIn considering future effluent trends, predictions made in this study are based on current rateconstants from EMO and NWD and are thus limited to estimating effluent quality assuming thatsite conditions remain the same in the future. The addition of till covers and other progressivereclamation activities will reduce both water infiltration and oxygen availability within thedump, and the effluent quality changes as a result of these activities is beyond the scope of thisstudy.5.5.3 MethodAs mentioned in Section 4.4.2, the first order reaction equation is:= (5.3)where dS/dt rate decrease of solid phase sulfide (mol/yr), k2 = initial oxidation rate (mol/yr),and kj = sulfide oxidation rate constant (yr I).Only two input parameters, kj and k2 are required for this model. Sulfide oxidation rateconstants for EMO and NWD used in the model are given in Table 5.9. By integrating equation5.3, sulfide remaining at time t can be expressed as:(54)Ic1At time t = 0, the original sulfide content S0 is therefore given by:S0=!2_ (5.5),and hence:142k2=S01 (5.6)Since larger rock particles are expected to break down in size during the modeled time period,the entire dump is considered to be the “active” mass. Although rate constants given in Table5.9 are calculated using only 50 percent of the dump as the active mass, check calculationsindicate that insignificant error is introduced by using these values for the temporal modeling.Total sulfur content at dump construction (1=0) was back calculated from time of waste rockdump drilling (collection time of acid base accounting samples) using the annual estimate ofannual sulfur released from dump from September 1992 to October 1993.Total available alkalinity in each dump area is assumed to be only the estimated carbonatemineral proportion of average acid consuming potential (ACP). From Section 3.3.6, therelationship at Island Copper between acid-volatilized carbon dioxide and ACP is:C02(mol I kg) = 0.OO66ACP(kgCaCO3It)— 0.055 (5.7)Table 5.12 gives calculations of available alkalinity in the EMO and NWD dump areas.The model assumes that at dump construction, average temperature of the dump is equal to thenormal average annual air temperature at the minesite (8°C).Since future temperature gradients are uncertain, three trials using different temperaturescenarios are given. The first two scenarios use calculated gradients based on actual temperaturemeasurements of EMO and NWD drill holes. For extrapolation into the future, the North Westdump calculated gradient of +0.37°C per year from 1989 to 1994 is adopted (Section 2.3.9).The two scenarios, test both a constant and decaying temperature gradient. The third scenario143tests the effect of constant dump core temperature as measured in 1993 (for EMO) and 1994 (forNWD). The three scenarios are:i) scenario 1, assuming that the temperature gradient will remain constant at +0.37°C per yearto a maximum average dump temperature of 50°C (above which bacterial activity issubstantially reduced and sulfide oxidation rates decrease (Harries and Ritchie, 1981)),ii) scenario 2, assuming that the initial temperature gradient of +0.37°C per year will decreaseat a rate of 0.5 percent per year to a minimum average dump temperature of 15°C, andiii) scenario 3, that temperatures in the waste rock dumps will remain at levels of 17.0°C forEMO and 20.2°C for North West dump.Table 5.12 Available alkalinity in EMO and NWD dump areasEstimated Estimated Portion of ACPDump Available Mass of Available as AvailableArea Average ACP Alkalinity Dump* Alkalinity Alkalinity(kg CaCO3It) (mol C02/kg) (tonnes) (mol) (%)EMO 18.67 0.0675 4.670(106) 3.152 (10) 36NWD 49.16 0.2675 9.S43(10) 2.552 (108) 54* from Li (1991) and UBC MMPE (1990a)The change in sulfide oxidation rate constant is related to the change in temperature by theArrhenius equation (Russell, 1980):1ogk = logk + Ea (.i__!_) (5.8)a 2.303R 1 7144where ka and kb are rate constants at temperatures Ta and Tb (temperatures in K), Ea is theactivation energy for pyrite (taken as 14,000 cal/mo! or 58,576 joules/mol (Cathies, 1975)), andR is the ideal gas constant (8.3 14JKmol’).Table 5.13 gives the input parameters for modeling of the EMO and NWD dump effluent.Table 5.13 Input parameters for temporal modeling of EMO and NWD dump effluentDump k1 Avg. Dump Temp. k1Area Sept/92 to Aug/93 Sept/92 to Aug/93 (8°C, 1=0)(yr1) (°C) (yr1)EMO 0.001915 17.0 0.000880NWD 0.003313 19.8 0.001208Estimated TotalDump Year of Dump Year of ABA Estimated Total Sulfur S0 at DumpArea Construction Sampling Sulfur at Sampling Construction (1=0)(t=0) (moles) (moles) (mol/yr)EMO 1981 1988 2.432(10) 2.458 (109) 2,163,000NWD 1983 1989 3.719(108) 3.775(108) 456,100For each one year time step, the model outputs the rate of sulfide oxidation dS/dt. Assuming anaverage annual total precipitation of 2000 millimetres and that 75 percent of total precipitationreports each dump’s drainage ditch, and knowing the horizontal surface area of the dump, anaverage annual sulfate concentration in the ditch drainage is calculated. The sulfide remainingin the dump at each time step (S(i9) is determined by subtracting the sulfide consumed during theone year time step from the previous S(t).145For each time step, a new sulfide oxidation rate constant k1 and sulfide oxidation rate k2 arecalculated. The new sulfide oxidation rate constant is determined by using the new temperaturefor the time step and applying the Arrhenius equation (5.8), and the new sulfide oxidation rate isdetermined from equation 5.5, substituting S(t) for S0. Sulfate concentration is determinedusing:504 (mg/i) = [](96ooo) / [(0. 75)(2.0)(A)(1 000)] (5.9)where 96,000 is the moles to milligrams sulfate conversion factor, 0.75 is the proportion of totalprecipitation reporting to the drainage ditch, 2.0 is the estimated total annual precipitation in themine area, and 1,000 is the cubic metres to litres conversion factor. A is the horizontal area ofthe dump in square metres.The modeling of both alkalinity consumption and acidity concentration is linked to modeledsulfide oxidation by the molar calcium and magnesium to sulfate ratios given in Table 5.9. It isassumed that this ratio will be constant over the modeled time period and that alkalinityconsumption will be equal to sulfide consumption times this ratio. The amount of unbufferedacidity, that is net acidity in each dump’s effluent, is estimated using an equation similar to 5.9:Acidity (mgCaCO3/ 1)=— dAlk ](i 00000)/ [(0. 75)(2. 0)(A)(1 000)] (5.10)where dAik/dt is the rate of alkalinity consumption, and 100,000 is the moles to milligramscalcium carbonate conversion factor.Renton et. a! (1988) noted that in chemical kinetics, reactions exhibit first order behavior onlyuntil approximately 63 percent (1 oo[i — eq]) of the reactant is consumed. This was validated forARD applications in small scale field experiments. Therefore, this model is considered to bevalid for amounts of total sulfide consumed between 0 and 63 percent.146The model was formulated and tested using a spreadsheet program, where graphical resultscould be easily generated.5.5.4 ResultsFigures 5.8 to 5.10 and 5.12 to 5.14 graphically show EMO and North West dump temporalmodeling results for the three temperature scenarios.As mentioned in Section 5.5.3, the first order model is considered valid only until 63 percent ofthe original sulfide is consumed. Because of their different rate constants and the twotemperature scenarios tested, each trial of the model has a unique prediction period, and theseare given in Table 5.14.Table 5.14 Valid prediction periods for first order model trialsYears of Valid PredictionDump Area Temperature Temperature TemperatureScenario 1 Scenario 2 Scenario 3EMO 108 410 551NWD 99 298 387As expected, temperature scenario 1 shows the higher ultimate sulfate and acidity concentrationsfor both EMO and NWD. Given this temperature regime, peak concentrations are expected tooccur between the years 2060 and 2080 and be in the range of over 10,000 mg/l sulfate and over4000 mg CaCO3/1 acidity for EMO, and just under 5,000 mg/I sulfate and 750 mg CaCO3/Iacidity for NWD. Peak values for all trials correlate well with peak temperatures in the dump.908070060 —5040 E302010n14810020001500‘•0C,<100050:I1900 2000 2100 2200 2300Year2400 2500L— Sulfate (mgIl) — Temperature — Acidity (mg CaCO3II)2600Figure 5.10 EMO predicted sulfate and acidity concentrations, temperature scenario 35000 100904000 80703000 60o 502000 I100:1975 1985 1990 2000Year1980 1995Sulfate (mg/I) — Temperature— Acidity (mg CaCO3/I) -- Actual Avg. Annual S04-A- Actual Avg. Annual AcidityFigure 5.11 Comparison of EMO average annual sulfate and acidity concentrations withpredicted values using temperature scenario 2149500040003000! 20000100001980 2000 2020Year2040 2060100908070C.)60z5041)0.40 E302010A2080SuIfate (mg/I) — Temperature —Acidity (mg CaCO3/I)IFigure 5.12 NWD predicted sulfate and acidity concentrations, temperature scenario 12500 100902000 .8070C.)2 1500 60I-o1000 40ci)Cl)30500 .2001’ “I I I I:01950 2000 2050 2100 2150 2200 2250 2300Year—Sulfate (mg/I) — Temperature — Acidity (mg CaCO3/l)Figure 5.13 NWD predicted sulfate and acidity concentrations, temperature scenario 2>.C.,01)C’,1200100080060040020001900 2000 2100Year2200 2300908070C-)605040 E3020102400[Sulfate (mg/I) — Temperature — Acidity (mg CaCO3/I)Figure 5.14 NWD predicted sulfate and acidity concentrations, temperature scenario 35000 IflI)904000. 80703000. 60o 501)1975 1980 1985 1990 1995 2000Year— Sulfate (mg/I) — Temperature— Acidity (mg CaCO3/I) Actual Avg. Annual S04-- Actual Avg. Annual AcidityFigure 5.15 Comparison of NWD average annual sulfate and acidity concentrations withpredicted values using temperature scenario 2150151If the more conservative scenario 2 temperature gradient is adopted, the model predicts that peakconcentrations will occur sooner, but will be not as high in magnitude as the scenario 1 results.The peak values are predicted to occur during the years 2040 to 2060. At this time sulfate andacidity values in EMO drainage are predicted to be over 4000 mg/l and just under 2000 mgCaCO3/i, respectively. NWD drainage sulfate and acidity concentrations are predicted to beover 2000 mg/l and over 250 mg CaCO3/lacidity, respectively.If, as in scenario 3, dump core temperatures do not increase in the future, sulfate and acidityconcentrations will gradually decline, with peak concentrations occurring in 1993 and 1994 ofjust under 2000 mg/i sulfate and approximately 750 mg CaCO3/1 acidity for EMO drainage andunder 1200 mg/i sulfate and less than 200 mg CaCO3/lacidity for NWD drainage.5.5.5 Validation and CalibrationValidation of acid rock drainage weathering models is difficult because of the general lack oflong-term field data (Steffen, Robertson and Kirsten, 1989).Some validation, and calibration of this model was derived using historical effluent quality data.Annual averages of both sulfate and acidity concentrations of EMO and NWD sampling stationswere used.Figures 5.11 and 5.15 show actual versus predicted data for EMO and NWD. In both dumps,the model has underestimated sulfate concentration and overestimated acidity. Reasonsspeculated for this discrepancy are:i) an inappropriate value for pyrite activation energy (Ea, 58,576 J/mol used),ii) an underestimation of dump temperature at time of construction, andiii) the relatively low sulfate loads calculated from the 1992 to 1993 data compared withprevious data.152Based on literature surveyed, pyrite activation energies can range from 10.7 to 25.6 kcallmol(44,769 to 107,100 J/mol, respectively) (Halbert et. al, 1983). These extremes of activationenergies were used instead of the 58,586 J/mol originally assumed in the initial trials. The highactivation energy trial gave a much poorer fit to the actual data than the original trial, but thelow activation energy trial did not show any improved fit to the actual data. It appears that i) theactual activation energy of pyrite in the dump is in the low range, and ii) no significantimproved fit to actual data is realized with changes in activation energy.The validity of the initial dump core temperature assumption of 8°C was tested by assuminginitial temperatures of 9, 10 and 12°C. The initial temperature gradient was recalculated toaccount for the new initial temperature. A noticeably better fit of actual to modeled sulfateconcentrations was obtained, however acidity concentrations showed more deviation.A third possible explanation for the difference is that the model is based on calculated sulfideoxidation conditions from September 1992 to August 1993, and sulfate concentrations for EMOin this time period were only slightly higher than the year before. Similarly, lower sulfateconcentrations than the previous year were calculated for NWD. This resulted in a lowercalculated rate constant for both dumps than would have been obtained from earlier data. It istoo soon to tell if the one year’s data is indicative of an improving trend for the Island Copperwaste rock dump effluent quality, but based on both examples from other dumps and thesignificant sulfur reserves still within the Island Copper piles, it is unlikely that sulfide oxidationwill begin to abate at this early date.5.5.6 DiscussionThis temporal model, although more sophisticated than a linear estimation, is very simplecompared with some other models which attempt to predict oxygen transport and heatproduction processes, for example, Cathles and Apps (1975). Several factors should be kept inmind when considering this model:153i) the model is based on the premise that there is an existing waste rock dump drainingmeasurable and net acidic effluent, andii) oxygen availability and intra-dump water transport characteristics, although not quantified,are “pseudo steady state” for the particular dump and the corresponding sulfate and acidityloads have been measured. As long as neither oxygen availability nor intra-dump watertransport conditions change significantly, they do not need to be known or estimated.Rather than attempting to predict conditions of a new dump, this study addresses the simplerproblem of predicting future behavior of already net acid-generating dumps, based on presentand historical conditions. Thus, a simpler model may be all that is necessary. To quoteNicholson (1992): “it is better to pose our uncertainties in the context of a simple model than acomplex one.”The temporal sulfide oxidation model illustrates the dependence of sulfide oxidation rate onaverage dump core temperature. This relationship has been verified by others in the field(Cathies and Apps, 1975, Harries and Ritchie, 1981). Unfortunately, present temperature dataare considered insufficient to confidently predict future trends, and at best, a range of effluentquality can be currently predicted.The worst case is considered to be temperature scenario 1 which ultimately plateaus at 50°Caverage dump temperature. Such high temperatures have been measured at Equity and MineDoyon operations (Morin, 1991, and Université Lava!, 1991), however, a relatively short periodof time was required to achieve these temperatures. The low temporal temperature gradientmeasured in the North West dump may indicate that Island Copper dumps will never attain theheat production and correspondingly high sulfide oxidation rates that other dumps have.However, based on ARD potential categorization, the North West dump has significantly lessstrongly acid generating material (type III) than EMO or Beach dumps (Figure 5.5 and 5.6). TheCap, with the highest down-hole temperatures of all the on land dump drill holes, is also154considered to have a large amount of strongly acid-generating material. Heat productionbehavior of the North West dump, therefore, may not be directly applicable to other net acidgenerating dumps at the minesite.As discussed, the model assumes a constant ratio of sulfate to acidity, meaning that the dumpwill continue to buffer acidity at the same rate as measured in 1992 to 1993. In reality, theability of the dump to buffer acidity will likely decrease over time. This implies that actualacidity levels will be higher than predicted.When temperatures stabilize, concentrations of sulfate and acidity will gradually decrease. Thisis supported by the decrease in leachate sulfate and acidity concentrations during the 40 weekcolunm tests conducted at constant temperature. However, temperature monitoring resultsindicate that a low, positive temporal temperature gradient is plausible in the North West dump,EMO and Cap areas, therefore there is potential for increases in effluent sulfate and acidityconcentrations. The magnitude of the increase can not be determined at this time due to lack ofdump temperature data, and some unanswered questions on model accuracy.1556.0 CONCLUSIONS AND RECOMMENDATIONS6.1 ConclusionsThe heterogeneity of the waste rock dump material is reflected by the high variances inthe drill hole acid base accounting analyses. The results do confirm the significantamount of potentially buffering till which comprises about one third of the materialunderlying most of the North dump. Insufficient sampling is evident in some areas,particularly the Cap, with only one drill hole and seven acid base accounting analyses.The combination of push and free dumping methods has contributed to dumpheterogeneity, and has also made prediction of water flow through the dump difficult.Oxygen levels in 1989 in the North West dump indicate that nearly all locations in thepile had sufficient oxygen at that time for sulfide oxidation. Pore gas oxygen levels inone of the column tests indicates that low oxygen levels in some areas may be limitingARD generation in highly oxidized zones and within 15 to 30 centimetres of the surface.However, on a dump scale, very few regions are thought to have significantly depletedoxygen levels. Convective flow of air through the dump is evidenced by perceptiblewarm, moist air flow out of drill holes in the Cap and EMO dump areas.Elevated temperatures in the EMO, Cap and North West dump areas are indicative ofsignificant pyrite oxidation. The maximum measured temperature, from the Cap drillhole, is 24.3°C. Available data from the North West dump indicates that maximumtemperatures in that area are stabilizing in the low 20°C level. Due to the lack ofhistorical data for the Cap and EMO, conclusions on temperature stability cannot be madeat this time. Compared with other monitored ARD sites (for example Equity and Mine156Doyon), the Island Copper on land dumps are relatively “cool”; this is reflected in acidityconcentrations from the EMO and NWD drainages being lower than typical ARD bymore than an order of magnitude (see Table 1.1).Overall, kinetic test work of the eight waste rock samples did not indicate worsening ofwater quality with time. Samples which produced net acidic leachate at test initiationcontinued to do so throughout the course of the experiment, and samples initiallyproducing net alkaline leachate showed no indication of increasing sulfide oxidation withtime. Based on the kinetic test work, rock at Island Copper has been classified into threecategories:i) type I rocks, which are interpreted to have sufficient excess alkalinity to do somedegree of buffering on infiltrating acidic drainage,ii) type II rocks, which although possibly generating alkaline leachate at present, are notregarded to have sufficient excess alkalinity to adequately buffer infiltrating acidicdrainage, but are not expected to significantly contribute to net acidity of the wasterock dump; andiii) type III rocks, which are presently producing leachate with high net acidity.Type III rocks tend to be of variable lithology but in the samples are stronglyhydrothermally altered to a sericite-chlorite-clay (SCC) assemblage, and have estimatedpyrite contents of greater than 2 percent. The hot, acidic fluids which circulated along theporphyry dyke and volcanic contact zone during and after ore emplacement not onlydeposited pyrite but caused extensive leaching of primary feldspars and carbonateminerals, thus leaving the rock mass with both acid generation potential and littleneutralizing capacity. Type II rocks are also of variable lithology, but are less alteredthan type III rock. Sampling thus far indicates that pyrophyllite breccia comprises most157of the material in this category. Type I rocks are exclusively of Bonanza Volcaniclithology, are less altered than type III rock, and contain carbonate minerals.The acid base accounting boundary criteria between type II and III samples are a netneutralization potential of -25 kg CaCO3/t, and an acid consuming to acid producingpotential ratio of 0.3:1.Applying the acid base accounting criteria of the ARD potential categories to the wasterock dumps, the dumps or dump areas considered to be producing net acidic leachate areestimated to contain a minimum of 14 percent of type III material. The EMO and Beachdump areas contain the highest amounts of type III material (53 and 43 percent,respectively). The Old North dump is estimated to contain only 2 percent, while theentire North dump is estimated to contain just over 9 percent of type III material.Comparisons between water quality estimated from kinetic tests and actual water qualityfrom the EMO and North West dump areas indicate that kinetic test p4rameters such assulfide oxidation rate constant, sulfate loads, and molar calcium and magnesium loadscannot be confidently scaled to field conditions. However, estimated net acid load andmolar calcium and magnesium to sulfate ratios do appear to be scalable, and therefore,can be estimated for the Old North, Cap, and Beach dump areas. Results, given in Table5.11, indicate that the effluent contributed by Old North dump material has significantexcess alkalinity. The estimate for the Cap returned effluent quality more alkaline thanexpected (its actual effluent quality is thought to be comparable to EMO drainage), and itis believed that the limited number of samples from this dump have resulted in anunderestimate of the amount of type III material. Effluent quality from the Beach dumpis estimated to be similar in magnitude to EMO, however, due to the unique oxygenation158conditions and temperature distributions of the Beach dump, this prediction may not beaccurate.Temporal modeling of the EMO and NWD drainage effluent quality indicates that if the1988 to 1994 calculated temperature gradient for North West dump (+0.37°C/year)persists, this will be reflected in significant increases in sulfate and acidity concentrations.However, if temperatures stabilize, concentrations are predicted to similarly stabilize andthen slowly decrease. Although the principal of the model is believed to be correct, somecalibration work is still required to have confidence in the quantities predicted.6.2 RecommendationsContinued monitoring of down hole temperatures on all of the on-land waste rock dumpsis strongly recommended. Sampling frequency should be approximately three months,and a minimum of two year’s monitoring (from January 1993, the initiation of monitoringof the North dump drill holes) is required to assess temperature stability of the Northdump.This study has suffered in some areas due to lack of sampling data in the Cap region ofthe North dump. However, this may be adjusted for by assuming that the Cap has rock,and hence drainage quality, similar to the EMO dump area.Decommissioning of the waste rock dumps will likely include a combination of coveringor relocating the rock, and continued collection and perhaps treatment of effluent.159Covers in the form of spreading 0.3 to 0.5 metres of till on the dump surface will reduceinfiltration and can, based on literature, result in decreased oxygenation of the waste rockdumps. Almost all reclaimed areas of the North dump were covered with till for thepurpose of aiding revegetation, and there is sufficient till remaining to cover the rest ofthe dump. The amount of improvement in dump drainage quality as a result of applying awaste rock dump soil cover is still debatable (Morin et al., 1991). This may be in partdue to accumulated acidic products within covered dumps delaying a perceivableimprovement in effluent.The waste rock dump literature review of Morin et a!. (1991) proposes that primary airtransport into the dump is from the base and pile edges. Therefore, if excess material isavailable, a thicker till cover should be applied on sides and base of the Cap, the onlyunreclaimed dump area known to be net acid generating. Careful infilling of the metaland wood refuse pit on the Cap may significantly reduce oxygen transport in this area.Where possible, the segregation of drainage from the known acid generating regions ofthe on land dumps will considerably improve the remaining drainage water quality.160REFERENCESBHP-Utah Mines Ltd., 1986. Methods Manual, Environmental Department, Island CopperMine, 106 p.BHP-Utah Mines Ltd., and Rescan Environmental Services, 1988. South Wall Pushback:Description of Project and Related Environmental Issues. Prepared for Vancouver IslandRegional Reclamation Advisory Committee.BHP-Utah Minerals International, 1990. Island Copper Mine Closure Plan.Bonn, H.L., McNeal, B.L., and O’Connor, G.A., 1985. 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Modelling of Long Term Acid Rock Drainage from Waste Dumps at IslandCopper Mine, Port Hardy, B.C.: Year-End Progress Report, University of British Columbia,unpublished report prepared for G.W. Poling and BHP Minerals Canada Ltd.Lister, D., Poling, G., Home, l.A., and Li, M.G., 1993. Prediction and Reality: “Static analysesversus actual rock weathering in waste dumps at Island Copper Mine, Port Hardy, B.C.”, inProceedings of17th Annual B. C. Mine Reclamation Symposium, Port Hardy B.C., pp.109-118.Ministry of Energy, Mines and Petroleum Resources, 1993. Interim Policy for Acid RockDrainage at Mine Sites, Prepared by B.C. Reclamation Advisory Committee, 13 p.Morin, K.A., 1990. Acid Drainagefrom Mine Walls: the Main Zone Pit at Equity Silver Mines.Prepared for British Columbia Acid Mine Drainage Task Force, 109 p.Morin, K.A., Gerencher, F., Jones, C.E., Konaseuish, D.E., and Harries, J.R., 1991. CriticalLiterature Review of Acid Drainage from Waste Rock. MEND Report 1.11.1.162Morin, K.A., 1992. Draft Report: Pit-Wall Assessment at Island Copper Mine: Implicationsfor Mine Closure. Morwijk Enterprises, report prepared for BHP Minerals Canada Ltd.Morin, K.A., 1994. Prediction of Minewater Chemistry at Island Copper’s On-Land Dumps.Prepared for BHP Minerals Canada Limited, Island Copper Mine, in press.Morwijk Enterprises Ltd., 1993. Mine Rock and Tailings Geochemistry and Prediction of WaterChemistry. Bell 92 Project, Closure Plan, Supp. Doe. E, 189 p.Nicholson, R.V., 1992. “A review of models to predict acid generation rates in sulphide wasterock at mine sites. in draft proceedings, International Workshop on Waste Rock Modelling,Sept.29-Oct. 1, Toronto.Norecol Environmental Consultants Ltd., 1988. Cinola Gold Project Stage II Report, Volume V,Environmental Research and Special Studies, Prepared for City Resources (Canada) Limited.Osatenko, M.J., and Jones, M.B., 1976. “Valley Copper”, in Brown, A.S.,ed., PorphyryDeposits ofthe Canadian Cordillera, CIM Spec. Vol. 15, pp.130-143.Perelló, J.A., Arancibia, O.N, Burt, P.D., Clark, A.H, Clarke, G.A., Fleming, J.A., Himes, M.D.,Leitch, C.H.B., and Reeves, A.T., 1992. “Porphyry copper-molybdenum-gold mineralization atIsland Copper, Vancouver Island, B.C.”, presented at Northwest Mining Association ShortCourse “Porphyry Copper Model - Regional Talks and Settings”, Tuscon, Arizona and Spokane,Washington, Nov.28-Dec. 1, 1992.Perelló, J.A., Fleming, J.A., O’Kane, K.P., Burt, P.D., Clarke, G.A., limes, M.D., and Reeves,A.T., 1994. “Porphyry copper-gold-molybdenum mineralization in the Island Copper cluster,Vancouver Island”, in Schroeter, T., ed., Porphyry Deposits of the Northwestern Cordillera ofNorth America, CIM Spec. Vol. 46, in press.Perry, E., 1985. “Overburden analysis: an evaluation of methods”, Proceedings, Symposium onSurface Mining Hydrology, Sedimentology and Reclamation, Lexington, Kentucky, College ofEngineering, U. of Kentucky, pp.369-375.Renton, J.J., Rymer, T.E., and Stiller, A.H., 1988. “A laboratory procedure to evaluate the acidproducing potential of coal associated rocks”, Mining Sci. and Tech., Vol.7, pp.227-235.Rescan Consultants Inc., 1992. Island Copper Mine Decommissioning and Closure Plan,Hydrological and Metal Loadings Study, Phase I Report, Prepared for BHP Minerals CanadaLimited, Island Copper Mine.163Ritcey, G.M., and Silver, M., 1982. “Lysimeter investigations on uranium tailings atCANMET”, CIM Bulletin, Vol.75, No.846, pp.134-143.Russell, J.B., 1980. General Chemistry, New York, McGraw-Hill, 797 p.Singleton, G.A. and Lavkulich, L.M., 1987. “Phosphorus transformations in a soilchronosequence, Vancouver Island, British Columbia”, Can. J. Soil Sci. 67: pp.787-793.Sobek, A.A., Schuller, W.A., Freeman, J.R., and Smith, R.M., 1978. Field and LaboratoryMethods Applicable to Overburden and Mine Soils, Cincinnati, Ohio, U.S. EnvironmentalProtection Agency, Report EPA-600/2-78-054.Sobek, A.A., Bambenek, M.A., and Meyer, D., 1982. “Modified soxhiet extractor for pedologicstudies”, Soil Sd. Soc. Am. J. 46: pp 1340-1342.Steffen Robertson and Kirsten (B.C.) Inc., 1989. Draft Acid Rock Drainage Technical Guide,VoL I, Prepared for the B.C. AMD Task Force, BiTech Publishers, Vancouver.Steffen Robertson and Kirsten (B.C.) Inc., 1993. Rock Pile Water quality Modelling, Phase I -Final Draft Report. Unpublished report to MEND prediction committee, August 1993.Université Laval Groupe de Recerche en Geologie de L’Ingenieur, 1991. Acid Mine DrainageGenerationfrom a Waste Rock Dump and Evaluation ofDry Covers using Natural Materials:La Mine Doyon Case Study, Quebec. Executive Summary (en anglais) Prepared for Service dela Technologie Miniere Centre de Recherches Minerales, 22 p.University ofBritish Columbia, Dept. of Mining and Mineral Process Engineering (UBCMMPE), 1 990a. Island Copper Mine - North West Dump Study, Stage Report II, Humidity CellTest Results, Prepared for Island Copper Mine.University of British Columbia, Dept. of Mining and Mineral Process Engineering (UBCMMPE), 1 990b. Island Copper Mine - North West Dump Study, Stage Report I, Prepared forIsland Copper Mine.University of British Columbia, Dept. of Mining and Mineral Process Engineering (UBCMMPE), 1990c. Acid Mine Drainage Study ofthe North Dump, Final Report, Prepared forIsland Copper Mine.Van Zyl, D.J.A., Hutchison, I.P.G., and Kiel, J.E., ed., 1988. Introduction to Evaluation, Designand Operation of Precious Metal Heap Leaching Projects, Society of Mining Engineers, Inc.,pp.61-67.Vos, R.J., and O’Heam, T.J., 1993. “Use of zeolite to treat acid rock drainage from Britanniaminesite”, in Proceedings of] 7th Annual B. C. Mine Reclamation Symposium, Port Hardy B.C.,pp.223-232.164APPENDIX IPETROGRAPRIC REPORT ON TEN POLISHED THIN SECTIONS FROM THE ISLANDCOPPER DEPOSIT, B.C. FOR ACID ROCK DRAINAGE STUDIESReport for:Diane Lister, Invoice attachedDepartment of Mining and Metallurgy,University of British Columbia,Vancouver, BC. December 6, 1993Samples submitted: Ten, from surface dumps (presumably most ofthe samples come from the open pit).SUMMARY:The samples submitted form a suite of slightly oxidized,variably pyritic, altered porphyritic and volcanic rocks. Theintent of the sampling was to obtain specimens as oxidized aspossible by geologic weathering to determine, if possible, thecharacteristics of oxidation. The samples submitted, however,have only been subjected to weathering for a short time from ageological perspective. This is evident from inspection of thehand samples, which show only traces of limonite developed, andon outside surfaces only. In thin section, the specimens showmainly only a thin rind of limonite (± minor included erraticquartz and sericite grains), and only rarely does limonitepenetrate the interior of the sample along fractures. Weatheringalteration (as opposed to hypogene hydrothermal alteration) formsmainly very thin rinds up to 150 j.m thick except in one sample(4—8, from which two sections were cut) in which a 2—3 cm zone of“bleaching” (supergene ?clay alteration) is superposed onhydrothermal chloritic alteration.Most sulfide is pyrite, generally euhedral and disseminatedand without differences in various parts of the section or invarious gangue hosts. Minor veinlet-controlled chalcopyrite ispresent in two samples(4-8b and 3-7), one with inclusions ofbornite (3—7), and traces of galena and ?sphalerite are includedin pyrite in 8—1. Magnetite, with minute inclusions ofchalcopyrite, is also found in this sample (8—1).Carbonate is found in only one sample (8—1), as rarecrystals in a ?zeolite vein; zeolite is also present in 6—1 asveins or matrix to massive pyrite. Feldspar (plagioclase) occursonly in 8-1; gypsum was not observed; sericite is common andabundant, as are chlorite, clay, and quartz in these mainlyphyllic, argillic, propylitic, or advanced argilic alteredsamples of intermediate volcanic rocks (andesite—?dacite). Rareminerals in the highly aluminous, advanced argillic alterationinclude blue dumortierite and clear ?diaspore.Craig H.B. Leitch, Ph.D., P. Eng.(604) 666—4902 or 921—8780_:Page 2 1652-8: QUARTZ-PYROPHYLLITE-SERICITE-DUMORTIERITE-CLAY-PYRITE(ADVANCED ARGILLIC) ALTERED PORPHYRYOn the fresh cut face, the hand sample is light creamy grey-white with spots of blue dumortierite and scattered pyrite, andis presumably from the hypogene high alumina alteration(pyrophyllite-dumortierite) zone that capped the Island Copperdeposit. The specimen is not magnetic, and shows no reaction tocold dilute Rd. It is scratched by steel. The outside iscoated by pale tan—coloured (?jarositic), soft pulverulentlimonite which does not appear to penetrate into the sample. Inpolished thin section, the mineralogy is:Quartz 30%Pyrophyllite 20%Sericite 15%Clay 15%Chlorite 10%Dumortierite 5%Pyrite 3%Rutile 2%Limonite <1%The sample is composed of a generally fine-grained, tightlyinterlocking intergrowth of quartz and phyllosilicates, thelatter probably developed after feldspars. Quartz is generallysubhedral and less than 0.1 mm; pyrophyllite forms radiatingmasses of flakes to 0.1 mm diameter, whereas sericite is finer,forming subhedral flakes about 20 jm in size. Large patches of afine—grained (25—40 4LLm) low birefringence mineral look to bedistinctly green in some places, with anomalous bluebirefringence and length—slow character suggesting an Fe—richchlorite; however, elsewhere a similar mineral but lacking thegreen colour may be clay, possibly kaolinitic.In places there are patches of coarser quartz (to 0.25 mm),pyrite, dumortierite and rutile. Dumortierite (blue in handspecimen) forms colourless sub— to euhedral crystals up to 0.5 mmlong; rutile (or leucoxene) is found as very fine—grained patchespseudomorphing former Ti oxide crystals up to 0.3 mm long.Pyrite forms subhedral, scattered crystals up to 1.5 mm diameterthat contain inclusions of quartz and phyllosilicate up to 0.3 mmacross. Almost all the pyrite occurs in the coarse—grainedpatches, and is all similar in habit (disseminated; no veinlets).There does not appear to be any change in character of the pyritefrom crystal edge to center, and there is no evidence ofoxidation of individual crystals (no limonite rimming orpenetrating along fractures). The polish of pyrite crystals isexcellent except at the edges of the section; grain boundariesare generally smooth to rarely decussate. There are no othersuif ides visible.Limonite is confined to narrow fractures less than 0.1 mmthick, which near the outside margin of the sample becomepervasive (affect 50% of the rock). In this sample, hydrothermal(advanced argillic) hypogene alteration is easily distinguishedfrom recent weathering, which appears to be restricted tolimonitic fracture coatings. No iron oxide rind on the specimenis visible in thin section.166Page 32-9: QUARTZ-SERICITE-PYRITE (PHYLLIC) ALTERED FINE FELDSPAR?OUARTZ PORPHYRYFine—grained porphyry consisting of 20—30% 1 mm whitefeldspar crsytals and patches of disseminated pyrite, probablyafter former mafic sites, in a buff aphanitic matrix. There arerare dark brown patches of ?secondary biotite, and scattered 1.5mm amygdules of a hard white mineral. The rock in general issofter than steel; it shows no reaction to HC1, and is notmagnetic. The outside is coated with soft, pulverulent, verypale tan-coloured (?jarositic) limonite. In polished thinsection, the modal mineralogy is approximately:Sericite (after feldspars) 50%Muscovite (after mafic phenocrysts) 5%Quartz (mainly matrix) 25%(phenocrysts, veins) 5%Pyrite 10%Relict feldspar 5%Rutile <1%This rock consists of highly altered feldspar and mafic mineralrelics in a very fine—grained siliceous groundmass. Feldsparcrystals show sub- to euhedral outlines up to 1 mm long, and havebeen almost completely pseudotnorphed by fine—grained (<0.1 nun)sericite. Rarely, feathery anhedral feldspar remnants to 0.05 mmlong are seen in the feldspar sites. Mafic crystals also haveeuhedral outlines up to 0.5 mm in diameter and have beenpseudomorphed by coarser—grained sericite or muscovite aseuhedral flakes up to 0.3 mm diameter, and in places by pyrite.Former quartz ?phenocrysts or ainygdules are up to 1.7 mm across,and composed of coarse subhedral to euhedral crystals that arehighly fractured, somewhat strained and partly replaced by finegrained secondary silica and lesser pyrite in places. Similarquartz is found in rare quartz veins that are up to 0.3 mm thick.The groundinass is formed of extremely fine, rounded quartzcrystals up to 25 j.m diameter.Pyrite forms generally subhedral crystals up to 1 mmdiameter that frequently contain silicate inclusions up to 0.05nun diameter, with rare rutile inclusions. Pyrite grainboundaries vary from smooth and rounded to rough and highlydecussate. There is no apparent change in the character orassociation of the pyrite across the section; all pyrite grainsare disseminated rather than controlled along veinlets. Polishis good except at the edges of the section, and there is noobvious difference between the cores and rims of crystals. Noother suif ides are visible; carbonate, zeolite and gypsum appearto be absent.Limonite is essentially absent from this section (althoghseen on the outside of the hand sample, no rind can be seen ormeasured in the section). Rutile is common as fine—grairiedreplacements of former Ti02 minerals that were up to 0.15 nunlong.Alteration to quartz-sericite-pyrite (phyllic assemblage) isintense and easily differentiable from supergerie oxidation andweathering, the effects of which are confined to the very outersurfaces of this sample.Page 4 1673-7: SERICITE-CLAY-CHLORITE ALTERED FINE FRAGMENTAL ?VOLCANICLight grey-green, coarsely textured igneous rock containinggrey-white patches to 0.5 cm diameter and dark green chioriticpatches and minor disseminated pyrite. There is rio reaction tocold dilute MCi and no magnetism; the rock is about as hard assteel. Limonite is confined to rare traces of orange—browngoethite on fractures. In polished thin section, the modalmineralogy is approximately:Sericite 45%Clay (?) 20%Chlorite 15%Quartz (?partly secondary) 15%Pyrite 3%Rutile 1%Chalcopyrite (rare ?bornite) trThis appears to have been a fine fragmental rock, composed ofsubangular to subrounded clasts of ?volcanic rock up to about 0.5cm size in a matrix of similar but more finely comminutedmaterial, before thorough sericite-chiorite-clay alteration,accompanied by minor pyrite. Relict textures in the clasts arevariable, from coarsely porphyritic (sericitized feldsparpseudomorphs to several mm long) to finely ?amygdular (0.1 mmquartz). However, the intense alteration has largely obscuredthe primary derivation of the fragments.Sericite forms abundant fine euhedral flakes and rosettes,rarely up to 50 um in diameter. Some patches are clearlypseudomorphs of former phenocrysts, probably feldspar, but othersappear to be after volcanic shards. Other fragments are replacedby very fine-grained (10-25 m) flakes of a mineral that may beclay such as kaolinite; it appears to be intermixed with orgradational to the sericite. Some feldspar crystals arepseudomorphed by masses of a brownish (only partly translucent)mineral that may be clay-altered feldspar.Chlorite is found in discrete patches up to 1.2 mm across,in places rimming cores of sericite. Chlorite flakes aresubhedral and up to 25 jm diameter, with optical characteristics(length—fast, weak green colour, anomalous birefringence)suggestive of a Fe:Mg ratio about 1:1, Quartz is found as finesub— to anhedral crystals up to 25 4um diameter in both fragmentsand matrix, and may be partly secondary.Pyrite in this sample forms fine, scattered disseminatedcrystals up to 1 mm diameter with sub- to euhedral outlines.Most have smooth boundaries, but some are highly decussate.Inclusions are of gangue and are mainly rare. I see no change inthe character or disseminated character of the pyrite across thesection or with gangue host; most are found in fine—grained clay—sericite. Rare chalcopyrite is seen to 0.25 mm across, withhighly anhedral outlines and very fine (5—10 LLm) inclusions of?bornite. Rutile is common, as very fine crystals rarely to 0.1mm size. There is no liinonite in the section.This is an intensely clay—sericite—chlorite±pyrite altered?fragmental volcanic rock, showing no microscopic evidence ofrecent (supergene weathering) alteration. Carbonate, zeolite andgypsum appear to be absent.168Page 54-8a: SERICITE-QUARTZ-CHLORITE-PYRITE ALTERED COARSE FRAGMENTALVOLCANICCoarsely fragmental volcanic rock containing largesubrounded to subangular clasts up to 2 cm in size with darkgreen chioritic alteration (softer than steel) in a grey,siliceous matrix (harder than steel). The hand specimen showsrare traces of magnetism, but does not react to cold dilute HC1.There is a clear weathering rind about 2.5 cm thick developedfrom the outside of the sample, in which the green colour isbleached to grey-white. The polished thin section covers onlythis bleached portion. Soft, pulverulent limonite (goethitic)and ?clay coats the outside surface of the sample but does notpenetrate the sample. Mineralogy in section is:Sericite, clay 50%Quartz (largely secondary?) 35%Chlorite 10%Pyrite 5%Rutile <1%This is a thoroughly quartz—sericite-chlorite—pyrite alteredfragmental volcanic, in which the original textures are largelydestroyed by the alteration. Most of the alteration is hypogene,but as noted from the hand specimen, in the area from which thesection is cut, at least part of the clay-sericite alteration maybe supergene (due to weathering processes). This distinctioncannot, however, be made in thin section.Sericite forms very fine subhedral flakes, rarely up to 50jm in diameter, and in rosettes to similar size. In places theremay be minor clay (finer-grained, lower birefringence) intermixedwith the sericite. Quartz is abundant, mainly secondary, in theform of anastamosing veinlets up to 0.5 mm thick, and as adjacentor disseminated patches of finer replacement silica. Crystals inthe veins are up to 0.25 mm in diameter; in the fine patches,they average around 25-50 j.m. Chlorite is found as sub- toeuhedral flakes to 0.1 mm diameter, with bright blue anomalousinterference colours and green pleochroism indicating moderatelyhigh Fe content (Fe/Mg around 0.6). It is intimately associatedwith rutile, and probably results from the alteration of formermafic minerals (± Ti02 minerals) in the original volcanic rock.Carbonate, zeolite, feldspars, and gypsum appear to be absent.Pyrite forms coarse, cubic, euhedral crystals up to 2 mmsize, disseminated througout the section, generally away from anyveins or fractures. There is no clear association with anyparticular gangue mineral, and therefore no change in associationacross the section. Most crystals have smooth, regular, straightboundaries against gangues, with minor gangue inclusions beingcommon and leading to somewhat poor polishing of the crystals.Cores of crystals are richer in inclusions than the rims. Noother sulf ides are present, but rutile crystals are present bothas separate crystals and inclusions in pyrite to 0.1 mm.Limonite is very rare in the section, where it is restrictedto the periphery of the rock, along a few thin fracture margins,and as rare fine stains in chlorite and sericite near rutile. Itis not, however, present near pyrite.169Page 64-8b: INTENSELY CLAY-SERICITE-CHLORITE-QUARTZ (±HYDROBIOTITE,PYRITE) ALTERED VOLCANIC FRAGMENTALThe hand specimen for this sample is very small, and showsno traces of oxidation or limonite even on the outside surface;minor white material there may be only mud. The fresh cutsurface shows a medium-grained, green, chioritic altered volcanicrock that does not react to cold dilute HC1 and is slightlymagnetic. It is much softer than steel, implying little quartz.Modal mineralogy in polished thin section is:Clay—sericite 50%%Chlorite (Fe-rich) 20%Quartz (mainly secondary) 20%Hydrobiotite 5%Pyrite 3%Rutile 1%Apatite <1%Chalcopyrite trThis rock is similar to 4-Ba except that chlorite is moreabundant. If it is from the green (less weathered) part of 4-8,then it clearly shows the difference between hydrothermalalteration (green, chloritic) and recent weathering alteration(bleached, clay-sericite rich). Large domains (subrounded tosubangular ?volcanic clasts, to 1 cm size) consisting mainly ofchlorite, ruti].e, relatively coarse-grained (50-100 jnu) sericiteor muscovite, and in places some pyrite, are hosted in a finer—grained (10—25 jim) mesh of clay-sericite. There are also domainsof almost pure quartz (secondary, up to 0.5 mm subh- to anhedralcrystals, possibly fragments of altered plutonic rock. Minoramounts of apatite, as minute crystals up to 0.1 mm long, arefound associated with the coarse quartz.Chlorite has very strong anomalous blue and purpleinterference colours and green pleochroism, with length—slowcharacter, indicating Fe-rich composition about 0.6 to 0.7Fe/(Fe+Mg) ratio. Subhedral flakes and radiating rosettes are upto 0.25 mm in diameter. Chlorite is not associated with pyrite,but frequently is found in domains (?former mafic phenocrystrelics) that contain small crystals of a brown, weaklypleochroic, flaky mineral of similar size to chlorite that may behydrobiotite. This mineral might be associated with theweathering front in this rock (it could be the first stage in thebreakdown of the chlorite, which is the mineral most noticeablylost during the weathering).Pyrite is found as scattered, euhedral crystals up to 0.75mm in size or as aggregates to 1 mm of finer cubic crystals. Thepyrite is not clearly associated with any gangue mineral or withthe numerous quartz veins; the only exception to this is that thefine—grained aggregate occurs in a domain of chlorite. Traces ofchalcopyrite are present as anhedral crystals to 0.05 in long,clearly distributed only along a thin quartz veinlet. Most ofthe pyrite polishes very well to a smooth surface, with very fewinclusions showing, but concentrated in larger crystals at thecores, with clear rims (suggesting pyrite ?overgrowths). Wherecrossed by a quartz veinlet, the pyrite shows elongate quartzinclusions, also suggesting possible late overgrowths.Page 7 1706-1: CLAY-?SERICITE-CHLORITE ALTERED. ?DACITIC VOLCANIC PORPHYRYPale grey—green, fine feldspar-mafic mineral porphyry;softer than steel, slightly magnetic, no reaction to cold diluteHC1. Outside of sample is coated by thick coating of soft,pulverulent ?oxides and clay, generally creamy—coloured but tanin places. Within the rock, the effects of weathering appearconfined to hairline fractures. Mineralogy in polished thinsection is approximately:Sericite 25%Clay (?kaolinitic) 25%Quartz (partly secondary) 25%Chlorite 10%Pyrite 10%Feldspar (plagioclase microlites, relict) 5%Rutile, sphene <1%The section appears to be overly thin, making identifications onthe basis of interference colours difficult. However, it isclearly a porphyritic volcanic rock in which former feldsparphenocrysts (30%, euhedral, up to 1 mm long) have been completelyreplaced by a fine-grained (to 50 inn) matted mineral that may besericite, although the birefringence (as noted above) looks to betoo low. It could be a clay mineral, possibly kaolinitic, if thesection is of true (30 J.Lm) thickness. Former mafic phenocrysts(15%, euhedral, up to 0.5 mm long) have been pseudomorphed bychlorite, Fe—Ti oxides such as sphene and rutile, and pyrite.There were micrphenocrysts of Fe-Ti oxides up to 0.2 mm in size,now replaced by sphene and/or rutile. The groundmass isaphanitic, and consists of very fine-grained (25—30 inn) quartz,clay (after plagioclase microlites, which are variably preservedin places) and fine Fe—Ti oxides (rutile and ?sphene), typical ofa dacitic volcanic. Carbonate, zeolite and gypsum are absent.Along a single fracture crossing the slide, all original mineralsappear to be converted to clay; this could be due to supergene(weathering) alteration since it is along this fracture in thehand specimen that weathering is seen to be taking place.Hydrothermal alteration is clay-sericite-chiorite, or argillic incharacter.Pyrite forms euhedral cubic crystals up to 1 mm diameter, orin places aggregates of finer cubes, that are disseminated evenlythrough the specimen. In detail, it appears to show a preferencefor altered mafic sites, with chlorite, but its size and habitare no different in those sites than in the groundmass. Pyriteis not found along veins nor along the fracture crossing theslide, supporting its identication as a supergene rather than ahydrothermal feature. In some areas, the pyrite crystals arestrongly fractured (notably at the edges of the section, butcontain only rare inclusions of silicate or rutiJ.e. Elsewhere,the crystals contain a few inclusions (mostly at crystal cores)but are unfractured. The boundaries of pyrite are smooth exceptfor aggregate grains, which are irregular. There are no othersuif ides visible. Limonite is not seen in thin section, eitheraround pyrite, along fractures, or on the outside of the sample,so the thickness of the weathering rind cannot be judged.171Page 86—2: MASSIVE PYRITE VEIN (MINOR SERICITE-OUARTZ-?ZEOLITELWEATHERED TO CLAY-LIMONITE ON OUTSIDE SURFACES AND FRACTURESMainly massive pyrite, presumably from a vein of at least 2cm thickness. Some traces of a siliceous, altered walirock areattached. There is a relatively thick (1 mm) weathering oroxidation rind developed, in which buff-cream ?clays and browngoethitic limonite are abundant. This penetrates rarely along afew fractures into the rock. The specimen is not magnetic andshows no reaction to cold dilute HC1. In polished thin section,the modal mineralogy is:HvpogenePyrite 75%Sericite 5%Zeolite (?) 5%Quartz (secondary, i.e. part of the vein) 5%Rutile trSupergeneClay 5%Limonite (goethite ± ?jarosite) 5%Pyrite, the main component of this sample, is found asinterlocking subhedra]. crystals up to 1.5 mm across, containingsome larger crystals up to 4 mm in length. It is possible thatthe finer hosting crystals have been cataclasized (broken bydeformation), since the larger crystals show prominentfracturing. Inclusions (silicate and rare rutile) are not commonin the pyrite except in a few areas of the section, without anyobvious connection to other features. No other suif ides are seenin the section. The interstices between pyrite crystals arefilled with a network of gangue minerals.Gangue minerals hosting the pyrite appear to be mainlyquartz, sericite and rare ?zeolite. Quartz forms anhedral,interlocking crystals up to 0.1 mm diameter, and sericite formssubhedral flakes to 50 j.m diameter. The mineral tentativelyidentified as zeolite is found as sub- to euhedral crystals up to0.5 mm long, with well—developed longitudinal cleavage and lessercross—cleavage; birefringence is low (0.005—0.010), relief islower than epoxy, and the crystals are length-slow withextinction angle of about 20°. Optic angle is small andnegative; these characteristics fit a range of zeolites, such asstilbite, chabazite or scolecite; although the large extinctionangle favours scolecite, zeolites are notably difficult toidentify optically with certainty.Towards the outside of the section, a cloudy or semi—opaquealteration becomes prevalent; this is probably clay, a weatheringalteration, mixed with minor limoriite. In places, crystals oraggregates to 0.25 mm with extreme birefririgence could bejarosite, a mineral expected in the oxidation of massive pyrite.Carbonate, feldspar, and gypsum appear to be absent.172Page 97-1: CLAY-SERICITE-CHLORITE-OUARTZ-EPIDOTE ALTERED VOLCANICFine-grained, grey-green, homogeneous finely porphyriticvolcanic flow rock, strongly hydrothermally altered, with minordisseminated pyrite. Cut by rare limonitic fractures; outside isstrongly coated by a weathering rind up to 0.1 mm thick of brightorange—brown (goethitic) limonite typical of oxidation of lowsulfide contents. The specimen is softer than steel due to thealteration, and shows a trace of magnetism, probably relict frommagnetite in the unaltered volcanic; it shows no reaction to colddilute HC1. Mineralogy in polished thin section is approximately:Clay—sericite 45%Quartz (partly secondary) 25%Chlorite 20%Epidote 5%Pyrite 2%Rutile, leucoxene 2%Limonite (goethitic) 1%This is a strongly clay—sericite-quartz—chlorite (propyliticargillic) altered, finely porphyritic volcanic. Former euhedralto subhedral feldspar and mafic phenocrysts, respectively up toabout 0.5 mm and 0.25 mm, are pseudomorphed by clay-sericite andchlorite±epidote. They are set in a groundmass of quartz(probaby partly secondary) as anhedral, highly interlockedcrystals up to 50 ,.Lm size, pius minor sericite and rutile offiner grain size (15—20 ILm). Sericite replacing former feldsparsoccurs as minute scaly flakes of about 10—20 jnn size. It appearsto be mixed with lesser amounts of a semi—opaque or lowerbirefringence material that could be clay and/or intermixedclay/epidote (saussurite). This material is even finer-grained,perhaps 5—10 jnn in size. The clay could be the result ofweathering, rather than hydrothermal alteration.Chlorite replacing former inafic sites forms subhedral flakesup to 25 j.m diameter, with pale green colour, weak anomalous bluebirefringence, and length-slow character suggesting anintermediate Fe/(Fe+Mg) ratio about 0.5. In places, fineeuhedral crystals of epidote or clinozoisite (Fe-poor epidote) to25 jnn are found in the relict inafic sites. Rarely, quartz,pyrite and ?sphalerite as 20-30 jim crystals are also found. Apoorly preserved spheroidal texture to other chioritic patchessuggests they may be remnants of ?volcanic glass rather thanmafic phenocrysts. Rounded patches up to 0.5 mm diameter offine—grained quartz and ?ciay may represent the sites of formeraxnygdules. Carbonate, zeolite, feldspar, and gypsum are not seen.Pyrite forms scattered, disseminated crystals of sub- toeuhedral habit up to 0.5 mm diameter. Inclusions of silicatesand rutile are found in most crystals but are not volumetricallyabundant and show no obvious distribution patterns (cores vs.rims). Apart from the occurrence of a few pyrite grains inaltered mafic sites, there is no clear control on pyritedistribution (no veins, no concentrations). No other sulf idesare visible; no limonite coatings are seen on pyrite crystals. Athin (up to 100 jim) goethitic limonite rind can be seen on thespecimen, and in places limonite stains penetrate for 50 jim orare found along rare fractures.Page 101738-1: PLAGIOCLASE PORPHYRITIC, ANDESITIC VOLCANIC FLOW ALTERED TOCHLORITE-EPIDOTE-PYRITE (PROPYLITIC) AND LATE ZEOLITE-CALCITEFine—grained, dark grey, siliceous (harder than steel)altered volcanic probably originally similar to 7-1 (beforealteration). The rock contains strongly magnetic small darkspots and disseminated pyrite, but shows only traces of reactionto cold dilute HC1 in late fractures containing a white mineral.Fractures, along which alteration was concentrated, are common.The outside of the specimen is coated with a soft mixture oforange—brown limonite and white ?clay. In polished thin section,the mineralogy is approximately:Plagioclase feldspar (?andesine) 55%Chlorite 20%Pyrite, trace galena, sphalerite inclusions 10%Epidote 5%Clay (?) 5%Ilmenite 2%Rutile, sphene, leucoxene 1%?Zeolite (fractures only) 1%Carbonate (?calcite; fractures only) <1%Magnetite (trace chalcopyrite inclusions) <1%The bulk of this rock is composed of plagioclase feldspar, asmedium to large euhedral phenocrysts up to 2 mm long (3.5 mmwhere agglomerated). They are twinned and show traces oforiginal compositional growth zonation, implying that thepresently observed composition of about andesine (An35), based onextinction angles of about 22° for Y010, is primary.Plagioclase also forms the bulk of the groundmass, as finemicrolites of about 0.1 to 0.3 mm length, although there is atendency to senate texture (all intermediary sizes betweenmicrolites and phenocrysts are seen). Most plagioclase crystalsshow only mild alteration, to clay—sericite and minor epidote(saussuritization), along cleavages and fractures.Former mafic sites are replaced by fine—grained (50-100 j.in)chlorite and lesser epidote, with minor ilmenite and ?sphene.Chlorite crystals show blue anomalous birefringence, greenpleochroism, and length-slow character typical of Fe:Mg ratiosabout 0.6; epidote shows no pleochroism, indicating an Fe—poorcharacter like that of clinozoisite.The groundmass to plagioclase microlites is so fine-grainedthat it is difficult to identify; it appears to be a mixture of10—20 jm ?clay, chlorite, and Fe-Ti oxides (rutile, leucoxene).In the late fractures, feathery bladed short crystals of ?zeolite(low relief, birefringence about 0.010, length-fast) to about 0.1mm are mixed with subhedral rhombs of carbonate up to 0.2 mm insize, presumably calcite by its reaction to MCi. Rare grains ofinagnetite to 0.1 mm, with 10—20 m inclusions of chalcopyrite,are found in these fracture veins.Pyrite occurs as both disseminated cubic crystals up to 1 mmin diameter, as well as elongate patches of subhedral 0.25 mmcrystals distributed along microfractures and veinlets. Thedisseminated euhedra characteristically display smooth boundariesand zre zoned with a clear core (occasionally containing a fewlarge inclusions) and a rim full of inclusions, both silicate and174Page 11traces of galena and sphalerite (30 jnn). Pyrite crystals alongfractures are less euhedral, with larger, irregularly distributedinclusions, and have irregular boundaries against silicateshosting them.A thin rind, locally up to 100 j.m thick, of limonite isfound around the outer rim of the specimen. There is noobservable penetration of limonite into the sample. Grains ofquartz and sericite caught up in the limonite are proabablyaccidental, agglomerated during weathering and erosion. As inother samples, a thin zone up to 150 j.m thick appears to rim thesample, in which ?clay is more prevalent; this may be alterationdue to weathering as opposed to the pervasive propylitic (clay—chiorite-epidote—pyrite) hydrothermal alteration.175Page 128-2: INTENSELY OUARTZ-SERICITE-?CLAY-?DIASPORE (ADVANCEDARGILLIC) ALTERED ROCK; NO SULFIDES OR LIMONITENo hand sample provided. In polished thin section, themineralogy is approximately:Quartz (largely secondary) 45%Sericite 35%?Clay (?kaolinitic) 15%?Diaspore 5%Rutile 1%This specimen contains no suif ides. It is made up of large areasup to 7 mm across of either coarse (to 1 mm) anhedral or fine (to0.1 mm) subhedral quartz, locally with other minerals intermixed,in a matrix of fine sericite and quartz. In this matrix, quartzis anhedral to subhedral and up to about 50 j.&m in diameter;sericite forms subhedral flakes to about the same size. Both areintimately intermixed. Fine sub- to euhedral crystals to 20 j.tmlong of rutile, with red—brown internal reflections (Fe—richcomposition) are scattered throughout the matrix and in thequartz-rich patches.Other minerals in the quartz-rich patches include areas of alow—relief, low—birefringence mineral with brown “colour” (semiopaque character), length—fast, that could be a kaolinitic claymineral such as halloysite (subhedral flakes up to 25 m size).There is also a second (?) clay mineral with similar opticalproperties but which is clear, and finer grained (10—15 nm).Also included in these areas are clusters of radiating, euhedral,clear crystals up to 0.25 nun long (high relief, highbirefringence, length-fast) that may be diaspore (Al hydroxide).This mineral is found in some of the highly aluminous, advancedargillic alteration zones of Vancouver Island.There is no observable weathering rind or rim of limonite onthis sample, and no traces of limonite are seen in the interiorof the specimen; this is understandable, given the lack of anysulfide. Carbonate, zeolite, feldspars and gypsum are notpresent. All the alteration appears to belong to the advancedargillic assemblage (quartz-sericite-caly-?diaspore); none can beattributed to weathering. The protolith lithology of thisintensely altered rock can no longer be distinguished.176APPENDIX 2 List of Sample Numbers and DescriptionSample # Site # Location!DescriptioI I Coil; pre-test2 1 Coil; pre-test3 1 Coil; pre-test4 2 Coi 2; pre-test5 2 Coi 2; pre-test6 2 Coi 2; pre-test7 3 Coi 3; pre-test8 3 Coi 3; pre-test9 3 Coi 3; pre-test10 4 Coi 4; pre-test11 4 Coi4;pre-test12 4 Col 4; pre-test22 2 HC 7; pre-test23 4 HC 8; pre-test24 5 HC 1; pre-test25 6 HC 6; pre-test26 7 HC 4&5; pre-test27 8 HC 2&3; pre-test28 Till; Upper Caps29 Till; L.N. Dump30 1 Coil; post-test31 1 Coil; post-test32 1 Coil; post-test33 2 Coi 2; post-test34 2 Coi 2; post-test35 2 Col 2; post-test36 3 Col 3; post-test37 3 Col 3; post-test38 3 Col 3; post-test39 4 Col 4; post-test40 4 Coi 4; post-test41 4 Col 4; post-test•AST..VANCOUVERs.c.:...:E.pEo(6o4)253...3j58PAZ(604)25317161•GEOCHEMICALANALYSISCERTIFICATETheUniversityofBritishColumbiaFile#93—3258Page1DeptofMining&MineraL,VancouverBCV6T1Z4Submittedby:DianeListerMoCuPbZnAgNiCoMnFeAsUAuThSrCdSbBiVCaPLaCrMgBaTiBALNaKVpç4IppnpçnpçiipçnppappIIp’anXppiippnPF’(I15PiflppwZXppmppmXPPZKKppmSAI4PLE#0001000200030004000500060007000800090010001100120022002300240025002600270028RE0028002900300031003200330034003500360037003800390040004100420043STANDARDC5480727401.8362333237.33385<2<21133.62<2883.42.0658321.48121.19154.16.13.0913490818981.8312232687.6240<5<221034.3<2<2842.49.0678361.5864.18153.85.11.061546614311251.7222031926.7034<5<2<2966.1<2<2822.38.0647291.46129.19123.46.08.05<16142110433.826209576.0626<5<2<2612.02345.63.080323.8736.02111.81.04.1211013364413.635208275.4125<5<2<2491.9<2<247.64.0753261.1033.0292.02.03.12<17254902981.027238936.1021<5<2<2621.3<2<247.69.084427.9436.02111.93.06.1413259949216.51286942.2921<5<2<2105.9<2<262.89.089412.6234.06141.59.08.06<12542733121.51276481.8315<5<2<270.4<2<236.88.095316.6018.04151.34.04.04<12262832108.3984351.5915<5<2<2100.4<2<2371.04.078312.5224.05131.56.06.0412973714112.61395193.1216<5<2260.4<23431.14.0655ii1.0441.02101.78.06.1211963711111.614115913.6218<5<2<288.3<2<2501.31.0675131.1349.03102.02.12.0912384720128.616105723.6019<5<2<292.4<22531.22.0686121.2254.0392.00.09.101511877317.528179315.8320<5<2<2621.53<246.61.079331.9536.0381.8.04.1212565719180.628116533.6717<5<2<297.7<2<2521.48.0726201.2656.0392.12.08.12<1628814952252.0853149417.6339<5<2<211332.3<2<2833.48.04341062.2632.07154.10.16.04<1217797812159.63223271513.1490<5<2<247<.2<23862.56.0353361.4014.08132.10.04.211123253164202.81620670913.87101<5<2<21381.0<2<287.71.0714231.8736.15134.13.05.06256528248.52474011.5628<5<2<2251.62315.49.090310.2413<.0114.80.01.05<14191983.125125833.9213<5<2266.5<2<2802.39.053536.9626.2761.87.10.0523178877.124125723.6611<5<2<264.3<2<2782.37.050534.9325.2651.82.08.051115197170.927157614.129<5<2<293.9<2<2832.00.0564331.0734.2562.30.12.06175938110681.7242132288.1237<5<22945.82<2882.14.0708431.6481.1693.80.10.071752090720562.4222234978.7035<5<2<29710.23<2881.88.0707401.63135.17113.95.09.07<1653711714441.5272232868.0439<5<2<2947.8<2<2842.22.0687441.6881.16103.84.09.06<16114132239.630189585.9313<5<2<2701.0<2<255.85.0713611.2145.0392.43.06.13<1514763235.538199706.5012<5<2<250.8<2<256.67.0754481.1834.0392.25.05.13<1611565367.5291710516.2717<5<2<2751.7<2<251.53.0764311.1048.0382.15.04.14<12346920103.21575262.4413<5<2<260.4<2<236.73.086324.5219.04121.34.04.05<12871633159.61486402.3714<5<2<268.8<2<2401.00.082325.6320.05151.57.05.05<12863051147.41486482.4320<5<2<283.7<2<242.95.086320.6429.05651.62.05.0512484417140.523116854.7225<5<2<271.62<2591.18.0786261.2356.0392.23.08.1312983121147.423106404.7213<5‘2<264.6<22541.08.0736321.1358.0272.19.08.15<12466015102.421115734.7118<5<2<256.3<2<2581.22.0766291.2044.0372.08.06.1313864451227.31387112.5718<5<2<21091.02<244.93.092411.6436.05121.75.08.0712483520131.416105853.9116<5<2<294.5<2<2551.25.0696121.2458.0372.21.09.13<11662391227.1673110463.9841177365219.0141656.50.0873661.90189.08331.90.06.149CD CD I 11ICP.500GRAMSAMPLEISDIGESTEDWITH3ML3-1-2HCL-HNO3-H20AT95DEC.CFORONEHOURANDISDILUTEDTO10MLWITHWATER.THISLEACHISPARTIALFORMNFESRCAPLACRMGBATIBVANDLIMITEDFORNAKANDAL.-SAMPLETYPE:PULPSairLesbeginning‘RE’aredupLicatesamLes.DATERECEIVED:NOV101993DATEREPORTMAILED:AJWSIGNED.JD.TOYE.C.LEONG,J.WANG;CERTIFIEDB.C.ASSAYERS178vv;v0 -, I. .0Z OD000 0a,t’ — 0.0—,0.0<—w.0*ot--0.E -00. —.,0”0.0n NZ 0..frN‘.E 0.& . N N NccCE p,’’O’. 0c -•a)00000 00’C —C. W.0I-NNN — ->E c00.0N’0 ,..& 0. .fl ‘0.0 U’.E NNNN ntn&vvvv —0E -.‘.E NU’ Ils.0’O’0 U’.LE NNNVJN -—& VVVV PflE NNNNN I’.V VVVVZE fU’.U’a vvvvv —a CCE N.f’.$l’.SO ,‘.<a0. CCw1. ‘0U. 0 ‘.0N.tW U°‘“°‘‘0.U’U’.’0 0OE .—‘-‘000 —N ———E iP.Ot-I —& N — N N‘E ‘0..tN.30 0CE C O.0U% ‘CN&.0 E ‘0’0 ‘0 W W—DC ‘0O’’’ N‘. •..t0’0I•’. ‘0aOE !-,O’0NIts ‘0NNN —I.00. .U’,0P’..0z< 0000W(n 0000 V179APPENDIX 4 Calculation Method for APP and APPS2given that 1 weight percent equals 10 kg/tonne,APPS=wt%Sx 10kg <lOOgCaCO3/molit 32gS/molandAPPS2(kgCaCO3/ t) = { wt%S _[wt%S04 32gS / mol 10kg lOOgCaCO3/ mol96gSO4/mol)jj it 32gS/molSieveAnalysisSample:001-3Date:18-Oct-93Mass(g):434.9Prolect:IslandCopper -ARDStudyDesc.:colpre-testDoneBy:DL_________________________________________________Mesh#OpeningOpeningMassSveMassSveMassSampWt.%Wt.%(Can.)(in.)(mm)(g)+Samp(g(g)PassingRetainedSizeDistribution001-31.060.750.530.3180.26540.18760.13280.0937120.0661160.0469200.0331pan 300.0234400.0165500.0117700.00831000.00591400.00412000.00292700.00214000.0015pan26.5475.5475.519524.2617.913.2469.4577.59.5480.3536.96.7471.1511.44.75469.5501.73.35460.2482.82.36452.2471.61.7416.8429.61.18374.9383.70.85354.1363.3253.2286.60.6324.93310.425322.1326.80.3324.2328.10.212318.2321,40.15293.2296.20.106289.3291.80.075245.5248.20.053272.2274.50.038267.7270253.2255.6TOTAL10FFIIIll I,,’’C100.0078.5553.8040.8431.6224.2419.0714.6311.709.687.586.185.114.213.482.792.221.601.080.550.093.7108.156.640.332.222.619.412.8 8.89.233.4 6.1 4.73.93.23.02.52.72.32.32.4436.8mFFl00:E1III1I1,ELi0.0021.4524.7512.969.237.375.174.442.932.012.11 1.401.080.890.730.690.570.620.530.530.55100.00IIIII IIIIIlfl11111II111/40C35! (0-—C20)4444(—Iliii0.uI150.110OpeningSize(mm)1010I——I-—WI.I— 00SieveAnalysisSample:004-3Date:Mass(g):606.9Project:IslandCopper-ARDStudyDesc.:cotpre-testDoneBy:DLMesh#OpeningOpeningMassSveMassSveMassSampWt.%Wt.%(Can.)(In.)(mm)(g)+Samp(g(g)PassingRetainedSizeDistribution1.0626.5475.5475.50.0100.000.00004-30.7519524.2570.446.292.377.630.5313.2469.4523.353.983.488.900.3189.5480.3525.545.276.027.46100jiiiiiiti—ñ[I°0.2656.7471.1534.663.565.5310.48IIII!—LI---i.11-Ij.N*TDII_—I ILI40.1874.75469.5526.256.756.179.36.L_III111111IIIIIILllzlII111111IIIIIIIi1’°60.1323.35460.2513.753.547.348.83—-—-—80:09372.36452.2504.151.938.788.57?.E:.o120.06611.7416.8459.742.931.697.08,.I—.—25160.04691.18374.9407.232.326.365.33—.‘—-V.pan2°003310851976660t.-_________300.02340,6324.9353.628.715.024.74:VV400.01650.425322.1345.423.311.183.85V0.10500.01170.3324.2341.917.78.252.920.010.1I10100700.00830.212318.2331.012.86.142.11Openingsize(mm)1000.00590.15293.2303.610.44.421.721400.00410.106289.3296.57.23.241.19%Passing—I—WI%Retained2000.00290.075245.5251.25.72.290.942700.00210.053272.2277.04.81.500.794000.00150.038267.7270.73.01.010.50pan253.2259.36.11.01TOTAL605.8100.0000SieveAnalysisSample:007-3Date:20-Oct-93Mass(g):731.5Project:IstandCopper-ARDStudyDesc.:colpre-testDoneBy:DLMesh#OpeningOpeningMassSveMassSveMasaSampWt.%Wt.%(Can.)(in.)(mm)(g)+Samp(g(g)PassingRetainedSizeDistribution1.0626.5475.5475.50.0100.000.00007-30.7519524.2583.659.491.828.180.5313.2469.4600.0130.673.8317.990.3189.5480.3581.0100.759.9613.87FFR1fLFflITE1ERF!U1T°0.2656.7471.1558.086.948.0011,97E:f4540.1874.75469.5533.964.439.138.87:[Itfllf:1111111—ttti[hhilMo60.1323.35460.2512.051.831.997.13—-[j[1JllU4IftlZ[lulLflhII[3580:09372.36452.2496.644.425.886.11.jIj=IiII11E120.06611.7416.8448.131.321.574.31:JJ-’:1[fflj:HEITII1ftII-25160.04691.18374.9397.122.218.513.06—-[Ufihl—-L1111111—-FF1111—1-I-filL200.03310.85354.1378.924.815.093.42i:1 HIIEFUII1ll1.l5pan356.8471.3114.5=tffl:FB141:T1=riiiii300.02340.6324.9343.418.512.552.55III11EElHt1111flillF400.01650.425322.1338.015.910.362.19-L11iJ1I._.-14-141}lf-liTtlEI1TIIF5500.01170.3324.2337.913.78.471.89•o-F’lIHI’+H+-H+I+I—144+H’o700.00830.212318.2330.712.56.751.72OpeningSize(mm)1000.00590.15293.2304.411.25.211.541400.00410.106289.3299.710.43.771.43——Wi.%Passing—4--WI.%Retained2000.00290.075245.5253.88.32.631.142700.00210.053272.2280.78.51.461.174000.00150.038267.7273.15.40.720.74pan253.2258.45.20.72TOTAL726.1100.0000SieveAnalysisSample:010-1Date:25-Oct-93Mass(g):675.6Project:islandCopper-ARDStudyDesc.:coipre-testDoneBy:DL_____________________________________________________Mesh#OpeningOpeningMassSveMassSveMassSampWI.%WI.%(Can.)(in.)(mm)(g)+Samp(g(g)PassingRetainedSizeDistribution010-11.060.750.530.3180.26540.18760.13280.0937120.0661160.0469200.0331pan 300.0234400.0165500.0117700.00831000.00591400.00412000.00292700.00214000.0015pan‘U26.5475.5475.519524.2659.613.2469.4574.09.5480.3545.66.7471.1511.34.75469.5522.73.35460.2509.02.36452.2496.91.7416.8450.31.18374.9401.10.85354.1381.7356.8451.90.6324.9343.40.425322.1337.70.3324.2336.60212318.2328.20.15293.2302.00.106289.3295.90.075245.5251.20.053272.2277.00.038267.7271.6253.2261.6TOTALIliii‘I’llIIIFrC 0 a100.0079.9264.4054.7248.7540.8633.6326.9922.0318.1414.0511.308.997.155.674.363.382.541.821.25iiIii IIIII0.0135,4104.665.340.253.248.844.733.526.227.695.118.515.612.410.0 8.86.65.74.83.98.4674.2ITllhIzr°°zI4nm—141m11‘f-T-flTlWtflTllT5°=1{HIIIIE11iEllllE,n-141111—’-14t11I1E_-111111tttiiit10.0020.0815.519.695.967.897.246.634.973.894.092.742.31 1.841.481.310.980.850.710.581.25100.00TIllll’30TithE511111-401111111111-35(0 C+1111jjjjj-20n’HjAl 0.01IIIlll01lli11111OpeningSIze(mm)10100——WL%Passing—i—Wt.%Retained00 c)SieveAnalysisSample:022-2Date:28-Oct-93Mass(g):391.7Project:IslandCopper-ARDStudyDesc.:HGpre-testSite#2DoneBy:DL______________________________________________Mesh#OpeningOpeningMassSveMassSveMassSampWt.%WI%(Can.)(in.)(mm)(g)+Samp(g(g)PassingRetainedSizeDistribution022-21.0626.5475.5475.50.0100.000.000.7519524.2524.20.0100.000.000.5313.2469.4469.40.0100.000.000.3189.5480.3539.559.284.8615.140.2656.7471.1521.350.272.0312.8440.1874.75469.5517.848.359.6812.3560:1323.35460.2496.636.450.379.3180.09372.36452.2484.832.642.048.34120.06611.7416.8443.126.335.316.72160.04691.18374.9395.020.130.175.14200.03310.85354.1378.724.623.886.29pan356.8450.493.6300.02340.6324.9343.919.019.024.86400.01650.425322.1338.716.614.784.24500.01170.3324.2337.813.611.303.48700.00830.212318.2328.610.48.642.661000.00590.15293.2302.69.46.242.401400.00410.106289.3296.16.84.501.742000.00290.075245.5250.55.03.221.282700.00210.053272.2278.15.91.711.514000.00150.038267.7270.32.61.050.66pan253.2257.34.11.05TOTAL391.1100.00100—-------——________FE,,jhhiF=ZjE=1,1.liii,iiii_IIIiiiiIP1111111Iil?IIIiI___SIlillililI111111,—-t—II-I--Jt-Ili.-—I--4—I-4Ii-lI--—-l—I-l-I—II-II4——i--i_I-Ii-IiIIIlullIIIllIlulI11111110..LLLLLLLLLI.‘‘I”III‘_L.L.LLLL’:EIItt:EU)a--—1—rrrlr,n—ri—I-I,-I,Ir——-l—rl-rI,Ir,—I-—I—pip-ut,——,i_iI_IIIIL,1_I—I—I-4tIIII-.——I—l-I-i--II-III_-.l—_i—I-I,-IIIIt-—-l—t-t-I--IjA-r--—,I-,,,,,ut———I—r,-I--,tin—--r11llItl-—-1-t-t-l-I7In——t--l-I-.t-IlIl-—-P—t--rI—n-Iti-—r.i-iirIuSLILI__LJ_IJLILIL_J_LLLILILI..._LJ_IJLILIIIIuliluIIIIIIIIIIlilillilIIlIlill11111111IIIllillI-,,i.t’t,._ihIll?,,LI_hulhIl_r_l._I‘‘t’1998_:1l:huuII,,:—-L;,:-,—,III,PI1-i;;TFiHF1fiiii0OpeningSize(nan)--IM. %Passing—.-.M.%Retained00 .SieveAnalysisSample:024-1Date:28-Oct-93Mass(g):206.4Project:IslandCopper-ARDStudyDesc.:HCpre-testSite#5DoneBy:DL______________________________________________Mesh#OpeningOpeningMassSveMassSveMassSampWt.%Wt.%(Can.)(in.)(mm)(g)+Samp(g(g)PassingRetainedSizeDistribution1.0626.5475.5475.50.0100.000.000.7519524.2524.20.0100.000.000.5313.2469.4472.32.998.591.410.3189.5480.3533.152.872.9725.620.2656.7471.1508.837.754.6818.2940.1874.75469.5491.221.744.1510.5360.1323.35460.2475.114.936.927.2380.09372.36452.2465.012.830.716.21120.06611.7416.8425.48.626.544.17160.04691.18374.9382.17.223.053.49200.03310.85354.1362.07.919.213.83pan356.8397.440.6300.02340.6324.9330.65.716.452.77400.01650.425322.1327.65.513.782.67500.01170.3324.2328.94.711.502.28700.00830.212318.2322.44.29.462.041000.00590.15293.2297.24.07.521.941400.00410.106289.3292.73.45.871.652000.00290.075245.5248.63.14.371.502700.00210.053272.2274.82.63.111.26400.0.00150.038267.7269.82.12.091.02pan253.2257.54.32.09TOTAL206.1100.00024-1——I-.H4-IH—--.-—rrrn—rrc—C1TrIiii,I1111111I11111111SI11111111I111111--4-I--II-III-—-4I-4IISf-l-I.-CCIIIH——f-.4-4-IHHI11111II4IIll111111111IIIIIIIfrIIII111111I11111111I11111111IIIJIIIIi—_1—4-.199B•IIIrIIIII:fIIIIIIIlIIrryIIl1——r——I—IIrIII-1-rrrIrIII——I,I,rIIIr—-rrnrIn—r1rIII0.1IIIIILl0.010.1110100Op.ningSize(mm)Hz55w19.i.%Re{ak1ej00I-,’SieveAnalysisSample:025-fDate:28-Oct-93Mass(g)255.1Project:IslandCopper-ARDStudyDesc.:HCpre-testSite#6DoneBy:DL_____________________________________________Mesh#OpeningOpeningMassSveMassSveMassSampWt.%Wt.%(Can.)(in.)(mm)(g)+Samp(g(g)PassingRetainedSizeDistribution1.0626.5475.5475.50.0100.000.000.7519524.2524.20.0100.000.000.5313.2469.4469.40.0100.000.000.3189.5480.3511.030.787.9412.060.2656.7471.1506.335.274.1113.8340.1874.75469.5497.728.263.0311.0860.1323.35460.2484.324.153.569.4780.09372.36452.2475.323.144.489.08120.06611.7416.8435.018.237.337.15160.04691.18374.9388.613.731.945.38200.03310.85354.1370.015.925.706.25pan356.8422.365.5300.02340.6324.9336.811.921.024.68400.01650.425322.1332.710.616.864.17500.01170.3324.2332.78.513.523.34700.00830.212318.2326.07.810.453.061000.00590.15293.2300.57.37.582.871400.00410.106289.3294.85.55.422.162000.00290.075245.5248.93.44.091.342700.00210.053272.2276.84.62.281.814000.00150.038267.7270.02.31.380.90pan253.2256.73.51.38025-1Il_luZiZttIibttZrlt41tliI1IZtIIIr!t:tOtl==Cl]oa::1]II]]:1:1:1DC=]:CCDEI——l—l—1-l-lI-IH——I--I-I*I4l4Il—I*I+Il_—--I—l—l-l—II-I—1—rrI]nIl—1II,-nI-,l—;.i-—I—I--II1W—1rri—Irl—II•IlllIlli—iIIIl.4I—1—1111111—I11111II_IlIIIIj__SlIIIIP.IIIIlLII_I.I1.110r1114111I1i1I]IiIilE*14I11i3996—-1—1—1-1-11-114l—44+14141——-l-—I—I—I4-l4-lI-——I—I-l-I-4I-Ic::CUDJLJ.1JIlL.:_LLI00._4_I1Il__i:l_l1-Ui4_I1-:_i.1-l141,I:41:U1tf-.i998rri:CtrI;IIllIr:Ui1rrlIlI:r[rIndll1IC:nl:ClUll——-1—I—rI—IdIIFI•ll4I1—l—I——IrI,-lr-——l—-r—rI-—ItI-J.LLIJLIII__I_I_IJ_I1III.L_I__I_JIIL._J_LLIJLILIL,IIIIIII.II11111I*__IIII)—.11.LIIII11111111I11111111IIprIII\I11111111111l11—rrrIIrIr\II1111111—I111111111111111III111110_i-———I——I1—4———1———4—4———l—l—lIIIIIIIIIIIIIIIIIII00010.1110100OpengSIze(mm)°Passrng-.—M.%RetaiedTOTAL254.5100.00SieveAnalysisSample:027-2Date:28-Oct-93Mass(g)200.2Project:IslandCopper-ARDStudyDesc.:HCpre-testSite#8DoneBy:DLMesh#OpeningOpeningMassSveMassSveMassSampWt.%Wt.%(Can.)(in.)(mm)(g)+Samp(g(g)PassingRetainedSizeDistribution1.0626.5475.5475.50.0100.000.00027-20.7519524.2524.20.0100.000.000.5313.2469.4469.40.0100.000.000.3189.5480.3511.631.384.1615.8410059.94II60.1323.35460.2478.218.052.539.11::I:I:I:1:80.09372.36452.2471.719.542.669.87103996120.06611.7416.8431.514.735.227.44rnrI1600469118374938721232900622iiiirii200.03310.85354.1366.612.522.676.33IIpan356840304621I9983000234063249333586183243511111LILII400.01650.425322.1329.47.314.633.69II-I500011703324233005811692941I1ITTI_flI1I1rrr\-700.00830.212318.2323.04.89.262.430.1‘“II1000.00590.15293.2297.74.56.982.28OpeningSize(mm)1400.00410.106289.3292.73.45.261.72____________________2000.00290.075245.5248.32.83.851.42--Wt.%RetainedI2700.00210.053272.2274.32.12.781.064000.00150.038267.7269.61.91.820.96pan253.2256.83.61.82TOTAL197.6100.0000SieveAnalysisSample:028Date:05-Nov-93Mass(g)2341.8Project:IslandCopper-ARDStudyDesc.:TillComposite-UpperCapsDoneBy:DLMesh#OpeningOpeningMassSveMassSveMassSampWt.%Wt.%(Can.)(in.)(mm)(g)+Samp(g(g)PassingRetainedSizeDistribution2.0050.8643.8643.80.0100.000.001.5038.1586.5842.3255.889.0510.951.0626.5475.5755.9280.477.0412.010280.7519524.2587.162.974.352.690.5313.2469.4556.487.070.623.720.3189.5480.3556.175.867.383.25100026567471155148036394344LICIIIi]&.1I4LrEiF40.1874.75469.5541.772.260.853.09-I1111:-1--:III60132335460253407385769316iTI111111IrITI80.09372.36452.2546.894.653.644.05101E3996120.06611.7416.8509.092.249.693.95•çII-1:,1u‘IrrrITITI/rrTTIlTT1TITITr)rIiillE16004691.18374.9466.091.145.793.90--1-rrr1TTT7-1-r11rTrr11nnrrctT.01£LIITII[—ILIII—IIIUUL—L£LIII—200.03310.85354.1488.7134.640.035.76IIIIII7II111111II1111111TIlTpan356.81293.5936.71Ei;Er:Ilic:ElcI!Ii19983000234063249436011113527476I‘I11-1EL400.01650.425322.1468.5146.429.006.27---1T---5000117033242524720052042858700.00830.212318.2520.6202.411.758.67oIIIIIIIIIIIWO1000.00590.15293.2450.5157.35.026.73OpenlngSlze(mm)1400.00410.106289.3367.678.31.673.352000.00290.075245.5262.416.90.940.72I2700.00210.053272.2283.811.60.450.504000.00150.038267.7274.06.30.180.27pan253.2257.34.10.18TOTAL2335.6100.00Comment:blindingbyfineparticleson40#to140#sieves;thereforeprobablesizemisrepresentation00 00SieveAnalysisSample:029Date:02-Nov-93Mass(g)2878.4Project:IslandCopper-ARDStudyDesc.:TillComposite-L.N.DumpDoneBy:DL_____________________________________________Mesh#OpeningOpeningMassSveMassSveMassSampWt.%Wt.%(Can.)(in.)(mm)(g)+Samp(g(g)PassingRetainedSizeDistribution0292.0050.8643.8643.80.0100.000.001.5038.1586.51105.5519.081.8818.121.0626.5475.5634.1158.676.345.540.7519524.2628.5104.372.693.640.5313.2469.4640.6171.266.725.980.3189.5480.3619.7139.461.854.870.2656.7471.1601.8130.757.284.5640.1874.75469.5573.7104.253.643.6460.1323.35460.2556.195.950.303.3580.09372.36452.2559.9107.746.533.76120.06611.7416.8513.496.643.163.37160.04691.18374.9462.187.240.123.05200.03310.85354.1487.3133.235.464.65pan356.81362.11025.3300.02340.6324.9452.9128.030.994.47400.01650.425322.1460.9138.826.154.85500.01170.3324.2505.3181.119.826.32700.00830.212318.2456.3138.115.004.821000.00590.15293.2413.6120.410.794.201400.00410.106289.3405.7116.46.734.062000.00290.075245.5331.185.63.742.992700.00210.053272.2350.478.21.012.734000.00150.038267.7288.721.00.280.73pan253.2261.17.90.28TOTAL2863.5100.00100LISILl——.2_CCTStIIl——I_.2.44211.21..—..2—C=2.15994:1:r[[31::r:1:1:1]n::::c[[[I]L1IIiI1I.._L.I.I..IJIlII•.1.1.111lIJI__1_t.II_lAIrI1112111I.1paIl1111111111.1I11111I11111II11.1111111II1111111I111111110_J_LLLIIII_/_alL——uu__LLLL3996 0S—I_I.I-LISII7_—A._I_LI4Lila—_L.I.1.111UL—-I—LI-LIII.C—-1rVrrtk#I——t—I-r-Itnit——r1111nr-—-1rVrItiemrrrl1TITIli1nrrmT,lrIrIr—vrrrlrl—IrT1111111111111111nnr—IrrCITA..1..LI-LI/till...I..1_I__IAI_Ill—_i_.111IJLJI...J..1.L.1111II1111111I21111111I1111111111111III1:.::;:::.:.Ill:ntIIFrITIJ-tr.qillrIfrI0.1IIIIIIiII.—l—..l—IIIIIIIIIiiiiiliiii:00.010.1110100OpeningSize(mm)hPassing.2MComment:blindingbyfineparticleson50#to140#sieves;thereforeprobablesizemisrepresentation00190APPENDIX 6 Moisture Contents, Sites 1 through 4 Sample PitsSites I through 4 Sample Pit ProfilesSITE# PROFILE# FROM(m) TO(m) MOISTURE%1 1 0 0.1 1.51 1 0.1 0.5 2.61 1 0.5 1 2.82 1 0 0.3 6.92 1 0.3 0.3 9.33 1 0 0.08 9.83 1 0.08 0.2 2.23 1 0.2 0.5 3.93 1 0.5 1 2.53 2 0 0.08 7.93 2 0.08 0.2 2.73 2 0.2 0.5 3.23 2 0.5 1 4.44 1 0 0.1 4.14 1 0.1 0.3 3.34 1 0.3 0.5 1.84 1 0.5 1 2.7191APPENDIX 7 Leachate Quality Analytical TechniquesDissolved MetalsAppoximately 1.5 litres was filtered through O.45um cellulose nitrate for dissolved metals analyses. Onetwentieth of the total leachate volume was taken from the filtrate and added to a four week compositesample, with the remaining one litre of filtrate becoming the weekly dissolved metals sample. Allsamples were preserved with trace metal grade concentrated nitric acid (8 ml acid per 1000 ml ofsample) before being sent for analysis.pHpH was measured using a Corning combination electrode and Coming 150 pH/ion meter. The electrodewas calibrated using 7.00 and 4.01 buffer solutions immediately prior to sample measurement, andchecked using the 7.00 buffer every five samples measured. The Coming 150 pH/ion meter wasequipped with an automatic sensor which outputs a pH value when the meter estimates that equilibriumwas reached. For leachate pH measurement, a second equilibrium reading was taken after reachinginitial equilibrium to ensure that the meter has recorded a true value. The pH measurement procedurewas altered after week 6 when it was discovered that the electorde was getting coated with a precipitatefrom the leachate. Subsequently, the electrode was briefly immersed in 10% HC1 solution betweensample measurements. This amendment produced more consistent results than previously.EhEh was measured using a platinum and calomel reference electrode. As in the pH measurementprocedure, both electrodes were briefly immersed in 10% HCI between sample measurements to preventprecipitate build-up. A standard +430 mV(cal.) reference solution was measured immediately prior tosample measurements.As in pH measurement, the meter was used in automatic equilibrium sensing mode, and two consecutivemeasurements were made for each sample to ensure that equilibrium had been attained. Results wererecorded in millivolts with respect to the calomel electrode, and Eh with respect to the hydrogenelectrode were calculated using:Eh (mV H°) = Eh (mV cal.) + (430-S) + 244,where S = measured Eh (mV cal.) of +430 mV standardConductivityConductivity was measured using a Brinkmann electrode and Brinkmann 660 Conductometer, or aRadiometer conductivity meter. The Brinkmann meter was calibrated with a commercial standardsolution immediately prior to sample measurement, while the Radiometer meter was calibratedinternally. The electrodes were occasionally soaked in 10% HC1 to prevent excessive buildup ofprecipitate. Results were recorded in mS/cm.192Total AlkalinityTotal alkalinity for samples with pH greater than 4.5 was measured using the 1CM EnvironmentalMethods (1986) procedure. One hundred ml of leachate was titrated with 0.02 N HCI to pH 4.5endpoint. The volume of 0.02 N HCI consumed was recorded and total alkalinity calculated using:Total Alkalinity (mg CaCO3/l)= 50,000 N * Vvswhere: N = normality of HCI (0.02)V = volume (ml) of HCI required to reach pH 4.5V= sample volume (ml)AcidityAcidity for samples with pH less than 6.0 was measured using the 1CM Environmental Methods Manual(1986). Fifty ml of leachate was boiled with five drops of concentrated hydrogen peroxide for severalminutes to oxidize interfering ferrous ions and cooled to room temperature. The solution was titratedwith 0.01 N NaOH until pH remains above 8.3 for at least 10 seconds. The volume of NaOH consumedwas recorded and acidity calculated using:Acidity (mg CaCO3/l)= V*N*5.000Vswhere: V = volume NaOH (ml)N = normality NaOHV= volume of sample (ml) (50.00 ml)SulfateSulfate was measured turbimetrically using a slightly amended procedure to the 1CM EnvironmentalMethods Manual (1986) Leachate was diluted, based on its conductivity to give an estimated sulfateconcentration between 20 and 50 ppm. The one hundred ml aliquot was added to 20 ml of acetatebuffer solution and stirred briefly. Barium chloride was added and the solution stirred for exactly oneminute. A portion of the solution was immediately poured into a 1 cm pathlength spectrophotometer cellwhich was then placed in a Perkin-Elmer Lambda 8 UV/VIS Spectrophotometer. Sample absorbencewith respect to an acetate buffer-distilled water reference solution was recorded at 420 nm after four tofive minutes. Absorbence was used to determine ppm sulfate from a calibration curve.Absorbence was recalibrated every five readings using the reference solution, and a known standard wasusually included in each run.193APPENDIX 8 Leachate Quality Analytical ReplicatesUNIVERSITY OF BRITISH COLUMBIADEPT. OF MINING AND MINERAL PROCESS ENGINEERINGLEACHATE ANALYSIS PARAMETE pHREPLICATE TESTING UNIT: pH unitsDate Sample I.D. Week # RepI.#1 RepL#2 IDELTAI DELTA %I02-Oct-92 1 6.919 7.034 0.115 1.6502-Oct-92 2 2.822 2.799 0.023 0.8202-Oct-92 3 7.278 7.089 0.189 2.6302-Oct-92 4 7.421 7.563 0.142 1.9006-Nov-92 1 8.366 8.350 0.016 0.1906-Nov-92 2 2.579 2.563 0.016 0.6206-Nov-92 3 8.081 8.180 0.099 1.2206-Nov-92 4 7.968 7.943 0.025 0.3107-Dec-92 1 8.283 7.794 0.489 6.0807-Dec-92 2 2.391 2.414 0.023 0.9607-Dec-92 3 8.280 7.957 0.323 3.9807-Dec-92 3 7.911 7.849 0.062 0.7907-Dec-92 4 8.484 8.397 0.087 1.0310-Dec-92 3 14 8.266 8.443 0.177 2.1230-Jan-93 1 20 7.572 7.898 0.326 4.2130-Jan-93 2 20 2.305 2.378 0.073 3.1230-Jan-93 3 20 6.979 7.631 0.652 8.9330-Jan-93 4 20 7.572 7.628 0.056 0.7420-Feb-93 4 24 7.762 7.82 0.058 0.7427-Feb-93 2 25 2.396 2.395 0.001 0.0430-Mar-93 4 29 7.875 7.91 0.035 0.4415-Apr-93 2 31 2.277 2.279 0.002 0.0902-May-93 3 34 8.078 7.663 0.415 5.2711-May-93 4 35 7.865 7.834 0.031 0.3917-May-93 2 36 2.236 2.141 0.095 4.3425-May-93 1 37 8.506 8.498 0.008 0.0907-Jun-93 3 39 8.195 8.170 0.025 0.3114-Jun-93 4 40 7.884 7.901 0.017 0.2212-Aug-93 HC2 1 4.125 4.129 0.004 0.1012-Aug-93 HC6 1 2.469 2.471 0.002 0.0817-Aug-93 HC4 2 2.918 2.918 0 0.0017-Aug-93 HC5 2 2.843 2.816 0.027 0.9524-Aug-93 HC3 3 4.390 4.408 0.018 0.4124-Aug-93 HC7 3 3.345 3.346 0.001 0.0330-Aug-93 HCI 4 7.609 7.576 0.033 0.4330-Aug-93 HC8 4 7.077 7.134 0.057 0.8009-Sep-93 HC5 5 2.826 2.822 0.004 0.1409-Sep-93 HC6 5 2.326 2.321 0.005 0.2214-Sep-93 HC2 6 4.535 4.557 0.022 0.4814-Sep-93 HC4 6 2.672 2.671 0.001 0.04# Duplicates 40Std. Deviation 0.148 1.982X Std. Dev. 0.295 3.95194UNIVERSITY OF BRITISH COLUMBIADEPT. OF MINING AND MINERAL PROCESS ENGINEERINGLEACHATE ANALYSIS PARAMETE ConductivityREPLICATE TESTING UNIT: mS/cmDate Sample I.D. Week # RepI.#1 RepI.#2 IDELTAI IDELTA %02-Oct-92 1 0.551 0.404 0.147 30.7902-Oct-92 2 4.350 4.310 0.040 0.9202-Oct-92 3 0.482 0.596 0.114 21.1502-Oct-92 4 2.390 2.310 0.080 3.4008-Nov-92 1 0.218 0.234 0.016 7.0808-Nov-92 2 2.640 2.630 0.010 0.3808-Nov-92 3 0.292 0.200 0.092 37.4008-Nov-92 4 1.640 1.610 0.030 1.8509-Dec-92 1 0.257 0.261 0.004 1.5409-Dec-92 2 3.940 3.810 0.130 3.3509-Dec-92 3 0.210 0.207 0.003 1.4409-Dec-92 3 2.110 2.210 0.100 4.6309-Dec-92 4 0.235 0.233 0.002 0.8530-Jan-93 2 20 3.93 3.95 0.020 0.5130-Jan-93 3 20 0.18 0.165 0.015 8.7030-Jan-93 4 20 2.18 2.19 0.010 0.4612-Feb-93 3 23 0.23 0.216 0.014 6.2819-Feb-93 4 24 2.09 2.11 0.020 0.9527-Feb-93 2 25 3.34 3.38 0.040 1.1905-Mar-93 1 26 0.3 0.296 0.004 1.3425-Mar-93 3 28 0.225 0.227 0.002 0.8801-Apr-93 4 29 1.308 1.306 0.002 0.1515-Apr-93 2 31 4.49 4.48 0.010 0.2210-May-93 3 34 0.179 0.176 0.003 1.6911-May-93 4 35 0.792 0.797 0.005 0.6317-May-93 2 36 4.330 4.360 0.030 0.6925-May-93 1 37 0.271 0.273 0.002 0.7407-Jun-93 3 39 0.184 0.182 0.002 1.0914-Jun-93 4 40 0.539 0.556 0.017 3.1112-Aug-93 HC2 1 1.470 1.460 0.010 0.6812-Aug-93 HC6 1 3.610 3.640 0.030 0.8317-Aug-93 HC4 2 2.180 2.180 0.000 0.0017-Aug-93 HC5 2 2.440 2.440 0.000 0.0024-Aug-93 HC3 3 0.241 0.241 0.000 0.0024-Aug-93 HC7 3 0.755 0.760 0.005 0.6630-Aug-93 HCI 4 0.151 0.150 0.001 0.6630-Aug-93 HC8 4 0.354 0.393 0.039 10.4409-Sep-93 HC5 5 1.890 1.900 0.010 0.5309-Sep-93 HC6 5 3.930 3.960 0.030 0.7614-Sep-93 HC2 6 0.199 0.196 0.003 1.5214-Sep-93 HC4 6 2.520 2.310 0.210 8.70# Duplicates 41Std. Deviation 0.047 7.962X Std. 0ev. 0.095 15.92195UNIVERSITY OF BRITISH COLUMBIADEPT. OF MINING AND MINERAL PROCESS ENGINEERINGLEACHATE ANALYSIS PARAMETE EhREPLICATE TESTING UNIT: mVDate Sample l.D. Week # Repl.#1 Repl.#2 IDELTA1 IDELTA %I33916 1 274.0 279.6 5.6 2.0208-Nov-92 2 579.8 574.0 5.8 1.0108-Nov-92 3 288.8 275.9 12.9 4.5708-Nov-92 4 259.0 287.4 28.4 10.4009-Dec-92 1 376.4 391.0 14.6 3.8109-Dec-92 2 671.0 613.2 57.8 9.0009-Dec-92 3 366.2 327.0 39.2 11.3109-Dec-92 4 358.5 369.2 10.7 2.9430-Jan-93 1 20 293.3 306.9 13.6 4.5330-Jan-93 2 20 533.7 530.4 3.3 0.6230-Jan-93 3 20 315.0 286.9 28.1 9.3430-Jan-93 4 20 260.4 274.4 14.0 5.2430-Jan-93 4 20 630.8 615.3 15.5 2.4915-Feb-93 3 23 575.5 553.6 21.9 3.8820-Feb-93 4 24 320.6 319.2 1.4 0.4405-Mar-93 1 26 285.4 287.6 2.2 0.7725-Mar-93 3 28 313.1 324.6 11.5 3.6101-Apr-93 4 29 321.4 278.8 42.6 14.2015-Apr-93 2 31 563.7 558.3 5.4 0.9602-May-93 3 34 326.0 345.2 19.2 5.7211-May-93 4 35 282.6 287.8 5.2 1.8217-May-93 2 36 592.8 591.5 1.3 0.2225-May-93 1 37 503 527 24.0 4.6607-Jun-93 3 39 546 582 36.0 6.3814-Jun-93 4 40 586 584 2.0 0.3412-Aug-93 HC2 1 593 610 17.0 2.8312-Aug-93 HC6 1 758 758 0.0 0.0017-Aug-93 HC4 2 757 762 5.0 0.6617-Aug-93 HC5 2 770 769 1.0 0.1324-Aug-93 HC3 3 685 653 32.0 4.7824-Aug-93 HC7 3 713 720 7.0 0.9830-Aug-93 HCI 4 548 569 21.0 3.7630-Aug-93 HC8 4 623 682 59.0 9.0409-Sep-93 HC5 5 700 701 1.0 0.1409-Sep-93 HC6 5 806 806 0.0 0.0014-Sep-93 HC2 6 654 638 16.0 2.4814-Sep-93 HC4 6 745 745 0.0 0.00# Duplicates 37Std. Deviation 15.7 3.652X Std. Deviaton 31.3 7.30196UNIVERSITY OF BRITISH COLUMBIADEPT. OF MINING AND MINERAL PROCESS ENGINEERINGLEACHATE ANALYSIS PARAMETE AcidityREPLICATE TESTING UNIT: mg CaCO3/IDate Sample I.D. Week # Repl.#1 Repl.#2 IDELTAI IDELTA %I10-Oct-92 2 2058 2040 18 0.8818-Nov-92 2 1852 1813 39 2.1304-Jan-93 2 17 1840 1910 70 3.7311-Jan-93 2 18 2440 2510 70 2.8308-Feb-93 2 22 2285 2384 99 4.2427-Feb-93 2 25 1645 1570 75 4.6716-Apr-93 2 31 2680 2605 75 2.8417-May-93 2 36 2090 2110 20 0.9512-Aug-93 HC6 1 1465 1510 45 3.0317-Aug-93 HC4 2 835 915 80 9.1424-Aug-93 HC3 3 10 10 0 0.0024-Aug-93 HC7 3 154 144 10 6.7130-Aug-93 HC8 4 0 9 909-Sep-93 HC5 5 645 620 25 3.9509-Sep-93 HC6 5 2430 2430 0 0.0014-Sep-93 HC2 6 20 10 10 66.6714-Sep-93 HC4 6 610 1080 470 55.62# Duplicates 17Std. Deviation 109 20.032X Std. Dev. 218 40.05197UNIVERSITY OF BRITISH COLUMBIADEPT. OF MINING AND MINERAL PROCESS ENGINEERINGLEACHATE ANALYSIS PARAMETER AlkalinftyREPLICATE TESTING UNIT: mg CaCO3/IDate Sample I.D. Week # RepI.#1 RepI.#2 IDELTAI IDELTA %I10-Oct-92 1 105.5 107.0 1.5 1.4110-Oct-92 3 99.5 94.0 5.5 5.6810-Oct-92 4 193.0 196.0 3 1.5418-Nov-92 1 98.0 107.6 9.6 9.3418-Nov-92 3 76.0 76.0 0 0.0018-Nov-92 4 150.5 149.5 1 0.6704-Jan-93 1 17 88.4 88.5 0.1 0.1104-Jan-93 3 17 55.5 56.5 1 1.7904-Jan-93 4 17 105.0 108.0 3 2.8208-Feb-93 1 22 87.5 88.5 1 1.1408-Feb-93 3 22 49.0 50.5 1.5 3.0208-Feb-93 3 22 108.5 108.5 0 0.0008-Feb-93 4 22 128.4 132.0 3.6 2.7605-Mar-93 1 26 89.5 90.0 0.5 0.5625-Mar-93 3 28 53.5 53.5 0 0.0005-Apr-93 4 29 91.0 89.5 1.5 1.6601-May-93 3 34 42.0 42.5 0.5 1.1811-May-93 4 35 93.0 94.0 1 1.0725-May-93 1 37 85.5 87 1.5 1.7407-Jun-93 3 39 42.5 42 0.5 1.1814-Jun-93 4 40 108.5 107.5 1 0.9312-Aug-93 HC8 1 12 13 1 8.0017-Aug-93 HC8 2 9 9 0 0.0030-Aug-93 HCI 4 21 19.5 1.5 7.41# Duplicates 24Std. Deviation 2.1 2.654.3 5.30198UNIVERSITY OF BRITISH COLUMBIADEPT. OF MINING AND MINERAL PROCESS ENGINEERINGLEACHATE ANALYSIS PARAMETER SulfateREPLICATE TESTING UNIT: mg/I0Date Sample I.D. Week # RepI.#1 RepI.#2 IDELTAI IDELTA %I29-Sep-92 2 5750 7000 1250 19.6129-Sep-92 4 1650 1625 25 1.5316-Oct-92 1 100 107 7 6.7616-Oct-92 2 3000 2250 750 28.5716-Oct-92 3 142 146 4 2.7816-Oct-92 4 1600 1575 25 1.5725-Nov-92 1 113 105 8 6.9025-Nov-92 2 4180 4120 60 1.4525-Nov-92 3 96 106 10 9.9025-Nov-92 4 1725 1760 35 2.0115-Dec-92 4 14 1600 1625 25 1.5515-Dec-92 4 14 70 79 9 12.0811-Jan-93 1 18 3800 4050 250 6.3711-Jan-93 3 18 44 58 14 27.4511-Jan-93 4 18 1550 1575 25 1.6021-Feb-93 4 24 1450 1475 25 1.7127-Feb-93 2 25 2550 2450 100 4.0009-Mar-93 1 26 64 64 0 0.0017-May-93 2 36 62 59 3 4.9605-Apr-93 4 29 750 750 0 0.0020-Apr-93 2 31 3600 3900 300 8.0010-May-93 3 34 46 42 4 9.0911-May-93 4 35 330 320 10 3.0817-May-93 2 36 3050 2800 250 8.5525-May-93 1 37 65 60 5 8.0015-Jun-93 3 39 50 48 2 4.0815-Jun-93 4 40 195 160 35 19.7217-Aug-93 HC2 1 870 965 95 10.3517-Aug-93 HC6 1 2800 2800 0 0.0017-Aug-93 HC4 2 1450 1600 150 9.8417-Aug-93 HC5 2 1650 1700 50 2.9924-Aug-93 HC3 3 80 100 20 22.2224-Aug-93 HC7 3 350 350 0 0.0030-Aug-93 HC1 4 48 48 0 0.0030-Aug-93 HC8 4 178 178 0 0.0014-Sep-93 HC2 6 74 80 6 7.7914-Sep-93 HC4 6 1450 1425 25 1.7417-Sep-93 HC5 5 1070 1110 40 3.6717-Sep-93 HC6 5 2900 3200 300 9.84# Duplicates 39Std. Deviation 234.7006082 7.456785232X Std. 0ev. 469.4012165 14.91357046ColumniGeneralParametersCal.Vol.Vol.AverageMoistureMassPumpedLeachateFlowCont.pHEhCond.AlkalinityAciditySulphateWeek(kg)(I)(I)(mI/mm)(wt.%)(mVH)(mS/cm)(mgCaCO3/l)(mgCaCO3/i)(mg/I)164.45.6252.0980.575.107.642.681650264.95.3254.9750.535.957.461.0470600364.63.4753.3700.345.537.050.4999250485.011.17510.7851.116.176.920.5512080564.95.8505.7650.586.046.914530.4610650664.95.5005.3800.556.048.045070.36112100764.83.4503.4150.345.858.024730.5097109864.99.3008.9400.926.048.135120.46109980965.05.6255.4500.566.238.375180.22109971064.75.7005.4200.565.677.904910.31981021164.93.7003.5700.366.048.265070.32981091265.39.3258.9900.956.797.826400.30108711365.05.5505.5700.546.237.796200.26104601465.05.7505.4000.596.238.496010.31102741564.93.5503.4240.355.978.645040.3291841665.18.7508,1641.016.408.64584-0.28112701765.05.7504.8400.496.198.676190.2188621864.95.8255.2700.575.978.055560.259375()1965.03.8003.3230.386.197.985110.278673a.2065.09.1258.9200.906.197.905370.249358E21.65.16,2505.9200.606.408.155440.2510146CD2264.95.0754.7700.525.957.995860.2888662364.93.5003.1800.355.958.025800.3083662464.710.2009.3401.005.748.075440.2994622565.04.5753.7700.466.177.895290.2893682664.95.0755.7500.505.958.005070.309064272.1003.0940.218.095450.316963287.8007.7760.768.165930.338762294.6504.5700.548.124890.2896563065.07.0006.4200.696,168.154890.309064313.7253.6400.377.864920.297972329.6009.3500.847.875600.298762335.0505.0700.508.215410.25284493465.35.9255.1800.586.818.335130.3039066353.7503.2200.378.065520.30476763611.10010.5401.258.365040.31197483765.34.6504.0200.486.818.515270.27185.565385.1254.9200.517.974130.298472394.0504.0300.407.984200.30682854065.510.2259.4001.007.228.175100.2879647Column2GeneralParameters16-Nov-93Col.Vol.Vol.AverageMoistureMassPumpedLeachateFlowCont.pHEhCond,AlkalinityAciditySulphateWeek(kg)(ml)(ml)(mI/mm)(wt.%)(myH)(mS/cm)(mgCaCO3/l)(mgCaCO3/l)(mg/I)160.36.0250.5700.629.502.2016.7732000260.35.7255.3650.579.502.539.102600011500360.33.2503.2350.329.502.685.1152006400461.011.00010.0401.1010.932.824.3549003750560.75.6505.5200.5610.312.707834.0820403200660.94.8754.2600.4810.732.818004.0319803000760.03.2503.2500.328.842.597933.9322303425860.99.3508.8300.9310.732.498113.8820203525960.85.3705.5500.5310.522.588212.64169036001060.85.8255.4700.5810.522.548143.44185035251160.83.9003.7200.3810.522.358243.90229041501261.29.6759.2400.9811.382.489213.72209037401360.95.5505.4200.5410.732.419153.94177035501461.05.8505.2000.6010.942.388094.24200039001560.8,3.7503.5260.3710.472.268294.43226043501661,08.8258.3661.0210.942.248263.72223035251760.85.9005.1600.5010.472.208293.73184032751860.85.5254.8700.5410.472.378413.72247039251960.83.6003.3500.3610.472.378204.50283044502060.911.40011.1201.1310.712.387783.93238032002161.06.7256.5200.6410.962.378093.34178025502260.84.8504.6700.5010.452.378333.88228034002360.73.5503.1780.3510.222.308414.43309045002460.812.52512.0401.2310.452.398293.75229032002560.85.7005.9000.5710.452.408393.34161025502661.04.2755.7000.4210.942.368384.0425003250273.4003.1790.342.147674.7930344200288.5008.5860.832.158454.3929754300294.6004.6200.542.258424.09220929503061.06.8006.2200.6710.942.298144.3724003400313.5753.7700.362.288084.49268037503210.2009.6200.892.328304.1321603100336.2505.6200.612.238333.85177027003461.55.9505.5200.5811.882.228604.0921802900353.8003.2200.382.268464.6127703650369.5259.4901.072.248384.33209030503761.05.9255.9200.6110.942.228523.6315352300385.7005.6200.572.278583.8119062500394.0004.0300.392.138584.11228033504060.810.87510.5301.0710.452.358543.517002250CColumn3GeneralParameters16-Nov-93Col.Vol.Vol.AverageMoistureMassPumpedLeachateFlowCont.pHEhCond.AlkalinityAciditySulphateWeek(kg)(ml)(ml)(mi/mm)(wt.%)(myH)(mS/cm)(mgCaCO3/l)(mgCaCO3/l)(mg/I)163.55.8001.2400.5912.978.142.561800263.75.4005.0100.5413.447.272.12481560363.53.3753.3300.3312.977.300.6580325463.910.90010.4101.0913.907.280.48100125563.65.1004.9300.5113.206.934530.63100100664.15.0504.8400.5014.228.205280.4398140763.94.0503.9800.4013.818.094970.3787139863.79.4259.1400.9313.408.275250.3487100963.84.8004.6500.4713.608.085330.29881041063.85.8005.6200.5713.608.134840.2176981164.03.7503.7200.3614.018.585260.26861011264.29.4759.4900.9614.427.836090.2668621364.05.9255.7700.5714.017.966100.2159491464.06.0505.7000.6214.018.275980.2059501564.0.3.8003.8280.3813.938.635520.3160551664.28.7008.2611.0014.388.335660.0865501764.05.4504.0800.4613.938.765530.1956441864.05.1004.7700.5013.938.185530.1857511964.23.6503.3600.3614.388.035360.2059522064.210.57510.5401.0414.387.635590.184836216426.1256.0700.5814.387.845860.1545332264.24.6254.3200.4814.367.855560.2049472364,13.4503.0550.3414.147.856150.2357662464.212.40011.5901.2214.368.075810.1748442564.04.6004.6500.4613.917.966390.1847452664.24.7755.5000.4714.367.835450.244849273.0852.9370.317.975180.245563287.5257.0940.738.065570.235462293.9503.8200.468.155760.2154563064.46.7506.2700.6614.837.895070.225056313.3253.2800.337.914960.225062328.0256.9090.707.915580.204739336.1005.6200.608.175670.19147463464.46.3006.2200.6214.838.085710.17940.542353.8753.3200.397.965450.20444.3503610.05010.4901.137.775450.17237553764.66.1756.0700.6415.288.185630.1563540386.1005.8200.617.845620.1738.542394.3004.2600.428.25460.18442504064.510.1509.6901.0015.067.815940.1583932Column4GeneralParameters15-Nov-93Cd.Vol.Vol.AverageMoistureMassPumpedLeachateflowCont,pHEhCond.AlkalinityAciditySulphateWeek(kg)(ml)(ml)(mi/mm)(wt.%)(myH)(ms/cm)(mgCaCO3/l)(mgCaCO3I1)(mg/I)I60.86.0001.9650.616.398.022.621750260.86.3255.2100.636.397.842.472401900361.03.3753.1850.336.857.622.111941650461.310.92510.6951.097.547.422.392161575561.24.5754.9000.467.267.344562.401931600661.45.4755.2800.547.677.905292.301931600761.03.2503.2300.326.867.884952.201541600861.49.6009.3400.957.677.835272.191831525961.15.7755.5000.577.067.975031.6417416251061.25.5005.3200.547.267.444991.8815115501161.13.6753.6700.367.068.045572.0412317401261.59.2008.9900.947.677.786202.0818116401361.45.8255.4200.567.677.856032.1113316001461.25.9455.7500.617.268.185322.3913716251561.13.7753.8060.377.108.504932.4413316501661.28.9508.1641.037.348.315542.0814517201761.1.5.7004.7600.497.068.435522.2210517601861.05.4254.9700.536.887.915542.2011615601961.03.7253.3270.376.887.855112.33lii16502061.211.15011.7501.107.327.635042.1912215002161.26.2255.9200.597.347.915382.1010715002261.05.3004.8200.556.667.895972.1810816002361.23.5253.1900.357.307.835782.169815002461.212.02511.8401.187.307.765052.0912914502561.25.7255.9500.577.307.825472.049613502661.24.4755.6000.447.307.756391.92104900273.2353.0940.328.105181.81721150287.5507.9510.747.805501.50111900294.4504.2200.527.885441.31917503061.26.2755.6200.627.307.904961.22107625313.1753.1300.327.894841.2384690329.5009.2540.837.645400.9398420336.1255.6700.607.965570.78983303461.55.9505.6700.587.778.115440.76114.5260353.7503.1700.377.865280.79933303610.4759.8401.187.825260.75115.52003761.66.0005.9200.628.058.245390.59101210385.9755.6200.607.785580.58107230393.9753.9400.398.095580.63882354061.710.80010.4501.068.237.885860.54108.5195416.7506.4200.698.005480.4699140425.4005.1200.548.045360.6199.5195433.0002.9650.307.785250.60792654461.79.1258.6850.908.237.905510.581082100 t’JColumn1DissolvedMetals16-Nov-93WeekAg(mg/I)Al(mg/I)As(mg/I)Ba(mg/I)Be(mg/I)BI(mg/I)Ca(mg/I)Cd(mg/I)Co(mg/I)Cr(mg/I)Cu(mg/I)Fe(mg/I)K(mg/I)Li(mg/I)Mg(mg/I)Mn(mg/I)Mo(mg/I)Na(mg/I)10.260.00136100.00220.0150.0191.8150.060832 30.0530.0008980.0010.00590.00740.532.80.02027.040.0280.0007650.0010.00390.00610.391.80.01719.050.0330.000762<0.00020.00290.00520.361.80.006117.060.0420.0006670.00020.00260.00460.272.00.003715.070.0300.000668<0.00020.00290.00460.362.10.001614.080.0300.000666<0.00020.00270.00610.282.00.001813.090.0270.0006640.00060.00420.00460.311.80.002211.0100.0270.000563<0.00020.00180.00400.211.90.001410.0110.0360.000564<0.00020.00150.00330.232.00.001310.0120.0210.000562<0.00020.00150.00700.191.80.00148.113<0.015<0.20<0.200.044<0.005<0.1055.9<0.010<0.015<0.015<0.010<0.030<2.00.0191.7<0.0050.0457.914<0.015<0.20<0.200.049<0.005<0.1065.2<0.010<0.015<0.015<0.010<0.030<2.00.0191.91<0.0050.0438.215<0.015<0.20<0.200.045<0.005<0.1056.1<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.65<0.0050.0426.916<0.015<0.20<0.200.045<0.005<0.1060.2<0.010<0.015<0.015<0.010<0.030<2.00.0171.77<0.0050.0417.317<0.015<0.20<0.200.044<0.005<0.1051.4<0.010<0.015<0.015<0.010<0.030<2.00.0151.61<0.0050.0566.618<0.015<0.20<0.200.046<0.005<0.1060.9<0.010<0.015<0.015<0.010<0.030<2.00.0151.75<0.0050.0486.519<0.015<0.20<0.200.049<0.005<0.1057.6<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.76<0.0050.0456.820<0.015<0.20<0.200.039<0.005<0.1049.6<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.45<0.0050.0495.221<0.015<0.20<0.200.039<0.005<0.1048.2<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.43<0.0050.0495.322<0.015<0.20<0.200.049<0.005<0.1055.1<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.66<0.0050.052623<0.015<0.20<0.200.053<0.005<0.1056.4<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.77<0.0050.0526.424<0.015<0.20<0.200.044<0.005<0.1058.4<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.6<0.0050.0485.325<0.015<0.20<0.200.05<0.005<0.1055.7<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.74<0.0050.0536.226<0.015<0.20<0.200.042<0.005<0.1051.6<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.53<0.0050.048527<0.015<0.20<0.200.058<0.005<0.1052.1<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.96<0.0050.0587.328<0.015<0.20<0.200.05<0.005<0.1057.9<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.73<0.0050.0475.529<0.015<0.20<0.200.046<0.005<0.1051.5<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.62<0.0050.0495.530<0.015<0.20<0.200.046<0.005<0.1055.8<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.66<0.0050.0495.531<0.015<0.20<0.200.046<0.005<0.1050<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.6<0.0050.0495.332<0.015<0.20<0.200.044<0.005<0.1053<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.52<0.0050.0514.833<0.015<0.20<0.200.045<0.005<0.1043.5<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.49<0.0050.036534<0.015<0.20<0.200.043<0.005<0.1053.6<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.57<0.0050.0364.735<0.015<0.20<0.200.05<0.005<0.1051.8<0.010<0.015<0.015<0.0100.032<2.0<0.0151.66<0.0050.0345.136<0.015<0.20<0.200.039<0.005<0.1048.1<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.34<0.0050.0364.137<0.015<0.20<0.200.036<0.005<0.1043.4<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.26<0.0050.0365.738<0.015<0.20<0.200.05<0.005<0.1051.5<0.010<0.015<0.015<0.0100.04<2.0<0.0151.64<0.0050.037539<0.015<0.20<0.200.044<0.005<0.1052.1<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.64<0.0050.0364.940<0.015<0.20<0.200.038<0.005<0.1049.5<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.38<0.0050.0373.9CColumn1DissolvedMetalsWeekNi(mg/I)P(mg/I)Pb(mg/I)Sb(mg/I)Se(mg/I)Sn(mg/I)Sr(mg/I)Th(mg/I)Ti(mg/I)V(mg/I)W(mg/I)Zn(mg/I)0.0740.0760.0610.0150.0150.0160.0150.0410.00710.00300.0063<0.10<0.010<0.030<0.10<0.005<0.10<0.010<0.030<0.100.016<0.10<0.010<0.030<0.100.011<0.10<0.010<0.030<0.100.016<0.10<0.010<0.030<0.10<0.005<0.10<0.010<0.030<0.100.013<0.10<0.010<0.030<0.100.005<0.10<0.010<0.030<0.10<0.005<0.10<0.010<0.030<0.10<0.005<0.10<0.010<0.030<0.100.008<0.10<0.010<0.030<0.100.006<0.10<0.010<0.030<0.100.008<0.10<0.010<0.030<0.100.013<0.10<0.010<0.030<0.100.006<0.10<0.010<0.030<0.10<0.005<0.10<0.010<0.030<0.10<0.005<0.10<0.010<0.030<0.10<0.005<0.10<0.010<0.030<0.100.009<0.10<0.010<0.030<0.10<0.005<0.10<0.010<0.030<0.10<0.005<0.10<0.010<0.030<0.10<0.005<0.10<0.010<0.030<0.100.008<0.10<0.010<0.030<0.10<0.005<0.10<0.010<0.030<0.100.03<0.10<0.010<0.030<0.100.045<0.10<0.010<0.030<0.10<0.005<0.10<0.010<0.030<0.10<0.005<0.10<0.010<0.030<0.100.03816-Nov-932 3 4 5 6 7 8 9 10 11 12 13<0.020<0.30<0.050<0.20<0.20<0.300.62814<0.020<0.30<0.050<0.20<0.20<0.300.71315<0.020<0.30<0.050<0.20<0.20<0.300.6116<0.020<0.30<0.050<0.20<0.20<0.300.6917<0.020<0.30<0.050<0.20<0.20<0.300.59918<0.020<0.30<0.050<0.20<0.20<0.300.67119<0.020<0.30<0.050<0.20<0.20<0.300.67920<0.020<0.30<0.050<0.20<0.20<0.300.55121<0.020<0.30<0.050<0.20<0.20<0.300.54622<0.020<0.30<0.050<0.20<0.20<0.300.63623<0.020<0.30<0.050<0.20<0.20<0.300.66424<0020<0.30<0.050<0.20<0.20<0.300.61325<0.020<0.30<0.050<0.20<0.20<0.300.63626<0.020<0.30<0.050<0.20<0.20<0.300.56927<0.020<0.30<0.050<0.20<0.20<0.300.69928<0.020<0.30<0.050<0.20<0.20<0.300.63629<0.020<0.30<0.050<0.20<0.20<0.300.61830<0.020<0.30<0.050<0.20<0.20<0.300.63531<0.020<0.30<0.050<0.20<0.20<0.300.59232<0.020<0.30<0.050<0.20<0.20<0.300.59333<0.020<0.30<0.050<0.20<0.20<0.300.58334<0.020<0.30<0.050<0.20<0.20<0.300.59835<0.020<0.30<0.050<0.20<0.20<0.300.62136<0.020<0.30<0.050<0.20<0.20<0.300.52937<0.020<0.30<0.050<0.20<0.20<0.300.47838<0.020<0.30<0.050<0.20<0.20<0.300.62939<0.020<0.30<0.050<0.20<0.20<0.300.61940<0.020<0.30<0.050<0.20<0.20<0.300.543I’JColumn2DissolvedMetals16-Nov-93WeekAg(mg/I)Al(mgJI)As(mg/I)Ba(mg/I)Be(mg/I)Bi(mg/I)Ca(mg/I)Cd(mg/I)Co(mg/I)Cr(mg/I)Cu(mg/I)Fe(mg/I)K(mg/I)Li(mg/I)Mg(mg/I)Mn(mg/I)Mo(mg/I)Na(mg/I)138000.22823.16717001.4690200462 37600.0234300.25141100.26153331544100.0135100.117.6770.1866131152500.00125400.153.5630.32347.61062400.00125500.143700.233171072800.00195600.163.5990.17378.31182400.00195200.143.21100.11357.71092000.00165500.112.71000.12286.19.3102000.00245600.132.91300.11296.59.3112400.00355700.153.31800.12337.210122200.00335100.132.81800.1296.58.113<0.015197<0.20<0.010<0.005<0.104840.1080.5430.0222.64175<2.00.05126.55.64<0.0308.414<0.0152230.22<0.010<0.005<0.104700.1170.5890.0242.88218<2.00.05727.75.93<0.0308.515<0.0152190.27<0.010<0.005<0.104000.1150.580.0322.68243<2.00.05425.85.78<0.0307.716<0.0152190.23<0.010<0.005<0.103790.1060.5710.0282.63249<2.00.054265.77<0.0307.617<0.0151880.21<0.010<0.005<0.103770.1030.4990.0192.27222<2.00.04623.15.11<0.0307.418<0.0152580.26<0.010<0.005<0.103790.1310.6580.0322.97322<2.00.05928.76.41<0.0308.1190.0182950.29<0.010<0.005<0.103870.1530.7470.033.38404<2.00.06832.27.2<0.030920<0.0152030.22<0.010<0.005<0.102950.1140.550.0292.3291<2.00.04924.25.32<0.0306.721<0.015149<0.20<0.010<0.005<0.102610.0930.4130.0221.81223<2.00.03719.34.17<0.0306.2220.015210<0.20<0.010<0.005<0.102990.1110.5730.0342.48374<2.00.06226.65.7<0.0307.7230.0252520.23<0.010<0.005<0.103120.140.6690.0452.87507<2.00.07733.27.2<0.0308.424<00151850.24<0.010<0.005<0.102630.1060.5310.0352.19311<2.00.06531.86.53<0.0307.425<0.015137<0.20<0.010<0.005<0.102310.0790.4190.0281.82234<2.00.04626.75.28<0.0307.226<0.0151700.24<0.010<0.005<0.102330.0960.5080.0352.06336<2.00.05629.35.89<0.0306.927<0.0152220.26<0.010<0.005<0.102530.120.6680.0492.69506<2.00.077387.8<0.0308.828<0.0152100.3<0.010<0.005<0.102380.1240.6430.0492.52475<2.00.08140.28.21<0.030829<0.0151730.23<0.010<0.005<0.102170.1040.5690.0352.23376<2.00.06638.87.77<0.0308.230<0.0151950.25<0.010<0.005<0.102210.1080.6270.0462.42453<2.00.07541.38.23<0.0308.231<0.0151880.27<0.010<0.005<0.102090.1070.5960.0462.3453<2.00.074418.18<0.030832<0.0151650.23<0.010<0.005<0.101970.0940.5720.0422.12400<2.00.06739.77.9<0.0307.733<0.015136<0.20<0.010<0.0050.11550.0860.4520.0341.79306<2.00.0593446.69<0.0307.234<0.015165<0.20<0.010<0.0050.111740.0960.5450.0392.06374<2.00.06838.97.54<0.0307.135<0.015198<0.20<0.010<0.0050.151910.1110.6270.0512.41480<2.00.082468.94<0.0308.136<0.015147<0.20<0.010<0.0050.141550.0930.5110.0311.89352<2.00.07439.37.78<0.0307.237<0.015104<0.20<0.010<0.005<0.101330.0650.3940.0271.51236<2.00.05533.56.52<0.030738<0.015122<0.20<0.010<0.005<0.101420.0650.4350.0351.74297<2.00.069377.2<0.0307.239<0.015150<0.20<0.010<0.0050.111490.0770.5130.0452.03372<2.00.08443.38.41<0.030840<0.015112<0.20<0.010<0.005<0.101300.070.4090.0321.59263<2.00.06938.87.57<0.0307c,IColumn2DissolvedMetals16-Nov-93WeekNi(mg/I)P(mg/I)Pb(mg/I)Sb(mg/I)Se(mg/I)Sn(mg/I)Sr(mg/I)Th(mg/I)Ti(mg/I)V(mg/I)W(mg/I)Zn(mg/I)16102 3110449523621724821917101911221219130.6170.42<0.050<0.20<0.20<0.300.74<0.10<0.010<0.030<0.1016.2140.6870.49<0.050<0.20<0.20<0.300.795<0.10<0.010<0.030<0.1017.4150.6730.67<0.050<0.20<0.20<0.300.671<0.100.011<0.030<0.1018.3160.6550.74<0.050<0.20<0.20<0.300.678<0.100.014<0.030<0.1017.6170.5690.51<0.050<0.20<0.20<0.300.639<0.100.011<0.030<0.1015.4180.730.82<0.050<0.20<0.20<0.300.711<0.100.013<0.030<0.1020.3190.8461.16<0.050<0.20<0.20<0.300.766<0.100.014<0.030<0.1023.1200.5930.77<0.050<0.20<0.20<0.300.558<0.100.016<0.030<0.1016.9210.4520.35<0.050<0.20<0.20<0.300.479<0.100.012<0.030<0.1012.6220.631.01<0.050<0.20<0.20<0.300.602<0.100.015<0.030<0.1017.5230.7851.69<0.050<0.20<0.20<0.300.638<0.100.019<0.030<0.1021.5240.5761.22<0.050<0.20<0.20<0.300.537<0.100.014<0.030<0.1016.7250.4810.53<0.050<0.20<0.20<0.300.486<0.100.011<0.030<0.1012.1260.5581.13<0.050<0.20<0.20<0.300.52<0.100.016<0.030<0.1014.4270.7621.93<0.050<0.20<0.20<0.300.6<0.100.02<0.030<0.1019280.7242<0.050<0.20<0.20<0.300.563<0.100.019<0.030<0.1018.6290.6411.29<0.050<0.20<0.20<0.300.555<0.100.015<0.030<0.1015.6300.7121.72<0.050<0.20<0.20<0.300.584<0.100.02<0.030<0.1016.9310.6841.79<0.050<0.20<0.20<0.300.55<0.100.021<0.030<0.1016.5320.6381.45<0.050<0.20<0.20<0.300.552<0.100.017<0.030<0.1015.1330.530.83<0.050<0.20<0.20<0.300.5070.610.015<0.030<0.1012340.6121.19<0.050<0.20<0.20<0.300.5370.660.018<0.030<0.1013.2350.7071.93<0.050<0.20<0.20<0.300.6141.030.026<0030<0.1015.4360.5751.3<0.050<0.20<0.20<0.300.5060.850.019<0.030<0.1012.6370.4510.48<0.050<0.20<0.20<0.300.4410.530.017<0.030<0.109.61380.4860.73<0.050<0.20<0.20<0.300.4870.620.019<0.030<0.1010.2390.5771.06<0.050<0.20<0.20<0.300.530.750.023<0.030<0.1011.8400.4470.77<0.050<0.20<0.20<0.300.4680.490.019<0.030<0.109.32Column3DissolvedMetals16-Nov-93WeekAg(mg/I)Al(mg/I)As(mg/I)Ba(mg/I)Be(mg/I)Bi(mg/I)Ca(mg/I)Cd(mg/I)Co(mg/I)Cr(mg/I)Cu(mg/I)Fe(mg/I)K(mg/I)Li(mg/I)Mg(mg/I)Mn(mg/I)Mo(mg/I)Na(mg/I)10.1740.00026600.00550.0380.0132.4200.89842 30.0930.00011500.00390.0340.00920.513.80.251540.0170.0001860.00150.0210.00610.332.10.0498.950.0240.0003750.00080.0150.00820.291.90.0158.660.0420.0002850.00080.0130.00610.312.10.00888.370.0180.0002830.00090.0120.00820.382.10.00588.180.0150.0002650.00050.0120.00520.211.50.00375.990.030.0002560.00040.00910.0150.321.40.00415.9100.0120.0002540.00050.00820.00480.281.50.00295.9110.0120.000255<0.00020.00450.00240.371.80.0027.1120.0120.0002430.00020.00340.0390.231.20.00174,913<0.015<0.20<0.200.022<0.005<0.1038.3<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.06<0.0050.0945.214<0.015<0.20<0.200.02<0.005<0.1036.2<0.010<0.015<0.015<0.010<0.030<2.0<0.0150.972<0.0050.0934.815<0.015<0.20<0.200.024<0.005<0.1038<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.05<0.0050.1025.216<0.015<0.20<0.200.016<0.005<0.1031.8<0.010<0.015<0.015<0.010<0.030<2.0<0.0150.784<0.0050.0853.817<0.015<0.20<0.200.019<0.005<0.1034.7<0.010<0.015<0.015<0.010<0.030<2.0<0.0150.945<0.0050.1065.118<0.015<0.20<0.200.025<0.005<0.1039.3<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.07<0.0050.1045.119<0.015<0.20<0.200.023<0.005<0.1038.2<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.06<0.0050.1095.220<0.015<0.20<0.200.015<0.005<0.1028.7<0.010<0.015<0.015<0.010<0.030<2.0<0.0150.674<0.0050.0883.321<0.015<0.20<0.200.015<0.005<0.1025.5<0.010<0.015<0.015<0.0100.048<2.0<0.0150.646<0.0050.0683.522<0.015<0.20<0.200.021<0.005<0.1033.7<0.010<0.015<0.015<0.010<0,030<2.0<0.0150.948<0.0050.0934.923<0.015<0.20<0.200.029<0.005<0.1040<0.010<0.015<0.015<0.0100.04<2.0<0.0151.27<0.0050.0996.524<0015<0.20<0.200.023<0.005<0.1031.2<0010<0.015<0.015<0.010<0.030<2.0<0.0150.859<0.0050.0854.125<0.015<0.20<0.200.023<0.005<0.1031.7<0.010<0.015<0.015<0.010<0.030<2.0<0.0150.918<0.0050.0875.326<0.015<0.20<0.200.023<0.005<0.1031.7<0.010<0.015<0.015<0.010<0.030<2.0<0.0150.891<0.0050.0854.527<0.015<0.20<0.200.027<0.005<0.1037.4<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.16<0.0050.0926.728<0.015<0.20<0.200.031<0.005<0.1037.8<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.15<0.0050.0885.629<0.015<0.20<0.200.029<0.005<0.1035.9<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.04<0.0050.095.830<0.015<0.20<0.200.027<0.005<0.1036.3<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.04<0,0050.0865.531<0.015<0.20<0.200.031<0.005<0.1034.7<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.1<0.0050.0886.132<0.015<0.20<0.200.028<0.005<0.1034.1<0.010<0.015<0.015<0.010<0.030<2.0<0.0150.934<0.0050.0834.933<0.015<0.20<0.200.025<0.005<0.1028.9<0.010<0.015<0.015<0.0100.062<2.0<0.0150.829<0.0050.0674.634<0.015<0.20<0.200.023<0.005<0.1029.2<0.010<0.015<0.015<0.0100.166<2.0<0.0150.788<0.0050.065435<0.015<0.20<0.200.027<0.005<0.1030.7<0.010<0.015<0.015<0.010<0.030<2.0<0.0150.886<0.0050.075.136<0.015<0.20<0.200.019<0.005<0.1023.8<0.010<0.015<0.015<0.010<0.030<2.0<0.0150.605<0.0050.0373.337<0.015<0.20<0.200.017<0.005<0.1022.8<0.010<0.015<0.015<0.0100.064<2.0<0.0150.62<0.0050.0373.838<0.015<0.20<0.200.018<0.005<0.1026.1<0.010<0.015<0.015<0.0100.044<2.0<0.0150.738<0.0050.0384.239<0.015<0.20<0.200.024<0.005<0.1028.8<0.010<0.015<0,015<0.0100.042<2.0<0.0150.872<0.0050.0514.940<0.015<0.20<0.200.017<0.005<0.1024,3<0.010<0.015<0.015<0.010<0.030<2.0<0.0150.686<0.0050.0383.61.40.320.110.0660.0720.0670.0620.040.0350.0320.0350.0370.0290.0240.0290.0210.030.0240.0320.0240.0240.0210.0340.0270.030.0250.0410.0370.0450.0370.0480.0470.0510.0420.0510.0450.050.0430.047Column3DissolvedMetals16-Nov-93WeekNi(mg/I)P(mg/I)Pb(mg/I)Sb(mg/I)Se(mg/I)Sn(mg/I)Sr(mg/I)Th(mg/I)Ti(mg/I)V(mg/I)W(mg/I)Zn(mg/I)2 3 4 5 6 7 8 9 10 11 12 13<0.020<0.30<0.050<0.20<0.20<0.300.155<0.10<0.010<0.030<0.1014<0.020<0.30<0.050<0.20<0.20<0.300.146<0.10<0.010<0.030<0.1015<0.020<0.30<0.050<0.20<0.20<0.300.146<0.10<0.010<0.030<0.1016<0.020<0.30<0.050<0.20<0.20<0.300.125<0.10<0.010<0.030<0.1017<0.020<0.30<0.050<0.20<0.20<0.300.138<0.10<0.010<0.030<0.1018<0.020<0.30<0.050<0.20<0.20<0.300.157<0.10<0.010<0.030<0.1019<0.020<0.30<0.050<0.20<0.20<0.300.151<0.10<0.010<0.030<0.1020<0.020<0.30<0.050<0.20<0.20<0.300.11<0.10<0.010<0.030<0.1021<0.020<0.30<0.050<0.20<0.20<0.300.101<0.10<0.010<0.030<0.1022<0.020<0.30<0.050<0.20<0.20<0.300.131<0.10<0.010<0.030<0.1023<0.020<0.30<0.050<0.20<0.20<0.300.156<0.10<0.010<0.030<0.1024<0:020<0.30<0.050<0.20<0.20<0.300.12<0.10<0.010<0.030<0.1025<0.020<0.30<0.050<0.20<0.20<0.300.124<0.10<0.010<0.030<0.1026<0.020<0.30<0.050<0.20<0.20<0.300.12<0.10<0.010<0.030<0.1027<0.020<0.30<0.050<0.20<0.20<0.300.143<0.10<0.010<0.030<0.1028<0.020<0.30<0.050<0.20<0.20<0.300.143<0.10<0.010<0.030<0.1029<0.020<0.30<0.050<0.20<0.20<0.300.138<0.10<0.010<0.030<0.1030<0.020<0.30<0.050<0.20<0.20<0.300.14<0.10<0.010<0.030<0.1031<0.020<0.30<0.050<0.20<0.20<0.300.131<0.10<0.010<0.030<0.1032<0.020<0.30<0.050<0.20<0.20<0.300.134<0.10<0.010<0.030<0.1033<0.020<0.30<0.050<0.20<0.20..<0.300.12<0.10<0.010<0.030<0.1034<0.020<0.30<0.050<0.20<0.20<0.300.115<0.10<0.010<0.030<0.1035<0.020<0.30<0.050<0.20<0.20<0.300.126<0.10<0.010<0.030<0.1036<0.020<0.30<0.050<0.20<0.20<0.300.1<0.10<0.010<0.030<0.1037<0.020<0.30<0.050<0.20<0.20<0.300.096<0.10<0.010<0.030<0.1038<0.020<0.30<0.050<0.20<0.20<0.300.103<0.10<0.010<0.030<0.1039<0.020<0.30<0.050<0.20<0.20<0.300.114<0.10<0.010<0.030<0.1040<0.020<0.30<0.050<0.20<0.20<0.300.095<0.10<0.010<0.030<0.1000Column4DissolvedMetals16-Nov-93WeekAg(mg/I)Al(mg/I)As(mg/I)Ba(mg/I)Be(mg/I)Bi(mg/I)Ca(mg/I)Cd(mg/I)Co(mg/I)Cr(mg/I)Cu(mg/I)Fe(mg/I)K(mg/I)LI(mg/I)Mg(mgII)Mn(mg/I)Mo(mg/I)Na(mg/I)10.360.00036500.00590.0950.0172.9331.8932 30.490.00026300.00070.0220.0151.4321.34540.50.00026500.00360.0570.0150.99321.32450.0420.00036500.00060.0240.010.77311.21960.0060.00036500.00020.0220.010.7310.841670.0150.0002640<000020.0160.00850.72300.481580.0860.0002640<0.00020.0270.00610.62260.341290.0390.00026400.00030.0230.0030.65210.1510100.0480.0002640<0.00020.0090.00610.56180.0679.5110.0090.0001640<0.00020.00710.0030.61170.0379.8120.0180.0001640<0.00020.0120.00610.5140.0457.813<0.015<0.20<0.200.029<0.005<0.10658<0.010<0.015<0.0150.014<0.030<2.0<0.01512.20.023<0.0307.814<0.015<0.20<0.200.026<0.005<0.10617<0.010<0.015<0.0150.014<0.030<2.0<0.0159.810.018<0.0307.115<0.015<0.20<0.200.035<0.005<0.10646<0.010<0.015<0.0150.012<0.030<2.0<0.0158.910.015<0.0307.516<0.015<0.20<0.200.028<0.005<0.10612<0.010<0.015<0.0150.018<0.030<2.0<0.0157.080.014<0.030617<0.015<0.20<0.200.038<0.005<0.10666<0.010<0.015<0.015<0.010<0.030<2.0<0.0156.310.009<0.0306.7180.029<0.20<0.200.035<0.005<0.10686<0.010<0.015<0.0150.0160.037<2.0<0.0155.390.0120.0365.819<0.015<0.20<0.200.039<0.005<0.10646<0.010<0.015<0.015<0.010<0.030<2.0<0.0154.830.0060.0336.420<0.015<0.20<0.200.025<0.005<0.10665<0.010<0.015<0.015<0.010<0.030<2.0<0.0153.610.0060.0384.721<0.015<0.20<0.200.039<0.005<0.10608<0.010<0.015<0.015<0.010<0.030<2.0<0.0152.890.007<0.0305.322<0.015<0.20<0.200.047<0.005<0.10640<0.010<0.015<0.015<0.010<0.030<2.0<0.0152.750.0050.0346.123<0.015<0.20<0.200.06<0.005<0.10638<0.010<0.015<0.015<0.010<0.030<2.0<0.0152.830.0050.0337.924<0.015<0.20<0.200.037<0.005<0.10623<0.010<0.015<0.0150.013<0.030<2.0<0.0151.920.0050.0314.725<0.015<0.20<0.200.044<0.005<0.10604<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.5<0.0050.033526<0.015<0.20<0.200.046<0.005<0.10488<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.35<0.005<0.0305.127<0.015<0.20<0.200.062<0.005<0.10457<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.81<0.0050.032828<0.015<0.20<0.200.048<0.005<0.10395<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.38<0.0050.0315.629<0.015<0.20<0.200.045<0.005<0.10304<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.150.0050.0325.230<0.015<0.20<0.200.052<0.005<0.10300<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.190.0050.0325.831<0.015<0.20<0.200.061<0.005<0.10289<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.45<0.0050.0377.232<0.015<0.20<0.200.049<0.005<0.10213<0.010<0.015<0.015<0.010<0.030<2.0<0.0150.875<0.0050.0374.633<0.015<0.20<0.200.058<0.005<0.10152<0.010<0.015<0.015<0.010<0.030<2.0<0.0150.949<0.005<0.0305.134<0.015<0.20<0.200.059<0.005<0.10161<0.010<0.015<0.015<0.010<0.030<2.0<0.0150.953<0.005<0.030535<0.015<0.20<0.200.075<0.005<0.10154<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.360.005<0.0307.536<0.015<0.20<0.200.059<0.005<0.10132<0.010<0.015<0.015<0.010<0.030<2.0<0.0150.807<0.005<0.0304.637<0.015<0.20<0.200.069<0.005<0.10103<0.010<0.015<0.015<0.010<0.030<2.0<0.0150.91<0.005<0.0305.438<0.015.<0.20<0.200.086<0.005<0.10114<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.16<0.005<0.0306.739<0.015<0.20<0.200.086<0.005<0.10116<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.36<0.005<0.0307.840<0.015<0.20<0.200.062<0.005<0.10110<0.010<0.015<0.015<0.010<0.030<2.0<0.0150.827<0.005<0.0304.641<0.015<0.20<0.200.062<0.005<0.1088.3<0.010<0.015<0.015<0.010<0.030<2.0<0.0150.845<0.005<0.0304.942<0.015<0.20<0.200.095<0.005<0.10102<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.33<0.0050.0357.443<0.015<0.20<0.200.112<0.005<0.10105<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.63<0.0050.03511.244<0.015<0.20<0.200.088<0.005<0.10107<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.08<0.0050.0315.8Column4DissolvedMetals16-Nov-93WeekNi(mg/I)P(mg/I)Pb(mg/I)Sb(mg/I)Se(mg/I)Sn(mg/I)Sr(mg/I)Th(mg/I)Ti(mg/I)V(mg/I)W(mg/I)Zn(mg/I)10.382 30.0740.2650.1360.1270.05480.1490.12100.065110.035120.09413<0.020<0.30<0.050<0.20<0.20<0.304.46<0.10<0.010<0.030<0.100.0614<0.020<0.30<0.050<0.20<0.20<0.304.04<0.10<0.010<0.030<0.100.07515<0.020<0.30<0.050<0.20<0.20<0.303.96<0.10<0.010<0.030<0.100.06416<0.020<0.30<0.050<0.20<020<0.303.48<0.10<0.010<0.030<0.100.09517<0.020<0.30<0.050<0.20<0.20<0.303.49<0.10<0.010<0.030<0.100.0318<0.020<0.30<0.050<0.20<0.20<0.303.06<0.10<0.0100.034<0.100.06219<0.020<0.30<0.050<0.20<0.20<0.302.96<0.10<0.010<0.030<0.100.02120<0.020<0.30<0.050<0.20<0.20<0.302.6<0.10<0.010<0.030<0.100.05821<0.020<0.30<0.050<0.20<0.20<0.302.38<0.10<0.010<0.030<0.100.03222<0.020<0.30<0.050<0.20<0.20<0.302.33<0.10<0.010<0.030<0.100.04323<0.020<0.30<0.050<0.20<0.20<0.302.33<0.10<0.010<0.030<0.100.03124<0.020<0.30<0.050<0.20<0.20<0.302.03<0.10<0.010<0.030<0.100.06725<Q.020<0.30<0.050<0.20<0.20<0.301.82<0.10<0.010<0.030<0.100.0326<0.020<0.30<0.050<0.20<0.20<0.301.51<0.10<0.010<0.030<0.100.01927<0.020<0.30<0.050<0.20<0.20<0.301.46<0.10<0.010<0.030<0.100.00628<0.020<0.30<0.050<0.20<0.20<0.301.26<0.10<0.010<0.030<0.100.01229<0.020<0.30<0.050<0.20<0.20<0.301.01<0.10<0.010<0.030<0.100.00630<0.020<0.30<0.050<0.20<0.20<0.301.03<0.10<0.010<0.030<0.100.00731<0.020<0.30<0.050<0.20<0.20<0.301.01<0.10<0.010<0.030<0.10<0.00532<0.020<0.30<0.050<0.20<0.20<0.300.743<0.10<0.010<0.030<0.10<0.00533<0.020<0.30<0.050<0.20<0.20<0.300.649<0.10<0.010<0.030<0.10<0.00534<0.020<0.30<0.050<0.20<0.20<0.300.627<0.10<0.010<0.030<0.10<0.00535<0.020<0.30<0.050<0.20<0.20<0.300.658<0.10<0.010<0.030<0.10<0.00536<0.020<0.30<0.050<0.20<0.20<0.300.536<0.10<0.010<0.030<0.10<0.00537<0.020<0.30<0.050<0.20<0.20<0.300.489<0.10<0.010<0.030<0.10<0.00538<0.020<0.30<0.050<0.20<0.20<0.300.514<0.10<0.010<0.030<0.10<0.00539<0.020<0.30<0.050<0.20<0.20<0.300.534<0.10<0.010<0.030<0.10<0.00540<0.020<0.30<0.050<0.20<0.20<0.300.478<0.10<0.010<0.030<0.10<0.00541<0.020<0.30<0.050<0.20<0.20<0.300.423<0.10<0.010<0.030<0.10<0.00542<0.020<0.30<0.050<0.20<0.20<0.300.473<0.10<0.010<0.030<0.10<0.00543<0.020<0.30<0.050<0.20<0.20<0.300.518<0.10<0.010<0.030<0.10<0.00544<0.020<0.30<0.050<0.20<0.20<0.300.481<0.10<0.010<0.030<0.10<0.005HumidityCellsGeneralParameters16-Nov-93Vol.Vol.Pro-LeachAddedCollectedWtr.LevelpHEhCond.AlkalinityAciditySulphateCell#DateWeek(I)(I)(mm)(mVH)(mS/cm)(mgCaCO3/l)(mgCaCO3/l)(mg/I)103-Aug-9301.0000.86007.850.40109104-Aug-9300.5000.52607.670.2062104-Aug-9300.5000.48007.700.1955109-Aug-9310.5000.6147.984700.1624.548116-Aug-9320.5000.42807.685420.1822.058123-Aug-9330.5000.51757.425440.1114.534130-Aug-9340.5000.45047.565480.1519.548106-Sep-9350.5000.38917.713840.2026.565113-Sep-9360.5000.469107.765140.1324.035203-Aug-9301.0000.77604.240.62290204-Aug-9300.5000.56404.250.61265204-Aug-9300.5000.47404.250.59290209-Aug-9310.5000.5214.125931.47105870216-Aug-9320.5000.49104.366710.4552215223-Aug-9330.5000.49204.376570.221088230-Aug-9340.5000.44804.426540.212078206-Sep-9350.5000.42814.486280.32<10125213-Sep-9360.5000.508104.546380.20580303-Aug-9301.0000.83205.130.50250304-Aug-9300.5000.61504.320.34158304-Aug-9300.5000.48104.270.34165309-Aug-9310.5000.0825.176240.4925316-Aug-9320.5000.25884.486170.3321125323-Aug-9330.5000.47304.416530.2410100330-Aug-9340.5000.39904.376440.4420198306-Sep-9350.5000.50754.406310.3210140313-Sep-9360.5000.522104.416330.3320150403-Aug-9301.0000.85002.756.1052500404-Aug-9300.5000.51502.813.072550404-Aug-9300.5000.50502.773.262750409-Aug-9310.5000.6272.827662.5422301975416-Aug-9320.5000.45882.927572.189151600423-Aug-9330.5000.48832.827552.2812051790430-Aug-9340.5000.35442.727852.5510901500406-Sep-9350.5000.36402.587832.8312701880413-Sep-9360.5000.41172.677452.3111101425HumidityCellsGeneralParameters16-Nov-93Vol.Vol.Pre-LeachAddedCollectedWir.LevelpHEhCond.AlkalinityAciditySulphateCell#DateWeek(I)(I)(mm)(mVH)(ms/cm)(mgCaCO3/l)(mgCaCO3/I)(mg/I)503-Aug-9301.000086102.895.3548500504-Aug-9300.5000.49802.803.052675504-Aug-9300.5000.52602.842.742175509-Aug-9310.5000.6762.817722.8214402150516-Aug-9320.5000.41322.8477024410451700523-Aug-93305000.49802.847480.249551475530-Aug-9340.5000.19972.947561.39370700506-Sep-9350.5000.34612.827011.906201110513-Sep-9360.5000.506102.847341886101125603-Aug-9301.0000.74002.3812.70190000604-Aug-9300.5000.55802.525.706750604-Aug-9300.5000.48402.455.555750609-Aug-9310.5000.6102.477583.6115102800616-Aug-9320.5000.494102.527233.4413202450623-Aug-9330.5000.50902.647083.0513102150630-Aug-9340.500051182.487753.1414402075606-Sep-9350.5000.37722.328063.9624303200613-Sep-9360.5000.49482.287594.7634804925703-Aug-9301.0000.83102.862.801650704-Aug-9300.5000.52002.932.051350704-Aug-9300.5000.50002.931.911212709-Aug-9310.5000.5013.167300.90195425716-Aug-9320.5000.616163.236940.88192375723-Aug-9330.5000.48403.357200.76145350730-Aug-9340.5000.41223.297120.79124360706-Sep-9350.5000.40663.247180.75115310713-Sep-9360.5000.42053227060.97150450803-Aug-9301.0000.89006.650.77350804-Aug-9300.5000.56107.270.59272804-Aug-9300.5000.50007.040.49245809-Aug-9310.5000.6917.405670.7613.0422816-Aug-9320.5000.593127.005770.469.0220823-Aug-9330.5000.50116.806140.335.55158830-Aug-9340.5000.591147.136230.398.0<10178806-Sep-9350.5000.44876.975580.4175<10140813-Sep-9360.5000.41616.725840.516.010250L’3HumidityCellsDissolvedMetals16-Nov-93CellComp#WeekAg(mg/I)Al(mg/I)As(mg/I)Ba(mg/I)Be(mg/I)BI(mg/I)Ca(mg/I)Cd(mg/I)Co(mg/I)Cr(mg/I)Cu(mg/I)Fe(mg/I)K(mg/I)U(mg/I)Mg(mg/I)111-2<0015<0.20<0.200.04<0005<0.1023.3<0.010<0.015<0.015<0.010<0.030<2.0<0.0154.55123-4<0.015<0.20<0.200.013<0.005<0.1017.4<0.010<0.015<0.015<0.010<0.030<2.0<0.0153.68135-6<0.015<0.20<0.200.029<0.005<0.1021.9<0.010<0.015<0.015<0.010<0.030<2.0<0.0154.47211-2<0.0152.54<0.200.0260.006<0.102140.1210.123<0.0151.750.4272.9<0.0159.48223-4<0.0150.23<0.200.011<0.005<0.1034.30.015<0.015<0.0150.228<0.030<2.0<0.0151.02235-6<0.015<0.20<0.200.011<0.005<0.1058.80.013<0.015<0.0150.193<0.030<2.0<0.0150.814311-2<0.0150.4<0.200.011<0.005<0.1048.90.0260.028<0.0150.383<0.030<2.0<0.0152.17323-4<0.0150.38<0.200.011<0.005<0.1053.60.0270.027<0.0150.407<0.030<2.0<0.0152.19335-6<0.0150.36<0.200.011<0.005<0.1072.50.0270.027<0.0150.397<0.030<2.0<0.0152.06411-2<0.015167<0.20<0.010<0.005<0.101740.1160.223<0.0152.1324.9<2.00.05847.6423-4<0.015151<0.20<0.010<0.005<0.102000.0720.166<0.0152.2246.7<2.00.06833.1435-6<0.015133<0.20<0.010<0.005<0.102410.050.141<0.0151.880.6<2.00.05726.6511-2<0.015195<0.20<0.010<0.0050.121960.1350.255<0.0152.6726.4<2.00.06859.8523-4<0.015102<0.20<0.010<0.005<0.101600.0560.116<0.0151.6227.9<2.00.04526.2535-6<0.01579.4<0.20<0.010<0.005<0.102120.0430.082<0.0151.2721.3<2.00.03824.4611-2<0.015125<0.20<0.010<0005<0.103280.0370.2140.0763.53192<2.00.07365.16234<0.01578.4<0.20<0.010<0.005<0.102110.0170.160.0542.47247<2.00.04530.7635-60.0321310.35<0.010<0.005<0.103050.0320.3620.13.76819<2.00.06141.6711-2<0.01521.3<0.20<0.010<0.005<0.1099.30.030.09<0.0150.6241.84<2.00.028.94723-4<0.01514.9<0.20<0.010<0.005<0.1080.80.0210.06<0.0150.4521.17<2.00.0176.48735-6<0.01514.3<0.20<0.010<0.005<0.101410.0210.062<0.0150.4811.22<2.00.0156.92811-2<0.015<0.20<0.200.04<0.005<0.10139<0.010<0.015<0.015<0.010<0.030<2.0<0.0153.68234<0.015<0.20<0.200.025<0.005<0.1071.2<0.010<0.015<0.015<0.010<0.030<2.0<0.0151.62835-8<0.015<0.20<0.200.025<0.005<0.10130<0.010<0.015<0.015<0.010<0.030<2.0<0.0152.2HumidityCellsDissolvedMetals16-Nov-93CellComp#WeekMn(mg/I)Mo(mg/I)Na(mg/I)NI(mg/I)P(mg/I)Pb(mg/I)Sb(mg/I)Se(mg/I)Sn(mg/I)Sr(mg/I)Th(mg/I)Ti(mg/I)V(mg/I)W(mg/I)Zn(mg/I)111-20.022<0.030<2.0<0.020<0.30<0.050<0.20<0.20<0.300.103<0.10<0.010<0.030<0.100.008123-40.012<0.030<2.0<0.020<0.30<0.050<0.20<0.20<0.300.079<0.10<0.010<0.030<0.100.007135-60.012<0.0302.5<0.020<0.30<0.050<0.20<0.20<0.300.097<0.10<0.010<0.030<0.100.006211-24.55<0.0303,82.46<0.30<0.050<0.20<0.20<0.301.04<0.10<0.010<0.030<0.1017.5223-40.491<0.030<2.00.406<0.30<0.050<0.20<0.20<0.300.153<0.10<0.010<0.030<0.101.97235-60.387<0.030<2.00.367<0.30<0.050<0.20<0.20<0.300.175<0.10<0.010<0.030<0.101.6311-20.999<0.030<2.00.591<0.30<0.050<0.20<0.20<0.300.25<0.10<0.010<0.030<0.103.94323-41<0.030<2.00.641<0.30<0.050<0.20<0.20<0.300.272<0.10<0.010<0.030<0.104.01335-60.946<0.030<2.00.694<0.30<0.050<0.20<0.20<0.300.252<0.10<0.010<0.030<0.103.81411-233.3<0.030<2.01.15<0.30<0.050<0.20<0.20<0.300.232<0.100.0310.058<0.1018.7423-421.7<0.0302.50.784<0.30<0.050<0.20<0.20<0.300.3<0,100.050.037<0.1010.9435-616.7<0.0302.40.3990.43<0.050<0.20<0.20<0.300.26<0.100.054<0.030<0.107.29511-241.1<0.030<2.01.15<0.30<0.050<0,20<0.20<0.300.257<0.100,0330.065<0.1023.552‘3-417.2<0.030<2.00.476<0.30<0.050<0.20<0.20<0.300.227<0.100.0350.034<0.109535-615.6<0.030<2,00.422<0.30<0.050<0.20<0,20<0.300.208<0.100.0220.03<0.106.37611-216.3<0.030<2.01.440.64<0.050<0.20<0.20<0.300.152<0.100.2530.054<0,106.42623-47.58<0.030<2.00.7310.85<0.050<0.20<0.20<0.300.086<0.100.2390.063<0.103.76635-610.5<0.030<2.01.075.38<0.050<0.200.26<0.300.069<0.100.6770.075<0.106.13711-21.99<0.030<2.00.34<0.30<0.050<0.20<0.20<0.300.073<0.10<0.010<0.030<0.104.68723-41.43<0.030<2.00.266<0.30<0.050<0.20<0.20<0.300.058<0.10<0,010<0.030<0.103.35735-61.51<0.030<2.00.297<0.30<0.050<0.20<0.20<0.300.064<0.10<0.010<0.030<0.103.58811-20.113<0.0304.9<0,020<0.30<0.050<0.20<0.20<0.300.842<0.10<0.010<0.030<0.100.007823-40.046<0.0302.3<0.020<0.30<0.050<0.20<0.20<0.300.435<0.10<0.010<0.030<0.100.005835-60.047<0.0303.1<0.020<0.30<0.050<0.20<0.20<0.300.543<0.10<0.010<0.030<0.100.007-UniversityofBritishColumbiaDepartmentofMiningandMineralProcessEngineeringIslandCopper WasteRockColumnTestsC-)0 0 1.PoreGasAnalysisResultsDate:28-Mar-94o.:10J11.:0j0.1 1.:C11.3. 10.18.:0.:18.’0.1220.0.0.1620.0.1920.0.0.390.1419.20.11.0.370.1319.19.1.0.390.10IMol%02Mol%C02Column#Distfromtop(rTlweek39IWeek40Week41Week42Week43IWeek44July28week39IWeek40Week41Week42Week43Week441July2810.220.20.50.030.0010.520.20.50.030.0010.8219.70.150.1511.1119.70.220.2311.4220.00.260.3411.7220.00.240.342495D32 B--9 032B34I3B41I7472700.219.019.018.619.619.120.320.71.0.080.070.080.110.040.300.516.316.616.618.017.818.9202.140.280.210.250.290.190.690.815.415.716.017.517.518.019.41.0.450.400.460.560.390.961.14.315.015.416.716.817.418.81.0.660.640.700.760.641.141.413.514.515.116.716.817.518.41.0.990.870.840.820.801.231.713.413.615.016.616.717.818.21.1.101.000.990.980.961.22ir-CMP021.021.021.021.021.021.1210.050.070.040.030.040.040.0419•4I 9.1.0.340.2319i21.0.1020.0.100.180.160.272.773.0.4010.480.0.10216APPENDIX 11 Beach Dump CharacterizationProportions of rock in each ARD potential category (Figure 5.6) and the estimated currenteffluent conditions for the Beach dump (Table 5.11) used acid base accounting data from threeholes drilled in 1988. An additional seven holes have since been completed in the Beach dumparea.The entire length of each of the three 1988 drill holes was used for estimating acidity and sulfateconcentrations of insitu water in the Beach dump. However, only the portion of the dump abovemean sea level (1000 feet elevation using Island Copper co-ordinate system) is considered tohave potential for sulfide oxidation and release of metals and net acidity. The remainder,permanently submerged in Rupert Inlet, is not expected to oxidize. Approximately 13 milliontons (11.8 million tonnes) of the total 595 million tons (540 million tonnes) are expected to beabove the 1000 foot elevation level at time of mine closure (Ian Home, pers. comm.). Since1988, Island Copper has routinely monitored water quality from both the Beach dump drill holesand from sea water directly off of the Beach dump face. Results are given in the minds annualenvironmental assessment reports, and will also be discussed in the mine closure plan to bepublished in 1994.BHP (1990) calculated mean NNP values by drill hole using both: i) the entire hole, and ii) theinterval above 1000 feet elevation. However, two sample paired t-test analysis of this dataindicates that there is no significant difference in between mean NNP’s calculated using the twomethods. The Beach dump was constructed using mainly push dumping (Section 2.3.3), andmaterial from each truckload is vertically distributed in moderately steeply dipping two metrewide bands. Therefore, one would not expect a significant variance in acid base accountingresults between upper and lower elevations of the dump.21715 20______________________________________________>-J0ciCl)-200.0< -400Z -600-80a)-100• Mean NNP (kg CaCO3It)Fig. 1 Comparison of Beach dump mean NNP values between the interval above sea level andthe entire drill hole (n= 10 holes)In conclusion, the prediction of acidity and sulfate concentrations of insitu water in the Beachdump done as part of this study could be further refined by using the entire ten hole database.However, use of only those samples above 1000 feet elevation appears statistically unjustified.Column leach testing of Beach dump material, to be initiated at Island Copper Mine in late Aprilor early May 1994, will provide further information on the sulfate, acidity and metal loadingfrom this dump area.-100 -80 -60 -40 -20 0 20Entire Length of Hole

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