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UBC Theses and Dissertations

The ores of Copper Mountain, British Columbia 1933

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TIE CBB5 OF COPPER SIOIKfTAIH A Thesis submitted for the Degree of SASfiG OF ARTS ' . i n the Department of GSOLO.Gy. I HE • US I ViiliS ITI W-BMTlQB COLOMBIA A p r i l , I9BS I. IEKIGBUGTIQK AND ACKHOV/JuBDGSiKJiTS. ........................... I I I . TOPOGRAPHY.. „............................... ..................... 3 I I I . GEOLOGY. o 5 Geological n i s t o r y . , . , . . . , . . 5 B . . . » . . « . » . « . . . » . » < » . » t o 5 Local Geology* ...................................... •» 6 (a ) Older Roclcs.»......................... 6 (b) Stocks-phases.......................... 8 (c} Other Int rusives...................... 10 {d) I3strusives............................ 14 I?. ORE DEPOSITS........... . .14 (a ) Structure......................................... 14 (b ) Fracturing....................................... 17 (o} Relation to Copper Mountain Stock................20 (dj Composition: Ore. 22 Gangue......................... ..•.....» 24 Al t e r a t i o n . . . ..................24 (e) Mineralogy ami Para genesis.......................25 ilypogene i'jinei'ai i za tion,»............ 30 Supergene Enriabsent............... S3 {fj Origin........... .................43 7. SUMMARY, COECJLUSIOSfS. <;..... .............. 46 Bibliography........................48 ILLUSTRATION Page Plate I. Index Map of B r i t i s h Columbia „. ................. I Plate I I . Geological and Topographical Map of Copper ilountain Area... ..........in folder at ba Plate I I I . Cross -flection aJ o-",.y l i n e .'•'> of Geological i2ap........ ..... 9 Plate IV. Photograph of 3imilkameen Hiver Valley. 4 Plate ¥. Photograph of G1OT.V-.HO1G and "Mine Dyke" .12 Plate VI. Fig . I. Photograph of Glory-Hole and v e r t i c a l l y dipping "Dylce".... 13 Pig, 2. Photograph of Glory-Hole and G l a c i a l Debris..........,.,«. 13 Plate VII. Plan and Cross Sections of Copper fountain Orebodios...... 16 Plate V I I I . Photograph showing Practtires i n the Ore..•.»•».««..••.... ...18 Plate IXo Camera Lucida Drawing showing'relation betv/eon Bornite and Pe^patttio Material i n i'ractures..... . . . . 2 i Plate A« P i g . I. Camera Lucida Drawing, Hematite l a t e r than ilagnetite..... .29 Pi g . 2. Camera Lucida Drawing, Blades of. Hematite i n Gangue.......29 Plate XI. _ P i g . I. Camera Lucida Drawing, Calcite l a t e r than Bomite.........31 PIg B 2. Camera Lucida Prav;ing„ Calcite l a t e r than r.!a<?net-ite.......31 -Plate XII, Pig. I. Camera Lucida Drawing, Calcite l a t e r than chalcopyrite... .32 Pig . 2. Camera Lucida Drawing, Calcite l a t e r than Hematite,.......32 Plate X I I I . . . . . Pig . I . Photomicrograph, Chalcopyrite l a t e r than isornif e..........34 Pig. 2. Photograph, polished surface of Ore, Blades of Chalcopyrite... Plate XIV. ' • - i i g . I. Camera Lucida Drawing, Chalcopyrite l a t e r than Bornite....35 Pig. 2. Camera Lucida Drawing, Chalcopyrite l a t e r than Bornite.. ..35 Plate XV. , - Pig. I. Photomicrograph, Graphic Intorgrowth of Bornite & Chalcocite.. a o o o a e o o a a o O i Pig. 2. Photomicrograph, Graphic inte r growth of Bornite & Clialcocito.. s o o o e o e o s D « <)? Plate r / I . i^ago Pi g . I. Camera Lucida Drawing, Chalcoeite Vein i n Bornite.....«... 39 Pig . 2. Camera Lucida Drawing, Chalcocite rimnnng Boniite.........39 Plate XVII. P i g . I«'Camera Lucida Drawing, C o v e l l i t e replacing Bornite and Chalcopyri t e.............. o Fig. 2„ Camera Lucida Drawing, Covellite replacing Chalcopyrite...41 Plate XVIII» Pig. I 0 Camera Lucida Drawing, Covellite replacing Chalcopyrite Pi go 2. Camera Lucida Drawing, Co v e l l i t e and Chalcocite replacing Chalcopyrite and B o r n i t e . « a . « . « « 4 2 Plate XIX. F i g . I. Photomicrograph, Covellite replacing Bornite and Chalcopyrite...........44 Pi go 2,, Photomicrograph, rjupergeno Chalcocite c u t t i n g across Chalcopyrite.„......... 44 Plate XX. / Pig. I. Camera Lucida-Drawing, Supergene Chalcopyrite replacing Bomite............... .45 Pig. 2. Camera Lucida Drawing, Supergene Chalcopyrite and Cov e l l i t e In Bornite.. ...»-....«...«*«««, *:«45 BRITISH OOLmiBIA • I. IKT3G J)UCTIOH AlW ACPTJQWHBDGEHMTS. The Copper Mountain Mine whose ores are discussed In t h i s report ia a property belonging to the Granby" Consolidated Mining, Smelting and Power Company. It i s one of the p r i n c i p a l copper deposits i n B r i t i s h Colombia, ranking t h i r d with a production In 1522 of 225 Gi-1,7S8 pounds of copper along with small amounts of gold and s i l v e r . Phe denos.it Is situated ir, the Sitoilkaraeen D i s t r i c t of B r i t i s h Columbia, (Plate I J, twenty miles north of the Canada, United atates boundary and twelve miles south of Princeton with which i t i s connected by a good auto road and a bra is oh of the K e t t l e Valley Railroad both of which pass through Ailenby where the mine ores are concentrated. Princeton i s 150 miles east of Vancouver* i'or a detailed description of the physical features, the geology and economic aspects of the area the reader Is referred to a publication of the Geological Survey of Canada by Dr. V. Dolmage which i s i n the course of publication. The writer Is very grateful to I r . Bolmage under whose supervision this woiv. was done, for help and advice at a l l timea. Acknowledgement i s here matio of the use given the writer by I r . Dolus ge of his manuscripts and maps on the area. It i s fr e e l y admitted thai a considerable amount of the information profered here has teen obtained frora.Ir. DoImage either through personal contact or his manuscripts. Por a l l t h i s tho w r i t e r expresses his thanks.- Appreciation i s also voiced to Mr. Alexander jraith PLATE I. Index map of southwestern B r i t i s h Columbia showing location of Copper v Mountain,  and Vx. C l i f f o r d 3. l o r d f o r f r e .uor.t helpful suggestions. I I . T u? 0 3:1-'-? i FY. The d i s t r i c t th situated i n the oimil^aseen River basin which i s bounded on the south by the Cascade llountain System, on the north by the i n t e r i o r plateaus of B r i t i s h Columbia and on the east by the Okanagan Valley. The .'•iailkamcen basin Is part of the extonsive, comparatively f l a t plateau system which ranges through central B r i t i s r ; Columbia. Elevations range from 3000 to SOCO feet. There i s a gradual r i s e to the south where the plateau merges with the high and ragged Sascade System. The dirailkameen r i v e r i s the chief drainage feature of the area. It r i s e s In the Hosomeen mountains, a part of the Cascade system, and flows north to Princeton where i t unites with the Tnlameen r i v e r . The trend i s then southeast to a point just below the ^9th. p a r a l l e l where the Tulameen flows into «=. Ghanagan r i v e r . The topography i s f a i r l y mature and i s characteristic of a plateau region. It i s succession of f i a t topped ridges with a gentle northward slope. The vaxleys are V shaped except where modified by .glaciers* The larger t r i b u t a r i e s of the hirailicwaeen are separated by rounded spurs, Copper fountain being-e:cempletive of the spur l y i n g between tho oimillcameen on t.-.e west and V.'olf creel:, i t ' s largest tributary on ti..o east. The topography of the area under immediate discussion i s shown on the accompanying geological and topographical mar) (Plate I I , i n i'oMerj, A section along the l i n e A3 (Plate III) shows the nature of tuo f l a t topped rounded spurs and tho V shaped v a l l e y s . (Plate' £V). PLATE IV. Photograph of Similkameen .River • valley showing a t y p i c a l V shaped valley. The Similkameen River i s entrenching i t s e l f i n the bottom. Part of the mine workings can be seen i n the distance on the l e f t . View looking south.  • i l l . GEOLOGY. GEOLOGICAL. HI3xu.il' The Copper fountain d i s t r i c t i s part of a much larger area which i s quite s i m i l a r geologically. This d i s t r i c t i s bounded on the west by the Coast Bange b a t h o l i t a and on the east b~ Dawson's inswap series consisting of Precaribriariechists. The Shuswap series i s overlain by the Cache Creek series consisting of limestone and other sediments with intercalated volcai-.ics. The hieola series of probable T r i a s s i c age i s found above the Cache Cree:-: and consists of voicaaics and a r g i i l i t o s . . The Wolf Creek formation of probable T r i a s s i c age are the oldest rocks encountered In the map area. These rocks occupy alarge part of the area napped, are e n t i r e l y volcanic and are steeply folded along a nortmvest- . sotttheast a s i s . Extending into the Jurasoic are more volcanics and sediments*, These are above the Cache Creek se r i e s . Above these again are a thlc?; series of fine-grained sediments with a few t u f f s , x*anging i n age from Upper t-nrassic to Lower Cretaceous. Batholitlric intrusions on an. Immense scale took place In the period, extending from the l a t e Jurassic to the Tertiary,, These intrusions consisting l a r g e l y of various phases of d i o r i t e were responsible for the folding and elevation"of the older formations and the subsequent recession of ..part.and the retention of the rest of tr.e marine waters. This resulted in continental sediments o-' Lower Cretaceous age being deposited. In Upper Cretaceous time intrusion of b a t l o l i t h s was again the order of events with contemporaneous folding and In some cases overturning of the older roo>*:s. This orogenic movement was' followed, by erosion, extrusion of lavas and deposition of some continental Tertiary sediments.. The•Iliocene period was characterised by further orogeny, intrusions of ba~h.pl i t l i s and extrusions taking place on a.-large scale«> These various periods of intrusi v e and extrusive a c t i v i t y are shown to a certain i n the map area,.. The older Volf Creek volcanics are intruded by several augite-diorite stocks, the largest and most important economically being the Copper Mountain stock, part of which i s exposed i n the west central part of the sheet* The Voigt stoctt. occupies a somewhat smaller area i n the-northeasts This l a t t e r stoc : i s probably connected 'with the Smelter La :e stoc it a small part of which i s exposed ir . the canyon of the Similtomocn r i v e r i n the extreme north. Pefpatite and other d-ise-s ranging i n age from Mesozoic to Tertiary cut ihe uolf Creiak forastion ar.<d the stocks in various places* in the extreme northeast comer i s asmaller area of granite known as the Verde Greek granite.. Post Oligocoae lavas overly the older r o c s i n the northern part of the area*. The thic.t mantle of g l a c i a l m a t e r i a l s shows that i n Pleistocene time glaciers r/ere active over the region. LOCAL SBOLOSY (a) Older Hocks. The oldest roc. .s oncomitored in the map area consist of a series of volcanic.- flo:.vs, t u f f s and breccias and are c a l l e d the Wolf Creek formation* These stocks underly a large part of the area, o-.vjopt for two stocks and some younger volcanics i n the extreme noi*th 0 The beds of th i s formation s t r i k e i n a northwesterly d i r e c t i o n and d i p at steep angles 0 The series varies over the area* i n the south they consist of fine-grained, well bedded and banded dark brown tuff3o Amygdaloidal basalts are exposed in the v i c i n i t y sout& of the Copper ^fountain stock i n the Similkameen canyon. The .Volf Creek formation in the northern part of the 7 TAB! E OF POll-.IATIOES E11A PERIOD PGSEiATicasr LITBOLOOICAL OHAHACTBSISTIOS CE-TOZOIC Alluvium UHC0KF03KITY | PLEI3T0CEKE G l a c i a l D r i f t USCGHFQHMITY J POST 0LIG0C2KE "Tertiary Volcanica" Plows, Breccias, and necks of Enstatite, Andesite and basalt © ; "iline Dykes" P e l s i t e porphyry, quarts porphyry, and Granophyro. POST . . • . OLIGOGEliEV ''Verde Creek Granite" -Granite Pegmatite Dykes Jlonzonite and Syenite Pegmatite. Voigt Stock ' Augite, Diorite, 1 Syeuo- d i o r i t e (orthoclase d i o r i t o j o Smelter Lake Stock Augite, D i o r i t e , Syenc— d i o r i t e (orthoclase diorite)© Orthoclase- A l b l t e pegmatite Copper fountain d <. ~ ~ i . 1— Syenodiorite (orthoclase— d i o r i t e ) jJonsonito. UHCCHFORMm. T Syenogabbro (orthoclase- g?.bbro }« MSSO;;OIC Lost Horse Intusives S t o c s and S i l l s of Augite, D i o r i t e & D i o r i t e Porphyrite* OA •  I M 3DSIVE COBTACT | iVoAEOLuIC ;7olf Creek Pormation Andesite. Basalt, . Trachyte, Breccias, Plows and Tuffs,, 8 map area i s made up largely of ba s a l t i c flows. A phase of this formation composeo. of medium to coarse dark green breccias i s very important i n that i t contains the orebodies of the d i s t r i c t . This phase consists of angular and rounded green to black porphyritic fragments i n a fine grained matrix. Augite and andesine-iabradorite are the dominant minerals with minor amounts of hornblende, biotite and magnetite. Shearing i s intense i n th i s formation and pegmstitic material has been impregnated widely. Dr. Do linage doubtfully correlates these roc :s with hawson's l l i c o l a Series of T r i a s s i c a g e (b) STOOItSo Ptoses, Intruded into the steeply folded wolf Greek formation ore two and perhaps three d i s t i n c t stoe.cs of medium coarse grained-material and d i o r i t i c i n composition. The Yoigt and Sneltor lake stocks are probably one and the same, being connected beneath the Tertiary lava flows* The Copper Mountain stock ;.-hich occupies a large area i n the central po rt i on of the d i s t r i c t mapped i s of prime importance on account of the r e l a t i o n i t bears to the ore deposits. The 'Copper. fountain stock, i s 6 miles long by '6 miles .,ide and str i k e s northwest, i n composition, i t consists of orthociase, microcline, plagioclase, augite, b i o t i t e , hornblende and apatite? a l l i n varying amounts. A feature.of this stock i s i t s d i v i s i o n into three well defined zones consisting of a central core, an intermediate zone and an outer r,one«> These zones are w e l l shown i n the canyon of the SimilkaniGen r i v e r which cuts across the centre of the stock. The three zones(Plate I I I ) markedly d i f f e r both i n texture and composition. Gneissic structures are -common i n certain parts of the stock ana fa u l t s with s n a i l displacement are fre .nent'ly Cross section along l i n e AB as shown on on accompanying geological map, Plate I I (in folderj„ This section shows type of topography with ¥ shaped valleys, the perpendicular nature of the stock and the r e l a t i o n of the orebodies and dykes to the stock.. [See next page). COPPER PfOUNTA/N 4000 . 3SOO 3000 . Z5~00 2O00 _ 4S0O 4-000 3000 asoo 2000 feel- Above Sea Leva COPPER MOUNTAIN A R E A SECTION Sco/e^ , hcr/^.on i~o/ one/ ALONG AS ver/'/co/ ~~ / /nch fo /OOO feef found. The outer zone Is fine-grained and ranges from syenogaboro at the margin to syenodiorite on the inner-edge where i t grades into the intermed- ia t e zone. This 2one i s f a i r l y coarse i n texture and varies from aye-no— . d i o r i t e to moir: suite. The contact between this 2one and the core i s very sharp and tne texture changes to that of pegmatite* Acessory minerals such as augite and b i o t i t o disappear or are present only i n small quantitie and the dominant minerals are those of the feldspar group along with apatite as the acessory. Small amounts of chalcopyrite and bornite are scattered in this aone. ' • The stocks i n the northern part of the area are quite s i m i l a r i n mineral composition to the Copper Mountain stock,but d i f f e r i n that they are uniform i n character. On account of t h e i r homogeniety they are •• probably somewhat l a t e r i n age than the Copper fountain stock. The Volgt stock extends over a f a i r l y wide area i n the northwest part of the area : while the Smelter Lake stock occupies only a very small part i n the canyon of the Similkameen but extends f o r some distance to the north. These two stocks are probably joined beneath the Tertiary lavas which appear to separate them. They consist of dark grey medium-grained angite d i o r i t e or syenodiorite. (cj I&TiSJSlVJJSi. In the northern part of the area i n the v i c i n i t y of Lost Horse gulch are irregular .and poorly exposed intrusions consisting of l i g h t colored augite-diorite and pinkish grey monzonite or syenite. They are la r g e l y in the form of dykes and contain minor amounts of p y r i t e and chalcopyrite. This mineralisation probably originated from the stock magma as did these Intrusives. They are termed the Lost Horse Intnt3i ves and are s l i g h t l y older than the stock. II l a the areas adjacent to the stock are found syenitic pegmatite dykes made up of orthoclase,, a l b i t e , b i o t i t e and auglte along with disseminated bornite and chalcopyrite.• This pegmatitic material has been injected into the sheared and fractured voicanics of the o i f Creek formation i n the form of dykes. Insomuch as the pegmatites cut the stocks they are older, but l i k e the host Horse Intrusives they are si m i l a r i n mineral composition and r e l a t i o n to the stock and thus no doubt of the same o r i g i n . A large number of white and. creamy white granophyre and felsi.te porphyry dykes known as the "Mine Dykes" (Plate V) are p l e n t i f u l i n the area, especially i n the region adjacent to the Copper Mountain and Voigt stocks. They hinder e f f i c i e n t mining to a considerable extent i n the Copper Mountain Mine* These dykes extend for considerable distances, vary width up to 150 feet and divide into branches and come together again. . These dykes trend north and south and dip v e r t i c a l l y as shown In Plate I I I and Plate VI* The texture and composition are quite uniform. They cut the several stocks so are evidently older. The dykes themselves are cut by fine grained amygdaloidal andesite dykes which also cut the stocks* These l a t t e r dykes-are at right angles to the "iline Dykes". A large.body of reddish granite i s intruded into the rocics of the d i s t r i c t , a small part of which extends into the extreme northeast corner of the map area. The granite i s high i n quartz content which distinguishes i t r e a d i ly from the rest of tne roc .s of the region, i t i s termed the Verde Creek granite and i s older than the Voigt stock as i t cuts i t . un. l i t h o l o g i c a l grounds Dr. • Dclmage correlates i t with Cams e l l ' s Otter Oree/. granite of Post Oligocene age. PLATE V. Photograph of glory-hole at the Copper Mountain Mine with large l i g h t colored "Hine Dyke" well shown in the centre of the picture. In the lower part of the photograph fracture and f o l i a t i o n planes are shown. 12 PLATE V. i PLATE VI. i IG. I • Photograph of glory-hole at the Copper Mountain Mine «, The v e r t i c a l dip of the "Mine Dykes" i s brought out i n th i s photograph. PLATE V I . FIG. 2. Photograph of glory-ho1e at Copper Mountain. I.ote raant2e of g l a c i a l debris.  ; Dense fine-grained amygdaloidhl flows and also t u f f s and breccias occur i n the northern part of the area. These overly the '.Volf Greas. formation • unconformable- and outside the area overly •Oligocene sediments conformably. IW • ORE PEP08ITS. . . . (a j STRUCTURE. The f o l i a t i o n and fra c t u r i n g which occurred as a r e s u l t of stresses a f t e r intrusion of the Copper fountain stock created, channels for the passage of the ore bearing solutions. These f o l i a t i o n planes and the fractures control the tenor of the ore to a marked e-.:tont. As the stock slowly cooled pegmatitic material was exuded from the p r a c t i c a l l y congealed magma r e s u l t i n g In the formation of pegmatite dykes which penetrated the " o l f Creek formation. This was followed by the hydrothermal stage and the subsequent deposition of the ore along the fracture and f o l i a t i o n planes. S t i l l l a t e r the "Mine Dykes" -sere intruded and these are d i r e c t l y responsible for the present structure of the ore deposits. • The 'i&iuQ Dykes'' , l a t e r In age than the pegmatite dyses and ore bearing solutions, probably originated, at depth while the parent marjna of the stock was s t i l l l i p o i d . Possibly they followed up fracture planes p a r a l l e l to the stoc.:. to the e a r l i e r pegmatite dykes and the orebodios. These fracture planes might be caused by tension following the cooling and s o l i d i f i c a t i o n of the magna near the stock. The f o l i a t i o n and fracturing extend over a sone several hjmdred feet wide and p a r a l l e l to the length of the stock along the northeast contact. * The dy.:es have cut Into the mineralised breccias of the .Volf Creole formation. They are peculiar i n the way they divide and come together again. On account of this they might be termed "lode dykes" due to t h e i r s i m i l a r i t y to a cha r a c t e r i s t i c lode vein which shows tho same tendencies*. On the surface these dykes divide the mineralized breccias Into a series of orebodies which l i e between the perpendicular walls of the dykes. The mineralisation i s cut o f f at the inter-section of tho dykes* The edge of the mineralization and the walls of the dykes are coincident i n most cases in the immediate v i c i n i t y of the Stock contacts These facts are w e l l shorn i n the plan on Plate 'ill where the orebodies on the surface are outlined. The .orebodies on the number 2 l e v e l are also indicated. These •in most cases l i e d i r e c t l y beneath the surface showings but are much smaller i n size. This gives same of the orebodies a perpendicular form tapering at depth. In the cross sections on Plate ¥11 the r e l a t i o n of the orebodies to the "Hine Dykes" i s depict ecu The dykes have divided the mineralized breccias up Into a number of smaller orebodies. On the fourth and f i f t h ' l e v e l s i n the mine another orebody i s encountered l y i n g against the stoc.-i contact. This orebody has not been.affected by the "Mine Tykes"; i t ' s extent being controlled by the fractures. Two of tiie main orebodies are shown to be continuous from the surface to the f i f t h l e v e l at least in the sections. They are bounded by the "Mine Dykes". These two orebodies were i n a l l p r o b a b i l i t y one complete mineralised sone u n t i l the i n t r u s i o n of the dykes which resulted in.tho .division, into two separate bodies-. The f o l i a t i o n planes l i e p a r a l l e l to the stock while the fractures ID PLATS VII. Plan and cross- sections of Copper Mountain orebodies showing t h e i r r e l a t i o n to the "Mine Pykes" and the contact of the Copper Liountain stock. (See next page)» No-2 (.aw) £/. 3945 lo.2 Lwo( El. 0-3 LBYSI £). J77-9- ND.4-LBVOI EI. 3 5 8 4 - - No.5 Level El. 3384- Sfrucfural Sections A/ong ljne$ AS one/ CO Sho w/rt g Re/ahon o-f Ore Deposits To Copper- frfounTa/n SiocK Osic/ Af/tfe DtjKes 1 I Mine DyXes ^Pegmatite Oy/fes 3e/r/oc& Ore I J J Cu. Aft SfocfT I " | Wo/fCr^KForm. \C<^.\A/o.2Uve/Q> |;>VJ":"v.| Ore m Cross Section GEOLOGY A N D S T R U C T U R E OF O R E DEPOSITS AT COPPER M O U N T A I N MINE Scale I inch = 300 feet are i n a d i r e c t i o n at right angles to these, i t i s believed that the f o l i a t i o n planes formed the l i n e s of weakness by which the "Mine Dykes" made t h e i r way into the mineralised breccias In this v i c i n i t y , The sections on Plate VII c l e a r l y show the r e l a t i o n between the stock contact and the dykes* Adjacent to tho ore deposits but not a f f e c t i n g thorn to any extent are several small f a u l t zones s t r i k i n g north and south. I t i s evident then that the shape, breadth, and pitc h of the orebodies owe t h e i r c h a r a c t e r i s t i c structure to a large degree to the "".line Dyk.es" which have penetrated the mineralized breccias of the -Volf -Cre.ek formation i n this l o c a l i t y . (V-) I'MCTUHES. As a result of some form of stress the breccias of the Wolf Orees formation have been intensely fractured, This fracturing i s sot oaiform- but varies i n in t e n s i t y i n different parts of the formation* Those fractures are v e r t i c a l and normal to the contact of the stock, thus they s t r i k e at right angles to the f o l i a t i o n * Tho fractures are straight and approximately p a r a l l e l to one another (Plato VIII). In width they vary, but most of the.-?- are unite small and do not exceed an eighth of an Inch. In some of tho material studied the fractures were more than an inoh apart and quite regular while i n other specimens the fractures wore extremely close together and short. The fractures are exceedingly Important i n that they provided the channels f o r the ore bearing--• solutions. They allowed the solutions to penetrate to many parts of the breccias. The larger fractures and f o l i a t i o n planes afforded the main channels. while the smaller and more Indistinct ) PLATE VI I I . Massive block of Copper Mountain ore showing p a r a l l e l fractures.  ones permitted the mineral bearing f l u i d s to spread throughout the rock* The copper minerals of the main mineralisation period were deposited i n these fractures, hence the grade of the ore depends on the size of the fractures and the frequency with which they occur,, The fractures are. not confined to the ivolf Creek formation alone but are found also i n the Copper Mountain Stock, p r i n c i p a l l y i n tho v i c i n i t y of the ore deposits. They are also found i n the intermediate i f zone of the stock and near the pegnatite-intermediat o sons contact* These are mineralised, to a certain extent also, A p e c u l i a r i t y of the fracture system i s the fact that It i s almost ent i r e l y absent i n some places, while Immediately adjacent , the opposite Is true. In the cross sections on Plate VII the unraineralized portions of t the ToIf Creek formation between the dykes and adjacent to the stock contact are found to be free from fractures. The fractures are e a r l i e r than the period of ore deposition and •somewhat l a t e r than the stock intrusion*- Tho stresses that caused them were probnhly active over a period of 'time. The period of stress that • produced the wider and more constslant fractures feeing somewhat strongar K than that portion of the period which produced the smaller ones-. The fact •that the fracture system i s i n aones i s also indica t i v e of a longer period -of-stress.. •-, A large number of the fractures are f i l l e d with pegmatitic material. This i s particular!!;- true of the larger ones and the material Is essen t i a l l y felspar(orthoclase) and mica with minor amounts of epidote, augite and apatite. Quartz Is e n t i r e l y absent. Thus tho pegaatitle material i n tho fractures i s s y e n i t i c * . . Concentrated along the centre of the pegmatite veinlets which f i l l the fractures are important copper minerals consisting of. bomito,, chalco- p y r i t e , chalcocitc, and c o v e l l i t e . These minerals which are formed more or less i n a l i n e down tho centre of the vein are of s l i g h t l y l a t e r age (Plate IX) than the pegmatite material as they extend beyond the pegmatite veins and farther into the fractures. The smaller fractures have not been intruded by the pcgmatltie f l u i d s but they are mineralised with bornite and ehaleapyrite. hater c a i c i t e veinlets also penetrated these fractures, ohiefly down the centre, and In many places extended beyond the pegmatite*, {c) HihJ.TlJS TO COFPiki wmtfATB STOCit. The ore bodies of tho Copper nountain kine occur adjacent(Plates I I I ar.d VIIj to the contact of the Copper .fountain stock in breccias of the Wolf Creek formation. They are situated on the northeast side of the. stock and aro i n the form of several d i s t i n c t orebodiea which are .p a r a l l e l , both to each other and to. the stock contact. Pallowing ti.e Intusion of the Copper kkcjisala »i:ocv. and previous to i t ' s hydrothermai stage, f o l i a t i o n and fracturing' look jl-ioo „< result of stresses. I t i s c l e a r l y evident that these minor structures wore formed a f t e r the Intrusion, and as the. ore i s largely confined, to them, they-.are thus previous -to the hydro th'eraal stags of the stock which was responsible f o r the ore deposition. That the orebodies are genetically related to the stock i s indicated by the close proximity between these bodies and the stock, Tho presence of psgmatitic material i n the fractures i n the breccias which i s of the same composition as the pegmatite core of the stock, indicates a common o r i g i n . Tho absence of quartz i n both of these i s s i g n i f i c a n t . L further PLATE IX* Camera lucida drawing, of Copper k'ountain ore showing hypogene bornite. The deposition of the bornite has been controlled by the pegmatitle material i n the fractures, i--'sgnif ication. X 54. ?UTK IX i n d i c a t i o n ox the genetic relationship i s the presence of bomito and chalcopyrite i n the fractures i n the stock, the pegmatitic core, and as- ore minerals i n the breccias. (d) COMPOSITION . OilE. The ore at tho Copper Houutain Mno consists of mineral!sod breccias of the Wolf Creek formation. These breccias are andesitic and ba s a l t i c i n composition with quartz e n t i r e l y absent. The deposit Is of the contact metamorphic type and grades s l i g h t l y moro than 2;.C« Ws has been stated t h i s git;de depends on the number and the size of the fractures. The breccias adjacent to the. a too: contact have been impregnated with large'-quantities of b i o t i t e and augite. under the microscope the rock i s seen to consist of feldspars and augite into which have boon introduced large quantities of b i o t i t e andprobably some l a t e r augite. This- zone of b i o t i t e and augite i s not uniform, some parts being almost free from the impregnation while In other parts the b i o t i t e and augite are so Intense that i t i s d i f f i c u l t to interpret the o r i g i n a l characters of the rook. It occurs previous to the fr a c t u r i n g at the b i o t i t e and augite are absent from the fractures* , Idssemincted i n the biotitlr.e'd rock i s found bornite and ohalco- p y r i t e along with magnetite. The magnetite may be an o r i g i n a l constituent of the rook but I t i s more proh&blo that It was introduced into tho roek along with the bornite, chalcopyrite, b i o t i t e and augite. The bornite and chalcopyrito are Important but without the l a t e r period of metallisation they would not be i n su f f i c i e n t quantities to-make the breccias an ore. Following the period of fra c t u r i n g and f o l i a t i o n , Into the main rock mass to a - certain extent, and especially into the fractures was intruded pegniatitic material and copper .bearing solutions* The pegnatitic material was the f i r s t to enter the fractures. It consisted of a l b i t e , oligoclase, microcline, mica, epldote, angite and apatite. -3orne of" these minerals along with the a l t e r a t i o n products have penetrated t-.e rook on each side of the fractures, especially the larger ones. The result i s a l i g h t colored zone. These zones are white to green- i s h i n color adjacent to the fractures, while a J- of an inch away the color has gradually faded and the zone appears to merge with the rest of the rock. The minerals i n this zone are very f i n e and d i f f i c u l t to determine. It appears as i f they have l i t e r a l l y plugged the rock as copper minerals, •magnetite and hematite are almost e n t i r e l y absent. " l i g h t l y l a t e r than the introduction of the pegmatitic material and a f t e r i t had cooled slightly ard contracted to a certain extent, copper r i c h tenuous solutions followed along tho fractures and down the centre of the veinlets that f i l l the fractures and deposited Important minerals,, The The mineralisation consists of. bornite, chalcopyrite, chalcocite, hematite and c o v e l l i t e , These minerals are concentrated along the centre of the pegmatites In a f a i r l y continuous line*. • Sisal 1 amounts of these minerals are disseminated throughout the pegmatite also. The 3 ones bordering the pegmatites have prevented the passage of the ore solutions into the surrounding rock i n th e i r immediate vici n i t y . In these areas i t was noted that there was a heavy concentration of minerals in the veinlets, while immediately adjacent, mineralisation was almost e n t i r e l y absent. In the smaller fractures pegniatitic material i s absent to a large extent, often only a few scattered crystals being found* However the • . . • 'M - tenuous solutions penetrated these fractures and bomite, chalcopyrite, and some chalcocite was deposited.. Jupergene chalcocite. c o v e l l i t e , and chalcopyrite are absent from the smaller fractures. In some areas magnetite and hematite are concentrated, .'.here this Is the case, copper minerals are nearly always absent. The ore i s almost ent i r e l y free from p y r i t e , i t being noted i n only a few instances. About h a l f of the ore supply i s obtained b. glory-holing (Plate VI), the remainder by underground stoning and developement. GAB Glib. • • The gangue material i n the Copper llountain ore consists of the minerals of tho altered, breccias of'the 'Volf Creek formation. These breccias are andesitio to b a s a l t i c . The minerals composing the gangue are*, various feldspars, augite, b i o t i t o , epidote, .apatite, magnetite, hematite, s e r i c l t e and other a l t e r a t i o n products, c a l c i t e , and possibly some chlorite,* The "Sine lykes" where they penetrate and cut the orebodies are waste and have to be rained in most cases as they are not strong enough to stand aione 0 The breccias have been intensely altered by hydrothermal solutions eminating from the stock magna, Replacement has widened the fractures i n many places and the minerals have been attacked by these' solutions. The a l t e r a t i o n consists of b i o t i t e , augite, s e r i c i t e , c a l c i t e , and some epidote and zoisite*?* B i o t i t e and augite are widely spread throughout the breccias. The ferro-magnesian minerals have been altered to- s e r i c i t e , and the orthoclase feldspars to s e r i c i t e and c a l c i t e . Tho a l t e r a t i o n of the plagioclase 25 feldspars by the breakdown ofthe s o l i d solution of a l b i t e and anorthito into a dense aggregate composed of a l b i t e or orthoclase and x o i s i t e or epidote, along ivith variable amounts of c a l c i t e , s e r i c i t e , and calcium-aluminum s i l i c a t e s other than those of the epidote group Is termed sausseritisation by Williams .-to I t a pears that this i s the type of a l t e r a t i o n that has Williams, G.H. U . S . Geological Purvey, Bulla 62. page 67. taken place i n the Wolf Creek breccias to a certain extent. Orthoclase being the most resistant of the feldspars to a l t e r a t i o n , It Is as a result the most easily distinguishable and the one freest from alteration.- Apatite c r y s t a l s have not been attached and stand out c l e a r l y . The apatite i s confined to the altered zone. Al t e r a t i o n and bleaching by s e r i c i t e Is most common in the v i c i n i t y of the fractures. This i s probably responsible for the whitening of the aones adjacent to the fractures.' This a l t e r a t i o n i s d i s t i n c t l y l a t e r than the augite and b i o t i t e . (e) MIBEIiALOGY AED PAHAGEUISIS. The paragenisis of the ore at the Copper Mountain iline determined from the study of sections i s as follows: EYPGGh&S SUP SRGifKE luAillY LATS /.LI Gil hT ITE CHALCOPYIUTE BE2ATIEB PYA1TS BOM ITE CHALCOPYRITE CIIALCOCITJi CALCITE COVELLITE CHALCOCITB CHALCGPYllITE H Y P O G B E S E SUPH3.GEEB EABLY LATE MCEISTITE — - HEMATIT3 — - FYitlTS AUC-IiJirw BIOTITE B03H12E — — CHALCOPYRITE GEALCGCITK PEGMATITE IM FRACTURES CALCITii — - COVELLITE The sequence of events i s indicated i n the following summary* I. Wolf Greek formation intruded by the Copper fountain Stock.. 2 S Uissemination i n the breccias of the Wolf Creek formation of magnetite, bornito, and chalcopyrite and. the a l t e r a t i o n of the breccias by the injection of large amounts of b i o t i t e and augite. 5. Period of fracture and f o l i a t i o n , 4. Pegmatitic material injected into some of the fractures and further a l t e r a t i o n and plugging of some of the channelways. 5. Late hypogcne mind'slization. 6. Cal c i t e v e i n l e t s . 7„ Supergene mineralization.. fclagnetite: In the Copper .Mountain ore magnetite occurs as an acessory mineral 27 r e s u l t i n g from msgraatic d i f f e r e n t i a t i o n and i s pyrogenetic i n origin,. The magnetite Is f a i r l y v;ell scattered throughout the ore with l o c a l concentra- tions •> Bornite: Tho "bornite at the Copper liountain liine i s one of the most import- ant sulphide minerals,, I t i s en t i r e l y hypogeno In or i g i n and i s associated with chalcopyrite and chalcocite* In the early hypogsne stage bornite Is found disseminated through the breccias along with chalcopyrite. This mineralisation i s not intense enough to form ore. The breccias at this stage being i n r e a l i t y a protore. In the late hypogene stage bornite i s found associated with chalcopyrite and chalcocite, Chalcopyrite: ' Along with bornite, chalcopyrite forms.the most important mineral- i z a t i o n . I t i s found with bornite disseminated i n the breccias, with bornite i n the fractures, and as a svporgene mineral along the c a l c i t e veins and projecting as blades and segregated laths In bornite 0 The .relationships between chalcopyrite and. bornite are discussed l a t e r . Hematite: Hematite occurs frequently associated with magnetite but definetly l a t e r . It replaces the magnetite both marginally and i n t e r n a l l y (Plate.A, i ' i g o I j 0 I t ' s relationship to other mineralization i s more d i f f i c u l t to determine. In one specimen i n p a r t i c u l a r that was studied i t i s .-.uite apparent that hematite i s previous to the l a t e r bornite and chalcopyrite,. The c r i t e r i a i n d i c a t i n g t h i s being, the presence i n p i t s of the hematite-of blebs of bornite, and i n some places tho bornite'..being replaced by choice— p y r i t e a './here bornite borders hematite; under high magnification i t Is noticed, that a very thin rim of chalcopyrite separates i t from the hematite- This i s indicative no doubt of l a t e r chalcopyrite and bornite. The hematite i s confined largely to the altered zone. The solution carrying the hematite used the fractures as channelways, but evidently found d i f f i c u l t y in penetrating to any distance from these fractures due to tho concentration of pegmatitic material and a l t e r a t i o n products i n and adjacent to the fractures, and the consequent plugging of any channels that might have existed. hematite was found occurring as d i s t i n c t blades in the gangue material (Plate X, i'"ig 02} 0 I t was evidently affected by l a t e r calcite<> P y r i t e : P y r i t e i s conspicuously absent from the ore, i t being noted i n only a few instances and then i n only small p a r t i c l e s and. under high magnifications. Where noted i t appears to be hypogene. I t i s found as residual remnants i n hematite and early bornite. -Ghalcocite; Chalcocite i s abundant as a hypogene mineral and i s found with bornite i n .the fractures. Superegene bdue chalcocite occurs in smaller quantities as veinlets traversing chalcopyrite and bornite in f r:= •. nred zones, and to a certain extent with the disseminated bornite. The supergene chalcocite was formed as a product of the replacement of chalcopyrite and • bornite. The hypogene chalcocite bornite relations are discussed at greater d e t a i l subsequently. Calcite: One of the last stages a f f e c t i n g the ore deposit was the Intro- PLATE X. FIG. 'I. Camera, lucida drawing showing hematite(H) replacing magnetitefMj •Magnification X 275= , PLATE .X. FIG. 2. • Camera lucida drawing showing blades of hema111 e(H) in gangue(G). Cha1copyrite(Cp) on edge of f i e l d . Magnification X. 275. 29 duction of c a l c i t e . The c a l c i t e i n the form of veins, i n t r i c a t e l y cuts a l l the minerals except those of supergene o r i g i n . Calcite veins cut acres • and. are l a t e r than, bornite(Plate XI. F i g . I. ), magnetite(Plate XI. Pig. 2 j chalcopyrite(Plate XII. Pig. I . ] , hematite(?late XII. Pig. 2.), and hypogene chalcocite. In some cases cleavage craclcs i n boraite have been f i l l e d with this material. The supergene mineralization i s d i r e c t l y relates] to these c a l c i t e veins which are r e t i c u l a t e in. form. hypogene Ilinera l i za t i on: In the writer's opinion, the hypogene mineralIzation at the Copper fountain laine consists of two periods; the one an early stage and the other a l a t e stage. In the l a t e hypogene stage the early protore was enriched by the addition of more material and this resulted i n the format!01 of an- ore deposit.. • . The early hypogene stage of mineralization occurred previous to the f r a c t u r i n g and f o l i a t i o n . Associated with the introduction of large amounts of b i o t i t e and augite were minor amounts of sulphides consisting of bornite c h i e f l y and some chalcopyrite. These sulphides were carried i n solution from the slowly cooling stock magma and disseminated throughout the breccias of the Wolf Creek formation. The composition of these solution was such that bornite and chalcopyrite.were deposited. Iron and sulphur were present i n such proportions that both minerals were precipitated with the chalcopyrite phase l a s t i n g a l i t t l e longer than the bornite* These disseminated sulphides are confined c h i e f l y to the altered aone of the brecciaS o The l a t e hypogene phase of mineralisation i s responsible for the' or© at Copper Mountain. Into the fractures and f o l i a t i o n s of the breccias copper r i c h solutions penetrated and deposited bornite, chalcopyrite m\u PLATE XI. *IG. I. Camera lucida drawing showing c a l c i t e c r y s t a l i n hypogene bornite. This indicates that c a l c i t e i s l a t e r than bornite. Elagnification X 150. PLATE XI PIG. 2. . Camera lucida drawing showing c a l c i t e vein exit t i n g across and l a t e r than magnetite and the gangue. Calcite(C )e Magnetite(MJ. Magnification X 275.' 31 PLATE XII. PIG. I. Camera lucida drawing showing vein of calcite(C) l a t e r than chalcopyrite(CpJ. Magnification X 85. PLATE XII. PIG. 2. Camera lucida drawing showing veins of c a l c i t e l a t e r than chalco- pyrite} Cp ) and hematite(H). Note the parallelism of the walls of the c a l c i t e veins. Magnification X 85.  33 chalcocite In f a i r l y large amounts. The s\J.lphides i n these fracture zones occur c h i e f l y i n massive form with s l i g h t amounts disseminated i n the pegmatitic material which encloses the- veinlets,, The.ahsonco of pyrite Is held responsible for the association of bornite, chalcopyrite, and chalcocite. The f i r s t mineral to be precipitated out of the penetrating solutions was bornite followed closely by chalcopyrite and chalcocite. The chalcopyrite and chalcocite are d e f i n e t l y l a t e r than the bornite. Clnalcoeito and bornite, and bornite and chalcopyrite are found associated together but not chalcopyrite anc chalcoeito. The tenuous solutions that deposited the bornite and then the chalcopyrite were depleted In iron with only copper and sulphur remaining. As a result of t h i s and the breakdown of bornite chalcocite was the l a s t mineral to be precipitated. That the chalcopyrite was l a t e r than the bornite i s definetly established. It rims the bornite and l i n e s of chalcopyrite follow cleavage planes In bornite(?late XIII. F i g . I.}. The massive replacement of bornite by chalcopyrite i s shown i n a photograph of a polished section of ore(Plate X I I I . F i g . 2.j where blades of chalcopyrite as much as an inch i n length are seen to have the same pattern as the microscopic blades of chalcopyrite in bornite(?late XIII. Pig. I . j . This pattern i s somewhat triangular i n form. Further evidence of replacement of bornite by chalcopyrite Is shown in Plate XIV. Figs. I&2, where the bornite Is "bitten" into by the chalco- p y r i t e and the chalcopyrite forms convex curved outlines against the bornite. The f i n a l action of the copper r i c h solutions was the attac&.by- these solutions on bornite. This resulted i n the p a r t i a l breaking down of bornite and replacement b- chalcocite. The fact that the chalcopyrite i s not i n association with chalcocite would seem to indicate that i t i s a case of selective association, with the bornite being the subject of PLATS XIII. FIG. I. Micro-photograph showing lines of chalcopvrite(light grey) following cleavage planes i n bornite(dark grey), also chalcopyrite rimming and eating into hornite. A l l i n d i c a t i v e of l a t e r chaleopyrite. The gangue i s black. Uagnification X 550. PLATE XIII. PIG. 2. Photograph of polished surface of ore showing large blades of chalcopyrite in a triangular pattern. This i s Indicative of massive replacement of bornite by chalcopyrite. Magnificatio'n X 2. 34 PLATE XIV. FIG. I. ' Camera lucida drawing showing bornite(B) being "bitten" Into and replaced b;:- chalcopyrite(Cp). Bote curved convex outlines of chalco- pyrite against bornite. magnification X 550. PLATE XIV. FIG. 2. : \ Camera lucida drawing showing chalcopyrite l a t e r than bornite. The chalcopyrite forms convex.out- lines against the bornite and a long tongue of chalcopyrite extends into the bornite. Hematit'e(H). Gangue(G). Magnification X 275. 3b replacement. Sf the chalcocite were previous to the chalcopyrite, i t would be e-rpected that i t would at least be "rimmed"by i t i n i t ' s rim association with bornite. The chalcocite i s believed to be hypogene i n o r i g i n . It i s clear white i n color, which i s ch a r a c t e r i s t i c of hypogene chalcocite unless admixed with c o v e l l i t e when It then taxes on bluish tinge i n places. The supergene chalcocite i n this ore i s blue and t h i s distinguishes i t from the hypogene chalcocite but other c r i t e r i a are used. The chalcocite i s found In graphic intergrowths with bornite. In blades or laths cutting across bornite, and rimming bornite. I t Is believed that as a result of these replacement relationships, the nature of the chalcocite and i t ' s association with bornite, and the presence of chalcopyrite, that i t i s hypogene i n o r i g i n and s l i g h t l y l a t e r in age than the bornite© The deposition of a l l three of these minerals i s probably a case • of successive overlap. Tho graphic i n t e r grov/th between the bornite and chalcocite(?Iate XV. F i g . I&2.} i s interpreted as replacement.. In most cases where bornite and chalcocite were sttidied In the intergrowths, fine veinlets of chalcocite were noted c u t t i n g into tho lamed* ~\tsly adjacent bornite. The fact that the i n t e r growth phenomena Is not complete but i s found only In certain parts of the veinlets i s further indication of replacement and not contemp- oraneous deposition. The lobate intorgrowth' between these two minerals varies from extremely f i n e under the highest powers obtainable to quite coarse. There appeal's to be a gradual t r a n s i t i o n from graphic intergrowth to replacement by the chara c t e r i s t i c rim pattern. The chalcocite extends In wide masses into the bornite and then branches out on the sides into the cha r a c t e r i s t i c lobate replacement. Veinlets of" chalcocite traversing bornite • PLATE XV. PIG.' I, and PIG. 2„ ' Photomicrographs of graphic intergrowth of bornite and chalcocite which i s interpreted as replacement of bornite by chalcocite. ; ' Bornite(dark grey). Chalcocite(white)„ Gangue(black). Magnification X 275. 37 30- (Plate XVI. F i g . I,) seems- to be undoubted proof of replacement, and the fact that these veins extend from a rim of chalcocite(Plate XVI. Fig. 2.) would add further evidence. • i The continuity of the white chalcocite along the fractures from the areas of Intergrowth, to areas of rim replacement and traversing veinlets d e f i n e t l y establishes the fact that i t i s a i l one generation of chalcocite. A f i n a l i n d i c a t i o n of replacement i s evidenced by the extremely minute micro-veinlets of chalcocite which i n places traverse the lobes of bornite. The l a s t phase of the hypogene mineralisation i s represented by c a l c i t e v e i n l e t s which are fnund widespread throughout the ore. They are .reticulate i n form and are found cutting across a l l the ore minerals except those of supergene o r i g i n . These veinlets are important i n that the supergene solutions used them as passageways by which they were enabled to penetrate tile orebodies. The supergene minerals are d i r e c t l y associated with the c a l c i t e veinlets and the fractures. The fact 'that the c a l c i t e v e i n l e t s cut the b'ornite.and ohalcccito may he cited as further evidence for the hypogene origin, of • these sulphides. - . The walls of the c a l c i t e veins i n many places are d i s t i n c t l y p a r a l l e l . This suggests that there was possibly a certain amount of f i s s u r i n g l a t e r than the mineralization'but p r i o r to the introduction of c a l c i t e . . »- Supergene Enrichment; In the Copper Mountain Mine supergene enrichment i s not of very great importance. It has proceeded from the r e t i c u l a t i n g v einlets of c a l c i t e and the fractures. The simple sulphides of copper, namely c o v e l l i t e and chalcocite, have replaced the copper iron sulphides bornite and PLATE XVI. FIG. I. Camera lucida drawing snowing a vein of hypogene chalcocite(Cc) cutting across bomite(B). The chalcocite also rims the bornite. Gangue(G]. Magnification X £75® PLATE XVI. PIG. 2. Camera lucida drawing showing chalcocite replacing bornite by the characteristic rim pattern. Also blades of chalcocite i n bornite and massive replacement of bornite by-chalcocite. Hematite(H). Magnification X. 275.  chalcopyrite. The action of surface waters containing sulphuric acid, on hypo- gene bornite w i l l account for the formation of c o v e l l i t e , chalcocite, ferrous sulphate and hydrogen sulphide. The further reaction between these products accounts for the supergene chalcopyrite present. The action of cupric sulphate, which Is also present i n these waters, on primary chalcopyrite r e s u l t s i n the formation of c o v e l l i t e . The further reaction between cupric sulphate and c o v e l l i t e In the presence of sulphuric acid w i l l result i n chalcocite. C o v e l l i t e and chalcocite are precipitated a f t e r f e r r i c sulphate i s absent or almost so.f t Lindgren, W. Mineral P'eposits, 1928. Page 543. Supergene cove-lite which appears to be s l i g h t l y older than the chalcocite i s confined c h i e f l y to the fractures. I t replaces bornito and chalcopyrite marginally (Plate XVII. P i g . I&2.}.» It i s also found replacing disseminated bornite i n scattered areas throughout the ore. It i s only shorn to-advantage under high magnification. This i s especially true where c o v e l l i t e replaces bornite that i s disseminated. In several places i t Is found as blades c u t t i n g across narrow segments of bornite(Plato IX. F i g , 2}. The-marginal or rim replacement Is the best defined and i s well brought out i n Plate XVIII, P i g . I . C o v e l l i t e i s also found admixed with hypogene chalcocite. I t appears as dark blue feathery aggregates suggesting the breaking down and replacement of chalcocite by c o v e l l i t e . Is places tho replacement of hypogene sulphides by chalcocite Is d i s t i n c t l y - a supergene process. This chalcocite Is bluish i n color, i s not massive, and occurs replacing the three hypogene sulphides. In Plate- XVIII g Pig. 2 i t i s sho.vn as a la t h shaped veinlet cutting across chalco- p y r i t e and bornite and also as a segregated l a t h in the bornite. i t i s PLATE XVII. PIG. I. Camera lucida drawing showing supergene covellite(Co) replacing b orni t e(B J and cha i c opyrit e{Cp)» Cangue(G). Magnifioation X 275, PLATE XVII. i I G . 2. Camera lucida drawing showing supergene covellIte(Co ) replacing chalcopyrite(Cp). The c o v e l l i t e rims the chalcopyrite and i t ' s association with calcite(C) Is shown. Gangue(G). Magnification X 550. 41 P L A T E X V I I I . P I G . L Camera lucida drawing showing covellite(blue) replacing bornite (brown) and chalcopyrite(yellow). Gangue(greyJ. • Magnification X £75. P L A T E X V I I I . P I G . ' 2„ Camera lucida drawing snowing c o v e l l i t e (bluej replacing bornite. A l a t h of chalcocite(azure) cuts across bornite and chalcopyrite(Cpj and there i s a'segregated l a t h of supergene chalcocite i n bornite. Magnification X 27b. 42 43 confined c h i e f l y to the fractures, The supergene blue chalcocite i n c e r t a i n places as very fine blades (Plate XI/.. Pig. 2.) and feathery aggre- gates in the hypogene chalcocite and bornite. Under magnification of 550 diameters, isolated blades of supergene chalcocpyrite are noticed extending from r e t i c u l a t i n g c a l c i t e veinlets into adjacent hypogene bornite(Plate XX. Pig. I&2.). Those blades of chalcopyrite also occur adjacent to the c a l c i t e veinlets but disassociated. The age relations between these supergene minerals could not ,del"inetiy be established. The relations that were observed however suggests that the c o v e i l i t e i s s l i g h t l y older than the chalcocite and chalcopyrite. The supergene chalcopyrite i s found only i n the largest fractures, probably i n d i c a t i n g that i t i s the youngest of the three. [f I Origin: - . It i s believed that the ore deposits of the Cooper fountain liine are d i r e c t l y related to the hydrothexraal stage of the intrusion of the Copper Mountain stock. The hypogene ores at t h i s mine were deposited by hot magtiatic solutions emanating from the cooling stock magma. These hot solutions penetrated .the breccias, f i r s t disseminating bornite and chalcopyrite, .and then a f t e r f r a c t u r i n g further mineralization consisting of bornite chalco- p y r i t e and chalcocite. . The close proximity of the ore deposits to the stocj: as i s shown in Plate VII - scams to be conclusive evidence of the direct relationship of these ores to tho Intrusion. The absence of quarts from the ores and the stock i t s e l f , and the presence of bornite and chalcopyrite i n both adds further to the proof.. PLATE SIX. PIG- I. Photomicrograph showing covellite(Go) replacing bomite(B) and. chalcopyri t e(Cp). i'lagnification X 275. PLATE MIX. FIG. 2. Photomicrograph showing a fine, l a t h - l i k e veinlet of supergene chalcocite cutting across and replacing chalcopyrite. Magnification. X 275.  PLATE X X . P I G . I , • . Camera lucida drawing showing blades of supergene chalcopyrite(Cpj replacing bornite(Bj. The r e l a t i o n between chalcopyrite. and calcite(C) i s shown. Magnification A .550* Camera lucida drawing showing blades of supergene chalcopyrite'Cp) in borniteiB)„ Covellite is. shown replacing and. cutting across bornite. Coveilite(Co). Calcite(C). i & g n i f i o a t i o n X 275. .' . '• 45 46 S i m i l a r i t y i n mineral composition lends further evidence to the genetic relationship between the orebodies and the i n t r u s i v e . Pegmatitic material makes up the core of the stock and i s found i n many of the fractures besides the large veins or dykes In the v i c i n i t y of 'the deposit-., The large dykes that cut the ore deposits contain quarts i n places. This d i f f e r e n t i a t e s these dykes from the older rocks in mode of o r i g i n . The cross sections i n plate VII shows the orebodies p a r a l l e l i n g the contact of the -stock. One orebody Is i n direct contact with the stock and apparently widens i n depth. As previously stated, these orebodies are controlled by the extent of f r a c t u r i n g . It would seem therefore , that the solutions that deposited the copper-rich minerals eminated from deep . down and followed up the channels afforded by the f o l i a t i o n planes and the fracture sones. The fact that the walls of the stock are v e r t i c a l and i t i s ovoid to c i r c u l a r i n plan, conforms with the d e f i n i t i o n of a true stock. This suggests the p r o b a b i l i t y then that the stock was formed as a protuberence from a greater magmatic mass below« i t seems probable therefore, that, the ore bearing solutions proceeded from the magma chamber that was responsible f o r the stock. These solutions penetrated upward along tho f o l i a t i o n s and fractures and deposited •the minerals i n the order previously outlined. The whole process i s one of replacement as a result of contact mctamorphism with the fractured nature of the breccias f a c i l i t a t i n g metasomatism. V. SOmfAHY & CQIICLuBIOKS: SlBhlOOPtAPBT. I. The Copper Mountain Mine i s one of the three p r i n c i p a l deposits of copper i n B r i t i s h Columbia. Ho A resume i s given of the topography and geology,. "3. The deposit i s of the epigenetic,.contact motamorphic type, or i n other words pyrometasoaa11c«. 4. The source of the ores i s believed to be the magma chamber from which the Copper Mountain stock originated.. 5. A l t e r a t i o n consisting of b i o t i t i z a t i o n and s e r i c i t i z a t i o n extends i r r e g u l a r l y both In intensity and location from the stock contact outwards. Along with the b i o t i t i z a t i o n the f i r s t period of mineralization took place, when the breccias of the 'Coif Creek formation were mineralised to a certain extent,, . ' 6. The gangue material consists of the oxides magnetite, and hematite, the s i l i c a t e s epidote, and z o i s i t e , along with apatite, orthoclas a l b i t e , b i o t i t e , and calcite., 7 o Fracturing and f o l i a t i o n as a result of stresses affected the '.Volf Creek formation to an important extent adjacent to the stock. 8. Hypogene mineralization consists of an early and a l a t e stages The early stage previous to tho i'ractiiring and the l a t e stage subsequent to Ite. • 9. The l a t e stage of hypogene mineralisation which Is the' important one, consisted of the deposition i n the fractures by ascending thermal solutions of bornite, chalcopyrite, and .chalcocite i n the order named. 10. C a l c i t e v e i n l e t s , r e t i c u l a t e i n form, mark the end of the hypogene period and are important. 11. Supergene solutions have enriched the deposit to a certain extent by the deposition of c o v e l l i t e , chalcocite, and chalcopyrite. 48 Bibliography: Catherinet, Jules.,- Copper Hour.-tain, B r i t i s h Columbia, lingineering and Mining <3oumal, Vol. 79, 1905. pp. 125-26. 3>olmage, V.- Copper Mountain ores. Canadian Mining and Metallurgical B u l l e t i n , June 192to Dept. of Mines, B r i t i s h Columbia. Various annual reports. Kemp, J.i\>- Origin of Copper Maintain Ores. I.A.r.iI«B. Vol. 31. page 162 Lindgren, Mineral l e p o s i t s . 1928. Page 943-49. 0.3. Geological Survey: emmons, C/.H.- The J&irichment of Sulphide Ores. B u l l e t i n 529o Williams, G.H.- B u l l e t i n 62. Page 67. L E G E N D > < POST ECOCENEL U O N O i LU I T R \ASS\C ? Te.r7?'ary Volcanics Verde C/~eeK G ranif-e. Vo,g1 t Si-ocK J Copper StocK Wo/fCr&eK Form. Contours Lahe _ l J •Spring Geo/o^/cj/ Boundary Geo/ogica/ Boundary AppTOximaTet Road Trail Railroad Transmission Line U M,n& Dump X A Prospccr M,n& Tunnei 8f. , Bui/dings Height in Fec±f- \Z030 49f5 12.0 JO Geology cy \'.^o/mst\s , 7S£.J, Topography trcm sunsys by D. A..W<?tdt , A°22 Datum H f-tean Sea Level C O P P E R M O U N T A I N A R E A S I M I L K A M E E N D I S T R I C T B R I T I S H C O L U M B I A '3 a c c J . T t p e n / r / i e « « Harold H U r ; f l i APPROXIMATE MEAN DECIMATION . 192 3 Scale, 1:12,000 or I Inch to 100 0 Feet Feet ' S C O O IOOO S.OOO 3000 Contour interval SO r~e&t


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