UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Silver Cup mine, Lardeau : regional frame-work and structural ore control Trettin, Hans Peter 1957

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
831-UBC_1957_A6_7 T8 S4.pdf [ 3.39MB ]
Metadata
JSON: 831-1.0053029.json
JSON-LD: 831-1.0053029-ld.json
RDF/XML (Pretty): 831-1.0053029-rdf.xml
RDF/JSON: 831-1.0053029-rdf.json
Turtle: 831-1.0053029-turtle.txt
N-Triples: 831-1.0053029-rdf-ntriples.txt
Original Record: 831-1.0053029-source.json
Full Text
831-1.0053029-fulltext.txt
Citation
831-1.0053029.ris

Full Text

SILVER CUP MINE, LARDEAU REGIONAL FRAME-WORK AND STRUCTURAL ORE CONTROL by HANS PETER TRETTIN Ph.D., U n i v e r s i t y of Hamburg, 1952  A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF . MASTER OF SCIENCE In the Department of GEOLOGY AND GEOGRAPHY  We accept t h i s t h e s i s as conforming t o the standard r e q u i r e d  from candidates f o r the  degree o f MASTER OF SCIENCE  Members o f the Department of Geology and Geography  THE UNIVERSITY OF BRITISH COLUMBIA A p r i l , 1957  i  ABSTRACT  '  The S i l v e r Cup mine i s about 10 miles east of Trout Lake i n the C e n t r a l Lardeau. produced about 1.5 and  gold.  The  From 1895  t o 1915  it  m i l l i o n oz. of s i l v e r and some l e a d , z i n c ,  problem of the paper i s to study i t s geo-  l o g i c a l s e t t i n g and s t r u c t u r a l ore Eastwood has  controls.  shown that the mine i s c l o s e t o the  a x i a l plane of a major i s o c l i n a l a n t i c l i n e that i s overturned t o the southwest and plunging to the northwest. c o r r e l a t e d the greenstones  He  has  i n the core of the a n t i c l i n e  with  the top of the Bunker H i l l Group and has named the o v e r l y i n g b l a c k s l a t e s and p h y l l i t e s T r i u n e Formation.  These  s t r a t i g r a p h i c u n i t s were d i v i d e d i n t o three and respectively.  The  two  four members  r e p e t i t i o n of c e r t a i n horizons and  the  trend of contacts i n d i c a t e s that the major a n t i c l i n e here two  has  a p i c e s separated by a t i g h t l y compressed syncline.. Ninety f i v e per cent of the p r o d u c t i o n of the mine  came from a zone that has  a maximum l e n g t h of 300 f e e t , a  maximum w i d t h of 200 f e e t and has been stoped down t o f e e t below i t s outcrop.  1200  G e o l o g i c a l mapping shows that the  ore i s contained i n openings of a s t r u c t u r e that i s a comb i n a t i o n of a drag f o l d and a compressional  bulge which i s  d i p p i n g w i t h the host h o r i z o n to the northeast and r a k i n g  ii  s t e e p l y t o the northwest.  Host i s the b a s a l member o f the  Triune formation, a s i l i c e o u s g r a p h i t i c  slate.  Three other ore zones i n the v i c i n i t y o f the main zone have a s i m i l a r l e n t i c u l a r shape and s t e e p rake and a r e contained i n the same member, but they are not a l l i n the same s t r u c t u r a l p o s i t i o n w i t h r e s p e c t t o the two a p i c e s o f the major a n t i c l i n e .  These o b s e r v a t i o n s suggest t h a t the mechanical  p r o p e r t i e s of the host rock r a t h e r than a continuous s t r u c t u r e such as a f a u l t or a shear zone a r e r e s p o n s i b l e f o r the l o c a l i z a t i o n o f ore.  I t i s shown how the t e x t u r e of the host  rock,  the t h i c k n e s s o f the host member and the t e x t u r e of the overl y i n g rocks f a c i l i t a t e the f o r m a t i o n o f lens l i k e openings i f d i f f e r e n t i a l s t r e s s e s are a p p l i e d . Due t o the s t e e p rake of the s t r u c t u r e s , s t r e s s e s cannot  be r e l a t e d t o r e l a t i v e movement of outer  l a y e r s towards the a p i c e s of the a n t i c l i n e . not known but two hypotheses offered.  these  based  on f i e l d  Their o r i g i n i s evidence a r e  In p r e s e n t i n g the  this thesis in partial fulfilment  requirements f o r an advanced degree at the  of  University  o f B r i t i s h Columbia, I agree that  the  L i b r a r y s h a l l make  it  and  study.  f r e e l y available f o r reference  agree that  I  further  permission f o r e x t e n s i v e copying o f t h i s t h e s i s  f o r s c h o l a r l y purposes may  be granted by the  Department or by h i s r e p r e s e n t a t i v e .  Head o f  my  I t i s understood  that  copying or p u b l i c a t i o n of t h i s t h e s i s f o r f i n a n c i a l  gain  s h a l l not  Department o f  be allowed without my  Geology  The U n i v e r s i t y of B r i t i s h Vancouver 5\ Canada. Date  A p r i l , 30, 1957.  Columbia,  written  permission.  ACKNOWLEDGMENTS  The field  author i s indebted to a l l members of the  p a r t y that worked f o r the B r i t i s h Columbia Department  of Mines i n the Lardeau i n the summer of 1 9 5 6 . Eastwood has  Dr. G.E.P.  g i v e n much advice and support, i n the f i e l d  w e l l as l a t e r on;  Mr.  J . J . Twiss has  -work v e r y a c c u r a t e l y , and Mr.  as  done the plane t a b l e  Douglas I r v i n g and Mr.  Ian  Faulks have g i v e n a b l e and w i l l i n g a s s i s t a n c e . At the U n i v e r s i t y of B r i t i s h Columbia my work has been s u p e r v i s e d by Dr. W.H. for  White to whom I am  numerous h e l p f u l suggestions  and  ingratiated  criticisms.  The w r i t e r  has r e c e i v e d v a l u a b l e a d v i c e i n the p e t r o g r a p h i c work by Dr. K.C.McTaggart and for  a l s o wishes to thank Dean H.C.  direction. Mr. Wragge has  of  Gunning  g i v e n the p e r m i s s i o n to use  the S i l v e r Cup mine, and the Granby C o n s o l i d a t e d  and Smelting  plans Mining  and Power Company has k i n d l y s u p p l i e d r e p o r t s  that were w r i t t e n i n c o n n e c t i o n w i t h e x p l o r a t i o n work.  TABLE OF CONTENTS Page INTRODUCTION  1  I.  1  II.  SILVER CUP MINE 1.  L o c a t i o n and Access  1  2.  Distribution  2  3.  H i s t o r y , Development and P r o d u c t i o n  o f Ore Zones . .  2 6  OTHER ORE BODIES 1.  T r i u n e Mine  6  2.  Towser Tunnel  7  3.  Free Coinage Workings  7  I I I . PREVIOUS GEOLOGICAL WORK AND SOURCES OF 7  INFORMATION IV.  PROBLEM OF THE THESIS  8  V.  CURRENT FIELD WORK BY THE AUTHOR  9  PART I I.  10  STRATIGRAPHY 1.  General Statement  10  2.  Table o f Formations  11  3.  Lithology  12  A.  Green P h y l l i t e  12  B.  Green P h y l l i t e w i t h Augen S t r u c t u r e .  13  C.  Graphitic Slate  14  D.  Black P h y l l i t e  15  E.  Quartzite  16  (approaching p h y l l i t e )  Page 4.  5. II.  D e s c r i p t i o n o f Formations and Members . . . . 16 A.  Bunker H i l l Group, Uppermost Formation  B.  T r i u n e Formation  Environments  . 16 17 18  of D e p o s i t i o n  20  MAJOR STRUCTURE PART I I  I.  25  MINERALIZATION AND ALTERATION 1.  Mineralization  25  2.  Rock A l t e r a t i o n  26  3.  Age of M i n e r a l i z a t i o n and A l t e r a t i o n  . . . . 26 27  I I . STRUCTURAL ORE CONTROL 1.  S t r u c t u r a l C o n t r o l o f the Main Ore Zone . . . 27 A.  I n f o r m a t i o n from the s u r f a c e  27  B.  I n f o r m a t i o n from Mine Maps  29  C.  I n f o r m a t i o n from G e o l o g i c a l Mapping  D. 2.  3.  Underground  29  Interpretation  31  S t r u c t u r a l C o n t r o l s of Minor Ore Bodies . . . 33 A.  Sunshine Zone  34  B.  T r i u n e Mine  35  C.  Free Coinage Workings  D.  Towser Tunnel  Summary and C o n c l u s i o n s  . . . . . 36 36 38  Page 4.  Causes of the Ore C o n t r o l l i n g S t r u c t u r e s A.  Texture of the Host Rock  B.  Thickness of the Host Member and Texture of O v e r l y i n g Rock Type  C.  5.  .  39 39  . . .  41  D i f f e r e n t i a l Forces  42  (a)  General Statement  42  (b)  Hypothesis  I  43  (c)  Hypothesis  II  44  Practical Applications  45  BIBLIOGRAPHY  . .  47  ILLUSTRATIONS Plate I.  Page S i l v e r Cup  II.  3  Mine, view from the west  T r i u n e Mountain, view from the northwest  III.  S i l v e r Cup  A n t i c l i n e on F i v e - m i l e  view from S i l v e r Cup IV.  hillside, 21  Mine  M i n e r a l i z e d zone i n No.  V.  19  ...  4 l e v e l , No.  11 d r i f t  .  32 37  T r i u n e Mine, view from the northwest  Figure 1.  S e c t i o n through core of S i l v e r Cup  2.  S t r u c t u r a l trends Cup  3.  anticline  .  at the s u r f a c e of S i l v e r 28  and B l i n d leads A. S e c t i o n N 57 E v e r t .  O u t l i n e of orezones. ( S i l v e r Cup  and B l i n d leads)  S 33 E 66 NE  24  B.  Section  through S i l v e r C u l l e a d  . . . .  30  Maps i n -paefcek: oicop Cibinzf P 1.  G e o l o g i c a l Map of S i l v e r Cup and S c a l e 1 i n c h = 500 f e e t ,  2.  G e o l o g i c a l Map of S i l v e r Cup mine, S c a l e 1 i n c h = 100 f e e t .  3.  Surface  of S i l v e r Cup  S c a l e 1 i n c h = 10  T r i u n e Mines,  and B l i n d l e a d s . ( G e o l o g i c a l  Map  feet.)  3 l e v e l ( G e o l o g i c a l map;  s c a l e 1 i n c h = 30  4.  No.  feet).  5. 6.  No. 4 l e v e l ( G e o l o g i c a l map; s c a l e 1 i n c h = 30 f e e t ) . S i l v e r Cup Mine, composite l e v e l p l a n . (Photographic copy of o l d mine p l a n ; s c a l e reduced to approximately 1 i n c h = 100 f e e t . )  SILVER CUP MINE, LARDEAU REGIONAL FRAME-WORK AND STRUCTURAL ORE CONTROL  INTRODUCTION  I.  S i l v e r Cup Mine 1.  L o c a t i o n and Access The S i l v e r Cup mine i s l o c a t e d 50° 38'N, 117° 22«W  at  an e l e v a t i o n o f 6800 f e e t i n the C e n t r a l Lardeau.  It  l i e s on a n o r t h w e s t e r l y s l o p i n g h i l l s i d e below the S i l v e r Cup peak and above the south f o r k o f Lardeau Creek. The mine can be reached i n the f o l l o w i n g way:  a  road, passable f o r c a r s , leads from Trout Lake through Ferguson t o E i g h t m i l e , ( d i s t a n c e about 8 m i l e s ) .  The con-  t i n u a t i o n from there t o Towser camp, about two m i l e s l o n g , i s now i n poor r e p a i r but could e a s i l y be r e c o n d i t i o n e d f o r t r u c k use. Two cabins can be used at present i n Towser camp. The road from the camp s i t e t o No. 7 l e v e l has a s t e e p grade and i s i n places covered by s l i d e s . Trout Lake i t s e l f may be reached by road from K a s l o  2  v i a Lardeau and Gerard, by road and f e r r y from R e v e l s t o k e , v i a Arrowhead and Beaton, or d i r e c t l y by seaplanes. 2.  D i s t r i b u t i o n of Ore Zones N i n e t y f i v e per cent of the p r o d u c t i o n came from  two l e a d s that are p a r a l l e l t o each other and approximately p a r a l l e l t o the bedding which i s d i p p i n g s t e e p l y t o the northeast.  The n o r t h e a s t e r n zone, c a l l e d  " S i l v e r Cup l e a d " ,  has been mined from 12 l e v e l s t o about 1200 f e e t below i t s outcrop.  The southwestern zone, named " B l i n d l e a d " d i d not  crop out and ends a few hundred f e e t above the lowest workings.  These leads a p p a r e n t l y c o n s i s t e d of l e n t i c u l a r  shoots o f h i g h grade ore connected by low grade m a t e r i a l and s p a r s e l y m i n e r a l i z e d quartz s t r i n g e r s . About  1200 f e e t northwest of the main zone, another  ore body c a l l e d the "Sunshine" zone has been stoped t o about 200 f e e t below the outcrop. 3.  H i s t o r y , Development, and P r o d u c t i o n A l l m i n e r a l i z e d zones i n t h e a r e a were d i s c o v e r e d  e a r l y i n the e i g h t e e n n i n e t i e s .  In the f i r s t  stages the s u r -  face exposure of the S i l v e r Cup l e a d was developed by a s h a f t . When, from a lower point o f the h i l l s i d e , the S i l v e r Cup cross cut (No. 3 l e v e l ) was d r i v e n , a second zone of m i n e r a l i z a t i o n , c a l l e d the " B l i n d l e a d " , was encountered. lower a d i t  The next  (No. 4 l e v e l ) was placed 400 f e e t t o the northwest.  PLATE I S i l v e r Cup Mine View from the west  F S 3 4 7 R  = = = = = =  Free Coinage workings, dump. S u r f a c e of main zone. No. 3 - l e v e l dump. No. 4 - l e v e l dump. No. 7-level dump. Road  4  It  encountered l i t t l e m i n e r a l i z a t i o n here, only the a r e a  d i r e c t l y below the stopes of No. 3 l e v e l and the s u r f a c e workings  c o n t a i n e d ore.  a winze sunk from No. Cup  The next s t e p i n the development  was  4 l e v e l In the v i c i n i t y of the S i l v e r  lead. While t h i s work was  i n p r o g r e s s , the Sunshine bodies  had been developed from two l e v e l s . extended southward  and, at 1700  The lower l e v e l  f e e t from the p o r t a l , reached  the  S i l v e r Cup l e a d .  Although t h i s d r i f t  for  most of i t s way,  no h i g h grade ore was  on these workings, known as the No. haulage and base f o r development. opened up above the No. Below No.  found.  From then  7 l e v e l , became the main At f i r s t ,  two l e v e l s were below.  on the B l i n d l e a d are t o be  seen on mine maps, and the d r i f t s short.  f o l l o w e d shear zones  7 l e v e l , then four l e v e l s  10 l e v e l , no workings  was  on the S i l v e r Cup l e a d are  The costs of pumping water and h o i s t i n g ore from the  lower l e v e l s became e x c e e d i n g l y h i g h and at the same time ext e n s i v e e x p l o r a t i o n on No. 8 l e v e l d i d not f i n d a c o n t i n u a t i o n of  the Sunshine ore b o d i e s .  ment was water. out  T h e r e f o r e , by 1914,  stopped and the l e v e l s below No.  a l l develop-  7 surrendered t o the  T h e r e a f t e r only minor q u a n t i t i e s of ore were taken  of the upper l e v e l s by l e a s e r s . The h i s t o r y of the mine has been i n f l u e n c e d  c a n t l y by the methods of m i l l i n g . h i g h grade ore was  In the f i r s t  signifi-  p e r i o d , only  taken out and shipped t o Tacoma, the low  5 grade m a t e r i a l being s t o r e d i n the stopes t o t r e a t t h i s m a t e r i a l a m i l l was b u i l t and  connected  or dumps.  In order  i n 1905 at F i v e - M i l e  w i t h the S i l v e r Cup mine by a tram l i n e .  m i l l a l s o served the N e t t i L mine.  This  S e v e r a l thousand tons of  ore were m i l l e d , but due t o exceedingly h i g h t a i l i n g l o s s e s the p l a n t had t o be shut down a f t e r one year of o p e r a t i o n . A f t e r t h i s f a i l u r e , the customary method of h i g h grading was continued. of;  The ore shipped by 1914- had an approximate grade  gold $ 6 . 0 0 per t o n , s i l v e r 150 oz. per t o n , l e a d 30% and  some copper and z i n c .  The grade of the m a t e r i a l l e f t  on the  dumps was estimated as; g o l d $ 3 . 5 0 - $ 8 . 0 0 ; l e a d 3 . 5 - 4$, copper 1.0 37,  - 1.5%, s i l v e r 30 -  50 oz., z i n c 5 - 20%.  a s m a l l f l o t a t i o n m i l l was s e t up at Towser camp and a  tram l i n e t o the dump of No. 7 l e v e l was c o n s t r u c t e d . year 290 tons of concentrates were shipped the m i l l was a l s o operated  of low grade ore l e f t  to T r a i l .  In t h a t Apparently  i n 1941.  At present there a r e s t i l l  and  In 1936-  considerable quantities  on the dumps of No. 3 and No. 4 l e v e l s  of the o l d S i l v e r Cup s h a f t t h a t w i l l be u s e f u l should the  property ever be put i n t o p r o d u c t i o n a g a i n .  The t o t a l  pro-  d u c t i o n of the mine amounts t o 9600 tons of s h i p p i n g ores and s e v e r a l thousand tons of m i l l A new programme  feed.  of e x p l o r a t i o n i n t h i s mine was  s t a r t e d i n 1952-53 by the Granby Mining  and S m e l t i n g Company.  6  Number 7 and No. and  9 l e v e l s were d r a i n e d , r e h a b i l i t a t e d , mapped,  Ten diamond d r i l l h o l e s , 200  sampled.  t o 250  were completed t o t e s t f o r p a r a l l e l s t r u c t u r e s .  feet  long  T h i s work,  however, had no f u r t h e r consequences. II.  Other Ore Zones In the v i c i n i t y of S i l v e r Cup  ore zones that w i l l be t r e a t e d b r i e f l y .  mine are three  other  A l l were d i s c o v e r e d  at the same time as the S i l v e r Cup mine and  a l l produced  the  same type of ore. 1.  T r i u n e Mine The T r i u n e mine i s on the northwestern  T r i u n e Mountain, about 4000 f e e t southeast of the S i l v e r Cup  f a c e of  of the main zone  mine.  The mine has  f o u r a d i t s that are stacked  above each other and are between 350  and 650  on d i p  feet long.  The  upper t h r e e l e v e l s are connected by a r a i s e . The m i n e r a l i z e d zone was l o n g , 500  f e e t deep, and  the upper three l e v e l s .  probably  about 200  feet  4 t o 5 f e e t wide and s i t u a t e d between I t d i d not  extend  down to the  lowest  level. In the years 1901  t o 1905,  534  tons  of h i g h grade  ore were shipped which were assaying Ag 240-400 oz., 50%,  and Au  .9  oz.  The  p r o p e r t y stayed i d l e then and  Pb 35 was  -  7 worked a g a i n from 1916  t o 1919.  In t h i s p e r i o d s i m i l a r  high  grades were produced; the q u a n t i t i e s are unknown. 2.  Towser Tunnel "Towser t u n n e l " i s s i t u a t e d about 1800 f e e t  west  of the Sunshine zone.  The workings are about 500  northfeet  long and c o n s i s t of d r i f t s , c r o s s c u t s and a r a i s e t o the s u r face.  The ore body was  about 175 f e e t l o n g , between 4 and 5  f e e t wide and terminated at a depth of about 50 f e e t from the surface. 3.  The t o t a l p r o d u c t i o n i s not known. Free Coinage  Workings  The Free Coinage workings are s i t u a t e d about f e e t southeast of the main zone and comprise more than  300 1000  f e e t of d r i f t s , c r o s s c u t s , and r a i s e s and s e v e r a l open c u t s . There are no o r e b o d i e s , only a l a r g e number of s m a l l and s p a r s e l y m i n e r a l i z e d quartz v e i n s . III.  P r e v i o u s G e o l o g i c a l Work and Sources of I n f o r m a t i o n The only comprehensive d e s c r i p t i o n of the geology  of the Lardeau has been g i v e n by J.F.Walker, M.F. and H.C.Gunning i n the G.S.C. memoir 161 S i n c e 1953 Department  G.E.P. Eastwood  Bancroft,  (1929).  of the B r i t i s h  Columbia  of Mines has been s t u d y i n g a s e c t i o n i n the c e n t r a l  Lardeau t r y i n g t o work out s t r u c t u r e and s t r a t i g r a p h y i n more detail.  His work a l s o covered the a r e a of S i l v e r Cup  and  8 T r i u n e mines.  A p r e l i m i n a r y map  i s to be published  Information about development and mine i s contained Minister  i n the annual r e p o r t s  of Mines.  In 1903  mine and  TV.  Cannon i n 1941,  7 and No.  Problem of the  the  a study of  the r e g i o n a l  descriptions  the  alter-  of s t r u c t u r e s .  i n connection w i t h e x p l o r a t i o n workwere  by J . S u l l i v a n i n 1953. mapping of No.  the  of the B r i t i s h Columbia  i n i t s v i c i n i t y includes  a t i o n , some underground mapping, and  w r i t t e n by D.M.  of  Gunning's work at  mineralogy of the ore, the gangue, and  C o n f i d e n t i a l reports  production  R.W.Brock made a b r i e f d e s c r i p t i o n  f o r the G e o l o g i c a l Survey of Canada. S i l v e r Cup  1957.  in  by W.S.Hamilton i n 1951  S u l l i v a n a l s o d i d the  and  geological  9 levels.  Thesis  Problem of the t h e s i s i n g e n e r a l  i s to determine  the g e o l o g i c a l s e t t i n g of the mine w i t h i n the r e g i o n a l frame work that has  been e s t a b l i s h e d by Eastwood and  s t r u c t u r a l ore c o n t r o l .  A p a r t i c u l a r question  the d i s t r i b u t i o n of ore bodies and miner  has  guided e x p l o r a t i o n .  bodies are h o r i z o n t a l l y very short  and  Long e x p l o r a t i o n d r i f t s l i k e the No. tunnels  of the S i l v e r Cup  mine and  have shown no l a t e r a l extension question  extensive 7»  the  the concept  However, the  4, No.  the  a r i s e s from  from the h i s t o r y of  s e v e r a l ore zones occur on s t r i k e , and  continuous veins  to f i n d  of  ore  only In depth.  and No.  8  the Free Coinage workings  of the h i g h grade zones.  i s , whether more or l e s s continuous v e i n s  exist;  The and  9 i f n o t , why  the ore bodies are approximately on s t r i k e .  The  mineralogy of the ore w i l l be t r e a t e d only v e r y b r i e f l y . This s u b j e c t has been s t u d i e d by Gunning from a r e g i o n a l p o i n t of view. V.  Current F i e l d Work by the Author The author spent eight weeks of the season 1956  the problem  on  supported by a crew of one t o t h r e e h e l p e r s .  In  t h i s time the maps accompanying the paper were prepared. g e o l o g i c a l map  of the s u r f a c e of the main zone i s based  plane t a b l e work. was  The g e o l o g i c a l map  The on  of the S i l v e r Cup mine  produced mainly by plane t a b l e work but supplemented  by  tape and compass t r a v e r s e s and combined w i t h o l d mine p l a n s . The sheet i s an outcrop map significant  but such outcrops that are i n -  f o r the l o c a t i o n of c o n t a c t s because  s i t u a t i o n or because  of t h e i r  they are too h i g h l y a l t e r e d were n e g l e c t e d .  The geology of the a r e a not covered by the plane t a b l e survey was  p l o t t e d on a base map  inch.  at the s c a l e of 1000  L a t e r on t h i s base map  was  f e e t t o the  e n l a r g e d , and the major  r e s u l t s of the plane t a b l e survey were t r a n s f e r r e d t o i t . 3,  Only the l e v e l s No.  No.  4, No.  7 and No.  8 of the S i l v e r  Cup mine, the Towser t u n n e l and the Free Coinage workings a c c e s s i b l e or could be opened up. the Free Coinage workings because  of water and the No. e s t i n g f e a t u r e s we  Because Gunning had mapped  and S u l l i v a n the No.  the Towser t u n n e l was  were  7 level;  and  f l o o d e d w i t h two t o t h r e e f e e t  8 l e v e l has no m i n e r a l i z a t i o n or i n t e r -  only mapped the l e v e l s No.  3 and No.  4.  10  PART I .  I.  GENERAL GEOLOGY  Stratigraphy 1.  General Statement Eastwood recognized three major s t r a t i g r a p h i c  i n the a r e a .  units  The o l d e s t are green p h y l l i t e s that he c o r r e l a t e d  w i t h the top o f the Bunker H i l l  group.  They are o v e r l a i n by  the g r a p h i t i c s l a t e s and p h y l l i t e s o f the T r i u n e f o r m a t i o n . The youngest formation i s the Ajax Q u a r t z i t e . these rocks i s not e x a c t l y known.  The age o f  Hundreds o f f e e t lower i n  the s e c t i o n i s the Badshot Formation  t h a t has been c o r r e l a t e d  w i t h an o l d e r Cambrian limestone member of the L a i b f o r m a t i o n . C o n s i d e r a b l y higher up -is the C h r i s t i e P o i n t Group i n p a r t w i t h the previous M i l i f o r d Mississippian fossils.  (coinciding  Group) that c o n t a i n s  T h e r e f o r e the rocks i n t h i s  probably belong somewhere i n the o l d e r P a l a e o z o i c .  area The two  o l d e r u n i t s were d i v i d e d by the author i n t o t h r e e and f o u r members r e s p e c t i v e l y .  Because some rock types appear i n  s e v e r a l members, at f i r s t  the l i t h o l o g y w i l l be d e s c r i b e d i n  g e n e r a l and then, b r i e f l y , the i n d i v i d u a l formations and members.  TABLE OF FORMATIONS, FERGUSON AREA, LARDEAU; AFTER EASTWOOD EASTWOOD, 1957 FORMATION  WALKER AND BANCROFT 1929 AGE  LITHOLOGY T i l l , talus, alluvium. travertine  Some c a l c - t u f f s or  Quaternary  nonconformity small g r a n i t i c  intrusives  Cretaceous?  Kuskanax ?  r e l a t i o n s unknown s c a t t e r e d s m a l l stocks o f d i o r i t e and gabbro i n t r u s i v e contact l i m e s t o n e , almost e n t i r e l y  Badshot, band 2a  recrystallized  contact covered Staubert Formation  Q u a r t z i t e , p h y l l i t e , a r g i l l i t e , limestone  Beaton Formation  s i l t y s l a t e s and p h y l l i t e s , pebble-conglomerate, a r g i l l a c e o u s limestone  Lardeau s e r i e s  contact probably conformable Lardeau s e r i e s  contact covered Christie Point Group  s h a l e , c h e r t , s l a t e , l i m e s t o n e , sandstone, contains s e v e r a l f o s s i l i f e r o u s zones, one o f M i s s i s s i p p i a n Age  Carboniferous  Patches of M i l f o r d Group f o r lower p a r t , Lardeau s e r i e s Upper p a r t .  i—*  d i s c o n f o r m i t y (angular unconformity not proven) Lardeau Canyon Formation  p h y l l i t e , q u a r t z i t e , garnet, pebble conglomerate conformable contact  Ferguson Group  Grits  and black p h y l l i t e s  g r a d a t i o n a l contact Jowett Formation  greenstone, green p h y l l i t e , g r i t , black p h y l l i t e conformable contact  Ajax Quartzite  quartz  grit  conformable contact Triune Formation  b l a c k s l a t e s and p h y l l i t e s ; p h y l l i t e s and dolomite  l o c a l l y green  concordant contact Bunker Group  Hill  green g r i t t y p h y l l i t e and s c h i s t , dark grey a r g i l l i t e and p h y l l i t e , fragmental greenstones ( v o l c a n i c ) , limestones concordant contact probably d i s c o n f o r m i t y  Perrylode Formation  b l a c k p h y l l i t e , q u a r t z i t e , limestone contact covered  Badshot Formation  l i m e s t o n e , much r e c r y s t a l l i z e d  Badshot Formation  angular unconformity Mohican Formation  a r g i l l i t e , p h y l l i t e , argillaceous  limestone  Hamill series  probably angular unconformity G r i z z l i Notch Limestone  r e c r y s t a l l i z e d limestone  Hamill series  conformable contact Marsh-Adams Formation  impure q u a r t z i t e , green s c h i s t  Hamill series  contact probably conformable Mt. Gainer Quartzite  quartzite  Hamill series  3.  Lithology A l l rocks i n t h e area show the c h a r a c t e r i s t i c s o f  low-grade r e g i o n a l metamorphism and f i t i n t o the g r e e n s c h i s t facies.  They a l s o have been s u b j e c t e d t o carbonate,  and chromium-mica a l t e r a t i o n . A.  silica  (See P a r t I I , 1-2).  Green P h y l l i t e Macroscopic  Characteristics:  The rock i s a green p h y l l i t e w i t h a poor s c h i s t o s i t y . In  some places f i n e , l i g h t e r c o l o r e d spots show up that are  probably l i t h i c  fragments.  Microscopic Characteristics: A few t h i n s e c t i o n s show t h a t the rock i s made up dominantly  of l e n t i c u l a r fragments o f v o l c a n i c rocks which  are i n the order of a m i l l i m e t e r i n s i z e .  In the other s e c t -  ions the o r i g i n a l rock fragments are o n l y weakly The m i n e r a l assemblage c o n s i s t s dominantly  suggested.  of c h l o r i t e ,  (mostly p e n n i n i n e ) , a c t i n o l i t e , members o f the epidote group, f e r r i s t i l p n o m e l a n e , leucoxene was p o s s i b l e t o determine  the composition o f the p l a g i o c l a s e ,  i t was found t o be a l b i t e . due  and p l a g i o c l a s e ; wherever i t  The s c h i s t o s i t y o f the rock i s  t o the arrangement of the c h l o r i t e .  The m i c r o s c o p i c  c h a r a c t e r i s t i c s of the rock and i t s c l o s e a s s o c i a t i o n w i t h the l a p i l l i  t u f f suggest  an o r i g i n a l  tuff.  13 Alteration: The green p h y l l i t e i n many places i s c a r b o n a t i z e d . The  carbonate  u s u a l l y i s present i n u n i f o r m l y d i s t r i b u t e d  g r a i n s t h a t are about 200 microns p a r a l l e l t o the s c h i s t o s i t y .  i n s i z e and o f t e n elongate  The carbonate weathers r u s t y  brown and a t i n c i p i e n t stages gives a s p r i n k l e d appearance t o the s u r f a c e .  With h i g h e r degrees  of a l t e r a t i o n the whole  mass becomes r e d . B.  Green P h y l l i t e w i t h "Augen" S t r u c t u r e Macroscopic  Characteristics:  L i k e the t u f f t h i s rock i s a green p h y l l i t e ,  but  c h a r a c t e r i s t i c f o r i t are l i g h t e r c o l o r e d "augen" t h a t are u n i f o r m l y d i s t r i b u t e d through t h e whole mass. These l e n t i c u l a r fragments v a r y i n s i z e and a r e i n the average,  perhaps a cm.  long.  Some of them show v e s i c u l a r  texture. Microscopic Characteristics: M i c r o s c o p i c examination lapilli  tuff.  The  shows t h a t the rock i s a  "augen" appear t o be fragments of v a r i o u s  v o l c a n i c rocks such as amygdaloidal pyroxene-porphyries.  flows and f e l d s p a r and  The m a t r i x c o n s i s t s dominantly  of  c h l o r i t e , f i n e needles of a c t i n o l i t e and minerals of the e p i d o t e group, and of some leucoxene.  14 Alteration: L i k e the other greenstones, c a r b o n a t i z e d , and higher degrees  t h i s rock i s o f t e n  of a l t e r a t i o n d e s t r o y i t s  d i a g n o s t i c c h a r a c t e r i s t i c s ; but at moderate degrees augen s t r u c t u r e can s t i l l  the  be r e c o g n i z e d as l i g h t e r c o l o r e d  spots w i t h i n a network of dark brown l i n e s . C.  Graphitic Slate Macroscopic  (approaching  phyllite)  Characteristics:  The rock i s b l a c k and has s h i n e y cleavage i n c r o s s - s e c t i o n i t appears  rather s i l i c e o u s .  planes;  U s u a l l y the  cleavage i s not pronounced, but when s t r o n g l y weathered, the s l a t e i s q u i t e f i s s i l e and resembles phyllite.  very c l o s e l y the b l a c k  The absence of higher degrees  of a l t e r a t i o n .then i s  the o n l y d i a g n o s t i c f e a t u r e . Microscopic Characteristics: The dominant component of the rock i s q u a r t z . grains a r e g e n e r a l l y between 5 and  50 microns  most commonly between 10 and 20 microns.  in size  They are  The  and  fairly  angular and vary from elongate t o e q u i d i m e n s i o n a l i n shape. Up to 10$ of the s e c t i o n may  c o n s i s t of carbonaceous  matter  that occurs i n f i n e p a r a l l e l l a y e r s which o f t e n show f o l d s . A minor c o n s t i t u e n t i s muscovite.  T h i s m i n e r a l i s not  con-  c e n t r a t e d i n l a y e r s but occurs as i n d i v i d u a l f l a k e s o r i e n t e d i n v a r i o u s d i r e c t i o n s between adjacent quartz g r a i n s .  15 Alteration: The  rock i s a f f e c t e d by s i l i c i f i c a t i o n and  a t i z a t i o n , but that may  i t i s not  subject  obliterates i t s diagnostic  t o a complete a l t e r a t i o n properties.  Iron  carbonates  be present as brownish weathering nodules that  are u n i f o r m l y d i s t r i b u t e d .  carbon-  White quartz has  been  usually introduced  i n l a r g e r or f i n e r veins  that are p a r a l l e l to s c h i s t o s i t y or  occupy cross  Such cross  fractures.  curved shapes due  veins  o f t e n show p e c u l i a r  to d i f f e r e n t i a l movements w i t h i n  the  member. D.  Black P h y l l i t e Macroscopic C h a r a c t e r i s t i c s : In the member T2 the rock i s v e r y dark, f r a g i l e ,  and  fissile.  grey and  In the member B l the c o l o r v a r i e s  the t e x t u r e  Microscopic The  becomes more massive.  Characteristics:  dominant component of t h i s rock i s carbonaceous  matter that u s u a l l y amounts t o more than 50% It i s arranged i n p a r a l l e l l a y e r s and muscovite or c h l o r i t e .  Quartz and  p r i s e a t h i r d or l e s s of the rock. a few  and  to a b l u i s h  50 microns.  The  grains  may  of the  section.  be a s s o c i a t e d  with  perhaps f e l d s p a r may  com-  The are  elongate p a r a l l e l to the s c h i s t o s i t y .  g r a i n s i z e i s between  u s u a l l y l e n t i c u l a r and  16  Alteration: This rock type i s t o a much higher degree s u b j e c t to  a l t e r a t i o n than the g r a p h i t i c s l a t e .  nodules o f carbonates appear.  At i n c i p i e n t  With h i g h e r degrees  stages  the rock  g r a d u a l l y l o s e s i t s s c h i s t o s i t y and i s transformed i n t o a massive aggregate c o n s i s t i n g dominantly of carbonates may be v e i n e d by quartz and chromium mica and on f i r s t can h a r d l y be d i s t i n g u i s h e d from h i g h l y a l t e r e d  that sight  greenstones.  On c l o s e r examination, however, i t i s mostly p o s s i b l e t o detect the o r i g i n a l cleavage as s i l v e r y planes w i t h dark brown spots w i t h i n the r u s t y weathering mass. E.  Quartzite The q u a r t z i t e i s grey and has a poor c l e a v a g e .  It  i s made up mainly o f p o o r l y s o r t e d and r a t h e r angular g r a i n s of  quartz and some f e l d s p a r that range i n s i z e between  and 2 mm.  S m a l l amounts of micaceous m a t e r i a l ,  .2  dominantly  muscovite, are arranged i n f i n e , p a r a l l e l l a y e r s .  Grains o f  carbonate and opaque i r o n m i n e r a l s are s c a t t e r e d through the mass. 4.  D e s c r i p t i o n of the Formations  A.  Bunker H i l l Group, Uppermost Formation  and Members  Member B I . This member i s exposed  only i n the core o f the s o u t h -  western a n t i c l i n e where i t wedges out t o the northwest. maximum t h i c k n e s s here i s about one hundred f e e t .  The  The member  i s made up of t h i n l y interbedded b l a c k and green p h y l l i t e s ; the  green p h y l l i t e s appear t o be l i t h i c  tuffs.  Due t o the  l a c k of exposure and the h i g h degree of a l t e r a t i o n i t was not p o s s i b l e t o t r a c e i n d i v i d u a l beds, but i t seems that the two types i n t e r f i n g e r i r r e g u l a r l y ;  The t h i c k n e s s o f i n d i v i d u a l  beds v a r i e s from s e v e r a l f e e t t o f r a c t i o n s of an i n c h . Member B 2 . T h i s member c o n s i s t s o f green p h y l l i t e that probably is a l i t h i c  I t i s about 50 f e e t  tuff.  thick.  Member B 3 . Member B3 i s a green p h y l l i t e w i t h augen s t r u c t u r e and a l a p i l l i B.  tuff.  I t i s about 50 f e e t  thick.  T r i u n e Formation Member T l The member T l i s made up o f g r a p h i t i c s l a t e .  the  southwest  On  limb of the major a n t i c l i n e i t s t h i c k n e s s v a r i e s  from a few t o 150 f e e t , on the n o r t h e a s t limb i t ranges from 30 t o 300 f e e t .  These v a r i a t i o n s may i n part be due t o  sedimentary reasons, p a r t l y they may be p l a s t i c deformations. Member T2 This member i s made up dominantly of b l a c k p h y l l i t e but  i t a l s o c o n t a i n s lenses o f l a p i l l i  green p h y l l i t e s  t u f f and t u f f and o f  that were not s t u d i e d i n t h i n s e c t i o n s .  The  18 t h i c k n e s s of T2 v a r i e s :  on the southwest limb i t ranges be-  tween 200 and 400 f e e t , on the southeast 250  limb i t i s about  feet. Member T 3 The l i t h o l o g y of t h i s member i s the same as o f  Member T I :  i t c o n s i s t s of g r a p h i t i c s l a t e .  The apparent  t h i c k n e s s of the southwest limb i s about 1000 northeast due  f e e t , of the  limb about 550 f e e t ; but t h e r e may be r e p e t i t i o n s  t o f o l d i n g or f a u l t i n g . Member T4 Member T4 i s present only on t h e southwest  where i t i s about 200 f e e t t h i c k . g r a p h i t i c s l a t e and q u a r t z i t e . be due t o sedimentary  reasons  limb  I t c o n s i s t s of interbedded  The m i s s i n g o f t h i s member may or i t may have been caused by  squeezing, which i s q u i t e c h a r a c t e r i s t i c f o r the n o r t h e a s t limb o f the major 5.  anticline.  Environments o f D e p o s i t i o n The presence  of carbonaceous matter i n the Bunker  H i l l group as w e l l as i n the T r i u n e formation i n d i c a t e s dep o s i t i o n i n a b a s i n w i t h r e s t r i c t e d c i r c u l a t i o n and oxygen supply. sented  The dominant f e a t u r e d u r i n g most o f the time r e p r e i n t h i s s e c t i o n i s the s e d i m e n t a t i o n  suggests  a s l o p e (= c l i n o f o r m ) environment.  of s i l t  which  In the e a r l y p e r i o d  t h i s process was b r i e f l y overshadowed by a v o l c a n i c e x p l o s i o n  PLATE I I Triune  Mountain  View from the northwest A = Ajax Q u a r t z i t e w i t h i n f o l d s of T r i u n e and Jowett Formations. T4, T3 = members of the T r i u n e Formation 3 = No. 3 - l e v e l dump 4 = No. 4 - l e v e l dump To the l e f t  the a x i s of the c e n t r a l s y n c l i n e i s p l o t t e d  i n the source clastics.  The  area r e s u l t i n g i n the d e p o s i t i o n of  pyro-  r e s t r i c t e d l e n t i c u l a r shape of the l a s t  c l a s t i c f a c i e s may  be explained by submarine e r o s i o n .  the end of the p e r i o d d e p o s i t i o n s h i f t e d towards  pyroAt  coarser  sediments that f i n a l l y dominated i n the Ajax Q u a r t z i t e . s h i f t may II.  This  i n d i c a t e a change towards a s h e l f environment.  Major S t r u c t u r e Eastwood has  shown that a major f o l d which has  been t r a c e d f o r s e v e r a l m i l e s , extends i n t o the area S i l v e r Cup  and T r i u n e mines.  that i s overturned west.  I t i s an i s o c l i n a l  to the southwest and  of  anticline  plunges to the  north-  Our mapping i n d i c a t e s that t h i s a n t i c l i n e i n the  v i c i n i t y of S i l v e r Cup mine has  two  apices separated  by  a  t i g h t l y compressed s y n c l i n e . This concept i s based on the r e p e t i t i o n of c e r t a i n horizons  and the trend of c o n t a c t s .  t a i n e d from drag  folds.  Wo  i n f o r m a t i o n was  Although such s t r u c t u r e s a r e common  f a r t h e r out on the limbs, here, i n the core of the no drag f o l d was  ob-  found t h a t could be r e l a t e d w i t h  anticline, confidence  to the r e l a t i v e movement of outer l a y e r s towards the apex of the major a n t i c l i n e .  Furthermore, no c o n c l u s i o n s  about  fold  s t r u c t u r e could be drawn from bedding-cleavage r e l a t i o n s because the cleavage and  dips steeper  than the bedding on a l l limbs  g e n e r a l l y s t r i k e s 1 0 ° west of the a x i a l p l a n e s .  p l a n a t i o n can be given at present  No  ex-  f o r t h i s anomalous r e l a t i o n  21  PLATE I I I S i l v e r Cup A n t i c l i n e  on F i v e - M i l e h i l l s i d e  View from S i l v e r Cup mine The a n t i c l i n e  i s o u t l i n e d by the Ajax Q u a r t z i t e which, espec-  i a l l y on the southwest  limb, i s i n t r i c a t e l y f o l d e d .  22  it  i s not yet known i f there was  a second p e r i o d of r e g i o n a l  stress. The  outcrop map  shows that none of the members  could be t r a c e d continuously, but the d i s t r i b u t i o n of TI B3 may  be used as the key to the s t r u c t u r e .  Rocks of t h i s  type are exposed not only at the southwest and limbs  and  northeast  of the major a n t i c l i n e , but a l s o i n i t s c e n t r e .  centre B3 borders TI to the n o r t h e a s t and both wedge out to the southeast.  and  In the  to the southwest  The r e p e t i t i o n c o u l d be  e x p l a i n e d by c y c l i c d e p o s i t i o n and the wedging by the combined effect  of the r i s i n g topography and  an a n t i c l i n a l s t r u c t u r e .  I f t h i s were t r u e , B3 should widen w i t h depth and TI appear i n i t s c e n t r e on the steep s o u t h e a s t e r n s l o p e of the r i d g e between Alpha and S i l v e r Cup v e r t i c a l section. appear at a l l . cline. (1)  peaks, that provides an  However, B3  almost  t h i n s out and TI does not  This i n d i c a t e s a n o r t h w e s t e r l y plunging  T h i s e x p l a n a t i o n i s supported  by two  syn-  other f e a t u r e s :  In the core of the major s t r u c t u r e , near Towser t u n n e l ,  b l a c k p h y l l i t e crops out.  The appearance of t h i s rock  type  can be e x p l a i n e d by a s y n c l i n a l k e e l of the member T2. Supposing an a n t i c l i n a l s t r u c t u r e , we would have t o p o s t u l a t e a f a c i e s change or a complicated other evidence.  (2)  f o l d f o r which t h e r e i s no  Southwest of the centre the members B l  and B2 seem to p i n c h out to the northwest which i n d i c a t e s a n o r t h w e s t e r l y plunging a n t i c l i n e complementary to the syncline.  central  23 C o n s i d e r i n g the trends of the c o n t a c t s , the  topo-  graphy, and the approximate t h i c k n e s s of the members, the plunge  of these f o l d s was  c a l c u l a t e d t o be about 3 5 ° .  i s r e l a t i v e l y steep; plunges  obtained on drag f o l d s of the  Ajax Q u a r t z i t e are normally between 20° the plunge  This  and 3 0 ° .  Apparently  i n c r e a s e s i n the core of the a n t i c l i n e near  Triune basin.  The  occurrence of m i n e r a l i z a t i o n and  the  later  i n t r u s i v e s i n t h i s a r e a might have a r e l a t i o n t o such a s t r u c t u r a l anomaly. that i s based  But, at present t h i s i s a mere hypothesis  on l i t t l e  evidence.  I t may  w e l l be that the t r e n d  of contacts has been i n f l u e n c e d l a r g e l y by f a c i e s changes or s t r u c t u r a l squeezing and does not a l l o w to r e c o n s t r u c t the a n t i c l i n e i n such a manner.  N e v e r t h e l e s s , a composite  cross-  s e c t i o n has been prepared from s e c t i o n s at v a r i o u s l e v e l s (Figure 1 ) . were used  A plunge  i n this  of 33°  and p a r a l l e l t r e n d of the limbs  illustration.  No major f a u l t was  observed  i n the a r e a .  2 4  25  PART i i .  I.  ECONOMIC  GEOLOGY  M i n e r a l i z a t i o n and A l t e r a t i o n 1.  Mineralization The  mineralogy  o f t h e m i n e h a s b e e n d e s c r i b e d by  Gunning from a r e g i o n a l p o i n t o f view. s e c t i o n s w e r e s t u d i e d by t h e a u t h o r  A few p o l i s h e d  but no a d d i t i o n s c o u l d  be made.  The o r e m i n e r a l s i n t h e i r p a r a g e n e t i c s e q u e n c e a r e :  (oldest)  p y r i t e , c a r r y i n g s m a l l amounts o f s u b m i c r o s c o p i c gold. s p h a l e r i t e , w i t h minute blebs o f exsolved c h a l c o p y r i t e freibergite galena.  In the e a r l y stages  o f mining  r u b y s i l v e r was a l s o r e p o r t e d .  Of t h e gangue m i n e r a l s q u a r t z was f o u n d t h a n s p h a l e r i t e and e a r l i e r t h a n g a l e n a . fine fractures  t o be l a t e r  Carbonate  fills  i n a l l o t h e r m i n e r a l s a n d a p p e a r s t o be t h e  latest mineral. The  a s s e m b l a g e seems t o be t y p i c a l  lead-zinc-silver deposit.  f o r a mesothermal  The e x s o l u t i o n t e m p e r a t u r e  of  c h a l c o p y r i t e f r o m s p h a l e r i t e , h o w e v e r , was d e t e r m i n e d  by  Buerger  as 350°-400°C,  temperature  ( E d w a r d s , p. 9 8 ) , w h i c h  s l i g h t l y higher than that proposed  f o r t h e mesothermal group.  suggests  a  by L i n d g r e n  26  2.  Rock A l t e r a t i o n As p o i n t e d out by Gunning, rock a l t e r a t i o n i s a  common f e a t u r e i n the Lardeau and perhaps r e l a t e d t o the mineralization.  The dominant m i n e r a l group i n t r o d u c e d are Ca  Fe carbonates;  Mg  l e s s abundant are quartz and chromium bearing  mica of the f u c h s i t e - m a r i p o s i t e s e r i e s . F i e l d evidence and m i c r o s c o p i c examinations  show  that i n the S i l v e r Cup a r e a the chromium mica i s always a s s o c i a t e d w i t h quartz and  that both are l a t e r than the c a r -  bonates . The a l t e r a t i o n i s wide spread.  Due  to the l a c k of  exposure the s t r u c t u r a l c o n t r o l s c o u l d not be c l e a r l y n i z e d , but a l i t h o l o g i c a l c o n t r o l i s apparent;  recog-  the green  b l a c k p h y l l i t e s are much more s u s c e p t i b l e to a l t e r a t i o n the s i l i c e o u s black s l a t e .  3.  Age  than  Because the g r a p h i t i c s l a t e i s the  most f a v o u r a b l e rock type f o r ore d e p o s i t s i n t h i s a r e a a t i o n cannot  and  alter-  be used as a guide f o r e x p l o r a t i o n here. of M i n e r a l i z a t i o n  The age of the m i n e r a l i z a t i o n i s not known w i t h certainty. age  However, a lower l i m i t i s g i v e n by the  of the host rocks - lower P a l e o z o i c , and  probable  i t is likely  t h a t , as Gunning has p o i n t e d out, the m i n e r a l d e p o s i t s i n the Lardeau  are r e l a t e d t o neighbouring b a t h o l i t h i c  which are probably mostly Mesozoic  i n age.  intrusions  27  III.  Structural Ore Control 1.  Structural Control of the Main Ore Zone A.  Information from the Surface:  Detailed mapping on the surface revealed certain structural anomalies that probably are related to the l o c a l ization of the ore shoots. The most obvious feature is a pronounced curvature in the contact between B3 and TI, a feature quite unusual in this region where contacts are generally straight.  This  curvature resembles a dragfold indicating relative movement of the TI horizon to the northwest.  A small dragfold south-  east of the main deflection is in the same sense and rakes steeply (about 60°) to the northwest.  However, the trends  of schistosity do not everywhere conform to the dragfold pattern.  As shown on Figure 2 , at a zone southwest of the  contact the strata no longer follow a parallel course, but start curving in the opposite direction.  In the centre of  this zone of divergence are the old shaft and the f i r s t stopes of the Silver Cup lead. Lead is less clear.  The structural position of the Blind  The stopes of the lead are contained in  the major "bulge" but the contact TI - T3 is poorly exposed; only a few structural trends were available, and i t is also and  not quite clear where, to what extent the zone here was mineralized.  BLIND  LEAD  SILVER C U P r ^ L E A D  T2  Tl  0  10  FIG.2  20  B3  FEET  STRUCTURAL  TRENDS  STOPE  CONTACT  STRIKE  OF  SCHISTOSITY  AT  SURFACE  29 B.  Information  from Mine Maps  The  d i s t r i b u t i o n of stoped  areas  i n d i c a t e s that  nowhere i s the orezone more than 300 f e e t long whereas the rake l e n g t h i s more than 1200 f e e t . s h o r t a t the s u r f a c e , lengthens  The zone i s r e l a t i v e l y -  t o i t s maximum depth between  No. 3 and No. 7 l e v e l s , then shortens The  at g r e a t e r depth.  t o t a l w i d t h of the zone does not exceed 150 f e e t and i s  u s u a l l y l e s s than 100 f e e t . east and rakes  I t dips about 6 6 ° t o the n o r t h -  about 8 6 ° t o the northwest.  C.  Information  The  observations  from G e o l o g i c a l Mapping Underground underground may be summed up i n  three p o i n t s . (i)  The ore s t a y s i n the same member T I and at about the same  d i s t a n c e from the member B3 as at the s u r f a c e .  I t was not  p o s s i b l e , however, t o o u t l i n e the "bulge" underground.  This  s t r u c t u r e was n o t i c e d at the s u r f a c e by a d e f l e c t i o n of the contact and the trends  of s c h i s t o s i t y .  The c o n t a c t , however,  i s exposed underground at a few places o n l y , and the s t r u c t u r a l trends were not apparent because the d r i f t s u s u a l l y f o l l o w shear zones that are h i g h l y crumpled and show v e r y  irregular  attitudes. (ii) ever  L i t t l e ore has been l e f t  i n the l e v e l s  observed, the v e i n m a t e r i a l i s present  examined.  Where-  i n s t r i n g e r s or  v e i n s p a r a l l e l t o the s c h i s t o s i t y o f the country  rock.  I n d i v i d u a l s t r i n g e r s o f v e i n m a t e r i a l range i n w i d t h between  30  FiG.3 OUTLINES OF OREZONES A SECTION N57E / VERT. (SILVER CUP AND BLIND LEADS.) :  B SECTION S33E / 6 6 N E THROUGH SILVER CUP LEAD. :  a fraction  o f an  are  up  The  crumpling  not  have u n i f o r m  i n c h and  a foot, mineralized  to s e v e r a l f e e t wide.  tortion  seems t o be  t o the n e x t .  leads  A new  ( p e r h a p s due tensive  The  two  p e r s i s t s on s t r i k e  folding little the  not  ore  4 and  outside  No.  A  few  The  f r o m one  the  stope  mineralized  on  the  existence  surface  of  perfect dragfolds indicating but  general  conclusions  r e l a t i v e movement i n t h e s e  D.  con-  ex-  h i g h grade zone t h a t  northwest  directions.  u n i f o r m i t y t h a t no  the  7 levels  f o o t w a l l to the  i n other  The  can  do  shoots.  apparent  t o l a c k of exposure) i s the  i n No.  crumpled.  dragfolds  continuously  f e a t u r e underground not  only s p a r s e l y m i n e r a l i z e d .  ment o f t h e  are  of a s e r i e s of l e n t i c u l a r  crumpled zones  obtained  a whole  out w i t h i n t e n o r t w e n t y f e e t f r o m but  (iii)  is highly  a t t i t u d e s o r s e n s e o f movement.  usually dies  made up  w a l l rock  i n a l l d i r e c t i o n s and  v e i n normal to s t r i k e  but  The  z o n e s as  were  relative  there  are  move-  is also  p a t t e r n shows be  drawn  dragso  concerning  zones.  Interpretation  Examination of the  surface  showed t h r e e  significant  features: 1.  The  contact  fold with 2.  The  this  trends  contact  opposite in  steep  the  T1-B3  resembles  the  s e c t i o n through a  drag-  rake. of s c h i s t o s i t y  but,  are not  uniformly  at a c e r t a i n d i s t a n c e , are  direction.  The  overall picture.  trends  parallel  deflected in  of the a t t i t u d e s are  to the  lenticular  32  PLATE IV M i n e r a l i z e d zone i n No. 4 l e v e l , No. 11 d r i f t M i n e r a l i z a t i o n (white bands) i s s t r i n g e r - l i k e ; is  crumpled  the hostrock  3.  The S i l v e r Cup l e a d i s l o c a t e d i n the c e n t r e of d i v e r g e n t  attitudes.  The s t r u c t u r a l c o n t r o l o f the B l i n d l e a d i s not  c l e a r but i t i s contained i n the major zone o f deformation. From the d i s t r i b u t i o n of stoped areas on mine plans we concluded  t h a t the h i g h grade ore zone i s l e n t i c u l a r , d i p s  w i t h the host h o r i z o n t o the northeast, and rakes s t e e p l y t o the northwest. C o r r e l a t i n g these o b s e r v a t i o n s we a r r i v e at the concept  that the s t r a t a form a s t r u c t u r a l bulge t h a t i s  l e n t i c u l a r i n v e r t i c a l and h o r i z o n t a l s e c t i o n .  This s t r u c t u r e  contained zones of open space and low pressure that the d e p o s i t i o n of ore. p l a c e ; but the crumpling due  caused  Some i n t e r n a l s h e a r i n g may have of the w a l l rock i s perhaps  t o the adjustment o f s t r a t a remaining  taken  mostly  i n the c e n t r e o f  such openings t o the g e n e r a l s h o r t e n i n g of t h e s t r u c t u r e . Dragfolds at t h e c o n t a c t B3 - T l i n d i c a t e movement of the T l t o the northwest. thought  relative  T h i s movement i s  t o be r e s p o n s i b l e f o r the f o r m a t i o n of the major  bulge.  I t probably i n v o l v e d much l a r g e r p a r t s o f the h o r i z o n , as i n d i c a t e d by the shear zones i n No. 4 and No. 7 l e v e l s . the s h e a r i n g alone d i d not p r o v i d e s u f f i c i e n t ore  But  open space f o r  localization. 2.  S t r u c t u r a l C o n t r o l o f Minor Ore Bodies Due t o the l a c k of exposure or a c c e s s , the i n f o r -  m a t i o n about  the  main zone  much p o o r e r .  most for  is  other  ore bodies  H o w e v e r , a few f e a t u r e s and t h e s e  the  i n t e r p r e t a t i o n of  the s t r u c t u r a l ore c o n t r o l i n  between T I and B3 and p r e s e n t and g r a d e  i n the  is  two r o c k t y p e s  the No.  Such v e i n l e t s 7 level  p o r t a l w i t h i n the omic b e c a u s e  it  has  This  and r a i s e s  the  Host r o c k  greenstone.  that  f r o m remnants  feet  of  stopes  the  about  six  the  again indicate  Cup and B l i n d  feet  the econexavoided  t h e member T I . it  occurred i n It  o r e zone  is  that  reported were  that  i n that  T r i u n e body.  was  feet. is  10  The w i d t h  possibly  e x c e e d 200  a h i g h grade zone  and t h e  to  cut  not  obviously  7 level  deep and r e s e m b l e s  leads  faults  from  down t o N o . 7 l e v e l .  feet,  green-  and d i p p i n g  schistosity.  dimensions  Silver  and  i n an open  250  o r e was  The d e p t h p r o b a b l y d i d n o t  but r e l a t i v e l y  In the  b e e n m i n e d , and t h e  i n No. of  control  a p p a r e n t l y was  narrower.  narrow,  contact  but  two l e n s e s were p r e s e n t  l o n g and p e r s i s t e d is  type  of the  exposed  upper l e v e l  and 25  are exposed  of No. 8 l e v e l  between b u l g i n g p l a n e s  i n the  northeast  g e n e r a l l y not  ploration drifts  the  in small fissures  p o r t a l and a b o u t  level.  at  are d i f f e r e n t .  a r e commonly s t r i k i n g t o t h e southeast.  located  i n b o t h members;  stone the m i n e r a l i z a t i o n occurs  lenses  the  Sunshine, Z o n e  T h i s m i n e r a l i z e d zone  Judging  significant  a whole.  A.  above  are  common t o  them were n o t i c e d  that  features  the  of  a r e a as  the  i n the v i c i n i t y of  These  short,  respect Several  the small  35 7 l e v e l i n d i c a t e r e l a t i v e movement of T l to  d r a g f o l d s i n No. the northwest and the hanging w a l l .  one Due  d r a g f o l d suggests upward movement of to the l a c k of exposure at the s u r f a c e ,  however, an i n t e r p r e t a t i o n of the major s t r u c t u r e c o u l d not be made. B.  T r i u n e Mine  The mine was s u r f a c e exposures and mation was 1.  The  not i n s p e c t e d underground.  from o l d r e p o r t s the f o l l o w i n g i n f o r -  obtained.  dimensions of the stoped  i n depth, 200  The  500  zone are roughly  feet  5 f e e t i n w i d t h , which  f e e t i n l e n g t h , and  i n d i c a t e s a r e l a t i v e l y s h o r t and along d i p .  From the  flat  body that i s  s i m i l a r i t y of p r o p o r t i o n s  elongate  to the main zone  suggests perhaps another manto shaped body. 2.  The  ore zone i s contained  dominantly i n the h o r i z o n T l ;  the m i n e r a l i z a t i o n i n the greenstone seems to be cant. 3.  I t dips w i t h the host member s t e e p l y to the  The member T l here i s bordered  mass t o the northeast  and  that t h i n s out upward and  4.  northeast.  by a l a r g e greenstone  a s m a l l e r body t o the southwest to the southeast.  of the ore zone seems to l i e approximately stone  insignifi-  The  upper l i m i t  where the  green-  ends.  At the s u r f a c e some s h e a r i n g i s v i s i b l e i n the h o r i z o n T l .  At one  p l a c e s m a l l d r a g f o l d s , plunging  30°  to the  i n d i c a t e upward movement of the hanging w a l l .  northeast  Emmens s t a t e s  that the host rock o f the ore i s "much broken and t w i s t e d by l o c a l  disturbance". From t h i s i n f o r m a t i o n i t appears that the ore i s  l o c a l i z e d i n a shearzone w i t h i n the member T l and that the shearing  i s p o s s i b l y r e l a t e d t o the greenstone body at the  southwest.  (See s e c t i o n 4C) C.  Free Coinage Workings  The workings a r e mainly i n t h e members T l and T2; a c r o s s c u t extends through B3 and i n t o B2. are p r e s e n t ,  No ore bodies  only a l a r g e number of s m a l l quartz v e i n s which  are s p a r s e l y m i n e r a l i z e d .  Gunning's underground mapping  shows a l a r g e shear zone which r e f l e c t s the warping o f the T l h o r i z o n at the s u r f a c e . control.  T h i s shear zone i s the major  S t r u c t u r a l l y the quartz v e i n s a r e o f three  types:  1.  R e l a t i v e l y narrow v e i n s p a r a l l e l t o s c h i s t o s i t y .  2.  I r r e g u l a r , short but o f t e n r e l a t i v e l y wide lenses r e -  lated to intense 3.  Tension  crumpling.  f r a c t u r e s r e l a t e d t o major warps.  These f r a c t u r e s  are d i p p i n g s t e e p l y t o t h e northwest.  f e e t wide.  D.  Towser Tunnel  The  Towser ore body i s about 175 f e e t l o n g , 4 t o 5  I t terminates  about 50 f e e t below the present  f a c e but may have extended c o n s i d e r a b l y above i t . Host i s the member T l .  Drusy c a v i t i e s a r e present  sur-  rock  and the ore  PLATE V T r i u n e Mine View from the north-west TI,  T2, T3 = members o f the T r i u n e Formation s l a t e s and p h y l l i t e s ) .  (black  T2A = greenstone, probably t u f f , member o f the T r i u n e Formation B = Bunker H i l l Group, uppermost f o r m a t i o n , greenstone member W = workings  of T r i u n e mine, (No. 4 and No. 2 l e v e l s ) .  38 seems to have formed by open space f i l l i n g . access and exposure the c o n t r o l l i n g 3.  Summary and Two  But due  s t r u c t u r e was  to  not  limited  recognized.  Conclusions  f e a t u r e s are common to the four producing  zones:  1.  They are a l l i n the b a s a l member of the T r i u n e  2.  T r i u n e , main and Sunshine zone are deep but narrow and  s h o r t and seem t o be l e n t i c u l a r . the Towser body, but e r o s i o n has  The  same may  obscured  formation.  be t r u e f o r  the p i c t u r e here.  On the other hand, the zones are not a l l i n the same s t r u c t u r a l  position  w i t h r e s p e c t t o the ::t#o.' a n t i c l i n e s : !  the main zone and the Sunshine zone are on the southwest limb of the southwestern  anticline,  the Towser body i s on  the southwest limb of the n o r t h e a s t e r n a n t i c l i n e , and T r i u n e mountain the two  on  apices are no longer r e c o g n i z a b l e ;  the mine here i s on the southwest limb of the major  anticline.  There seems to be a c e r t a i n  p r e f e r e n c e of the showings f o r  the southwest s i d e t h a t may  have been caused  by  structural  reasons, but perhaps i s only a c c i d e n t a l because t h i s  area  i s b e t t e r exposed. The d e p o s i t s are i s o l a t e d of continuous  veins.  They may,  to e x t e n s i v e shear zones. where exposed i n the No. mine and  But  and c e r t a i n l y  not p a r t s  i n t h e i r o r i g i n , be the shear zones  4 and No.  related  themselves,  7 l e v e l s , of the S i l v e r  i n the Free Coinage workings, do not c o n t a i n ore.  Cup  The  only c e r t a i n c o n c l u s i o n we can draw i s that T I  seems t o be the f a v o u r a b l e member. graphic  ore c o n t r o l .  d i f f e r e n t types:  This implies a s t r a t i -  S t r a t i g r a p h i c ore c o n t r o l s a r e o f  they may be sedimentary, chemical  replacement d e p o s i t s ) or mechanical (with open space These d e p o s i t s  (with fillings).  a r e c e r t a i n l y n e i t h e r sedimentary nor o f the  replacement type;  (replacement d e p o s i t s would have p r e f e r r e d  the greenstone).  I t seems, t h e r e f o r e , t h a t the mechanical  p r o p e r t i e s of the host h o r i z o n under c e r t a i n s t r e s s c o n d i t i o n s were f a v o u r a b l e localized  f o r the formation  ore d e p o s i t s .  o f l e n t i c u l a r openings which  Next we w i l l  i n v e s t i g a t e what these  p r o p e r t i e s were l i k e and how such openings may have been formed. 4.  Causes of Ore C o n t r o l l i n g S t r u c t u r e s A.  Texture of the Host Rock  M i c r o s c o p i c a l l y the member T I c o n s i s t s o f s i l t s i z e d quartz  grains w i t h f i n e l a y e r s of g r a p h i t i c m a t e r i a l  i n between.  Two important mechanical p r o p e r t i e s r e s u l t  this  from  texture:  1.  low cohesion  and  the q u a r t z ,  2.  f a i r competence w i t h i n the quartz The  the rock  between the l a y e r s of g r a p h i t i c m a t e r i a l  layers.  g r a p h i t i c l a y e r s a r e p o t e n t i a l shear p l a n e s .  i s subjected  t o d i f f e r e n t i a l pressures  If  i t w i l l most  40  l i k e l y react to the components p a r a l l e l t o the s c h i s t o s i t y by s l i p p a g e on these p l a n e s .  Due t o the competence o f the  quartz l a y e r s these movements may be t r a n s m i t t e d r e l a t i v e l y f a r but w i l l d i e out because o f crumpling.  In t h i s  process  of movement and crumpling, l a y e r s that are separated by h i g h c o n c e n t r a t i o n s of carbonaceous  m a t e r i a l may break apart and  bend i n d i f f e r e n t d i r e c t i o n s , l e a v i n g l e n s l i k e openings i n the c e n t r e .  The l e n g t h and the width o f these' openings  be determined  will  by the s t r e n g t h o f t h e rock and by the con-  f i n i n g pressure.  The t h i r d dimension, however, i s not  dependent on these f a c t o r s ; i t i s l i m i t e d only by the extent of the f r o n t at which t h e d i f f e r e n t i a l f o r c e s are a c t i n g . Thus may be produced  openings  that are s h o r t and narrow but  r e l a t i v e l y deep. The other rock types i n the a r e a do not possess t h i s combination o f mechanical p r o p e r t i e s and t h e r e f o r e do not produce  the same type of s t r u c t u r e .  The b l a c k p h y l l i t e  has a much more pronounced s c h i s t o s i t y but a low competence. This rock f r e q u e n t l y shows i n t e n s e crumpling, but the deformations extend only over s h o r t d i s t a n c e s and c o n s i s t o f short  folds. The greenstone, on the other hand, possesses a f a i r  competence but a poor s c h i s t o s i t y .  I t does not show crumpling  at a l l and seems t o r e a c t t o f o r c e by p l a s t i c  deformation.  41  M i n e r a l i z e d openings i n the greenstone c o n s i s t of j o i n t s faults.  or  These s t r u c t u r e s are e s s e n t i a l c o n t r o l s i n the Sun-  shine Lardeau mine at Camborne, but they have no i n the S i l v e r Cup Bi  Thickness  importance  area. of the host h o r i z o n and mechanical  p r o p e r t i e s of the o v e r l y i n g p h y l l i t e With respect to l i t h o l o g y the h o r i z o n T3 i s as f a v o u r a b l e f o r ore l o c a l i z a t i o n as the member T l . we not  f i n d these l e n t i c u l a r s t r u c t u r e s i n T3?  One  ence between the two members i s t h e i r t h i c k n e s s : narrow, u s u a l l y l e s s than 100 1000  feet i n thickness.  Why  do  differ-  T l i s very  f e e t , whereas T3 ranges up  But what may  to  be the i n f l u e n c e of  thickness? The  amplitude  of these drag  or crumple f o l d s , that  seen to be the ore c o n t r o l i n the S i l v e r Cup  and T r i u n e  depends on the competence of the o v e r l y i n g h o r i z o n s .  The  b l a c k p h y l l i t e of the h o r i z o n T2 i s l e s s competent than s i l i c e o u s s l a t e of T l and T3.  The  however, has  Only a marginal  the same advantage.  the  formation of f o l d s w i t h i n  the narrow T i c e r t a i n l y i s f a c i l i t a t e d by the of the b o r d e r i n g T2.  area,  incompetence  zone of the member  T^  F u r t h e r i n s i d e of t h i s  h o r i z o n there w i l l be a higher r e s i s t a n c e to deformation. problem remains, why marginal  zone of T3.  there are no ore d e p o s i t s w i t h i n the In the next  s e c t i o n a few more p e c u l -  The  iarities  of TI w i l l be p o i n t e d out that may  p r o v i d e an answer  to t h i s q u e s t i o n . C.  D i f f e r e n t i a l Forces (a)  General Statement  The rake of the ore c o n t r o l l i n g drag and f o l d s i s s t e e p , almost v e r t i c a l , whereas the major c l i n e probably plunges not more than 30° br these s t r u c t u r e s cannot  40°.  crumple antiTherefore  be e x p l a i n e d by r e l a t i v e s l i p p a g e of  outer l a y e r s towards the apices of the major f o l d ; they seem to be r e l a t e d t o h o r i z o n t a l movements. At t h i s stage of mapping no obvious cause of such movements i s v i s i b l e .  A l l we n o t i c e i s a remarkably  uniform  trend of the f o l d s which i n d i c a t e a uniform pressure normal to the a x i a l p l a n e s . been caused present we  The h o r i z o n t a l displacements may  by f o r c e s of which we  have  have no knowledge; at  only can t r y and r e l a t e them somehow t o the g e n e r a l  regional pressure. The  two hypotheses  o f f e r e d are based on the f o l l o w -  ing f i e l d o b v e r s a t i o n s : 1.  Immediately  southeast of the main zone the b a s a l T r i u n e  begins t o t h i n and a c q u i r e s the shape of a wedge p o i n t i n g t o the s o u t h e a s t . 2.  The t h i n n i n g i s accompanied by a s e r i e s of deformations  43 that appear to be continuous:  at the main zone i s the  "bulge"; southeast from here, i n the v i c i n i t y Coinage  a d i t , the h o r i z o n i s warped; and  of the Free  farther southeast,  near the r i d g e , there i s evidence of i n t e n s i v e s h e a r i n g . The d r a g f o l d s near the main zone i n d i c a t e r e l a t i v e movement of the member TI t o the northwest. ment, the t h i n n i n g , and  I t seems that the move-  the deformation are r e l a t e d .  The t h i n n i n g of the TI may causes:  e i t h e r sedimentary  have had two  possible  changes or s t r u c t u r a l  deformation.  It d e f i n i t e l y does not i n d i c a t e the k e e l of a southwesterly plunging s y n c l i n e because t h e r e i s no r e p e t i t i o n of s t r a t i graphic horizons about such a f o l d a x i s . hypothesis sedimentary  Hypothesis  have acted:  second  do not exclude each o t h e r .  I.  I f the t h i n n i n g was mechanism may  first  changes are assumed; i n the  deformation; both hypotheses (b)  In the  sedimentary  the f o l l o w i n g  the r e g i o n a l f o r c e p r e s s i n g on  the wedge's i n c l i n e d f a c e had a component d i r e c t e d t o the northwest.  The component i s g i v e n by f  sin  alpha  cos a l p h a  where f i s the r e g i o n a l f o r c e and a l p h a the angle between the wedge's face and the a x i a l plane of the f o l d s .  The  factor  that has t o be a p p l i e d to the major f o r c e i s 0.07.  It i s  44  thought that the b a s a l T r i u n e r e a c t e d t o , t h i s component a not v e r y competent body, mainly  by crumpling  and p a r t l y by  movement that r e s u l t e d i n the formation o f d r a g f o l d s . q u e s t i o n i s whether the n o r t h w e s t e r l y  like  The  component of the  r e g i o n a l f o r c e was s t r o n g enough t o overcome cohesion and f r i c t i o n o f the r o c k s . (c)  Hypothesis I I  In the v i c i n i t y of the S i l v e r Cup mine the t h i n n i n g of the T l i s most pronounced where the o v e r l y i n g T l c o n t a i n s greenstone f a c i e s . the T l i s covered  Southeast by d r i f t .  T r i u n e mountain, i t s t i l l southeast  from here, i n the T r i u n e b a s i n , Where i t appears a g a i n , on  i s v e r y narrow and bordered  by a greenstone u n i t that may be continuous  the mass on the northwest s i d e o f the b a s i n . stone  width.  The greenstone,  with  Then the green-  t h i n s out and the b a s a l T r i u n e member begins  on the top of T r i u n e mountain i t has regained  to "the  t o widen;  its original  c o n t a i n i n g c o n s i d e r a b l e amounts of  f e l d s p a t h i c m a t e r i a l and p o s s e s s i n g a poor s c h i s t o s i t y i s a more competent rock than the b l a c k p h y l l i t e which i s made up dominantly o f carbonaceous matter and muscovite.  This i m p l i e s  that the greenstone w i l l transmit s t r e s s e s t o a higher  degree  than the p h y l l i t e which absorbs more energy i n the v a r i o u s processes The  of compaction, i n t e r n a l s h e a r i n g , and c o n t o r t i o n .  s p a c i a l r e l a t i o n between the t h i n n i n g of the b a s a l T r i u n e  member and the presence o f greenstone suggests  that i n the  45  process  o f f o l d i n g the l a t t e r rocks were p r e s s i n g harder on  the u n d e r l y i n g T I and squeezed i t out t o the northwest on the S i l v e r Cup s i d e and t o t h e southeast The  t h i n n i n g i s thought  on the T r i u n e  t o have been accomplished  e n t i a l movements on the planes o f s c h i s t o s i t y .  l o c a l i z e d ore.  Again  5.  developed  i t i s a problem  whether the d i f f e r e n c e s i n s t r e s s were s u f f i c i e n t p l i s h such  by d i f f e r -  As a r e s u l t  of these shear movements the d r a g f o l d s and bulges that subsequently  side.  t o accom-  deformations.  Practical Applications The  p r a c t i c a l r e s u l t of the paper i s that the  S i l v e r - l e a d - z i n c d e p o s i t s of the S i l v e r Cup and T r i u n e a r e a occur i n s t e e p l y r a k i n g , narrow, s h o r t , but deep, l e n t i c u l a r zones w i t h i n the b a s a l member of the T r i u n e f o r m a t i o n .  This  member should be explored s y s t e m a t i c a l l y from the s u r f a c e w i t h s u i t a b l e g e o p h y s i c a l or geochemical  methods.  Unfor-  t u n a t e l y , e l e c t r i c a l methods cannot be employed because of the g r a p h i t i c nature of the host r o c k . Wherever ore i s found, development should  primarily  f o l l o w down i t s rake w i t h the hope t h a t the zone i s many times  as deep as i t i s long or wide.  However, e r o s i o n may  have removed c o n s i d e r a b l e parts o f the o r e b o d i e s .  Extensive  e x p l o r a t i o n d r i f t s , as present on the No. 4, No. 7 and No. 8 l e v e l s o f the S i l v e r Cup mine and i n the Free Coinage workings  46  do not seem to be promising because the d e p o s i t s are not of the v e i n type. Judging from i t s l e n t i c u l a r shape the main ore zone of the S i l v e r Cup mine may  extend to g r e a t e r depth,  but i t i s not l i k e l y that the stope l e n g t h should i n c r e a s e ; unless another, s i m i l a r  s t r u c t u r e were encountered  there i s no evidence at p r e s e n t .  f o r which  BIBLIOGRAPHY  Brock, R.W., Summary Report on the Operations of the G e o l o g i c a l Survey f o r the year 1903, Ottawa, 1904, pp. 66A-71A. Cannon, P.M., Report on the P r o p e r t y o f the S i l v e r Cup Mine, Ferguson, B r i t i s h Columbia. Copper Mountain, B.C., 1 ? 4 1 . ( C o n f i d e n t i a l ) . Eastwood, G.E.P., Maps and Reports, C e n t r a l Lardeau Map-area. (Unpublished). Edwards, A.B., Textures of the Ore M i n e r a l s and t h e i r S i g n i f i c a n c e . Melbourne, 1 9 5 4 . Hamilton, W.S., S i l v e r Cup Mine, P r e l i m i n a r y Report, (Confidential). :  Sullivan.  J . . and P i c k a r d . E.H.. 1953, (Confidential).  S i l v e r Cup P r o p e r t y ,  Walker, J . F . , and B a n c r o f t , M.F., Lardeau Map-area. General Geology. M i n e r a l D e p o s i t s by H.C.Gunning.  BLIND  LEAD  SILVER  CUP  i  10  •  20  FEET  t  \ \  I V  2 STRUCTURAL TRENDS AT SURFACE STOPE  CONTACT  STRIKE  OF  SCHISTOSITY  t  SW  NE  NW  SURFACE  N.3-LEVEL  N.4-  LEVEL  *  N.9-LEVEL  N.I2-  -I  FIG.3  300 L  L E V E L  B  FEET  OUTLINES OF OREZONES  A= SECTION  N57E/  VERT. (SILVER CUP AND BLIND LEADS.)  B= SECTION  S33E/  66  NE THROUGH SILVER CUP LEAD.  

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.831.1-0053029/manifest

Comment

Related Items