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UBC Theses and Dissertations

Design of sub level caving method by means of mine model tests Sarin, Devinder Kumar 1970

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DESIGN OF SUB LEVEL CAVING METHOD BY MEANS OF MINE MODEL TESTS By DEVINDER KUMAR SARIN B. T e c h . ( H o n s ) . , I n d i a n I n s t i t u t e o f T e c h n o l o g y , K h a r a g p u r , I n d i a , 1962 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE i n t h e Depar tment o f MINERAL ENGINEERING We a c c e p t t h i s t h e s i s as c o n f o r m i n g t o t h e r e q u i r e d s t a n d a r d . THE UNIVERSITY OF BRITISH COLUMBIA A p r i l , 1970. I i In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l l m e n t o f t h e r e q u i r e m e n t s f o r an a d v a n c e d d e g r e e a t t h e U n i v e r s i t y o f B r i t i s h C o l u m b i a , I a g r e e t h a t t h e L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e a n d s t u d y . I f u r t h e r a g r e e t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y p u r p o s e s may b e g r a n t e d by t h e Head o f my D e p a r t -ment o r b y h i s r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l n o t be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . DEVINDER K. S A R I N . D e p a r t m e n t o f MINERAL ENGINEERING The U n i v e r s i t y o f B r i t i s h C o l u m b i a , VANCOUVER 8, C a n a d a . DATE: A P R I L , 1 9 7 0 . ABSTRACT D e s i g n c r i t e r i a o f t h e L o n g i t u d i n a l S u b - L e v e l C a v i n g method o f m i n -i n g , as i t w o u l d p a r t i c u l a r l y a p p l y t o Granduc M i n e s , has been s t u d i e d by means o f g e o m e t r i c a l l y s c a l e d mine m o d e l s . P r i n c i p l e s o f s i m i l a r i t y and t h e i r use i n t h e model t e s t work w i t h due c o n s i d e r a t i o n t o t h e s i m p l i f y i n g a s s u m p t i o n s have been a n a l y s e d . G r a v i t y f l o w t h e o r i e s o f g r a n u l a r m a t e r i a l as a p p l i c a b l e t o t h e b i n d e s i g n work have been used where p o s s i b l e i n t h e s t o p e d e s i g n . A t o t a l o f t h i r t y - s e v e n t e s t s on a 1:30 s c a l e model were c o n d u c t e d i n v o l v i n g v a r i o u s o r e b o d y c o n f i g u r a t i o n s . Q u a l i t a t i v e o b s e r v a t i o n s a r e r e -p o r t e d and t h e e f f e c t s t h a t w i l l have t o be d e a l t w i t h by t h e o r e t i c a l t r e a t -ment a r e d e s c r i b e d . W i t h i n r e a s o n a b l e e x p e r i m e n t a l a c c u r a c y , t h e draw f i g u r e s o f t h e f l o w o f b r o k e n o r e m a t e r i a l i n t h e model a r e d e t e r m i n e d . Based on t h e s e f i g u r e s , mine l a y o u t p a t t e r n s w h i c h w o u l d e n s u r e maximum o r e r e -c o v e r y w i t h minimum w a s t e d i l u t i o n f r o m t h e s t o p e s have been p r e s e n t e d f o r the mine d e v e l o p m e n t w o r k . Q u a n t i t a t i v e d e s i g n o f ' b l a s t r e t r e a t d i s t a n c e 1 d e p e n d i n g on change i n n a t u r a l c o n d i t i o n s o f the s t o p e , s u c h as m o i s t u r e c o n t e n t and c o n f i n i n g p r e s s u r e s , e t c . have been d e t e r m i n e d by m e a s u r i n g t h e f l o w p r o p e r t i e s o f the o r e m a t e r i a l w i t h T r i a x i a l c o m p r e s s i o n t e s t i n g e q u i p m e n t . A r e m a r k a b l e change i n t h e f l o w p r o p e r t i e s and hence t h e draw c o n f i g u r a t i o n i s p r e d i c t e d . Recommendat ions on f u r t h e r and a d v a n c e d work a r e i n c l u d e d on t h e q u a n t i t a t i v e d e s i g n o f s t o p i n g l a y o u t s f o r t h e modern s u b - l e v e l c a v i n g m e t h o d s . ACKNOWLEDGEMENTS The w r i t e r w i s h e s t o t h a n k D r . C. L. Emery f o r g u i d i n g h i s g r a d u a t e s t u d y p r o g r a m and f o r t h e a d v i c e r e c e i v e d d u r i n g t h i s i n v e s t i g a t i o n . G r a t e f u l a p p r e c i a t i o n i s e x p r e s s e d f o r t h e s u p p o r t r e c e i v e d f r o m t h e management o f Granduc O p e r a t i n g Company and t h e s e n i o r e n g i n e e r s f o r t h e i r encouragement and a l s o h i s c o l l e a g u e s i n t h e e n g i n e e r i n g d e p a r t m e n t o f whose v a l u a b l e c o n t r i b u t i o n s a r e t h a n k f u l l y a c k n o w l e d g e d . The a u t h o r i s g r a t e f u l t o P r o f e s s o r C r o u c h and D r . B a i n f o r t h e i r g u i d a n c e and c o n s t r u c t i v e c r i t i c i s m d u r i n g t h e d e v e l o p m e n t and p r e p a r a t i o n o f t h i s t h e s i s . The o p p o r t u n i t y i s t a k e n h e r e , as w e l l , t o a c k n o w l e d g e the e s s e n t i a l s u p p o r t r e c e i v e d f r o m h i s w i f e , S h e s h i , d u r i n g t h e p e r i o d o f s t u d y and d i s c i p i i n e . A p r i l , 1 9 7 0 STEWART, B. C. V TABLE OF CONTENTS PAGE CHAPTER 1 INTRODUCTION 1 1.1 L o c a t i o n and G e o l o g y 1 1 .2 P u r p o s e 1 1 .3 Scope 3 CHAPTER 2 STATE OF THE ART 5 2.1 G e n e r a l 5 2.2 P r i n c i p l e s o f g r a v i t y f l o w and d e s i g n o f m a s s - f l o w b i n s 9 2.3 P r i n c i p l e s o f s i m i l i t u d e i n t h e f l o w o f g r a n u l a r m a t e r i a l s 12 CHAPTER 3 THEORETICAL CONSIDERATIONS 15 3.1 G e n e r a l 15 3.2 Theory o f mode ls 15 3.3 G r a v i t y f l o w and d e t e r m i n a t i o n s o f t h e p a r a m e t e r s i n sub l e v e l c a v i n g 19 3.4 D e s i g n o f m a s s - f l o w b i n s v/s s t o p e d e s i g n . . . . 33 CHAPTER 4 CONSTRUCTION AND OPERATION OF THE TESTING EQUIPMENT 36 4.1 G e n e r a l 37 4.2 C o n s t r u c t i o n 37 4.3 Ore and w a s t e m a t e r i a l 40 4.4 E x t r a c t i o n d r i f t s and l o a d i n g b u c k e t 40 4.5 O p e r a t i o n o f t h e model 41 4.6 T r i a x i a l c o m p r e s s i o n t e s t i n g e q u i p m e n t 45 v i PAGE CHAPTER 5 TESTS DESCRIPTION PROCEDURES AND RESULTS 49 5.1 G e n e r a l 49 5.2 D e s c r i p t i o n o f model t e s t s 50 5.3 T e s t P r o g r a m 51 5.4 T e s t i n g p r o c e d u r e 52 5.5 T e s t r e s u l t s 56 5.6 D i s c u s s i o n on t h e l o n g i t u d i n a l sub l e v e l c a v i n g t e s t s 58 5.61 20 f t . o r e b o d y w i d t h 58 5-62 30 f t . o r e b o d y w i d t h 61 5.63 40 f t . o r e b o d y w i d t h 62 5.64 50 f t . o r e b o d y w i d t h 65 5-7 D i s c u s s i o n on t h e t r a n s v e r s e sub l e v e l c a v i n g t e s t s 68 5.8 Change i n t h e a n g l e o f s i i d i n g - d e t e r m i n e d by t r i a x i a l c o m p r e s s i o n t e s t i n g e q u i p m e n t 69 CHAPTER 6 CONCLUSIONS 72 CHAPTER 7 RECOMMENDATIONS FOR FURTHER WORK AND DISCUSSION 74 7.1 Recommendat ions f o r f u t u r e work 74 7.2 O p e r a t i o n a l and p r a c t i c a l d e t a i l 76 7.3 Comments on t h e q u a n t i t a t i v e d e s i g n o f t h e s t o p e s 82 v i i PAGE LIST OF REFERENCES , 84 APPENDIX I Theory o f mode ls 89 APPENDIX II T a b l e s 1 and IA - R e s u l t s 96 APPENDIX t i l T a b l e s 2, 3 and 4 104 APPENDIX IV T a b l e 5 ~ D e s i g n d a t a f o r t h e recommended l a y o u t s 108 APPENDIX V P i c t u r e s o f l o n g i t u d i n a l sub l e v e l c a v i n g model t e s t s 122 APPENDIX VI D e t a i l s on G e o l o g y 131 NOMENCLATURE v i i i <^  - R i n g g r a d i e n t a ^ " S e m i - m a j o r a x i s o f t h e e l l i p s o i d o f m o t i o n A - A r e a o f t h e o p e n i n g A w - W i d t h o f s i i c e bft - S e m i - m i n o r a x i s o f the e l l i p s o i d o f m o t i o n b . r . d . - B l a s t r e t r e a t d i s t a n c e B - W i d t h o f t h e e x t r a c t i o n d r i f t C - S i z e o f the e x t r a c t i o n a r e a d - A v e r a g e s i z e o f p a r t i c l e s d j - D i g g i n g d e p t h o f t h e s c o o p ds - S p h e r i c a l d i a m e t e r o f p a r t i c l e s D - D i a m e t e r o f l a r g e s t lumps i n b l a s t e d o r e Dh - H y d r a u l i c o r p e r i m e t r a l d i a m e t e r = k x A / p e r i m e t e r o f o r i f i c e ejvj - E c c e n t r i c i t y o f the e l l i p s o i d o f m o t i o n Efg - Volume of t h e e l l i p s o i d o f m o t i o n F.W. - Foot wal1 T - U n i t w e i g h t o f g r a n u l a r m a t e r i a l g - A c c e l e r a t i o n o f g r a v i t y h - H e i g h t o f e x t r a c t i o n d r i f t h' - H e i g h t o f t h e g r a v i t y f l o w h^ - H e i g h t o f t h e e l l i p s o i d o f m o t i o n H - Head of p a c k i n g above o p e n i n g H.W. - Hang i ngwa11 K - P r o p e r t i e s o f t h e lumpty m a t e r i a l Volume o f d i s c h a r g e A s i g n i f i c a n t d i s t a n c e Any p e r t i n e n t d i s t a n c e L e n g t h s c a l e Ore r e c o v e r y = % o r e r e c o v e r e d t o o r e b l a s t e d W i d t h o f p i l l a r between d r i f t s A n g l e o f i n t e r n a l f r i c t i o n B l a s t r e t r e a t d i s t a n c e ( s i n g l e o r m u l t i p l e r i n g b u r d e n ) T rue d e n s i t y o f s o l i d s B u l k d e n s i t y o f p a c k i n g Sub l e v e l i n t e r v a l (or ' S ' ) Swel1 f a c t o r (Volume o f s o l i d s + volume o f v o i d s ) . Volume o f s o l N a t u r a l a n g l e o f r e p o s e Normal s t r e s s on the f a i l u r e p l a n e H o r i z o n t a l s t r e s s on t h e v e r t i c a l s u r f a c e o f s l i d i n g V e r t i c a l s t r e s s A n g l e o f s i d e s l o p e s ( A n g l e o f i n c l i n a t i o n o f t h e hopper bo t tom) S h e a r s t r e s s on f a i l u r e p l a n e T o t a l e x t r a c t i o n = % o f r o c k l o a d e d t o o r e b l a s t e d (100%) V e l o c i t y o f d i s c h a r g e f r o m o p e n i n g Draw vo lume Volume o f c o n t a i n e r Volume o f d i s c h a r g e d m a t e r i a l A v e r a g e v e r t i c a l p r e s s u r e S p e c i f i c w e i g h t o f t h e m a t e r i a l o r dead w e i g h t ( D i m e n s i o n a l l y , FL~3) Waste d i 1 u t i o n = % o f w a s t e l o a d e d t o t o t a l r o c k l o a d e d (100%) Depth b e l o w t h e s u r f a c e x i L IST OF FIGURES FIGURE: PAGE 1. G r a v i t y f l o w o f g r a n u l a r m a t e r i a l 8 2. T r a n s v e r s e sub l e v e l c a v i n g 20 3. L o n g i t u d i n a l sub l e v e l c a v i n g 21 k. F a i l u r e i n c o h e s i o n l e s s g r a n u l a r m a t e r i a l p r e c e d e d by a r c h i n g 30 5. S t a n d a r d t r a n s v e r s e sub l e v e l c a v i n g l a y o u t 3k 6 A . Mine Model a s s e m b l e d f o r t r a n s v e r s e sub l e v e l c a v i n g 37 6B. M i n e Model a s s e m b l e d f o r l o n g i t u d i n a l sub l e v e l c a v i n g 38, 39 7. B l a s t p l a t e s ; wooden b l a s t i n g b l o c k , e x t r a c t i o n d r i f t and b u c k e t kl 8. T r i a x i a l t e s t i n g e q u i p m e n t k~J 9- C a l c u l a t i o n p r o c e d u r e f o r o r e r e c o v e r y , t o t a l e x t r a c t i o n and w a s t e d i l u t i o n 57 10. A n g l e o f s l i d i n g w i t h v a r y i n g m o i s t u r e c o n t e n t d e t e r m i n e d by t r i a x i a l t e s t 70 11. C o m p a r i s o n o f o r e r e c o v e r i e s v/s t o t a l e x t r a c t i o n s 6k 12. L o n g i t u d i n a l sub l e v e l c a v i n g -p o s s i b l e p o s i t i o n i n g o f e a s e r h o l e s 80 13. L o n g i t u d i n a l sub l e v e l c a v i n g - vee shaped l o n g h o l e f a n s 81 ]k. L o n g i t u d i n a l sub l e v e l c a v i n g - shows s e q u e n c e o f draw w i t h s i n g l e d r i f t on each s u c c e s s i v e sub l e v e l 123 t o 127 15. L o n g i t u d i n a l sub l e v e l c a v i n g - shows s e q u e n c e o f draw w i t h two e x t r a c t i o n d r i f t s on a sub l e v e l 128 t o 130 x i i L IST OF TABLES TABLE: PAGE 1. L o n g i t u d i n a l Sub L e v e l C a v i n g 97 t o 102 IA . T r a n s v e r s e Sub L e v e l C a v i n g . . 103 2. " R e s u l t s o f T r i a x i a l C o m p r e s s i o n T e s t s 105 3. S i e v e a n a l y s i s o f s a m p l e s u s e d i n t h e T r i a x i a l T e s t s 106 k. Ore m a t e r i a l u s e d i n t h e model 107 5 . Summary - D e s i g n d a t a f o r t h e recommended l a y o u t s 109 6. T e s t No . 33; L o a d i n g Sequence 121 7. T e s t No . 32; L o a d i n g Sequence 121 CHAPTER 1 1 * INTRODUCTION 1 . 1 L o c a t i o n and G e o l o g y : The Granduc M i n e i s n e a r t h e B r i t i s h C o l u m b i a - A l a s k a boundry i n rugged m o u n t a i n o u s c o u n t r y , a b o u t 36 m i l e s N o r t h w e s t o f S t e w a r t , B . C . A c c e s s t o t h e mine f r o m S t e w a r t i s made by means o f a 32 m i l e r o a d t o T i d e Lake Camp, f r o m where an 11 1/4 m i l e l o n g t u n n e l c o n n e c t s w i t h t h e m i n e . The C o n c e n t r a t o r i s l o c a t e d a t T i d e Lake Camp and t h e t o w n s i t e i s s i t u a t e d a t S t e w a r t . F o r t y - t h r e e m i l l i o n t o n s o f o r e , a v e r a g i n g 1.73% c o p p e r b e f o r e d i l u -t i o n , a r e r e p o r t e d t o have been i n d i c a t e d by d iamond d r i l l i n g (1966) . The d e p o s i t i s c l a s s i f i e d as M e s o t h e r m a l R e p l a c e m e n t . The o r e b o d i e s o c c u r i n f o l d e d and f a u l t e d s i l i c e o u s m e t a s e d i m e n t s c u t by f e l d s p a r p o r p h y r y d i k e s . M i n e r a l i z a t i o n c o n s i s t s e s s e n t i a l l y o f p y r r h o t i t e , c h a l c o p y r i t e , p y r i t e and s p h a l e r i t e . " 1 .2 P u r p o s e : T h i s t h e s i s i s c o n c e r n e d w i t h t h e d e s i g n o f t h e L o n g i t u d i n a l S u b -L e v e l c a v i n g m e t h o d , p a r t i c u l a r l y w i t h r e s p e c t t o t h e Granduc M i n e s . S u b -l e v e l c a v i n g , w i t h t r a c k l e s s e q u i p m e n t , has been c h o s e n as t h e m i n i n g m e t h o d . The p r i n c i p l e s f o r d e t e r m i n i n g t h e b e s t method f o r m i n i n g t h e Granduc o r e -b o d i e s have been b a s e d on h i g h p r o d u c t i v i t y (7,500 t o n s / d a y ) and low c o s t , t o g e t h e r w i t h the a c c e p t a b l e p r e m i s e o f good m i n i n g p r a c t i c e s , w h i c h i n c l u d e t h e d e s i r a b i l i t y o f maximum r e c o v e r y and minimum d i l u t i o n . In the t r a n s v e r s e as w e l l as i n t h e l o n g i t u d i n a l s u b - l e v e l c a v i n g , t h e o r e i s l o n g h o l e b l a s t e d , whereas t h e w a s t e i s c a v e d . T e s t d r i f t s d r i v e n * See A p p e n d i x VI f o r d e t a i l e d g e o l o g y . 2. i n t o t h e h a n g i n g w a l l , w h i c h i s m a i n l y i n t h e s e d i m e n t s , shows a marked d e -g r e e o f c r o s s - f r a c t u r i n g w h i c h r e n d e r s i t e a s i l y f r a g m e n t a b l e and l i a b l e t o c a v e . F u r t h e r m o r e , t h e r e o c c u r s a m a j o r f a u l t w i t h i n t e n t o t w e n t y f e e t away f r o m t h e h a n g i n g w a l l c o n t a c t . In the w o r s t c a s e , i n d u c e d c a v i n g may be r e q u i r e d . The w i d e r p o r t i o n s o f t h e o r e b o d y , w h i c h a r e d e f i n e d h e r e as a n y -where between f i f t y and one h u n d r e d and t w e n t y f e e t , a r e p l a n n e d t o be mined by t h e t r a n s v e r s e s u b - l e v e l c a v i n g method ( F o o t w a l l t o H a n g i n g w a l l r e t r e a t ) . T h i s has been p r i m a r i l y on t h e r e c o m m e n d a t i o n s o f t h e c o n s u l t a n t s as w e l l as on some f i e l d e x p e r i e n c e o b t a i n e d e l s e w h e r e i n Canada and a b r o a d . The w i n g s o f t h e o r e b o d i e s a r e n a r r o w and v a r y i n w i d t h s f r o m f i f t e e n t o f i f t y f e e t on t h e w h o l e ; a p p r o x i m a t e l y more t h a n 50% o f the t o t a l m i n e a b l e t o n n a g e s a r e t i e d up i n t h e s e n a r r o w w i d t h s , w h i c h c a l l f o r m i n i n g methods o t h e r t h a n t h e t r a n s v e r s e s u b - l e v e l c a v i n g . T h e r e f o r e , i t became i m p e r a t i v e f o r G r a n d u c M i n e s to c o n d u c t a s t u d y p r o g r a m t o d e t e r m i n e t h e b e s t method o f m i n i n g o f t h e s e a r e a s . L o n g i t u d i n a l s u b - l e v e l c a v i n g method ( r e t r e a t a l o n g t h e s t r i k e ) i s c o n s i d e r e d most s u i t a b l e i n t h i s c a s e . The p r i n c i p a l r e a s o n b e i n g t h a t t h e same e q u i p m e n t and the b a s i c d e v e l o p m e n t work as i s needed f o r t h e m i n -i n g o f a d j a c e n t t r a n s v e r s e s u b - l e v e l s t o p e s c o u l d be u s e d . P r e l i m i n a r y : p l a n n i n g o f t h e s e a r e a s has been done but not w i t h much e x a c t i t u d e , s i n c e t h i s f i e l d i s r e l a t i v e l y u n e x p l o r e d . F u r t h e r r e s e a r c h work was needed t o e s t a b l i s h t h e opt imum l a y o u t s , hence t h i s s t u d y was t a k e n u p . The i m p o r -t a n c e o f t h e s e t e s t s , l o c a l l y p e r f o r m e d , i s f u r t h e r e m p h a s i z e d by t h e f a c t t h e y s e r v e as a c o n s t a n t s o u r c e o f r e f e r e n c e f o r mine p l a n n i n g and l a y o u t w o r k . A l s o t h e p r e s e n c e a t t h e mine o f permanent r e c o r d s o f p i c t u r e s , s l i d e s and o t h e r v i s u a l a i d s d e v e l o p e d d u r i n g t h e c o u r s e o f t e s t i n g , a r e u s e f u l f o r the t r a i n i n g o f the mine p e r s o n n e l f r o m t i m e t o t i m e . 3. 1.3 S c o p e : A 1:30 s c a l e mine model was c o n s t r u c t e d a t t h e p r o p e r t y and t e s t s were c o n d u c t e d on a c a r e f u l l y drawn up t e s t p r o g r a m . Optimum l a y o u t o f t h e p r o d u c t i o n d r i f t s / d r a w p o i n t s on p r o p e r s u b - l e v e l i n t e r v a l depends on t h e s t u d y o f t h e " c a v e f i g u r e s " o r t h e " e l l i p s o i d o f m o t i o n " o f t h e b r o k e n r o c k i n t h e s t o p e s . T h e r e f o r e , a c t u a l o r e f r o m t h e mine c r u s h e d t o s i z e f o r t h e model work was u s e d t o d e t e r m i n e t h e s e f i g u r e s . The t e s t i n g was d i v i d e d i n -t o two a r e a s o f s t u d y : ( a . ) The f i r s t s e r i e s o f t e s t s were c a r r i e d o u t t o c h e c k t h e f i g u r e s w h i c h have a l r e a d y been used f o r the p l a n n i n g work o f the t r a n s v e r s e s u b - l e v e l c a v i n g methods f o r t h e w i d e r o r e -b o d i e s . T h i s has a s p e c i a l i m p o r t a n c e , f o r a c o m p a r i s o n o f t h e model work c o u l d be made w i t h t h e a c t u a l p e r f o r m a n c e s as some o p e r a t i o n a l e x p e r i e n c e i s o b t a i n e d a t a l a t e r d a t e . ( b . ) The s e c o n d s e r i e s o f t e s t s were p e r f o r m e d on t h e l o n g i t u d i n a l s u b - l e v e l c a v i n g m e t h o d . W i t h t h e h e l p o f t h e G e o l o g i c a l D e p a r t m e n t , a t a b l e was p r e p a r e d w h i c h showed t h e w i d t h s o f t h e o r e b o d i e s , w i t h t h e i r a s s o c i a t e d f o o t w a l 1 a n g l e s and t o n -n a g e s . T h i s h e l p e d i n p r o g r a m i n g t h e t e s t work i n o r d e r o f i m p o r t a n c e o f t h e s e a r e a s . T e s t s r e p r e s e n t i n g o r e b o d y w i d t h s o f 20', 30', **0', and 50' a t v a r i o u s f o o t w a l 1 a n g l e s and w i t h change in p a r a m e t e r s s u c h as s u b - l e v e l i n t e r v a l , l o c a t i o n o f e x t r a c t i o n d r i f t s and f o o t w a l 1 s l a s h , e t c . , were c a r r i e d o u t i n d e t a i 1 . Many p r e l i m i n a r y t e s t s were needed b e f o r e a s a t i s f a c t o r y t e s t i n g p r o c e d u r e c o u l d be d e v e l o p e d . A d i s c u s s i o n on some o f t h e p r o b l e m s e n c o u n t e r e d has been i n c l u d e d i n C h a p t e r s 3 and 5. A d d i t i o n a l t e s t i n g was done t o d e t e r m i n e t h e change i n f l o w p r o p e r -t i e s o f t h e b r o k e n o r e o v e r a range o f m o i s t u r e c o n t e n t s by u s i n g a T r i a x i a l C o m p r e s s i o n t e s t i n g e q u i p m e n t . The r e s u l t s a r e i n c l u d e d i n C h a p t e r 5-P r o p o s e d mine l a y o u t s based on t h e t e s t work a r e p r e s e n t e d i n A p p e n -d i x IV, and s u g g e s t i o n s on f u r t h e r and a d v a n c e d work a r e i n c l u d e d in C h a p t e r 7-CHAPTER 2 STATE OF THE ART 5. 2.1 G e n e r a l : S u b - l e v e l c a v i n g i n v a r i o u s p a t t e r n s o f b l a s t i n g a n d e x t r a c t i n g was t h e e a r l i e s t c a v i n g m e t h o d u s e d i n m i n e s w i t h w eak a n d i n c o m p e t e n t g r o u n d c o n d i t i o n s ; i n s p i t e o f a h i g h d i l u t i o n a n d r e l a t i v e l y l o w r e c o v e r y , i t was r e g a r d e d as t h e o n l y p r a c t i c a l m e t h o d a v a i l a b l e . W i t h m e c h a n i z e d d e v e l o p -ment a n d l o n g - h o l e d r i l l i n g e q u i p m e n t , i m p r o v e d b l a s t i n g t e c h n i q u e s a n d t h e a d v e n t o f t r a c k l e s s e x t r a c t i o n u n i t s , t h i s m e t h o d i s b e i n g i n c r e a s i n g l y c o n -s i d e r e d a n d a p p l i e d i n b a s e m e t a l a n d f e r r o u s m i n e s w i t h l a r g e , t h i c k a n d c o m p e t e n t o r e b o d i e s . T h i s i s b e c a u s e i t c a n be r e a d i l y m e c h a n i z e d , i t i s s a f e , s t a n d a r d i z a t i o n o f e q u i p m e n t p r e s e n t s f e w e r p r o b l e m s , s e l e c t i v i t y i n v a r i a b l e - g r a d e o r e b o d i e s i s p o s s i b l e a n d a l a r g e p r o p o r t i o n o f t h e d e v e l o p -ment i s i n o r e . T h e s e f a c t o r s a l l c o n t r i b u t e t o k e e p i n g c o s t s down a n d t h e m e t h o d i s now o f t e n p r e f e r r e d t o b l o c k c a v i n g o r l a r g e s u b - l e v e l s t o p i n g . Due t o t h e i n h e r e n t c h a r a c t e r i s t i c o f s u b - l e v e l c a v i n g , i n t h a t t h e t h i n c o l u m n o f o r e d r a w n w i t h e a c h f a n b l a s t i s b o u n d e d by t h e s o l i d w a l l o f t h e n e x t f a n on o n e s i d e a n d t h e c a v e d w a s t e on a l l t h e o t h e r s i d e s , t h e p r o b l e m s o f r e c o v e r y a n d d i l u t i o n a r e as g r e a t a s i n a n y o t h e r m e t h o d . D u r -i n g t h e l a s t t e n y e a r s o r s o a c o n s i d e r a b l e amount o f r e s e a r c h has b e e n c a r r i e d o u t i n many c o u n t r i e s , b o t h i n t h e f o r m o f s c a l e - m o d e l t e s t s a n d o f s t u d i e s c o n d u c t e d u n d e r n a t u r a l c o n d i t i o n s . T h i s r e s e a r c h h a s shown t h a t by i n t r o d u c i n g i m p r o v e d l a y o u t s b a s e d o n t h e d r a w c h a r a c t e r i s t i c s a n d e m p l o y i n g m o dern m i n i n g t e c h n i q u e s , a g o o d r e c o v e r y i n c o n j u n c t i o n w i t h a d i l u t i o n com-p a r a b l e t o t h a t o b t a i n e d w i t h a c a r e f u l l y c o n t r o l l e d b l o c k c a v e m e t h o d i s p o s s i b l e . I t has b e e n i n d i c a t e d , h o w e v e r , e s p e c i a l l y i n b a s e m e t a l o r e s , t h a t a s t r i c t p o s i t i v e d r a w c o n t r o l i s e s s e n t i a l t o t h e s u c c e s s o f t h e 6. m e t h o d . The t e r m ' p o s i t i v e ' i n t h i s c o n t e x t means o b t a i n i n g a c o m p r e h e n s i v e draw g r a d e and e x t r a c t i o n t o n s r e c o r d t o s t o p t h e draw a t t h e d e s i r e d p o i n t and a l s o t o g a i n r e l i a b l e r e c o v e r y and d i l u t i o n f i g u r e s i n e a c h d r a w p o i n t . 2 . 1 1 Theory o f S u b - L e v e l Cave D r a w : So f a r as i s known, t h e b u l k o f r e s e a r c h i n t o t h e s u b - l e v e l c a v i n g m i n i n g method has been c a r r i e d o u t i n Sweden a n d , i n p a r t i c u l a r , by t h e R o y a l I n s t i t u t e o f T e c h n o l o g y , S t o c k h o l m . J a n e l i d and K v a p i l ' s (^ 7) p a p e r on t h e p r i n c i p l e s and t h e o r y o f s u b - l e v e l c a v i n g i s p r o b a b l y t h e most a u t h o r i t a t i v e t o d a t e . Model e x p e r i m e n t s and u n d e r g r o u n d s t u d i e s a r e known t o have been c a r r i e d o u t i n A u s t r a l i a a t Mount I s a M i n e s , i n Zambia a t M u f u l i r a Copper M i n e s , i n Sweden a t K i r u n a and M a l m b e r g e t M i n e s , and i n Canada a t C r a i g m o n t M i n e s and F rood S t o b i e M i n e . I t i s n o t p o s s i b l e h e r e t o expound a l l t h e c h a r a c t e r i s t i c s i n v o l v e d i n s u b - l e v e l c a v i n g d r a w , b u t t h o s e t h a t have a m a j o r i n f l u e n c e on t h e method o f draw c o n t r o l , and t h e r e f o r e , on t h e u n d e r s t a n d i n g o f i t , a r e d e s c r i b e d . 2 . 1 2 Shape o f Draw: B a s i c a l l y , i t has been f o u n d t h a t t h e g r a v i t y f l o w o f b l a s t e d o r c a v e d r o c k , under p r e s s u r e , obeys t h e same laws and i s a p p r o x i m a t e l y s i m i l a r t o t h e f l o w o f g r a n u l a r m a t e r i a l i n a b u n k e r . B r o k e n r o c k e n t e r i n g a d r a w -p o i n t f l o w s f r o m a zone i n t h e shape o f an e l l i p s o i d . The a c t u a l g r o u n d drawn f l o w s f r o m what J a n e l i d c a l l s t h e ' e l l i p s o i d o f m o t i o n ' . T h i s , i n t u r n , d i s t u r b e s a l a r g e r z o n e , c a l l e d t h e ' l i m i t e l l i p s o i d 1 , w h i c h i s a p p r o x i m a t e l y f i f t e e n t i m e s t h e s i z e o f t h e e l l i p s o i d o f m o t i o n (see F i g . 1 A ) . I f t h e m a t e r i a l b e i n g drawn c o n s i s t e d o f l a m i n a t i o n s o f d i f f e r e n t c o l o u r s , and c o u l d be v i e w e d t h r o u g h a g l a s s p l a t e , t h e draw w o u l d a p p e a r t o be i n t h e f o r m o f a cone w i t h t h e apex a t t h e d r a w p o i n t and t h e s i d e s s l i g h t l y c o n c a v e (see F i g . I B ) . In F i g . I E . t h i s e l l i p s o i d o f m o t i o n i s marked E^. D i s t i n c t i o n can be made between i t s s e m i - m a j o r a x i s a ^ and i t s s e m i - m i n o r a x i s b^. The vo lume o f t h e e l l i p s o i d o f m o t i o n E^ a p p r o x i m a t e l y c o r r e s p o n d s t o t h a t o f t h e d i s c h a r g e d m a t e r i a l ( F i g . ID) and t o t h e vo lume o f t h e d i s -c h a r g e cone ( F i g . I C ) . T h e r e f o r e , the r e l a t i o n s h i p between t h e s e can thus be d e s c r i b e d b y : EN OO K N ^ VN 2 (.1) I f t h e vo lume V^ and t h e h e i g h t o f t h e e l l i p s o i d o f m o t i o n a r e known, t h e s e m i - m i n o r a x i s o f F i g . IE can be c a l c u l a t e d f r o m t h e f o r m u l a : b N / V N 2 (2) 2.094 h N The c h a r a c t e r i s t i c s o f t h e shape o f t h e e l l i p s o i d o f m o t i o n a r e d e t e r m i n e d by i t s e c c e n t r i c i t y e^ where 2 2 e N ( a N - b N ) 2 (3) The terms a ^ and b^ i n e q u a t i o n 2 (3) c o r r e s p o n d t o t h o s e o f F i g . I E . 8. FIG. IA GROUND UNDER PRESSURE IS DRAWN FROM A ZONE IN THE FORM OF AN ELONGATED ELLIPSOID,TERMED THE ELLIPSOID OF MOTION'. THIS DISTURBS THE GROUND IN A LARGER ZONE, TERMED THE LIMIT ELLIPSOID, FROM JANELID KVAPIL Limit ellipsoid Ellipsoid of motion FIG. IB RELATIONSHIP BETWEEN VISIBLE DRAW CONE AND ELLIPSOID OF MOTION AND LIMIT ELLIPSOID. MATERIAL DRAWN FROM B IS REPLACED BY MATERIAL GRAVITATING FROM AREAS A AND C. FROM JANELID AND KVAPIL. Limit ellipsoid Ellipsoid of motion Draw cone FIG. IC FIG. ID FIG. IE FORM OF ELLIPSOID OF MOTION AS A FUNCTION OF ELLIPSOID OF MOTION CUT PARTICLE SIZE OFF BY THE BUNK£R WALL FIG.I. GRAVITY FLOW OF GRANULAR MATERIAL 9. The c h a r a c t e r i s t i c s o f t h e shape o f t h e e l l i p s o i d o f m o t i o n , i . e . , i t s e c c e n t r i c i t y , a r e n o t c o n s t a n t , but depend v e r y much on the p a r t i c l e s i z e o f the m a t e r i a l . S m a l l e r p a r t i c l e s o f m a t e r i a l c o r r e s p o n d t o a s l i m m e r e l l i p -s o i d o f m o t i o n and t o a g r e a t e r e c c e n t r i c i t y . L a r g e r p a r t i c l e s e x t e n d t h e e l l i p s o i d i n w i d t h and i t s e c c e n t r i c i t y becomes l e s s . T h i s i s shown s c h e -m a t i c a l l y i n F i g s . 1 ( F , G , H ) . For t h e same m a t e r i a l , t h e e c c e n t r i c i t y depends on a number o f f a c -t o r s such as t h e s i z e o f the d i s c h a r g e o p e n i n g ( e n l a r g e m e n t o f t h e d i s c h a r g e o p e n i n g i n c r e a s e s t h e e c c e n t r i c i t y ) , t h e h e i g h t o f t h e e l l i p s o i d o f m o t i o n (a g r e a t e r h e i g h t i n c r e a s e s t h e e c c e n t r i c i t y ) , t h e v e l o c i t y o f d i s c h a r g e (a f a s t e r r a t e o f d i s c h a r g e i n c r e a s e s t h e e c c e n t r i c i t y ) , e t c . The laws i n c o n n e c t i o n w i t h g r a v i t y f l o w o f g r a n u l a r m a t e r i a l do not undergo any b a s i c c h a n g e s , even when t h e g r a v i t y f l o w i s p r e v e n t e d f o r v a r -i o u s r e a s o n s f rom d e v e l o p i n g f u l l y and s y m m e t r i c a l l y t o t h e v e r t i c a l a x i s . Such c a s e s a r i s e , fo r - e x a m p l e , i f t h e d i s c h a r g e o p e n i n g l i e s n o t i n t h e c e n t r e o f t h e b u n k e r b o t t o m , but i n t h e s i d e w a l l ( see F i g . l i ) . The f o r e g o i n g p r i n c i p l e s have been used by J a n e l i d and K v a p i l and o t h e r s i n d e t e r m i n i n g t h e p a r a m e t e r s o f p a r t i c u l a r l y t h e T r a n s v e r s e S u b -L e v e l C a v i n g m e t h o d . 2.2 P r i n c i p l e s o f G r a v i t y F low and D e s i g n o f M a s s - F l o w B i n s : P r i n c i p l e s o f g r a v i t y f l o w have been a p p l i e d i n t h e q u a n t i t a t i v e d e s i g n o f t h e b i n s f o r some t i m e now. Many r e f e r e n c e s on t h e s u b j e c t were r e v i e w e d w i t h t h e i n t e n t o f s t u d y i n g a p p l i c a t i o n s i n s t o p e d e s i g n . Some o f t h e s e a r e m e n t i o n e d h e r e . S i n c e the c l a s s i c a l work o f J a n s s e n (44), Ketchum (43) and J a m i e s o n on the g r a v i t y f l o w o f g r a i n s i n e l e v a t o r s and b u l k s o l i d s i n b i n s , 10. s e v e r a l w r i t e r s have d i s c u s s e d t h i s p r o b l e m . For e x a m p l e - K v a p i l (13, 14), B e r n a c h e (15), Mroz and D r e s c h e r (16), R o b e r t s (17), P e s c h l (19), Aytaman (22, 23, 24), H a n d l e y and P e r r y (31), J e n i k e 1, 3, 4, 5, 6, 36, 37, 38), J o h n s o n (7, 8, 9), W a l k e r (10, 11) and o t h e r s . A t t h e p r e s e n t t i m e , t h e r e a r e on r e c o r d , more t h a n 200 s e l e c t e d r e f e r e n c e s on t h e s u b j e c t o f F low o f G r a n u l a r M a t e r i a l s . However , by f a r t h e most i m p o r t a n t c o n t r i b u t i o n s t o t h e s t u d y o f t h e a p p l i c a t i o n o f t h e p r i n c i p l e s o f g r a v i t y f l o w i n the d e s i g n o f b i n s , has been made by J e n i k e , J o h n s o n and W a l k e r . T h e r e f o r e , w i t h o u t g o i n g i n t o any d e t a i l o f t h e works o f a l l the w r i t e r s a t t h i s s t a g e , w o r k s o f o n l y t h e l a s t t h r e e a u t h o r s m e n t i o n e d above have been d i s c u s s e d h e r e . The d e v e l o p m e n t o f a m a t h e m a t i c a l t h e o r y o f g r a v i t y f l o w o f such s o l i d s as O r e s , C o n c e n t r a t e s , Coa l and C h e m i c a l s , e t c . , by J e n i k e (37), i s b a s e d on t h e c o n c e p t s o f S o i l M e c h a n i c s and P l a s t i c i t y . W h i l e t h e c o n c e p t s o f t h i s t h e o r y were f o r m u l a t e d by him i n 1953, most o f t h e work was c a r r i e d o u t a t t h e b u l k s o l i d s F low L a b o r a t o r y (1957 - 1962), o f t h e Utah E n g i n e e r i n g E x p e r i m e n t S t a t i o n , U n i v e r s i t y o f U t a h . J e n i k e (3), has s t a t e d t h a t o n c e f l o w p r o p e r t i e s o f s o l i d s have been measured and a r e known, then t h e c r i t i c a l d i m e n s i o n s o f t h e h o p p e r w a l l s can be d e t e r m i n e d . I t i s w e l l known now, f r o m t h e w o r k s o f v a r i o u s a u t h o r s , t h a t f l o w p r o p e r t i e s o f s o l i d s v a r y , f o r i n s t a n c e , due t o changes i n m o i s t u r e c o n -t e n t , s i z e d i s t r i b u t i o n , s h a p e , b u l k d e n s i t y , a n g l e o f i n t e r n a l f r i c t i o n and t e m p e r a t u r e , e t c . , The c o n d i t i o n s o f l o w e s t f l o w a b i l i t y have t o be u s e d i n t h e c a l c u l a t i o n o f c r i t i c a l d i m e n s i o n s . A d i r e c t - s h e a r , c o n s t a n t r a t e o f s t r a i n m a c h i n e i s employed as a m e a s u r i n g u n i t . S p e c i m e n s o f t h e t e s t e d s o l i d a r e f i r s t c o n s o l i d a t e d w i t h i n ] 1. the s h e a r c e l l and t h e n s h e a r e d t o o b t a i n a r e l a t i o n between t h e c o n s o l i d a t -i n g p r e s s u r e and t h e r e s u l t a n t s t r e n g t h o f t h e s o l i d . T h i s g i v e s t h e p r i n -c i p l e f l o w p r o p e r t i e s o f t h e b u l k s o l i d s , n a m e l y , t h e f l o w - f u n c t i o n . The t e s t e r a l s o measures t h e a n g l e o f f r i c t i o n between a s o l i d and s a m p l e s o f w a l l m a t e r i a l s as w e l l as o t h e r p r o p e r t i e s used i n t h e d e s i g n o f f l o w . F l o w -a b i l i t y t e s t s can be c a r r i e d o u t f o r a range o f m o i s t u r e c o n t e n t , t o d e t e r -mine t h e maximum m o i s t u r e f o r w h i c h a s o l i d can s t i l l be h a n d l e d by g r a v i t y . W a l k e r ' s (10, 11) work was s t i m u l a t e d by t h e d i f f i c u l t i e s e x p e r i -e n c e d by C e n t r a l E l e c t r i c i t y G e n e r a t i n g B o a r d , B r i s t o l , E n g l a n d , in g e t t i n g wet f i n e c o a l t o f l o w t h r o u g h t h e b u n k e r s , h o p p e r s and c h u t e s , e t c . Most o f h i s work was c a r r i e d o u t between t h e p e r i o d 1961 t h r o u g h 1967. The a p p r o a c h a d o p t e d t o o b t a i n t h e d e s i g n d a t a f o r b u n k e r f l o w i s b a s i c a l l y s i m i l a r t o t h a t a d o p t e d by J e n i k e . However , W a l k e r (11), has s i m p l i f i e d t h e c a l c u l a t i o n t o d e r i v e t h e a p p r o x i m a t e s t r e s s e s t h a t w o u l d o c c u r w i t h i n a g r a n u l a r mater ia l f l o w i n g i n a b u n k e r and has c l a i m e d t h a t h i s use o f t h e r i n g s h e a r t e s t e r (12), compared t o t h e d i r e c t s h e a r t e s t e r o f J e n i k e , has p r o v e d more a g r e e -ment between t h e t h e o r y and t h e p r a c t i c a l d e s i g n . In e i t h e r c a s e , model t e s t s have been c a r r i e d o u t on h o p p e r s d e -s i g n e d by J e n i k e ' s and W a l k e r ' s m e t h o d . M a t e r i a l i s t e s t e d and a c o n t a i n e r i s b u i l t t h a t e n s u r e s t h e m a s s - f l o w . I t w o u l d be u s e f u l t o d e f i n e h e r e , two t y p e s o f f l o w p a t t e r n s ; m a s s -f l o w and f u n n e l f l o w o r p l u g f l o w . In m a s s - f l o w b i n s , a l l t h e s o l i d i s i n m o t i o n whenever any o f i t i s drawn o u t . In a f u n n e l - f l o w b i n , f l o w o c c u r s w i t h i n some c h a n n e l s u r r o u n d e d by n o n - f l o w i n g (dead) s o l i d . In a m a s s - f l o w b i n , i n w h i c h t h e f l o w c h a n n e l c o i n c i d e s w i t h t h e b i n i t s e l f a n d , h e n c e , i s d e f i n e d and c o n s t a n t , b i n l o a d i n g s a r e a l s o w e l l d e f i n e d and r e p r o d u c i b l e . 12. In a f u n n e l - f l o w , i t fo rms w i t h i n t h e s o l i d i t s e l f . The c h a n n e l may expand o r c o n t r a c t as t h e f l o w p r o p e r t i e s o f s o l i d s change w i t h v a r y i n g m o i s t u r e c o n t e n t and f r a g m e n t a t i o n , e t c . As a r e s u l t , l o a d i n g i n f u n n e l - f l o w b i n s i s more e r r a t i c and l e s s r e p r o d u c i b l e t h a n i n m a s s - f l o w b i n s . In a d d i t i o n t o the m a s s - f l o w b i n s and f u n n e l - f l o w b i n s , J e n i k e (3) has d e s c r i b e d a n o t h e r t y p e , i . e . , e x p a n d e d - f l o w b i n s , where use i s made o f a s h o r t m a s s - f l o w hopper u n i t u n d e r a f u n n e l - f l o w b i n . The m a s s - f l o w h o p p e r s e r v e s t o expand t h e s i z e o f t h e f l o w - c h a n n e l t o a d i m e n s i o n w h i c h e l i m i n a t e s t h e p o s s i b i l i t y o f r a t h o l i n g . I t can be added h e r e t h a t t h e d e s i g n o f T r a n s v e r s e Sub L e v e l C a v i n g o r L o n g i t u d i n a l Sub L e v e l C a v i n g f o r w i d e o r e - b o d i e s , can make a s p e c i a l c a s e o f a s e r i e s o f m a s s - f l o w h o p p e r s under a f u n n e l - f l o w b i n . H a n d l e y ' s (31), e x p e r i m e n t a l r e s u l t s f o r sand in t h e c o n v e r g i n g s e c t i o n s o f 65° and 70° h o p p e r s , has shown s i m i l a r i t y t o t h e r e s u l t s p r e d i c -t e d by the more r i g o r o u s s t r e s s s o l u t i o n o f J e n i k e , J o h n s o n and W a l k e r . C a l -c u l a t e d p r e s s u r e s o f t h e same o r d e r o f m a g n i t u d e , were o b t a i n e d as a c t u a l l y m e a s u r e d . The c l o s e s i m i l a r i t y o n l y a p p l i e s v e r y n e a r t h e h o p p e r o u t l e t and t h e i m p o r t a n c e o f p r e s s u r e s i n t h i s r e g i o n i s e m p h a s i z e d i n o r d e r t o f i n d w h e t h e r m a s s - f l o w w i l l be f u l l y d e v e l o p e d . A s m a l l p r e s s u r e s e n s i t i v e r a d i o p i l l was u s e d f o r t h e measurement o f i n t e r n a l s t r e s s e s d u r i n g f l o w . I t i s c l e a r t h a t the c o n d i t i o n s i n a s u b - l e v e l c a v i n g s t o p e , a r e d i f f e r e n t f r o m t h a t o f a b i n a n d , t h e r e f o r e , t h e a p p l i c a t i o n o f the p r i n -c i p l e s ' o f q u a n t i t a t i v e d e s i g n o f b i n s t o be used f o r s t o p e d e s i g n have o n l y a 1 imi t e d a p p l i c a t i o n . 2.3 P r i n c i p l e s o f S i m i l i t u d e i n t h e F low o f G r a n d u l a r M a t e r i a l s : A n o t h e r t o p i c o f p a r t i c u l a r i n t e r e s t t o t h i s p r o j e c t , i s the p r i n -c i p l e s o f s i m i l i t u d e so t h a t t h e b e h a v i o u r o f a p r o t o t y p e may be c o r r e c t l y 13. p r e d i c t e d f r o m t h e o b s e r v a t i o n s on a m o d e l . F o r t h i s t o be a c h i e v e d , i t i s n e c e s s a r y t o a s s e s s not o n l y t h e p h y s i c a l q u a n t i t i e s t h a t a r e r e l e v a n t t o t h e p r o b l e m , b u t a l s o t o u s e j u d g e m e n t t o r e d u c e them t o a w o r k i n g minimum by s e l e c t i n g t h e most s i g n i f i c a n t p a r a m e t e r s . A p p l i c a t i o n s o f d i m e n s i o n a l a n a l y s i s to model t e s t i n g , have been d e s c r i b e d by v a r i o u s a u t h o r s , but o n l y t h e i m p o r t a n t ones a r e m e n t i o n e d h e r e . Roscoe (25), has shown t h e use o f d i m e n s i o n a l a n a l y s i s f o r model t e s t i n g i n s o i l m e c h a n i c s t o a c e r t a i n d e g r e e . F o w l e r (28), i n h i s p a p e r , "The F low o f G r a n u l a r S o l i d s Through O r i f i c e s " , has d e r i v e d t h e p r e d i c t i o n e q u a t i o n s o f t h e w e i g h t d i s c h a r g e d p e r u n i t t i m e , f o r g r a n u l a r m a t e r i a l s t h r o u g h o r i f i c e s . He has e m p h a s i z e d t h e i m p o r t a n c e o f t h e use o f b u l k d e n -s i t y o v e r the t r u e d e n s i t y o f m a t e r i a l s a n d , a l s o t h e shape f a c t o r o f t h e p a r t i c l e s c o n s i d e r e d i n h i s a n a l y s i s . M a t t h e e (26), s t u d i e d the s e g r e g a t i o n phenomenon r e l a t i n g t o b u n k e r -i n g o f b u l k m a t e r i a l s w i t h t h e h e l p o f g e o m e t r i c a l l y r e d u c e d model b i n s and has d i s c u s s e d t h e s c a l e up o f t h e s e r e s u l t s . To r e d u c e t h e number o f e x p e r i -m e n t s , h e i n t r o d u c e d d i m e n s i o n l e s s g r o u p s and i n c l u d e d v a r i a b l e s l i k e g r a i n s i z e , g r a i n s i z e d i s t r i b u t i o n , p a r t i c l e s h a p e , p a r t i c l e d e n s i t y , f l o w a b i l i t y , a n g l e o f r e p o s e , r e s i s t a n c e t o a g g l o m e r a t i o n , s u r f a c e c h a r a c t e r i s t i c s , t h e shape and d i a m e t e r o f b u n k e r and i t s o r i f i c e , t h e h e i g h t o f m a t e r i a l i n t h e b i n , w a l l f r i c t i o n , t h e method o f f e e d i n g and d i s c h a r g i n g and o t h e r s . He r e -p o r t s t h a t , f o r a s o l u t i o n o f t h e p r o b l e m o f s e g r e g a t i o n , a l l the v a r i a b l e s t h a t i n f l u e n c e s e g r e g a t i o n and t h e e q u a t i o n s o f m o t i o n o f p a r t i c l e s , need t o be known. Such a s o l u t i o n i s n o t y e t p o s s i b l e . In "The B e h a v i o u r o f G r a n u l a r M a t e r i a l s i n F l o w - o u t o f H o p p e r s " by R e i s n e r (27), a r e l i s t e d t h e f a c t o r s i n f l u e n c i n g t h e e f f l u x as used i n t h e 14. f o r m u l a e o f v a r i o u s a u t h o r s . They a r e , f o r i n s t a n c e , d i a m e t e r o f t h e b i n , d i a m e t e r o f t h e o u t l e t , g r a i n s i z e , r e d u c e d a r e a o f e f f l u x , h e i g h t o f t h e s u r f a c e o f the s t o r e d m a t e r i a l i n t h e b i n , a r e a o f e f f l u x , c o h e s i v e f o r c e s , h y d r a u l i c r a d i u s , a c c e l e r a t i o n o f g r a v i t y , b u l k d e n s i t y o f t h e s t o r e d m a t e r -i a l , i n t e r n a l f r i c t i o n , a n g l e o f i n c l i n a t i o n o f t h e h o p p e r b o t t o m , s p e c i f i c w e i g h t , shape f a c t o r , t r u e f l o w f a c t o r and s p e c i f i c p r e s s u r e on t h e b o t t o m o f t h e b i n . I t i s n o t e d t h a t no s i n g l e a u t h o r has c o n s i d e r e d more than a h a n d -f u l o f v a r i a b l e s and a c o m p r e h e n s i v e a p p r o a c h i s l a c k i n g i n t h e l i t e r a t u r e s , t h e r e f o r e , i t can be c o n c l u d e d t h a t t h e r e i s no f o r m u l a so f a r , w h i c h can be used w i t h o u t any r e s t r i c t i o n f o r a l l t y p e s o f b i n s and a l l k i n d s o f b u l k m a t e r i a l s . '5-CHAPTER 3 THEORETICAL CONSIDERATIONS 3 . 1 Genera 1: A d i s c u s s i o n on the d e s i g n o f s u b - l e v e l c a v i n g s t o p e s , f r o m t h e model t e s t s , must i n e v i t a b l y i n c l u d e t h e a s p e c t s o f t h e t h e o r y o f model t e s t -i n g , t h e a p p l i c a t i o n s o f t h e g r a v i t y f l o w p r i n c i p l e s t o t h e g r a n u l a r m a t e r -i a l s and t h e i r a r c h i n g phenomenon, e t c . 3• 2 Theory o f M o d e l s : An a t t e m p t has been made t o a p p l y t h e t h e o r y o f m o d e l s , t o g e t an i n d i c a t i o n o f the r e l a t i o n s h i p o f t h e v a r i a b l e s t a k i n g p a r t i n t h e phenome-non so t h a t the o b s e r v a t i o n s made on t h e mine model may be used t o p r e d i c t t h e p e r f o r m a n c e o f t h e p r o t o t y p e , i . e . , t h e s t o p e . The p e r t i n e n t v a r i a b l e s c o n s i d e r e d i n t h i s a n a l y s i s , a l o n g w i t h t h e s i m p l i f y i n g a s s u m p t i o n s , a r e 1i s t e d i n Append i x I . E q u a t i o n (5) o f A p p e n d i x I i s r e w r i t t e n i n t h e d i m e n s i o n a l f o r m a s : _L p ( — ' — * — ' w J » 1 ' H ' ______ » Vc , dd_ , 0 , e l 3 \ ] ]2 j />s v 2 1 1 /°s l 3 1 A s i m i l a r e q u a t i o n may be w r i t t e n f o r t h e m o d e l : Vrn = p. / A i m , Am , Dhm , Wm. Im l 3 m V lm 1 2 m lm /°sm V 2 m Am , Vcm , ddm , 0 ~n— •• o m /•'sm P m lm S i n c e each e q u a t i o n r e f e r s t o t h e same t y p e o f s y s t e m , t h e f u n c t i o n s a r e i d e n t i c a l i n f o r m . , dm , Hm , 1 m 1 m e0 16. Now the " L e n g t h S c a l e " i s d e f i n e d as t h e r a t i o o f some p e r t i n e n t d i s t a n c e o r l e n g t h o f t h e p r o t o t y p e o f t h e c o r r e s p o n d i n g d i s t a n c e i n t h e model and i s d e s i g n a t e d as n , o r 1 = n l m in the c a s e o f t h e model used i n t h i s a n a l y s i s , n = 30. From t h e a b o v e , t h e d e s i g n c o n d i t i o n s f o r t h e model may be d e t e r m i n e d as f o l l o w s : ~T~ = ~T o r Vm = — 3 ( l a ) P m P n-3 In o t h e r w o r d s , vo lume i n t h e b u c k e t drawn f r o m t h e model i s 1 (30) 3 t i m e s vo lume o f t h e a c t u a l b u c k e t u s e d i n t h e m i n e . S i m i l a r l y , t h e o t h e r d e s i g n c o n d i t i o n s a r e d e r i v e d : Aim = A i ; o r Aim = A i 3 ( l b ) l m l n Am = A ; o r Am = A 3 ( l c ) ,2 l 2 n 2 Dhm _ _Dh_ ; o r Dhm = _Dh 3 ( i d ) Im 1 n wm. Im _ w. 1 . ; o r w m _ n .w . /°s . v^m 3 ( l e ) /°sm vm2 / > s . v 2 dm d , d /, ,-\ Tm = T ; o r dm = - 3 ( i f ) Hm H ,. H _ /, v 7 — = T ; o r Hm - — 3 ( g) lm - 1 ' n 3 /°bm Ph p, /°b./°sm , .... - T T — = x ; o r / bm = —'- 3 ( h) /->sm ps />s ' Vcm Vc Vc ., _ /. . v —=• = — = - ; o r m = Vc 3 ( l i ) l m 3 P 3 m r\J 17. ddm dd , , dd ^ = — ; or ddm = — 3 ( l j ) 0m = 0 3 ( l k ) em = e 3 ( l i ) Design Equat ion 3 ( lb) - S ince A r e fe rs to every d imens ion , t h i s equat ion imposes the c o n d i t i o n of geometr ica l s i m i l a r i t y in a l l respects between model and p ro to type . Both as to form o f the model , cross sec t ions at a l l p o i n t s , and loading p a t t e r n . Hence, the model was designed acco rd ing to t h i s . Design Equations 3 ( l c ) , 3 ( i d ) , 3 ( I f ) , 3 Og), 3 ( l i ) , and 3 ( l j ) i n d i c a t e that the design c o n d i t i o n s regarding the area of opening , h y d r a u l i c diameter of the opening , s i z e o f the p a r t i c l e , head o f packing above opening , volume o f con ta ine r and the d igg ing depth o f the scoop g ive complete freedom in the s e l e c t i o n o f the length s c a l e between the model and the p ro to type . Design Equat ion 3 (11) - i s s a t i s f i e d because the same s lope angles near the opening have been used as that in the mine. Design Equation 3 ( lk ) - i s s a t i s f i e d because ac tua l ore from the mine i s used in the model. The crushed rock fo r the model ( s i zes down to 1/4") g e n e r a l l y resembled in shape, the broken rock underground. No e f f e c t of moisture has been considered in the a n a l y s i s . Design Equat ion 3 ( le) - Here Psm / ° s 2 Therefore , w m = n.w. ^ V™ j - 3 (2) From Fowler ( 2 8 ) , approximate v e l o c i t y of d ischarge v from the o r i f i c e is g iven by: 0.185 v = • / nh \ 3 2g D n x / ^ j cms/sec - 3 (3) T h e r e f o r e , f r o m e q u a t i o n s 3 (2) and 3 (3) w m = n . w . m 0.236 x J 2 g m Dh^ 1.236 x J 2 g Dh" Dh m ds„ x / D h ds 0.185 0.185 18. - 3 (4) S i n c e t h e v a l u e o f ' g ' i s t h e same f o r t h e model and t h e p r o t o t y p e f o r e , by s o l v i n g E q u a t i o n 3 W , we o b t a i n : t h e r e , w m o r : w, m n .w . n w. T h e r e f o r e , E q u a t i o n 3 ( l e ) i s s a t i s f i e d w i t h i n p r a c t i c a l l i m i t s s i n c e E q u a t i o n 3 (3) a l l o w s t h e p r e d i c t i o n o f f l o w r a t e s t h r o u g h o r i f i c e s w i t h an o v e r a l l a c c u r a c y o f + 10 p e r c e n t . D e s i g n E q u a t i o n 3 ( l h ) - i n d i c a t e s t h a t c o r r e c t i o n s a r e needed t o be a p p l i e d t o t h e draw vo lumes - / ^ s m - f^s> b u t t h e e x a c t n a t u r e o f / ^ b i s not y e t known. To a p p l y c o r r e c t i o n s o r t o d e t e r m i n e t h e e x t e n t o f d i s t o r -t i o n i n t h e r e s u l t s o f o r e r e c o v e r y and t o t a l e x t r a c t i o n o b t a i n e d f r o m t h e model t e s t s , i t i s i m p e r a t i v e t o f i n d t h e s w e l l f a c t o r , t h e r e b y t h e b u l k d e n -s i t y ( /^b ) , o f t h e b r o k e n co lumn o f o r e i n t h e s t o p e . These measurements a r e not p o s s i b l e a t t h i s s t a g e u n t i l a w o r k i n g s t o p e i s - a v a i l a b l e f o r s u c h t e s t s . In c o n c l u s i o n i t can be s a i d t h a t , due t o d i f f i c u l t i e s i n s i m u l a t i n g c o n s o l i d a t i o n e f f e c t o f b l a s t i n g i n t h e s t o p e and t h e d e n s i t y d i f f e r e n c e b e -tween t h e mine o r e and t h e model o r e due t o n e g l i g i b l e e x p a n s i o n o f t h e b l a s t e d o r e i n t h e m i n e , r i g h t c o n d i t i o n s a r e not r e p r e s e n t e d i n t h e m o d e l . I t i s c l e a r , h o w e v e r , t h a t t e s t s w i t h c r u s h e d o r e g i v e q u a l i t a t i v e r e s u l t s w h i c h a r e not n e c e s s a r i l y h i g h e r o r b e t t e r t h a n c o r r e s p o n d i n g r e s u l t s f r o m t h e m i n e . So i t |s j u s t i f i e d t o c a r r y o u t t h i s t y p e o f t e s t i n g . 3•3 G r a v i t y F low and D e t e r m i n a t i o n o f t h e P a r a m e t e r s i n S u b - L e v e l C a v i n g : The g r a v i t y f l o w o f m a t e r i a l i n s u b - l e v e l c a v i n g c o r r e s p o n d s i n p r i n -c i p l e t o t h e c a s e o f F i g u r e 1 ( l ) b e c a u s e the g r a v i t y f l o w i n t h e s u b - l e v e l c a v i n g i s , f i g u r a t i v e l y s p e a k i n g , c u t - o f f by t h e w a l l o f t h e s l i c e . T y p i c a l s e c t i o n s i n t h e Case o f T r a n s v e r s e and L o n g i t u d i n a l S u b - L e v e l C a v i n g method a r e shown i n F i g u r e 2 and F i g u r e 3, r e s p e c t i v e l y . The s u b - l e v e l c a v i n g method i s c h a r a c t e r i z e d by a g r a v i t y f l o w o f lumpy m a t e r i a l b e c a u s e b o t h t h e b l a s t e d o r e and t h e w a s t e may c o n t a i n l a r g e lumps o f o v e r 16 i n c h e s o r s o . To o p t i m i s e the p r o d u c t i o n o f c l e a n o r e and m i n i m i z e c o n t a m i n a t i o n by w a s t e as w e l l as o r e l o s s e s , i t i s n e c e s s a r y t o d e t e r m i n e t h e o p t i m u m ; p a r a m e t e r s o f t h e s l i c e . T h i s i s m a i n l y a m a t t e r o f d e t e r m i n i n g t h e s u b -l e v e l i n t e r v a l S , t h e b l a s t r e t r e a t d i s t a n c e R j , t h e w i d t h o f s l i c e Z ^ , t h e r i n g g r a d i e n t c\ , t h e w i d t h B and h e i g h t h , o f t h e e x t r a c t i o n d r i f t s and t h e w i d t h P o f the p i l l a r s between d r i f t s . The p r e c i s e opt imum v a l u e s o f the p a r a m e t e r s o f s u b - l e v e l c a v i n g , i n c l u d i n g a l l d e t a i l e d e f f e c t i v e f a c t o r s , c a n o n l y be f o u n d on t h e b a s i s o f t h e t e s t s under n a t u r a l c o n d i t i o n s . However , J a n e l i d ' s b a s i c f o r m u l a e ( E q u a t i o n 2 (2) and E q u a t i o n 2 (3) g i v e a p p r o x i m a t e f i g u r e s f o r t h e p a r a -m e t e r s o f s u b - l e v e l c a v i n g w h i c h c a n be a p p l i e d i n p l a n n i n g t h e m i n i n g sys tem. The above a r e d i r e c t l y a p p l i c a b l e i n t h e d e s i g n o f T r a n s v e r s e s u b -l e v e l c a v i n g where the draw f i g u r e s a r e s y m m e t r i c a l s o l i d g e o m e t r i c a l s h a p e s ~1 0 tr 19 90- V FIG. 2 A D I A G R A M M A T I C V E R T I C A L S E C T I O N T H R O U G H L O N G I T U D I N A L A X I S O F E X T R A C T I O N D R I F T FIG. 2 B D I A G R A M M A T I C V I E W O F T H E S L I C E W A L L IN T H E P L A N E O F T H E S E C T I O N l - l O F FIG. 2 A FIG. 2 TRANSVERSE SUB LEVEL CAVING O FIG. 3A D I A G R A M M A T I C V E R T I C A L S E C T I O N T H R O U G H LONGITUDINAL A X I S O F E X T R A C T I O N DRIFT. FIG. 3 LONGITUDINAL SUB L E V E L CAVING FIG. 3B D I A G R A M M A T I C V I E W OF T H E S L I C E W A L L IN T H E P L A N E O F T H E S E C T I O N J - J O F FIG. 3A 22. b u t i n t h e c a s e o f L o n g i t u d i n a l S u b - L e v e l C a v i n g draw f i g u r e s a r e not s y m -m e t r i c b e c a u s e o f t h e a l m o s t p a r a l l e l , i n c l i n e d f o o t w a l l and h a n g i n g w a l l o f the s t o p e . T h e r e f o r e , draw f i g u r e s a r e t o be d e t e r m i n e d f o r each d i f f e r e n t c o n f i g u r a t i o n . C o n s i d e r a t i o n s g i v e n t o t h e d e s i g n o f p a r a m e t e r s s u c h as f r a g m e n t a t i o n , d r i f t w i d t h , d r i f t h e i g h t , f l o w t h r o a t , t h e d i g g i n g d e p t h o f t h e scoop and t h e r i n g g r a d i e n t , e t c . can be common t o T r a n s v e r s e as w e l l as L o n g i t u d i n a l S u b - L e v e l C a v i n g m e t h o d , b u t t h e d e s i g n c r i t e r i a f o r t h e s u b - l e v e l i n t e r v a l , p i l l a r w i d t h , b l a s t r e t r e a t d i s t a n c e , l o a d i n g p a t t e r n and l o c a t i o n o f d r i f t , e t c . a r e d i f f e r e n t f o r each m e t h o d . G e n e r a l l y , Model t e s t i n g was g u i d e d f r o m t h e f o l l o w i n g c o n s i d e r a t i o n s : 3.31 S u b - L e v e l I n t e r v a l : The s u b - l e v e l i n t e r v a l can be e x p r e s s e d by a s y m b o l i c f u n c t i o n o f t h e e f f e c t i v e f a c t o r s such a s : S = f (K, h' c , v , R d , x , m, B, P , % ) 3 (5) Where K = P r o p e r t i e s o f the lumpy m a t e r i a l w h i c h can be e x p r e s s e d i n s i m p l i -f i e d f o r as the p a r t i c l e s i z e h = H e i g h t o f t h e g r a v i t y f l o w . c = s i z e o f t h e e x t r a c t i o n a r e a . v = v e l o c i t y o f d i s c h a r g e f r o m t h e o p e n i n g . The o t h e r l e g e n d s a r e t h e same as i n F i g u r e 2 and F i g u r e 3-The a p p r o x i m a t e s u b - l e v e l i n t e r v a l i n t h e c a s e o f T r a n s v e r s e s u b - l e v e l c a v i n g i s c a l c u l a t e d f r o m t h e f o r m u l a : 2 3 -Where Rj i s the b l a s t r e t r e a t d i s t a n c e (which can be a r i n g burden o r a m u l t i p l e o f r i n g b u r d e n s ) . The r e s t r a i n t on the s u b - l e v e l i n t e r v a l o f e i t h e r 30' o r 60' f o r t h e model t e s t work was imposed, i n o r d e r f o r i t t o be c o m p a t i b l e w i t h 30' sub-l e v e l i n t e r v a l s a l r e a d y a c c e p t e d f o r the t r a n s v e r s e s u b - l e v e l c a v i n g o f the 1 C orebody between the e l e v a t i o n o f 3690' t o about 2900', so t h a t a c c e s s to a l l the o r e b o d i e s can be made w i t h t h e same d e v e l o p m e n t a l work from the ramp system. There can be a p o s s i b i l i t y t h a t w i t h no such r e s t r a i n t s as above, the optimum s u b - l e v e l i n t e r v a l might e x i s t between th e f i g u r e s o f 30' and 6 0 1 . S u b - l e v e l i n t e r v a l o f 601 and h i g h e r , however, have t o meet o t h e r add-i t i o n a l t e c h n i c a l and e c o n o m i c a l r e q u i r e m e n t s . 3-32 D i g g i n g depth o f the Scooptram: J a n e l i d (47) has a p p l i e d Rankine's t h e o r y on the d i s t r i b u t i o n o f the t r a j e c t o r i e s o f the maximum p r i n c i p a l s t r e s s e s and c a l c u l a t e d the optimum p e n e t r a t i o n o f the s c o o p t r a m i n t o the s l o p e . The t r a j e c t o r i e s o f the p r i n -c i p a l s t r e s s e s i n the s l o p e ( F i g u r e 3a) a r e i n c l i n e d a g a i n s t v e r t i c a l by 30° -ty*, w here y i s the n a t u r a l a n g l e o f r e p o s e . The t h e o r e t i c a l b e s t 2 depth x i s g i v e n by the p o i n t s 1 and 2 i n the above f i g u r e . In c o n f o r m i t y w i t h legends o f F i g u r e 2, t h e o r e t i c a l b e s t depth i s c a l c u l a t e d from the f o r m u l a : x ^ h . c o t ^ - h. t a n ^90° - f ^ 3 (7) t a k i n g f' = 50° f o r Granduc o r e . x = 5-16 f t . The d i g g i n g depth a p p l i e d i n p r a c t i c e s h o u l d reach t h e t h e o r e t i c a l f i g u r e . In the model t e s t s , a d i g g i n g depth o f approx. 2 i n . (2 i n . x 30 = 5 F t . ) was used. 2h. 3 .33 D r i f t W i d t h : W h i l e p l a n n i n g t h e minimum w i d t h o f t h e d r i f t , f r a g m e n t a t i o n o f t h e r o c k has been c o n s i d e r e d and u s e d i n t h e f o l l o w i n g f o r m u l a f r o m J a n e l i d ( 4 7 ) . Where D i s t h e d i a m e t e r o f t h e l a r g e s t lumps o f t h e b l a s t e d o r e and k i s t h e f a c t o r o f c o m p o s i t i o n o f t h e f r a g m e n t e d r o c k (used Nomograph f r o m J a n e l i d For t h e c a l c u l a t i o n o f k , used D - 1 6 " and assumed t h a t f r a g m e n t e d r o c k c o n s t i t u t e d o f lumps up t o 1 6 " k0%, medium s i z e up to 20%, s m a l l s i z e up t o k0%. I f p e r c e n t a g e o f f i n e s and damp c o n s t i t u e n t s s u c h as p o w d e r , e t c . i s a l m o s t n i l , t h e n B c a l c u l a t e s o u t t o be e q u a l t o 1 2 . 0 f t . and i f f i n e s a r e c o n s i d e r e d up t o 5%, t h e n B ^ 1 5 - 5 f t . T r a n s v e r s e s u b - l e v e l c a v i n g s t o p e s , f o r e q u a l l o a d i n g f r o m t h e s i d e s w i t h an 8 f t . w i d e s c o o p t r a m . The minimum s i z e o f t h e d r i f t used i n t h e n a r r o w and s t e e p l o n g i t u d i n a l s t o p e s t e s t s i s 12 f t . x 12 f t . T h i s c o n f o r m s t o t h e r e -q u i r e m e n t o f p r o p e r g r a v i t y f l o w and a l s o p e r m i t s t h e use o f p r o d u c t i o n d r i l l jumbos w i t h i n t h i s d i m e n s i o n . 3.34 L o c a t i o n o f D r i f t : T h e o r e t i c a l l y , i d e a l l a y o u t f o r the t r a n s v e r s e s u b - l e v e l s t o p e s i s when w i d t h o f d r i f t = w i d t h o f p i l l a r . T h i s e n s u r e s n e a r l y p a r a l l e l g r a v i t y f l o w . However , due t o p r a c t i c a l d i f f i c u l t i e s , t h e b e s t a r r a n g e m e n t i s t o p r o v i d e f o r s i d e s l o p e s . 3 (8) (k7) P. 144.) 16 f t . w i d e e x t r a c t i o n d r i f t s have been used f o r t h e p l a n n i n g o f 25. In t h e c a s e o f l o n g i t u d i n a l s t o p e s , a l t h o u g h i t has been i n d i c a t e d b e f o r e e l s e w h e r e t h a t g e n e r a l l y the o r e l o s s e s a l o n g t h e F.W. can be r e -duced by l o c a t i n g t h e d r i f t i n t h e F . W . , b u t i t i s c l e a r t h a t i n o r d e r t o l o c a t e t h e d r i f t s most f a v o u r a b l y , a s t u d y must be made f o r t h i s m i n e , c o n -s i d e r i n g a l l f a c t o r s f u l l y s u c h as t h e p e r f o r m a n c e o f t h e p r o d u c t i o n d r i l l i n g e q u i p m e n t , m a r g i n a l v a l u e s o f t h e o r e c o n t e n t i n t h e F.W. a t a p a r t i c u l a r l o -c a t i o n , and t h e r o c k s t a b i l i t y p r o b l e m s . T h i s l a s t p o i n t i s p a r t i c u l a r l y i m p o r t a n t when e x t r a w i d e d r i f t s a r e n e e d e d , e s p e c i a l l y i n t h e c a s e o f v e r y f l a t d i p p i n g o r e b o d i e s t o s u i t r i n g d r i l l i n g . 3-35 L o a d i n g P a t t e r n o r I n t e n s i t y o f L o a d i n g : The e x t r a c t i o n w i d t h i s g i v e n by t h e o p e r a t i n g r e a c h o f the s c o o p t r a m and by t h e l o a d i n g s y s t e m . The g r a v i t y f l o w a p p r o a c h e s more c l o s e l y a p a r a l -l e l f o r m (and t h i s i s i d e a l i n t h e c a s e o f T r . S u b - l e v e l c a v i n g ) i f t h e o p e r -a t i n g r e a c h o f t h e l o a d e r i s w i d e r and t h e l o a d i n g s y s t e m c o v e r s the w i d t h o f t h e e x t r a c t i o n d r i f t more f u l l y - u n d e s i r a b l e a r c h i n g o f t h e lumpy m a t e r i a l i s e a s i l y a v o i d e d t h i s way . When m i n i n g t h r o u g h l o n g i t u d i n a l d r i f t s i n n a r r o w d e p o s i t s i t i s a p p r o p r i a t e t o draw more b r o k e n o r e f r o m the f o o t w a l l s i d e than f r o m t h e h a n g i n g w a l l s i d e . L o a d i n g a t t h e f o o t w a l l s i d e s h o u l d be i n c r e a s e d , t h e s m a l l e r i s t h e i n c l i n a t i o n o f t h e d e p o s i t . 3.36 R i n g G r a d i e n t : R e s e a r c h i n Sweden has i n d i c a t e d t h a t t h e opt imum r i n g g r a d i e n t o r t h e f a n a n g l e , w i t h i n t h e a n g l e l i m i t s o f 60 - 120°, i s m a i n l y dependent on t h e r a t i o o f a v e r a g e o r e s i z e s t o w a s t e s i z e s . J a n e l i d and K v a p i l (47) p r o -duced a s i m p l e t a b l e w h i c h i s r e p r o d u c e d , i n a s l i g h t l y m o d i f i e d f o r m , b e l o w : 26. R a t i o o f Rock S i z e s : Fan A n g l e , a Ko/Kw > 1 P o s i t i v e , a < 9 0 ° Ko/Kw = 1 V e r t i c a l , a = 90° K Q / K W < 1 N e g a t i v e , a > 90° Where KQ i s t h e a v e r a g e p a r t i c l e s i z e o f t h e o r e , i s t h e a v e r a g e p a r t i c l e s i z e o f t h e w a s t e and i s t h e a n g l e between t h e h o r i z o n t a l and t h e f a n , away f r o m t h e d i r e c t i o n o f r e t r e a t (see F i g . 2 & 3)• The t h e o r y i s t h a t t h e r i n g g r a d i e n t ol, i s t o have t h e e f f e c t o f p r e -v e n t i n g as much as p o s s i b l e , t h e i n t e r m i x i n g o f w a s t e o r , i n v e r s e l y , t h e i n -t e r m i x i n g o f o r e i n t o w a s t e . A m a t e r i a l o f f i n e p a r t i c l e s i z e c a n , as a r e s u l t o f t h e g r a v i t a t i o n -a l f o r c e , f i l l t h e l o w e r l y i n g c a v i t i e s and gaps i n t h e m a t e r i a l o f c o a r s e p a r t i c l e s i z e , i . e . , f i n e o r e l y i n g o v e r lumpy w a s t e o r v i c e v e r s a . The r i n g g r a d i e n t i s so c h o s e n s u c h t h a t the opt imum c o n d i t i o n s a r e o b t a i n e d i n t h i s r e s p e c t . The r i n g g r a d i e n t i s , h o w e v e r , a l s o dependent on m i n i n g c o n s i d e r a -t i o n s — such as m a i n t a i n i n g a good brow and a good d r i l l e d f o o t a g e e f f i c i e n c y . P r o b a b l y b e c a u s e o f t h e s e c o n s i d e r a t i o n s , v e r y f e w , i f a n y , mines have a d o p t e d a backward s l o p i n g r i n g g r a d i e n t o r t h e f a n a n g l e and most have a d o p t e d a n g l e s v a r y i n g f r o m 70° t o 9 0 ° , d e p e n d i n g on t h e s e c o n d i -t i o n s . F o r t h e p u r p o s e s o f model t e s t w o r k , f r a g m e n t a t i o n o f o r e and w a s t e were assumed t o be e q u a l and hence o n l y v e r t i c a l f a n s have been t e s t e d . T h i s w o u l d need m o d i f i c a t i o n s , h o w e v e r , i f i n a c t u a l p r a c t i c e i t i s f o u n d t h a t Ko 27. 3-37 B l a s t R e t r e a t D i s t a n c e : From a t h e o r e t i c a l p o i n t o f v i e w , t h e b l a s t r e t r e a t d i s t a n c e RA, w i l l be g o v e r n e d by many f a c t o r s . In p r i n c i p l e , i t can be e x p r e s s e d by a s y m b o l i c f u n c t i o n o f t h e f o l l o w i n g f a c t o r s , where some o f t h e s e may be i n t e r d e p e n d e n t . R d = f (K , h ' c , v , S , x , m, B, c\ ) 3 (9) Where t h e f i r s t f o u r f a c t o r s a r e t h e same as used i n E q u a t i o n 3 (5) and t h e r e m a i n i n g f a c t o r s as shown i n F i g u r e s 2 and 3-The p r o p e r b l a s t r e t r e a t d i s t a n c e s h o u l d , i n t h e opt imum c a s e , c o r -r e s p o n d t o t h e g r a v i t y f l o w o f t h e b l a s t e d o r e i n t h e way shown i n F i g u r e s 2a and 3a. The opt imum b l a s t r e t r e a t d i s t a n c e (See F i g . 2 £ 3) f o r a v e r t i c a l s l i c e i n a t r a n s v e r s e s u b - l e v e l s t o p e c a n be c a l c u l a t e d f r o m t h e a p p r o x i m a t e f o r m u l a . R d > S J (1 - e 2 ) 3 (10) S u b s t i t u t e v a l u e o f e = 0.975, f o r a s u b - l e v e l i n t e r v a l ' S 1 o f 30 f t . f r o m J a n e l i d (47, F i g . 29, PP 142) i n E q u a t i o n 3 ( 1 0 ) . T h e r e f o r e : R d > 30 J~\ - (.975) 2 > 6.60 f t . B l a s t r e t r e a t d i s t a n c e s o f 5, 6 and 7 f t . a r e t e s t e d in t h e model f o r t h e t r a n s v e r s e s u b - l e v e l c a v i n g m e t h o d . No f o r m u l a i s a v a i l a b l e f o r t h e c a l c u l a t i o n o f b l a s t r e t r e a t d i s -t a n c e i n t h e c a s e o f l o n g i t u d i n a l s u b - l e v e l c a v i n g method b e c a u s e o f u n s y m -m e t r i c a l d r a w . T h e r e f o r e , s e c t i o n a l d i a g r a m s f o r each c o n f i g u r a t i o n a r e d r a w n , and b a s e d on e s t i m a t e d b e s t r e c o v e r i e s w i t h l e a s t d i l u t i o n ; opt imum b l a s t r e t r e a t d i s t a n c e s a r e d e v e l o p e d . A f t e r a l l o t h e r p a r a m e t e r s have been c h o s e n , such as s u b - l e v e l i n t e r -v a l , p i l l a r w i d t h , h e i g h t and w i d t h o f e x t r a c t i o n d r i f t and r i n g b u r d e n , e t c . and t h e mine d e v e l o p m e n t a l work i s s t a r t e d and k e p t ahead o f p r o d u c t i o n d a t e 28. f o r a y e a r o r t w o . B l a s t r e t r e a t d i s t a n c e i s , t h e n , by f a r t h e most i m p o r -t a n t v a r i a b l e w h i c h may g i v e any c h a n c e o f f l e x i b i l i t y in t h i s m e t h o d . A change i n b l a s t r e t r e a t d i s t a n c e can occur by v a r i a t i o n i n m o i s t u r e c o n t e n t . T h i s i s a m a t t e r o f c o n c e r n f o r Granduc M i n e s b e c a u s e o f s m a l l c o v e r o f w a s t e r o c k above t h e top most l e v e l . When t h e c a v e s t a r t s , i t w i l l p r o -b a b l y c o v e r a l a r g e c a t c h m e n t a r e a o f a t e r r a i n w h i c h i s c o v e r e d w i t h snow, a l m o s t e i g h t months i n a y e a r . Any hot a i r l e a k i n g t h r o u g h t h e cave m i g h t a c c e n t u a t e t h i s p r o b l e m , u n l e s s some a l t e r n a t i v e means o f w a t e r d i v e r s i o n a r e d e v i s e d . A l s o , v a r y i n g f r a g m e n t a t i o n (due t o t h e n a t u r e o f g r o u n d , e t c . ) and c o n s o l i d a t i o n ( caused by b i g g e r o r s m a l l e r e x p l o s i v e c h a r g e s a n d / o r by a v a r -i a b l e t h i c k n e s s o f t h e o v e r - l y i n g mat o f w a s t e r o c k ) h o l d d i f f e r e n t amounts o f m o i s t u r e c o n t e n t . T h i s t y p e o f s t u d y i s u s e f u l f r o m t h e p o i n t o f v i e w o f d e t e r m i n i n g an opt imum b l a s t r e t r e a t d i s t a n c e . T h e r e a r e two a l t e r n a t i v e s w h i c h can be c o n s i d e r e d f r o m a p r a c t i c a l s t a n d p o i n t . 1 . In t h e c a s e o f r i n g d r i l l e d s u b - l e v e l s w h i c h w i l l be k e p t i n r e a d i -ness b e f o r e a c t u a l p r o d u c t i o n , g e n e r a l l y w i t h a u n i f o r m r i n g b u r d e n t h r o u g h o u t , t h e s u b - l e v e l may have t o use a b l a s t r e t r e a t d i s t a n c e w h i c h i s an e x a c t m u l t i p l e o f t h e r i n g b u r d e n i n o r d e r t o be most p r o f i t a b l e i n p a r t i c u l a r l y changed s i t u a t i o n . 2. To s t u d y the v a r i a t i o n i n t h e depth o f t h e e l l i p s o i d o r c a v e f i g u r e b e f o r e h a n d w i t h respectHo p a r t i c u l a r r o c k type t o be e n c o u n t e r e d in t h e mine ( r o c k may b r e a k between t h e l i m i t s o f very f i n e t o c o a r s e ) and a l s o e x p e c t e d w e t n e s s i n t h e a r e a - so t h a t r i n g b u r d e n s may be v a r i e d and d e s i g n e d a c c o r d i n g t o the s p e c i f i c c o n d i t i o n s f o r d i f -f e r e n t p o r t i o n s o f t h e same s u b - l e v e l . 29. I f t h e f i r s t a l t e r n a t i v e i s more p r a c t i c a l and a c c e p t a b l e , t h e n t h e r e i s a need o f d e v e l o p i n g some f l o w c o r r e c t i v e measures to c a u s e t h e r o c k f l o w t o c o n f o r m w i t h t h e n e a r e s t s i n g l e o r m u l t i p l e r i n g b u r d e n - d e f i n e d as b l a s t r e t r e a t d i s t a n c e . P r i n c i p l e s o f a r c h i n g in t h e i d e a l s o i l s have been u t i l i z e d i n o r d e r t o know t h e change i n t h e d e p t h o f t h e e l l i p s o i d o f m o t i o n b e h i n d t h e s o l i d f a c e . From T e r z a g h i (kO), a r c h i n g i s one o f t h e most u n i v e r s a l phenomenon e n c o u n t e r e d i n s o i l s b o t h in t h e f i e l d and i n t h e l a b o r a t o r y . I f one p a r t o f t h e s u p p o r t o f a mass o f s o i l y i e l d s w h i l e the r e m a i n d e r s t a y s i n p l a c e , t h e s o i l a d j o i n i n g the y i e l d i n g p a r t moves o u t o f i t s o r i g i n a l p o s i t i o n between a d j a c e n t s t a t i o n a r y masses o f s o i l . The r e l a t i v e movement w i t h i n the s o i l i s o p p o s e d by a s h e a r i n g r e s i s t a n c e w i t h i n t h e zone o f c o n t a c t between t h e y i e l d i n g and t h e s t a t i o n e r y m a s s e s . S i n c e t h e s h e a r i n g r e s i s t a n c e t e n d s t o keep the y i e l d i n g mass i n i t s o r i g i n a l p o s i t i o n , i t r e d u c e s t h e p r e s s u r e on the y i e l d i n g p a r t o f t h e s u p p o r t and i n c r e a s e s the p r e s s u r e on t h e a d j o i n i n g s t a t i o n a r y p a r t s i n commonly c a l l e d ' a r c h i n g e f f e c t 1 and t h e s o i l i s s a i d t o a r c h o v e r t h e y e i l d i n g p a r t o f t h e s u p p o r t . R e f e r r i n g to F i g u r e h t h e l o c a l y i e l d o f t h e h o r i z o n t a l s u p p o r t o f a bed o f g r a n u l a r m a t e r i a l can be p r o d u c e d by g r a d u a l l y l o w e r i n g a s t r i p - s h a p e d s e c t i o n a . b . o f t h e s u p p o r t . A c c o r d i n g t o t h e r a d i a l s h e a r s t r e s s t h e o r y , as soon as t h e s t r i p has y i e l d e d s u f f i c i e n t l y i n a downward d i r e c t i o n , a s h e a r f a i l u r e o c c u r s a l o n g two s u r f a c e s o f s l i d i n g w h i c h r i s e f r o m t h e o u t e r b o u n d r i e s o f t h e s t r i p t o the s u r f a c e o f t h e g r a n u l a r m a t e r i a l . In t h e v i c i n i t y o f t h e s u r f a c e , a l l t h e g r a i n s move v e r t i c a l l y downward. T h i s has been d e m o n s t r a t e d by t i m e e x p o s u r e p h o t o g r a p h s , T e r z a g h i (hO). 30. A FIGURE 4. FAILURE IN COHESIONLESS GRANULAR MATERIAL PRECEDED BY ARCHING. (A) FAILURE CAUSED BY DOWNWARD MOVEMENT OF A LONG NARROW SECTION OF THE BASE OF A LAYER OF GRANULAR MATERIAL. (B) ENLARGED DETAIL OF DIAGRAM (A). 31. Such a movement i s c o n c e i v a b l e o n l y i f t h e s u r f a c e s o f s l i d i n g i n -t e r s e c t t h e h o r i z o n t a l s u r f a c e o f m a t e r i a l a t r i g h t a n g l e s . H e n c e , t h e s u r -f a c e s o f s l i d i n g have a shape s i m i l a r to t h a t i n d i c a t e d i n F i g u r e k by t h e l i n e s a.c. and b ' .d . The e q u a t i o n s f o r the s u r f a c e s o f s l i d i n g a.c. and b . d . have not y e t been s o l v e d . However , t h e e x p e r i m e n t s have s u g g e s t e d t h a t t h e a v e r a g e s l o p e a n g l e o f t h e s e s u r f a c e s d e c r e a s e s f r o m a l m o s t 90° f o r low v a l u e s o f Z/2b t o v a l u e s a p p r o a c h i n g {h5° + 0 12) f o r h i g h v a l u e s o f Z/2h-In t h e c a s e o f s u b - l e v e l c a v i n g s t o p e s , a h i g h v a l u e o f Z/2b e x i s t s n e a r t h e draw p o i n t c o n s i d e r i n g a f a i r l y t h i c k mat o f w a s t e r o c k o v e r l y i n g the b l a s t e d co lumn o f o r e . T h e r e f o r e , s t u d y o f t h e v a r i a t i o n i n t h e a n g l e (45° + 0 12) o r t n e a n g l e o f s i i d i n g i n t h e b r o k e n mass n e a r t h e o p e n i n g and t h e e v e n t u a l d e v e l o p m e n t o f t h e c u r v e d s l i d i n g s u r f a c e i s v e r y i m p o r t a n t i n d e t e r m i n i n g t h e most s u i t a b l e b l a s t r e t r e a t d i s t a n c e . A n g l e o f i n t e r n a l f r i c t i o n , '0' used i n t h e e x p r e s s i o n f o r a n g l e o f s l i d i n g [k5° + 0 /2) » ' s a f u n c t i o n o f v o i d r a t i o , m o i s t u r e c o n t e n t , a n g u -l a r i t y , p a r t i c l e s i z e and c o n f i n i n g p r e s s u r e s , e t c . A c c o r d i n g to 'Mohr - Coulomb F a i l u r e L a w ' . T* = C + 0 - t a n 0 3 (1 D Where <r i s t h e normal s t r e s s on the f a i l u r e p l a n e a t f a i l u r e and T* i s t h e s h e a r s t r e s s on t h e f a i l u r e p l a n e a t f a i l u r e , C s t a n d s f o r C o h e s i o n and i s e q u a l t o z e r o f o r C o h e s i o n l e s s m a t e r i a l s and 0 i s a n g l e o f i n t e r n a l f r i c t i o n V a l u e s o f 0 i n t h e p r e c e d i n g e q u a t i o n can be d e t e r m i n e d by means o f l a b o r a t o r y t e s t s . In o r d e r t o c a l c u l a t e t h e s t a t e o f s t r e s s l o c a t e d i m m e d i a t e l y above t h e y i e l d i n g s t r i p - T e r z a g h i has assumed t h e s u r f a c e s o f s l i d i n g a r e t o be v e r t i c a l as i n d i c a t e d by t h e l i n e s a ' . e . and b ' . f . ( F i g u r e h.). T h i s way t h e 32. p r o b l e m o f c o m p u t i n g t h e v e r t i c a l p r e s s u r e on t h e y i e l d i n g s t r i p becomes i d e n t i c a l w i t h t h e p r o b l e m o f c o m p u t i n g t h e v e r t i c a l p r e s s u r e on t h e y i e l d -i n g b o t t o m o f the p r i s m a t i c b i n s . The f o l l o w i n g f o r m u l a i s used t o d e t e r m i n e Where K = R a t i o between t h e h o r i z o n t a l and t h e v e r t i c a l p r e s s u r e - Taken as u n i t y i m m e d i a t e l y above t h e y i e l d i n g s t r i p , b = H a l f w i d t h o f t h e s t r i p (See F i g u r e 5) 0 = A n g l e o f s h e a r i n g r e s i s t a n c e . Y = U n i t w e i g h t o f the g r a n u l a r m a t e r i a l . C o n s i d e r i n g a u n i t w i d t h o f t h e y i e l d i n g s t r i p and by s u b s t i t u t i n g K = 1, b = 8, 0 = 4 2 ° , T = 100 I b s . / c u . f t . For Z = 6 0 ' = 887-9 l b s . / s q . f t . o r 6.15 P . S . I . F o r Z = 160' = 887-9 l b s . / s q . f t . o r 6.15 P . S . I . C o r r e s p o n d i n g normal s t r e s s ( c r h ) on t h e v e r t i c a l s u r f a c e o f s l i d i n g can be computed f r o m : OZ. - K. o - v 3 (13) The above a n a l y s i s i s a p p l i c a b l e t o t h e f l o w i n an open m a s s , b u t c o n s i d e r i n g the p a r t i c u l a r c a s e o f a s u b - l e v e l c a v i n g s t o p e w i t h s i d e s l o p e s - f o r m u l a s d e r i v e d f o r C o n v e r g e n t h o p p e r s w i t h s u r c h a r g e (See W a l k e r (10) ) f o r m a s s -f l o w a r e more r e l e v a n t i n c a l c u l a t i n g t h e n a t u r e o f s t r e s s e s c l o s e t o t h e o u t l e t i n s t o p e s . t h e v e r t i c a l s t r e s s on a h o r i z o n t a l s e c t i o n a t any d e p t h Z b e l o w t h e s u r f a c e f o r a C o h e s i o n l e s s m a t e r i a l . 3 (12) 33. The a v e r a g e v e r t i c a l p r e s s u r e V i s g i v e n by t h e f o l l o w i n g f o r m u l a : V = r h c 1 0 " ( f e ) c - ' ) + v ° ( f e ) c 3 ( , * > S u b s t i t u t e t h e f o l l o w i n g i n E q u a t i o n 3 (14) T = 100 l b s . / c u . f t . C = 3 . 1 3 ( t a k e n as the n e a r e s t a p p r o x i m a t i o n f r o m W a l k e r (10) T a b l e 2; P. 9 9 4 ; f o r c_, = 1 5 ° , 0 = 40° and S = 50°) and f r o m F i g u r e 5 h c = 41 f e e t h Q = 60 f e e t V Q = 100 x 100 l b s . / s q . f t . as t h e s u r c h a r g e v = loo x 4 i (\ - Ai \ 2.13) + 1 0 , 0 0 0 Al "\ 3 - 1 3 2 . 1 3 2 8 . 5 P . S . I  - i  . 3)   i "\ A range o f c o n f i n i n g p r e s s u r e s d e r i v e d f r o m E q u a t i o n s 3 (12) and 3 (14) w h i c h r e p r e s e n t t h e p r e s s u r e a t t h e o u t l e t s o f d i f f e r e n t s t o p e l a y o u t s c o u p l e d w i t h a range o f m o i s t u r e c o n t e n t t r i e d w i t h v a r y i n g s i e v e s i z e s o f t h e m a t e r i a l used were t e s t e d by means o f T r i a x i a l t e s t i n g m a c h i n e i n t h e l a b o r a t o r y a t U . B . C . D e t a i l s o f t e s t s c o n d u c t e d and t h e i r r e s u l t s a r e p r e -s e n t e d i n C h a p t e r s 4 and 5 3 .4 D e s i g n o f M a s s - F l o w B i n s v/s S t o p e D e s i g n : In o r d e r t o a s s e s s t h e s u b - l e v e l c a v i n g s t o p e s on t h e b a s i s o f m a s s -f l o w b i n and f u n n e l - f l o w b i n c o n d i t i o n , t h e f o l l o w i n g a n a l y s i s shows t h a t a v a r i e t y o f s i t u a t i o n s can d e v e l o p . F o r e x a m p l e : -A. T r a n s v e r s e s u b - l e v e l s t o p e s : can have m a s s - f l o w c o n d i t i o n on t h r e e 34. PRESENT EXTRACTION DRIFT-H FIGURE 5 . S T A N D A R D T R A N S V E R S E SUB L E V E L CAVING LAYOUT. 35. s i d e s and p l u g - f l o w c o n d i t i o n on one s i d e ( b a c k - e n d ) up t o t h e end o f t h e s i d e s l o p e s t o t h e n e x t sub l e v e l above and beyond t h a t h e i g h t i t has p l u g -f l o w c o n d i t i o n on t h r e e s i d e s and m a s s - f l o w c o n d i t i o n on one s i d e . B. L o n g i t u d i n a l Sub L e v e l S t o p e s : M a s s - F l o w P I u g - F l o w 1. Narrow & s t e e p l y * d i p p i n g s t o p e s can have = 3 s i d e s 1 s i d e 2. Narrow £ g e n t l y d i p p i n g s t o p e s can have = 2 s i d e s 2 s i d e s 3. Wide o r e b o d i e s , s t e e p l y d i p p i n g s t o p e s (2 E x t r a c t i o n d r i f t s on same l e v e l ) = 2 s i d e s 2 s i d e s h. Wide o r e b o d i e s , g e n t l y d i p p i n g s t o p e s (2 E x t r a c t i o n d r i f t s on same l e v e l ) = 1 s i d e 3 s i d e s F.W. d r i f t o r 2 s i d e s 2 s i d e s H.W. d r i f t NOTE: * S t e e p l y d i p p i n g w o u l d mean: d i p o f 75° and a b o v e . From t h e above i t a p p e a r s t h a t a s t o p e d e s i g n w i l l p r e s e n t many more v a r i a b l e s as compared t o the b i n d e s i g n a n d , t h e r e f o r e , J e n i k e and W a l k e r t h e o r i e s o f g r a v i t y f l o w as a p p l i e d f o r mass f l o w i n h o p p e r s and b i n s need a c o n s i d e r a b l e improvement b e f o r e t h e i r a p p l i c a t i o n can be e x t e n d e d t o t h e g r a v i t y f l o w o f b l a s t e d r o c k i n t h e s t o p e s . CHAPTER 4. 36. CONSTRUCTION AND OPERATION OF THE TESTING EQUIPMENT. 4. 1 G e n e r a l : The model and a l l a c c e s s o r i e s f o r i t have been c o n s t r u c t e d t o t h e s c a l e o f 1:30. P r e l i m i n a r y t e s t s were made on 1:60 s c a l e , b u t t h i s s c a l e was f o u n d t o be t o o s m a l l t o p e r m i t t h e d r a w i n g o f s e c t i o n a l d i a g r a m s and a l l o w p r o p e r s t u d y on t h e d i g g i n g p a t t e r n . One t e s t was made w i t h 1:20 s c a l e model and i t was f o u n d much e a s i e r t o w o r k w i t h , as t h e c h a n c e s o f d i s t u r b a n c e and d e v i a t i o n s a r e r e d u c e d . 4.2 C o n s t r u c t i o n : The model was made i n t h e shape o f a b o x , 3 f t . h i g h x 4 f t . w i d e x 18 i n . d e e p . ( see F i g u r e 6) I t was made o u t o f 2" x 4" l u m b e r , w i t h two v e r t i c a l s i d e s , m o v e a b l e i n s i d e t h e box t o a l l o w d i f f e r e n t p o s i t i o n s o f t h e sub d r i f t s , e t c . The back w a l l was c o v e r e d w i t h 1/2 i n . p l y w o o d , w h i l e t h e f r o n t w a l l was c o v e r e d w i t h 1/4" p l e x i g l a s s . The f r a m e c o n s t r u c t i o n was r e -i n f o r c e d w i t h 1/2" round b a r s , w h i c h s t r e n g t h e n e d t h e m o d e l . The p l e x i g l a s s f r o n t was s u p p o r t e d on the o u t s i d e by h o r i z o n t a l i r o n s t o p r e v e n t b u l g i n g , e t c . A p r o v i s i o n was made f o r two s i d e f r a m e s f o r t h e m o d e l , w h i c h p e r m i t t e d t h e e x t e n s i o n o f t h e model upwards as w e l l as s i d e w a y s , when d e s i r e d . .Upward e x t e n s i o n i s needed w h i l e d o i n g m u l t i p l e l e v e l t e s t s and s i d e e x t e n s i o n i s r e q u i r e d f o r t e s t i n g f l a t d i p p i n g l o n g i t u d i n a l s t o p e s . T h i s was a c h i e v e d by p l a c i n g an a d d i t i o n a l p l e x i g l a s s p l a t e on top o f t h e f i r s t o n e . T h i s f e a t u r e o f b u i l d i n g t h e model i n p o r t i o n s p r o v i d e d e a s e o f l o a d i n g and u n l o a d i n g t h e m o d e l . The model box was p l a c e d on two low h o r s e s , so t h a t s c o o p i n g f r o m i t s l o w e s t p a r t c o u l d be done c o m f o r t a b l y . F R O N T VIEW SIDE VIEW FIGURE 6 A . MINE MODEL A S S E M B L E D FOR T R A N S V E R S E SUB L E V E L CAVING. FRONT VIEW SIDE VIEW FIGURE 6B l i l MINE MODEL A S S E M B L E D FOR LONGITUDINAL SUB L E V E L CAVING. V_v> CO FIGURE" 6B (iii) ko. k.3 Ore and Waste M a t e r i a l : I t was assumed t h a t t h e maximum s i z e o f t h e o r e f r o m t h e p r o d u c t i o n b l a s t i n g s h o u l d not e x c e e d 20 i n . and t h e a v e r a g e s i z e i n t h e range t o 12 i n . - 16 i n . I t i s known, h o w e v e r , t h a t c o a r s e f r a g m e n t a t i o n makes t h e r e c o v e r y w o r s e . A v e r a g e g r a d e o r e was b r o u g h t f r o m t h e mine and c r u s h e d i n a s m a l l l a b o r a t o r y c r u s h e r . Choke f e e d i n t o t h e c r u s h e r was a v o i d e d , s i n c e t h a t p r o d u c e d more a n g u l a r o r e p a r t i c l e s . W i t h normal f e e d , t h e shape o f t h e c r u s h e d r o c k down t o a minimum s i z e o f ]/k i n . , had a p p r o x i m a t e l y t h e same shape as t h a t o f the b r o k e n o r e o b s e r v e d i n some o f t h e e x p e r i m e n t a l d r i f t s i n t h e m i n e . C r u s h e d r o c k was s c r e e n e d and t h e n mixed i n a p r o p o r t i o n t o have f r a g m e n t a t i o n d i s t r i b u t i o n s i m i l a r t o what was e x p e c t e d i n t h e a c t u a l o p e r a t i o n . The s c r e e n a n a l y s i s o f t h e o r e m a t e r i a l used i n each t e s t i s i n -c l u d e d i n T a b l e k, o f A p p e n d i x I I I . A p p r o x i m a t e l y 5,000 l b s . o f c r u s h e d o r e m a t e r i a l was p r e p a r e d . The o r e was t h e n p l a c e d i n t h e b i n s b e s i d e t h e m o d e l . A l t h o u g h n o t much i s known y e t about t h e f r a g m e n t a t i o n o f t h e c a v e d h a n g i n g w a l l , i t i s a s s u m e d , f o r model t e s t i n g , t h a t s i z e o f w a s t e i s t o be t h e same as t h a t o f t h e o r e m a t e r i a l p a r t i c l e s and a l s o , t h e g r a v i t y f l o w c h a r a c t e r i s t i c s t o be n e a r l y t h e same as t h a t o f t h e o r e . No o r e and w a s t e t e s t s have been p e r f o r m e d t o d e t e r m i n e t h e o r e r e c o v e r y and w a s t e d i l u t i o n e s t i m a t e s f o r r e a s o n s d e t a i l e d i n S e c t i o n 5-4. However , f o r t h e p u r p o s e s o f d e m o n s t r a t i o n a l t e s t s and f o r t h e l o a d i n g i n t e n s i t y t e s t s , e t c . , w h i t e d o l o -m i t e c r u s h e d to the same s i z e as t h a t o f o r e was used i n t h e m o d e l . k.k E x t r a c t i o n D r i f t s and L o a d i n g B u c k e t , E t c . : The e x t r a c t i o n d r i f t s were made o u t o f 1/6" g a l v a n i z e d p l a t e s , s c a l e d down t h i r t y t i m e s . The l o a d i n g b u c k e t was made o f 1/16" s t e e l p l a t e 41. and i t s d e s i g n i s e x a c t s c a l e d down copy o f t h e s c o o p t r a m S T - 4 A . I t s vo lume i s (30)3 = 27000 t i m e s l e s s t h a n t h e s c o o p t r a m b u c k e t and i t s d i g g i n g c h a r -a c t e r i s t i c s a r e a p p r o x i m a t e l y t h e same. The b u c k e t was pushed i n t o t h e muck p i l e , t h e n t u r n e d a r o u n d i t s p i v o t p o i n t s by p r e s s i n g down t h e d i g g i n g h a n d l e w i t h t h e thumb a t t h e same t i m e t h e b u c k e t was r a i s e d . One t e s t was a r r a n g e d a t 1:20 s c a l e . For t h i s p u r p o s e , a new s e t o f e x t r a c t i o n d r i f t s and s c o o p -t ram b u c k e t was made. The model box was the same as t h a t o f 1:30 s c a l e t e s t s . B l a s t p l a t e s , used f o r s e p a r a t i n g t h e o r e and w a s t e co lums d u r i n g l o a d i n g o f t h e model were made o u t o f 1/16" s h e e t p l a t e , (see F i g u r e 7)• 4.5 O p e r a t i o n o f t h e M o d e l : The model t e s t s were c a r r i e d o u t in a f u t u r e m i l l l a b o r a t o r y a r e a o f t h e d i m e n s i o n s a p p r o x . 40 f t . x 20 f t . T h i s p l a c e was a v a i l a b l e e n t i r e l y f o r model t e s t i n g . I t was q u i t e c o n v e n i e n t h e r e t o accommodate b e n c h e s , t a b l e s , s c r e e n s and t o o l s , e t c . , t o do any f i t t i n g s and c a r p e n t r y w o r k , e t c . A l t e r a t i o n s t o t h e model o f some s o r t were r e q u i r e d a l m o s t a f t e r e v e r y t e s t f o r the s t a r t o f a new c o n f i g u r a t i o n . D e t e r m i n a t i o n s o f t h e c a v e f i g u r e o r t h e draw f i g u r e s have been c a r r i e d o u t w i t h the model a r r a n g e d as d e s c r i b e d a b o v e . A d r i f t o p e n i n g i s c u t o u t a t t h e b o t t o m o f the f r o n t p l e x i g l a s s p a n e l . A wooden b l o c k , w i t h t h e same shape as the d r i f t h o l e , i s pushed i n t o t h e h o l e t h e same d i s t a n c e as t h e d e s i r e d b l a s t r e t r e a t d i s t a n c e . T h i s b l o c k was c u t w i t h an i n c l i n e i n t h e f r o n t so as a n a t u r a l a n g l e o f r e p o s e o f t h e r o c k i n t h e model c o u l d be d e v e l o p e d . The s i d e s l o p e s , i n t h e c a s e o f t r a n s v e r s e sub l e v e l c a v i n g t e s t , were p l a c e d on each s i d e o f t h e d r i f t . S l o p e s were s i m u l a t e d by p l y -wood boxes w i t h d e s i r e d s l o p e a n g l e . F o r l o n g i t u d i n a l sub l e v e l t e s t i n g , t h e FIGURE 7B WOODEN BLASTING BLOCK , EXTRACTION DRIFT, AND BUCKET 43. t h e H.W. and F.W. p a n e l s were f i x e d a t t h e d e s i r e d a n g l e and a d j u s t e d a l o n g t h e b a s e o f the model so as t o a d j u s t f o r t h e p r o p e r l o c a t i o n o f t h e d r i f t w i t h r e s p e c t t o the f o o t w a l 1 . Whenever F.W. s l a s h was needed t o be s t u d i e d , a f a l s e f l o o r was b u i l t on t h e top o f t h e F.W. p a n e l so as a r e c e s s c o u l d be c u t i n t o i t . See F i g u r e 15 i n A p p e n d i x V . The model was l o a d e d w i t h t h e o r e m a t e r i a l by s p r e a d i n g 2 i n . l a y e r s a t a t i m e and t h e n p l a c i n g marked s t o n e s on a s p e c i a l t h r e e d i m e n -s i o n a l p a t t e r n a t e a c h i n t e r f a c e . Each s u c h i n t e r f a c e had a g r i d o f 2 i n . x 2 i n . (5 f t . x 5 f t . , f u l l s c a l e ) . A t o t a l o f 4,200 r ed c o l o u r e d marked s t o n e s were r e q u i r e d f o r t h e p u r p o s e . T h i s s y s t e m had i t s o r i g i n a t t h e b o t t o m o f t h e model and 12 i n . t o t h e l e f t o f t h e d r i f t . The o r i g i n was moved some-t i m e s f o r f l a t l y d i p p i n g l o n g i t u d i n a l t e s t s and t h i s f a c t was n o t e d on t h e p a r t i c u l a r t e s t . The p r o c e s s o f l o a d i n g was r e p e a t e d i n t h i s m a n n e r , and l a y e r a f t e r l a y e r was p l a c e d u n t i l t h e model was l o a d e d h i g h enough t o p r o -v i d e a c a p p i n g o f a b o u t 20 i n c h e s , (50 f t . , f u l l s c a l e ) above t h e h i g h e s t e x p e c t e d c a v e f i g u r e c o n t o u r u n d e r s t u d y . The b l a s t i n g was s i m u l a t e d by p u l l -i n g a t t h e wooden b l o c k , w h e r e a f t e r , t h e l o a d i n g c o u l d s t a r t . F i v e b u c k e t s were drawn a t a t i m e and marked s t o n e s were p i c k e d as t h e y a p p e a r e d i n t h e t u n n e l . These s t o n e s were t h e n p l o t t e d on s e c t i o n a l d i a g r a m s c o v e r i n g t h e e n t i r e d e p t h o f the model a t 2 i n . i n t e r v a l s (5 f t . , f u l l s c a l e ) . P l o t t i n g was n o t done on t h e b a s i s o f c u m m u l a t i v e w e i g h t s b e c a u s e i t i s e r r o n e o u s . T h e r e f o r e , a l l p l o t s were made on t h e b a s i s o f vo lumes drawn o u t o f t h e b r o k e n m a s s . W i t h t h e a p p l i c a t i o n o f a p p r o p r i a t e s w e l l f a c t o r s , t h e s e p l o t s were m o d i f i e d . T h i s p o i n t i s e x p l a i n e d f u r t h e r under S e c t i o n 5.4. A f t e r the r e q u i s i t e amount o f s c o o p s have been drawn f r o m t h e m o d e l , i t was u n l o a d e d and a l l t h e marked s t o n e s were r e c o v e r e d f o r r e u s e . kk. Ore m a t e r i a l was p r o p e r l y mixed a g a i n , i f r e q u i r e d , and a s w e l l f a c t o r t e s t was made on the m a t e r i a l b e f o r e t h e n e x t t e s t was p e r f o r m e d . S i d e s l o p e s made up o f p l y w o o d boxes f o r t e s t i n g t r a n s v e r s e sub l e v e l s t o p e s and a l s o t h e F.W. and H.W. p a n e l s meant t o e x p e r i m e n t l o n g i t u -d i n a l s t o p e s , b o t h were c o v e r e d w i t h sand p a p e r t o g e t t h e same f r i c t i o n c o -e f f i c i e n t as f o r t h e o r e . T e s t s p e r f o r m e d by S w e d i s h e x p e r i m e n t e r s have shown t h a t t h e f r i c t i o n c o e f f i c i e n t s f o r r o c k on r o c k and r o c k on sand p a p e r a r e a l m o s t e q u a l to 0.7-4 . 5 1 T e s t s W i t h V i b r a t e d Column o f O r e : A few c h e c k t e s t s were made by v i b r a t i n g t h e co lumn o f o r e by means o f a s m a l l hand v i b r a t o r as d e t a i l e d in S e c t i o n 5.k. The l o a d i n g o f t h e model was a c h i e v e d by p u s h i n g a wooden b l o c k w i t h t h e same shape as t h e d r i f t h o l e i n t o the h o l e t h e same d i s t a n c e as t h e d e s i r e d b l a s t r e t r e a t d i s t a n c e . A b l a s t p l a t e , w h i c h had t h e same shape as t h e b l a s t , was put above t h e end o f t h e d r i f t b l o c k . Ore was f i l l e d t o j u s t above t h e b l o c k a n d , o f c o u r s e , b e h i n d the b l a s t p l a t e . The o r e between the b l a s t p l a t e and t h e p l e x i g l a s s was v i b r a t e d i n v e r t i c a l s e c t i o n s o f 2 i n c h e s . Ore m a t e r i a l was p l a c e d b e -h i n d and i n f r o n t o f the b l a s t p l a t e t o keep i t i n b a l a n c e as t h e l o a d i n g c o n t i n u e d . When t h e o r e had been v i b r a t e d up t o t h e l e v e l o f t h e b l a s t p l a t e t h e n t h e b l a s t p l a t e was p u l l e d o u t . From t h e r e o n , t h e model was l o a d e d n o r m a l l y i n 2 i n . l a y e r s and marked s t o n e s were p l a c e d on g r i d i n t e r s e c t i o n s u n t i l a c a p p i n g o f a t l e a s t 20 i n c h e s was a c h i e v e d . T h e r e a f t e r , t h e p r o -c e d u r e d e t a i l e d under S e c t i o n k.5 was r e p e a t e d and s e c t i o n a l d i a g r a m s were d r a w n . 45. 4.52 Ore and Waste T e s t s : Ore and w a s t e t e s t s w e r e p e r f o r m e d f o r the d e m o n s t r a t i o n a l p u r p o s e o n l y . In a few t e s t s , a 2 i n c h w a s t e band o f w h i t e d o l o m i t e was p l a c e d on t h e top o f t h e c o n t o u r s o f the d e s i r e d shape o f t h e b l a s t . As t h e s c o o p s were drawn f r o m t h e b o t t o m d r i f t , t h e f l o w o f t h i s band was v i e w e d f r o m t h e f r o n t p l e x i g l a s s p a n e l t o d e t e r m i n e t h e p r o p e r l o a d i n g s e q u e n c e , i . e . , e i t h e r f r o m the F.W. o r H.W. s i d e o f the d r i f t . P h o t o s o f the s e q u e n c e o f e v e n t s were c o n t i n u o u s l y t a k e n . Two s e t s o f t h e s e p i c t u r e s a r e shown i n A p p e n d i x V . F i g u r e 14 shows a l o n g i t u d i n a l s t o p e w i t h a s i n g l e d r i f t on two l e v e l s f o r a 30' o r e b o d y a t 65° F.W. a n g l e and F i g u r e 15 shows l o n g i t u d i n a l s t o p e w i t h two e x t r a c t i o n d r i f t s on t h e same l e v e l f o r a 50 f t . w i d e o r e b o d y a t 55° F .W. a n g l e . The c u m m u l a t i v e number o f s c o o p s drawn e i t h e r f r o m t h e F.W. o r H.W. s i d e o f the d r i f t a r e shown on t h e s i g n p l a c e d i n f r o n t o f the mode 1 . 4.6 T r i a x i a l C o m p r e s s i o n T e s t i n g E q u i p m e n t : These t e s t s were p e r f o r m e d t o s t u d y t h e f l o w a b i l i t y o f o r e s a m p l e s o b t a i n e d f r o m one p a r t i c u l a r p l a c e i n t h e m i n e . A number o f t e s t i n g m a c h i n e s a r e a v a i l a b l e i n t h e s o i l t e s t i n g t e c h n i q u e s . For e x a m p l e , d i r e c t s h e a r t e s t e r , r i n g s h e a r t e s t e r and T r i -a x i a l s h e a r t e s t e r , e t c . A t r i a x i a l t e s t i n g m a c h i n e was used f o r t h e above t e s t s , m a i n l y b e c a u s e o f i t s a v a i l a b i l i t y a t the U . B . C . l a b o r a t o r i e s f o r the s i z e o f the sample t e s t e d . (A m i x t u r e o f f i n e s t o 1/2" c r u s h e d r o c k . ) A c e l l f o r 4 - i n . d i a m e t e r s a m p l e s was used as t h e t e s t i n g e q u i p m e n t . F o r compacted s a m p l e s , t h i s c e l l p e r m i t s t h e use o f s t a n d a r d c o m p a c t i n g e q u i p m e n t . However , a v i b r a t o r was used to c o n s o l i d a t e the s a m p l e . Samples 46. up t o a maximum g r a i n s i z e o f 3/4 i n c h may be t e s t e d , a l t h o u g h s a t i s f a c t o r y t e s t s p e c i m e n s a r e more r e a d i l y o b t a i n e d i f t h e l i m i t i s p l a c e d a t t h e 3/8 i n c h s i e v e s i z e , B i s h o p and Henke l ( 4 1 ) . The h e i g h t o f t h e t e s t s p e c i m e n used was 8 i n c h e s . F i g u r e 8 shows the p i c t u r e s o f t h e t e s t s p e c i m e n and t h e t e s t i n g e q u i p m e n t . I t can be a r g u e d t h a t t r i a x i a l t e s t i n g e q u i p m e n t used as above may have the f o l l o w i n g l i m i t a t i o n s . 1. R e q u i r e d d e g r e e o f c o m p a c t i o n and u n i f o r m i t y may n o t be o b t a i n e d e v e r y t i m e a t e s t i s r e p e a t e d . 2. A new s a m p l e has t o be fo rmed each t i m e . T h i s f a c t o r i s i m p o r t a n t b e c a u s e a l a r g e number o f t e s t s have t o be p e r f o r m e d f o r c o m p l e t e d a t a . ( In t h e c a s e o f W a l k e r ' s R i n g S h e a r T e s t e r , any one s a m p l e may be used f o r a range o f c o n f i n i n g p r e s s u r e s , e t c . ) 3. E r r o r s c a u s e d due t o t h e use o f r u b b e r membrane a r o u n d the s a m p l e . (Up to 0.6 P . S . I . ) 4. A p p r o p r i a t e c o r r e c t i o n s need t o be a p p l i e d due t o t h e w e i g h t o f t h e s a m p l e i t s e l f - e s p e c i a l l y b e c a u s e o f t h e low p r e s s u r e s e x i s t i n g n e a r t h e o u t l e t o f t h e s t o p e s . T h i s a s p e c t has been n o t e d t o be p a r t i c u l a r l y i m p o r t a n t i n J e n i k e ' s a n a l y s i s , i n w h i c h c a s e , t a l l and n a r r o w m a s s - f l o w b i n s w i t h s m a l l o u t l e t o p e n i n g s have p r e s s u r e s i n the range o f 1 P . S . I . n e a r t h e o u t l e t and t h i s i s one o f t h e main r e a s o n s o f h i s use o f a low and s m a l l d i r e c t s h e a r t e s t e r f o r d e s i g n w o r k . PICTURE I. Sample ready for testing PICTURE 2. Failed sample PICTURE 3. Triaxial cell under loading (assembly) FIGURE 8 . TRIAXIAL TESTING EQUIPMENT 48. However , i n t h e c a s e o f S t o p e s w i t h c o m p a r a t i v e l y l a r g e r o p e n i n g s i z e , t h i s e r r o r may n o t be v e r y s e r i o u s , and i t can be seen f r o m t h e p r e c e d i n g E q u a t i o n s 3 (12) and 3 (14) t h a t p r e s s u r e s a r e i n t h e r a n g e o f 6 P . S . I . t o 30 P . S . I . d e p e n d i n g on w h e t h e r i t i s a f r e e m a s s - f l o w , o r f l o w on t h e s i d e s l o p e s , e t c . O b s e r v a t i o n s made and r e s u l t s o b t a i n e d f r o m t h e s e t e s t s a r e p r e s e n t e d i n T a b l e 2 o f A p p e n d i x I I I and i n C h a p t e r 5. 49. CHAPTER 5 TESTS DESCRIPTION PROCEDURES & RESULTS. 5. 1 Genera 1: The t e s t work was s t a r t e d w i t h t h e s t u d y o f t h e c a v e f i g u r e s i n o r e i n t h e open m a s s . Cave f i g u r e d e t e r m i n a t i o n s i n open mass mean t h a t t h e model was f i l l e d w i t h o r e m a t e r i a l and marked s t o n e and was w i t h o u t any o b -s t r u c t i o n s a g a i n s t a f r e e d e v e l o p m e n t o f g r a v i t y f l o w and c a v e f i g u r e s . In o t h e r w o r d s , no s i d e s l o p e s were p l a c e d on each s i d e o f t h e d r i f t . L o a d i n g was done f r o m t h e d r i f t and s e c t i o n a l d i a g r a m s p l o t t e d as d e s c r i b e d i n S e c -t i o n 4.5. These t e s t s a r e u s e f u l i n d o i n g t h e s o l i d g e o m e t r i c a l s t u d i e s o f the d i f f e r e n t s e q u e n c e s o f t h e f l o w and t h e y a r e a l s o o f f u n d a m e n t a l i m p o r -t a n c e f o r t h e u n d e r s t a n d i n g o f t h e g r a v i t y f l o w . One s e t o f s u c h c a v e f i g u r e s t e s t s i s s u f f i c i e n t t o s t u d y t h e t r a n s v e r s e sub l e v e l c a v i n g m e t h o d , but f o r t h e l o n g i t u d i n a l sub l e v e l c a v i n g t e s t s , such c a v e f i g u r e s s t u d i e s a r e e s s e n t i a l a l m o s t w i t h e v e r y p o s s i b l e c o n f i g u r a t i o n . T h i s was o b s e r v e d d u r i n g t h e p r e l i m i n a r y model t e s t s w h i c h were c o n d u c t e d by us b e f o r e , and i t was o b s e r v e d t h a t t h e p a r t i c l e movements a l o n g t h e H.W. c o n t a c t i s f a s t e r t h a n i n the r e s t o f t h e b r o k e n m a s s . T h e r e f o r e , f i r s t a few t e s t s were p e r f o r m e d i n o r d e r t o c h e c k t h e l a y o u t s o f t h e t r a n s v e r s e sub l e v e l c a v i n g w h i c h have been used i n the p l a n -n i n g work a l r e a d y . T h e r e a f t e r , a few m o d i f i c a t i o n s were done w i t h t h e model t o r e n d e r i t s u i t a b l e f o r t h e c o m p r e h e n s i v e t e s t i n g o f t h e l o n g i t u d i n a l sub l e v e l c a v i n g l a y o u t s , t h i s b e i n g t h e m a i n a r e a o f i n v e s t i g a t i o n o f t h i s t h e s i s . I n s t e a d o f t e s t i n g e v e r y p o s s i b l e c o n f i g u r a t i o n f o r t h e l o n g i t u d i n -a l sub l e v e l c a v i n g l a y o u t s , more e m p h a s i s has been g i v e n t o c h e c k t h e d e s i g n work o f t h e ' A ' o r e b o d y , w h i c h i s g e n e r a l l y n a r r o w and s t e e p l y d i p p i n g 50. ( w i d t h s r a n g e a p p r o x . between 1 5 ' t o h0' and d i p s v a r y between 65° t o 80°). The ' A ' o r e body i s one o f t h e f i r s t few a r e a s on t h e m i n i n g p r o g r a m . A f t e r t h e p r o c e d u r e s o f t e s t i n g and i n t e r p r e t a t i o n w i t h i n a c l o s e range o f a c c u r -a c y have been e s t a b l i s h e d , e x t e n d e d t e s t w o r k c o u l d be t a k e n up f o r any p a r t i c u l a r c o n f i g u r a t i o n a t t h e t i m e i t w i l l be r e q u i r e d t o c h e c k any l a y o u t . 5.2 D e s c r i p t i o n o f t h e Model T e s t s : T r a n s v e r s e S u b - L e v e l C a v i n g M e t h o d : A t o t a l o f e l e v e n t e s t s was d o n e . These c o m p r i s e d o f t e s t s i n t h e open mass and t e s t s w i t h s i d e s l o p e s o f lk", 79° and 8 4 ° . T h e r e f o r e , t h e t e s t s c o v e r e d 5° above and b e l o w t h e s t a n d a r d a d o p t e d p a t t e r n o f 79° s i d e s l o p e s . Two o f t h e above t e s t s were r e p e a t e d i n o r d e r t o e v a l u a t e any d i s c r e p a n c i e s due t o p e r s o n n e l e r r o r ; t h e s e were f o u n d t o be n e g l i g i b l e . T e s t s p e r f o r m e d i n t h e open mass i n d i c a t e t h a t the a n g l e o f s l i d i n g i s between 75° - 79°. I t i s r e a l i z e d , h o w e v e r , t h a t t h i s a n g l e i s a f u n c t i o n o f s i z e d i s t r i b u t i o n i n t h e b r o k e n mass and o t h e r f a c t o r s . L o n g i t u d i n a l S u b - L e v e l C a v i n g M e t h o d : T w e n t y - s i x t e s t s have been c o m p l e t e d f o r t h i s m e t h o d . Ore body w i d t h s o f 20', 30', k0' and 50', v a r y -i n g between f o o t w a l l a n g l e s o f 55° and 75° w i t h i n c r e m e n t s o f 5°, have been t r i e d . For the f i r s t few t e s t s , t h e e x t r a c t i o n d r i f t was p l a c e d i n f o o t w a l l c o n t a c t and draw c o n f i g u r a t i o n s were s t u d i e d . L a t e r , i t was d e c i d e d t o p l a c e t h e d r i f t w e l l i n t o the f o o t w a l l where f o o t w a l l a n g l e s were l e s s t h a n 70°. These r e s u l t s were compared w i t h s i m i l a r l a y o u t s w h i c h had used no f o o t w a l l s l a s h . Q u i t e e n c o u r a g i n g r e s u l t s were o b t a i n e d w i t h t h i s i m p r o v e -m e n t . Based on the above c o n s i d e r a t i o n s , t h e t e s t p rog ram was e v o l v e d . 51 A t o t a l o f t h i r t y - s e v e n t e s t s , one i n c l u d i n g o n 1:20 s c a l e c o v e r e d t h e e n t i programme. G e n e r a l b reakdown o f t h e t e s t s i s as f o l l o w s : 5.3 T e s t P r o g r a m : A . TRANSVERSE SUB -LEVEL CAVING TESTS : 1. Cave f i g u r e t e s t s in open m a s s . 2. T e s t w i t h 74° s i d e s l o p e s - c e n t r a l l o a d i n g . T e s t w i t h 74° s i d e s l o p e s - a l t e r n a t e l o a d i n g . 3. T e s t w i t h 79° s i d e s l o p e s - a l t e r n a t e l o a d i n g . 4. T e s t w i t h 84° s i d e s l o p e s - a l t e r n a t e l o a d i n g . B. LONGITUDINAL SUB-LEVEL CAVING TESTS: Orebody W i d t h : Footwal1 A n g l e s : Footwal1 S l a s h : 1. 20 f t . 60°, 65° no s l a s h 65° 90° s l a s h 65° 85° s l a s h 65° 80° s l a s h 65° 75° s l a s h 2. 30 f t . 60°, 65°, 75° no s l a s h 65° 80° s l a s h 3. 40 f t . 55°, 60°, 65° no s l a s h 65° 80° s l a s h 4. 50 f t . 55°, 70° 80° s l a s h ( i n d r i f t 'A') 5. 20 f t . 65° 80° s l a s h (1:20 s c a l e t e s t ) Some o f t h e t e s t s m e n t i o n e d i n ' A ' S ' B ' above were r e p e a t e d t o c h e c k the e f f e c t s o f d i f f e r e n t o r e m a t e r i a l , s w e l l f a c t o r s , l o a d i n g p a t t e r n 52. and t h e e f f e c t o f c o n s o l i d a t i n g co lumn o f o r e o v e r a d e s i r e d b l a s t r e t r e a t d i s t a n c e , by means o f a v i b r a t o r . The t e s t s were not c a r r i e d o u t i n any p a r t i c u l a r s e q u e n c e o r o r d e r , b u t were done a f t e r t h e e l i m i n a t i o n p r i n c i p l e , i . e . , i n f o r m a t i o n o b t a i n e d f r o m the p r e v i o u s t e s t s was used f o r t h e n e x t t e s t i n a p r o g r e s s i v e m a n n e r . 5.4 T e s t i n g P r o c e d u r e : A f t e r a few t e s t s had a l r e a d y been c o m p l e t e d , a c c o r d i n g t o t h e d e s -c r i p t i o n i n S e c t i o n 4.5, t h e p a r t i c u l a r a s p e c t o f l o a d i n g t h e model was s t u d i e d and t e s t e d , u s i n g e x i s t i n g f a c i l i t i e s . The p e r c e n t a g e o f v o i d s was t e s t e d b o t h i n t h e l o o s e l y p a c k e d and p a c k e d o r e m a t e r i a l , dependent upon the s c r e e n a n a l y s i s o f t h e m a t e r i a l b e i n g u s e d . C o n s i d e r a b l e c o n s o l i d a t i o n c o u l d be a c h i e v e d by p a c k i n g by means o f a v i b r a t o r . In o r d e r t o s t u d y t h e e f f e c t o f c o n s o l i d a t i o n , t h e b r o k e n o r e co lumn f o r a p a r t i c u l a r b l a s t r e t r e a t d i s -t a n c e was v i b r a t e d . T h i s was done on t h e a s s u m p t i o n t h a t c o n s o l i d a t i o n t a k e s p l a c e i n t h e d i r e c t i o n o f t h e e x t r a c t i o n d r i f t , b e c a u s e t h e m a j o r i t y o f t h e f r e e f a c e i s i n t h a t d i r e c t i o n . I t was f o u n d t h a t c a v e f i g u r e s do change d e p e n d i n g upon how t h e o r e m a t e r i a l was f i l l e d i n t h e model and c o n f i r m e d the v i e w t h a t g r a v i t y f l o w changes w i t h the change i n t h e b u l k d e n s i t y ( d e r i v e d f r o m t h e s p e c i f i c g r a v i t y and t h e v o i d s i n the b u l k ) . T h i s a s p e c t has an i m p o r t a n t b e a r i n g on t h e c a l c u l a t i o n o f t h e o r e r e c o v e r i e s , d i l u t i o n s and t h e t o t a l e x t r a c t i o n s based on t h e draw f i g u r e s . From t h e f o r e g o i n g , i t became a p p a r e n t t h a t t h e use o f p r o p e r s w e l l f a c t o r s f o r t h e choke b l a s t e d o r e co lumn and t h e muck i n t h e b u c k e t o f a s c o o p t r a m a r e i m p o r t a n t f o r t h e p r o p e r i n t e r p r e t a t i o n o f t h e draw f i g u r e s . I t i s c o n s i d e r e d , t h e r e f o r e , t h a t a model l o a d e d w i t h o r e and w a s t e 53. m a t e r i a l w i t h o u t p r o p e r c o n s o l i d a t i o n s i n t h e r e s p e c t i v e r e g i o n s w o u l d s e r v e no b e t t e r p u r p o s e t h a n b e i n g a v i s u a l a i d o n l y . F o r the above r e a s o n i n g , any q u a n t i t a t i v e a n a l y s i s based on t h e draw f i g u r e s o b t a i n e d f r o m t h e t e s t s u s e d as s u c h f o r t h e c a l c u l a t i o n o f p e r -c e n t a g e r e c o v e r i e s , w a s t e d i l u t i o n s and t o t a l e x t r a c t i o n , e t c . , w i l l be u n -r e a l i s t i c and m i s l e a d i n g . F o r t h e same r e a s o n , o r e and w a s t e t e s t s i n t h e m o d e l , w h i c h a r e a l s o e x t r e m e l y t i m e c o n s u m i n g f r o m t h e s o r t i n g p o i n t o f v i e w , were d r o p p e d f r o m t h e p r o g r a m . A few i l l u s t r a t i v e t e s t s and l o a d i n g i n t e n s i t y t e s t s were done as m e n t i o n e d i n S e c t i o n 4.3. Draw f i g u r e s a r e o b t a i n e d , t h e r e f o r e , by means o f s e c t i o n d i a g r a m s w i t h t h e h e l p o f m a r k e r g r i d s t o n e s as d e t a i l e d i n S e c t i o n 4.5, i n t h e c a s e o f e v e r y c o n f i g u r a t i o n s t u d i e d . T e s t i n g was c a r r i e d on w i t h t h e v i b r a t e d co lumn o f o r e ( S e c t i o n 4 . 5 0 - A f t e r t h e c o m p l e t i o n o f a few t e s t s , i t was f o u n d t h a t t h e use o f t h e v i b r a t o r i s n o t c o n t r o l l a b l e and t h e c o n s o l i d a t i o n s o b t a i n e d a r e n o t c o n s i s t e n t . F u r t h e r , the c o n s o l i d a t i o n s o b t a i n e d by t h i s method s t i l l c o u l d not r e p r e s e n t f u l l y t h e c o n d i t i o n s o f t h e a c t u a l b l a s t e d co lumn o f o r e , and c o r r e c t i o n s a r e needed t o i n t e r p r e t the r e s u l t s . T h e r e f o r e , t h e s e t e s t s were not c o n t i n u e d as a r e g u l a r p r o c e d u r e . The f i n a l p r o c e d u r e , h o w e v e r , e v o l v e d a f t e r t h e above e x p e r i m e n t a -t i o n and i t s d e s c r i p t i o n f o l l o w s , L o a d i n g o f the model was done w i t h o r e m a t e r i a l o n l y , w i t h o u t any v i b r a t i o n . M a r k e r s t o n e s were p l a c e d i n t h e e n t i r e vo lume o f t h e l o a d e d m a s s , in e a c h t e s t . Scoops were drawn w i t h t h e d e s i r e d l o a d i n g i n t e n s i t y (a r a t i o o f muck drawn f r o m t h e F.W. o r t h e H.W. o f t h e d r i f t ) , w h i c h was somet imes g u i d e d by t h e w a s t e band l a i d on t h e t o p o f t h e o u t l i n e o f t h e 5h. a c t u a l shape o f t h e b l a s t . E x t r a c t i o n v o l u m e s w e r e c o r r e c t e d w i t h t h e a p p l i -c a t i o n o f p r o p e r s w e l l f a c t o r s ( S e c t i o n 5-41) o f t h e m a t e r i a l i n u s e . C a l -c u l a t i o n s f o r o r e r e c o v e r y , w a s t e d i l u t i o n s and t o t a l e x t r a c t i o n s a r e made as c o n s i d e r e d i n S e c t i o n 5.43. 5.41 S w e l l F a c t o r : On r e v i e w i n g t h e work done a t M t . I s a , (50), i t i s n o t e d t h a t a c o n -f i n e d s w e l l f a c t o r o f 1.10 i s used f o r t h e b l a s t e d co lumn o f o r e , w h i c h i s c a u s e d by t h e e x p a n s i o n when a r i n g i s f i r e d . When t h e o r e i s e x t r a c t e d , a f u r t h e r e x p a n s i o n o c c u r s such t h a t an o v e r a l l s w e l l f a c t o r i s 1.5, b u t the i n t e r m e d i a t e s w e l l f a c t o r between 1.10 and 1.5 i s 1.37- In draw c o n t r o l , i n t e r m e d i a t e s w e l l f a c t o r i s an i m p o r t a n t v a r i a b l e . In o r d e r t o d e r i v e t h i s s w e l l f a c t o r o f t h e o r e m a t e r i a l i n t h e s c o o p b u c k e t u s e d f o r t h e model t e s t i n g , a few e x p e r i m e n t s were c o n d u c t e d . The v a l u e f o u n d was n o t much d i f f e r e n t f r o m t h e v a l u e o f s w e l l f a c t o r o f t h e a c t u a l m a t e r i a l used i n t h e model i n any t e s t (see T a b l e 1 S I A , A p p e n d i x I l ) . I t can be s a i d , t h e n t h a t i n s i t u s w e l l f a c t o r o f 1.37 used f o r t h e heaped b u c k e t i n t h e mine i s l e s s t h a n t h e o v e r a l l s w e l l f a c t o r o f 1.5 b e c a u s e o f c o n s o l i d a t i o n b r o u g h t about by t h e d i g g i n g a c t i o n o f t h e s c o o p o v e r a w i d e range o f f r a g m e n t a t i o n i n t h e draw p o i n t . I t s h o u l d be m e n t i o n e d h e r e t h a t t h e computed v a l u e s o f o r e r e -c o v e r i e s and t o t a l e x t r a c t i o n s a r e as good as t h e a s s u m p t i o n s made i n t h e > c a l c u l a t i o n s o f t h e s w e l l f a c t o r . W i t h some p r e l i m i n a r y e x p e r i m e n t s and. f i e l d o b s e r v a t i o n s , s w e l l f a c t o r s have been d e r i v e d f o r t h e b r o k e n r o c k l o a d e d i n t h e model and t h e i n s i t u s w e l l f a c t o r o f t h e l o a d e d b u c k e t f o r c a l c u l a t i o n w o r k . I t i s , h o w e v e r , known t h a t t h e r e a r e not v e r y p r e c i s e means a v a i l a b l e y e t f o r f i n d i n g t h e i n s i t u s w e l l f a c t o r o f t h e g r a n u l a r m a t e r i a l s . I t has been o b s e r v e d by v a r i o u s w o r k e r s t h a t c o n s o l i d a t e d g r a n u -l a r m a t e r i a l d i l a t e s as f l o w e n s u e s . Now t h a t c o n s o l i d a t i o n o f t h e o r e co lumn r e g i o n i n t h e model i s much l e s s t h a n t h a t o f t h e b l a s t e d co lumn o f o r e i n t h e s t o p e and i t was o b s e r v e d a l s o i n t h e model t h a t draw p r o c e e d s f a s t e r i n t h e upward d i r e c t i o n i n r e l a t i o n t o t h e d e p t h i n t h e model and on t h i s a c c o u n t a l o n e , i t can be p r e d i c t e d t h a t w a s t e d i l u t i o n s and t h e r e b y t o t a l e x t r a c t i o n s show h i g h e r v a l u e s i n t h e model t h a n what w i l l a c t u a l l y happen i n t h e m i n e . 5.42 Scoop F a c t o r : From t h e a b o v e , a s c o o p f a c t o r o r t h e number o f b u c k e t s t o be drawn f o r a p a r t i c u l a r b l a s t r e t r e a t d i s t a n c e has been c a l c u l a t e d as f o l l o w s : I n - s i t u vo lume o f r o c k b l a s t e d I n - s i t u S . F . o f t h e f o r t h e b . r . d . under i n v e s t i - X muck in t h e heaped g a t i o n . b u c k e t . SCOOP FACTOR = Volume o f the heaped b u c k e t (112 c u . f t . ) For s i m p l i c i t y , scoop f a c t o r s b a s e d on t h e above have been used p u r e l y f o r c o m p a r i s o n p u r p o s e s t h r o u g h o u t the c o m p u t a t i o n w o r k . In f a c t , t h i s f i g u r e w i l l have t o be a d j u s t e d i n a c t u a l p r a c t i c e s i n c e t h e o u t l i n e o f the draw vo lume s t a y s g e n e r a l l y o u t s i d e o f the o r e and w a s t e i n t e r - f a c e i n t h e s t o p e . 5.43 C a l c u l a t i o n P r o c e d u r e f o r Ore R e c o v e r y and T o t a l E x t r a c t i o n s : The vo lumes o f o r e and w a s t e , w h i c h a r e c o n t a i n e d by c a v e f i g u r e s o f d i f f e r e n t t o t a l e x t r a c t i o n s have been e s t i m a t e d f o r d i f f e r e n t s i z e s o f 56. b l a s t s . S i n c e t h e c a v e f i g u r e s a r e u n s y m m e t r i c a l , i t i s n o t p o s s i b l e t o use vo lume i n t e g r a t i o n and c o n s e q u e n t l y no r o t a t i o n a l s o l i d c o u l d be e s t a b l i s h e d . I n s t e a d , the vo lumes o f the c a v e f i g u r e s were e s t i m a t e d by u s i n g p r i s m o i d a l f o r m u l a s , by w h i c h t h e a r e a s o f v e r y t h i n s l i c e s o f the s o l i d f i g u r e s a r e m e a s u r e d . F i g u r e 9 shows t h e p r o c e d u r e f o r the c a l c u l a t i o n o f o r e r e c o v e r y , t o t a l e x t r a c t i o n and w a s t e d i l u t i o n s , e t c . , i n t h e s p e c i a l c a s e , when t h e o r e co lumn has been v i b r a t e d and has a d i f f e r e n t S . F . than t h e r e s t o f the m a s s . In a g e n e r a l c a s e , i . e . , when t h e S . F . o f t h e e n t i r e mass i s t h e same o r x = y i n F i g . 9, c a l c u l a t i o n s a r e m o d i f i e d a c c o r d i n g l y . 5-5 T e s t R e s u l t s : Ore r e c o v e r i e s , t o t a l e x t r a c t i o n s and w a s t e d i l u t i o n s a r e c a l c u -l a t e d as d e s c r i b e d i n S e c t i o n 5.^3 f o r a range o f sub l e v e l i n t e r v a l s and b l a s t r e t r e a t d i s t a n c e s . These a r e t a b u l a t e d i n T a b l e 1 and T a b l e IA i n A p p e n d i x I I . I t i s n o t p o s s i b l e t o d i s c u s s a l l t h e t e s t s h e r e but t h e most r e p r e s e n t a t i v e ones have been g r o u p e d a p p r o p r i a t e l y i n the above t a b l e s f o r c o m p a r i s o n p u r p o s e s . T a b l e 1 and IA , a l s o i n c l u d e t h e i n t e n s i t y o f l o a d i n g i n t h e e x t r a c t i o n d r i f t . H a n g - u p s and d i s t u r b a n c e s were o b s e r v e d d u r i n g s c o o p i n g t h e muck f r o m t h e m o d e l . However , c a v e f i g u r e s a r e drawn up a f t e r t h e g e n e r a l p a t t e r n o f draw w h i c h i s r e p r e s e n t e d i n the p r o p o s e d l a y o u t d r a w i n g s . Due t o t h e p r o b a b l e i n c o n s i s t e n c i e s i n t h e d e t e r m i n a t i o n o f s w e l l f a c t o r o f t h e v i b r a t e d o r e co lumn i n some o f t h e t e s t s , t h e c a l c u l a t e d v a l u e s o f t h e r e s u l t s m i g h t show v a r i a n c e . F o r t h i s r e a s o n , a few t e s t s were r e p e a t e d w i t h s w e l l f a c t o r s d e t e r m i n e d as c a r e f u l l y as was p o s s i b l e 57. ORE ZONE A WASTE ZONE B SECTION ORE PACKED WITH VIBRATOR VOLUME 'C 0' 5' 10' 15' 20' 25' 30' A TYPICAL SECTION ALONG THE CENTER OF THE EXTRACTION DRIFT ORE RECOVERY % Volume C T X x 100 = Or TOTAL EXTRACTION % WASTE DILUTION % (Volume C -fx ) + (Volume D-ry) V x 100 = T. e Volume D-i-y (Volume C-rx)+( Volume D-ry) x 100 = W, WHERE a = BLAST RETREAT DISTANCE UNDER STUDY b = x-a (VIBRATED COLUMN OF ORE ) V = IN SITU VOLUME OF THE ORE BLASTED IN THE BLAST RETREAT DISTANCE OF 'a' FIGURE 9 . C A L C U L A T I O N P R O C E D U R E FOR ORE R E C O V E R Y , TOTAL E X T R A C T I O N AND WASTE DILUTION. 58. w i t h i n t h e p r a c t i c a l r a n g e . T e s t s numbers 37, 36, 31, 33 and 32 f o r o r e b o d y w i d t h s o f 20', 30', 40' a t 65° F.W. a n g l e and 50' a t 55° and 70° F.W. a n g l e r e s p e c t i v e l y can be c o n s i d e r e d most r e p r e s e n t a t i v e f o r t h e c a l c u l a t e d v a l u e s o f o r e r e c o v e r y , t o t a l e x t r a c t i o n and w a s t e d i l u t i o n , e t c . From t h e s t u d y o f t h e T a b l e 1 & IA ( A p p e n d i x l l ) , i t can be s a i d t h a t the r e s u l t s o b t a i n e d f r o m g e o m e t r i c a l l y s c a l e d model has g i v e n u s e f u l i n f o r m a t i o n r e g a r d i n g t h e r e l a t i v e i m p o r t a n c e o f v a r i o u s l a y o u t s o r c o n -f i g u r a t i o n s , b u t t h e r e remains y e t t h e p r o b l e m o f p r o p e r l y s c a l i n g - u p t h e r e s u l t s t o p r e d i c t t h e b e h a v i o u r o f t h e s t o p e w i t h r e g a r d t o t h e a c t u a l o r e r e c o v e r i e s and t o t a l e x t r a c t i o n s . I t can be f o r e s e e n , t h a t t h e s e f i g u r e s w i l l have t o be c o n s t a n t l y r e v i s e d as more i n f o r m a t i o n i s l e a r n e d a b o u t t h e draw c h a r a c t e r i s t i c s , b o t h f r o m t h e model t e s t s , and f r o m a c t u a l c o n t r o l l e d draws i n t h e sub l e v e l c a v e a r e a s . A f u r t h e r m o d i f i c a t i o n o f t h e draw vo lume w i l l change t o t a l e x t r a c -t i o n s a c c o r d i n g t o the g r a d e i n t h e s t o p i n g a r e a . B e f o r e t h e d i s c u s s i o n on t e s t s i s s t a r t e d , t h e f o l l o w i n g n o t a t i o n s a r e d e s c r i b e d . 1. #, i n t h e d i s c u s s i o n on v a r i o u s t e s t s r e f e r s t o s e r i a l number i n T a b l e 1 o r IA i n A p p e n d i x I I . 2. Recommended l a y o u t p a r a m e t e r s b a s e d on t h e a n a l y s i s o f t h e r e s u l t s a r e p r e s e n t e d i n T a b l e V, A p p e n d i x IV. 3. C o n f i g u r a t i o n s ' A ' t o ' H ' i n A p p e n d i x IV show p r o p o s e d l a y o u t p a t t e r n s b a s e d on T a b l e V , A p p e n d i x IV. 5•6 D i s c u s s i o n on t h e L o n g i t u d i n a l Sub L e v e l C a v i n g T e s t s . 1 5.61 20 f t . Orebody w i d t h . 59. 5.611 A t 60° F.W. a n g l e @ 60 f t . S . L . I . #1 a t 7' b . r . d . ; no F.W. s l a s h ; O r = 59-5% Te = 83. #2 a t 7' b . r . d . ; 80° F . W . s l a s h ; O r = 85.0. Te = 134S. C o m p a r i n g #1 & #2; O r improves w i t h F.W. s l a s h . Te i n #1 show l e s s t h a n even 100.. T h i s i s e r r o r o n e o u s b e c a u s e the i n c r e a s e d f l o w a l o n g the H.W. C o n t a c t removed a l l t h e marked s t o n e s much f a s t e r and l a t e r , w a s t e was r i l l i n g in f r o m t h e v e r y top w i t h no m a r k e r s i n i t . So a p a r t o f t h e t o t a l e x t r a c t i o n was not shown on t h e s e c t i o n a l d i a g r a m s and h e n c e , c a l c u -l a t e d Te i s l e s s t h a n 100.. T h i s e r r o r can q u i t e p o s s i b l y a p p e a r w i t h n a r r o w o r e b o d i e s and f l a t t e r a n g l e s . However , c h a n c e s o f t h i s o c c u r r e n c e were removed by p l a c i n g t h e marked s t o n e s much beyond t h e top o u t l i n e o f t h e b l a s t . 5.6121 A t 65° F .W. a n g l e , 60 f t . S . L . I . @ 6 f t . b . r . d . #3> no F.W. s l a s h #4, 90° F .W. s l a s h #13, 85° F W. s l a s h #6, 80° F .W. s l a s h 0 v = 71 .0% , Te = 1 3 0 . O r = 8 6 . 6 . , Te = 146. 0 r = 8 4 . 6 . , Te = 1 3 8 . 0 r = 8 2 . 6 . , Te = 1 2 8 . C o m p a r i n g t h e a b o v e , i t shows t h a t 90° F .W. s l a s h g i v e s t h e b e s t o r e r e c o v e r i e s , but s p e c i f i c a t i o n s o f p r o d u c t i o n d r i l l jumbos s u i t b e s t t o the F.W. s l a s h o f 8 0 ° to t h e h o r i z o n t a l , w h i l e k e e p i n g a minimum p o r t i o n o f t h e d r i f t w i d t h i n t o t h e w a s t e r o c k . T h e r e f o r e , l a y o u t s w i t h 80° F .W. s l a s h (#6) can be s e l e c t e d even though i t p r o d u c e s s l i g h t l y l o w e r Ore r e c o v e r y compared t o 90° o r 85° F .W. s l a s h . I t s h o u l d be m e n t i o n e d h e r e t h a t t o t a l e x t r a c t i o n s used f o r any c o m p a r i s o n o f o r e r e c o v e r y a r e b a s e d on an assumed a v e r a g e g r a d e o f t h e 60. o r e b o d y . However , t o t a l e x t r a c t i o n s w o u l d have t o be a d j u s t e d a c c o r d i n g t o h i g h o r low g r a d e o r e i n any p a r t i c u l a r p o r t i o n o f t h e o r e b o d y . Now, c o m p a r i n g T e s t No. 27 (#5, 6) and T e s t No. 37 (#19, 20, 21, 22, 23, 24) a t 60 f t . S . L . I , and 80° F .W. s l a s h , i t shows t h a t b e s t o r e r e c o v e r -i e s and t o t a l e x t r a c t i o n s a r e o b t a i n e d on a c o m p a r a t i v e b a s i s , a t 8 f t . b . r . d . T h e r e f o r e , #20 w o u l d d i c t a t e t h e s e l e c t i o n o f opt imum l a y o u t p a r a -m e t e r s a t 60 f t . S . L . I . 5.6122 A t 65° F .W. a n g l e @ 45 f t . S . L . I . #15 a t 7' b . r . d . @ 85° F.W. s l a s h #26 a t 6' b . r . d . @ 80° F.W. s l a s h g i v e good o r e r e c o v e r i e s and t h e y a r e c o m p a r a b l e t o #20 as d i s c u s s e d i n S e c t i o n 5-6121. T h e r e f o r e , 45 f t . S . L . I , can be a p o s s i b l e l a y o u t p a r a m e t e r but a 60' S . L . I , i s more e c o n o m i c a l i n t h e s i m i l i a r c o n d i t i o n s . F u r t h e r , t h e s e l e c t i o n o f S . L - I - i s t o s a t i s f y t h e r e s t r a i n t o f e i t h e r 30 f t . o r m u l -t i p l e o f i t i n the c a s e o f G ran duc o v e r a l l d e v e l o p m e n t p rog ram i n t h e c u r -r e n t l y d e v e l o p i n g o r e b l o c k . 5-6123 A t 65° F.W. a n g l e & 30 f t . S . L . I . T e s t No. 28 (#17) and T e s t No. 37 (#27, 28, 29) show low o r e r e -c o v e r i e s compared w i t h 45 f t . o r 60 f t . S . L . I , i n t h e i r r e s p e c t i v e t e s t s . I t i s e a s y t o i n t e r p r e t t h a t f o r t h e same p e r c e n t a g e o r e r e c o v e r y and t o t a l e x t r a c t i o n s , a h i g h e r sub l e v e l i n t e r v a l w h i c h i s c o m p a t i b l e w i t h o t h e r p r a c t i c a l & o p e r a t i o n a l c o n s i d e r a t i o n s i s more e c o n o m i c a l a n d , t h e r e -f o r e , p r e f e r a b l e . From S e c t i o n s 5-611, 5-6121, 5-6122 and 5-6123, #20 i n T a b l e 1 i s 61 . t h e s e l e c t e d l a y o u t . I t i s shown as C o n f i g u r a t i o n A and S e r i a l No. 1 ( T a b l e 5) b o t h g r o u p e d under A p p e n d i x IV. 5.62 30 F t . Orebody W i d t h : -5.621 A t 60° F .W. a n g l e , 60 f t . S . L . I . & L o a d i n g I n t e n s i t y = H . W . : F .W.::1:3 T e s t No. 9 (#34, 35, 36, 37, 38 and 3 9 ) , w i t h no F.W. s l a s h , shows on a c o m p a r a t i v e b a s i s t h a t 60' S . L . I , and 8 f t . b . r . d . i s t h e b e s t . How-e v e r , i t was f o u n d w i t h f u r t h e r t e s t i n g t h a t o v e r a l l o r e r e c o v e r y v a l u e s can be improved w i t h t h e i n t r o d u c t i o n o f a F.W. s l a s h . 5.622 A t 65° F.W. a n g l e , 60 f t . S . L . I . , no F.W. s l a s h & 8 f t . b . r . d . #41, l o a d i n g i n t e n s i t y = H .W. :F .W.::3:1 ; 0 r = 54.7. Te = 110. #40, l o a d i n g i n t e n s i t y = H.W. :F .W.::1:1 ; 0 T = 81.0% Te = 113. The above shows c l e a r l y t h a t a l t e r n a t e l o a d i n g i s b e t t e r t h a n e x -c e s s i v e l o a d i n g f r o m t h e H.W. s i d e . A c o m p a r i s o n o f draw f i g u r e s r e p r e s e n t i n g #41 and #40 i s shown by C o n f i g u r a t i o n J & K ( A p p e n d i x IV) r e s p e c t i v e l y . A f u r t h e r improvement o f t h e draw f i g u r e i s b rough a b o u t by a F.W. s l a s h and an i n c r e a s e d i n t e n s i t y o f l o a d i n g on t h e F.W. s i d e a t t h e s t a r t o f l o a d i n g . T h i s i s shown by C o n -f i g u r a t i o n B (#49, S e c t i o n 5-6221). 5.6221 A t 65° a n g l e , 60 f t . S . L . I . & 80° F.W. s l a s h . L o a d i n g I n t e n s i t y = F i r s t 90 s c o o p s a r e drawn f r o m t h e F.W. s i d e o n l y and t h e r e a f t e r , a l t e r n a t e l o a d i n g i s done f r o m each s i d e o f the d r i f t . 62. T e s t No. 36 (#47 t o #52) shows t h a t 8 f t . b . r . d . (#49) r e n d e r s t h e b e s t o r e r e c o v e r y and l e a s t t o t a l e x t r a c t i o n w i t h t h e above l a y o u t p a r a -m e t e r s . 5.6222 A t 65° F .W. a n g l e , 45 f t . S . L . I . S 80° F.W. s l a s h . T e s t No. 36 (#53, 54 and 55) show o r e r e c o v e r y i s b e t t e r w i t h 6 f t . b . r . d . compared t o e i t h e r a 5 f t . o r 8 f t . b . r . d . 5.6223 A t 65° F.W. a n g l e , 30 f t . S . L . I . & 80° F .W. s l a s h . A g a i n , T e s t No. 36 (#56, 57 and 58) show t h a t b . r . d . o f 6 f t . i s b e t t e r t h a n 5 f t . o r 8 f t . But on the w h o l e , 30 f t . S . L . I , g i v e s low o r e r e c o v e r i e s and hence i t i s n o t p r e f e r a b l e . From S e c t i o n s 5-622, 5-6221, 5-6222 and 5-6223, i t i s seen t h a t #49 o f T e s t No. 36 s u g g e s t s t h e b e s t l a y o u t p a t t e r n , w h i c h i s shown as C o n -f i g u r a t i o n B and S e r i a l No. 3 ( T a b l e 5) i n A p p e n d i x IV. 5-623 A t 75° F .W. a n g l e & no F.W. s l a s h . T e s t No. 25 (#59, 60, 61, 62, 63 and 64) i n d i c a t e t h a t o u t o f a l l ' s u b l e v e l i n t e r v a l s ' and ' b l a s t r e t r e a t d i s t a n c e ' c o m b i n a t i o n s , #60 i s p r e -f e r a b l e . T h e r e f o r e , 60' S . L . I , a t 8' b . r . d . i s a c c e p t a b l e . P r o p o s e d l a y o u t i s shown as C o n f i g u r a t i o n F and S e r i a l No. 4 i n T a b l e 5, b o t h i n A p p e n d i x IV. 5.63 40 f t . Orebody W i d t h : -5.63I A t 55° F.W. a n g l e , No F.W. s l a s h and L o a d i n g Sequence = H . W . : F . W . : : 1 : 3 T e s t No. 14 (#65 t o #70) i n d i c a t e t h a t 30 f t . S . L . I , i s t h e b e s t compared t o 45 f t . o r 60 f t . S . L . I , a t b . r . d . o f 5 f t . o r 6 f t . I t i s c l e a r f rom t h i s t e s t t h a t i f no F.W. s l a s h i s u s e d , t h e n f o r 63. m o d e r a t e l y w i d e r o r e b o d i e s (30 f t . t o 50 f t . ) a t low F.W. a n g l e s (55° and be low) a l o w e r sub l e v e l i n t e r v a l w i t h a s m a l l b . r . d . i s d e s i r a b l e . N e v e r -t h e l e s s , w i t h t h e i n t r o d u c t i o n o f p r o p e r F .W. s l a s h , o r e r e c o v e r i e s c a n be improved f u r t h e r . 5.532 A t 65° F.W. a n g l e , no F .W. s l a s h and L o a d i n g Sequence = H . W . : F . W . : : 1 : 3 T e s t No . 13 (#71 t o #76) shows t h a t 45 f t . S . L . I , a t 8 f t . t o 7 f t . b . r . d . g i v e s b e t t e r r e c o v e r i e s compared t o e i t h e r o f 30 f t . o r 60 f t . S . L . I . I t i s i n t e r e s t i n g t o n o t e h e r e t h a t w i t h i n c r e a s e i n F.W. a n g l e t o 65° f r o m 55° as f r o m S e c t i o n 5.631, opt imum S . L . I , i n c r e a s e s t o 45 f t . i n p l a c e o f 30 f t . However , t h i s S . L . I , c a n n o t be i s o l a t e d f r o m t h e r e s t o f t h e o p e r a t i o n , so t h e o b v i o u s s e l e c t i o n w o u l d be i n f a v o u r o f a 60 f t . S . L . I , a t 5 f t . t o 6 f t . b . r . d . even though 30 f t . S . L . I , o r 45 f t . S . L . I , g i v e e q u a l o r b e t t e r o r e r e c o v e r i e s . 5.6321 A t 65° F.W. a n g l e , 80° F.W. s l a s h 6 L o a d i n g I n t e n s i t y = F i r s t 180 s c o o p s a r e drawn f r o m t h e F.W. s i d e o n l y a n d , t h e r e a f t e r , a l t e r n a t e l o a d i n g i s done f r o m e a c h s i d e o f t h e d r i f t . T e s t No. 31 (#77, 78, 79, 80, 81, 82, 83 and 84) compared 60 f t . , 45 f t . and 30 f t . S . L . I n t e r v a l s o v e r a range o f b l a s t r e t r e a t d i s t a n c e s . 60 f t . S . L . I , w i t h 8 f t . b . r . d . (#78) g i v e s t h e maximum opt imum o r e r e -c o v e r i e s . T h e r e f o r e , t h e f i n a l l a y o u t i s s u g g e s t e d by t h i s . C o n f i g u r a t i o n C f r o m S e r i a l No. 5 o f T a b l e 5 i n A p p e n d i x IV i s t h e p r o p o s e d l a y o u t . A g r a p h s h o w i n g t h e c o m p a r i s o n between o r e r e c o v e r i e s v/s t o t a l e x t r a c t i o n s f o r t h e recommended l a y o u t s o f 20', 30' and 401 o r e b o d i e s i s a t t a c h e d i n F i g u r e 11. rr LU > o o LU CC 100 90 80 70 60 50 40 30 20 10 - •— '+ J 9 * * • • • / / 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 TOTAL EXTRACTION ( % ) FIGURE II. COMPARISON OF ORE R E C O V E R I E S v /s T O T A L E X T R A C T I O N S FOR 2 0 ' , 3 0 ' A N D 4 0 ' OREBODIES AT 6 0 ' SUB L E V E L I N T E R V A L , 6 5 ° F.W. A N G L E AND 8 ' B L A S T R E T R E A T DISTANCE 20' OREBODY 30' OREBODY 40' OREBODY 65. 5.64 50 f t . Orebody W i d t h ; -5-641 A t 55° F .W. a n g l e , F.W. s l a s h i n D r i f t A ( see C o n f i g u r a t i o n D) and L o a d i n g I n t e n s i t y (see T a b l e 6 i n A p p e n d i x I V ) . T e s t No. 33 (#85, 86, 87 and 8 8 ) . C a l c u l a t e d o r e r e c o v e r i e s and t o t a l e x t r a c t i o n s a r e d e t e r m i n e d f o r 8 f t . and 6 f t . b . r . d . s e p a r a t e l y f o r l o a d i n g i n D r i f t A . S i m i l a r c a l c u l a t i o n s a r e made f o r b . r . d . o f 6 f t . and 4 f t . i n t h e c a s e o f D r i f t B. T h e r e a f t e r , v a r i o u s c o m b i n a t i o n s o f b l a s t r e -t r e a t d i s t a n c e s i n D r i f t A and D r i f t B a r e t r i e d (#93, 94, 95 and 96). |t i s seen t h a t a c o m b i n a t i o n o f 6 f t . b . r . d . i n D r i f t A and a l s o a 6 f t . b . r . d . i n D r i f t B (#95) r e s u l t i n b e t t e r o r e r e c o v e r i e s compared t o o t h e r c o m b i n a t i o n s . H e n c e , t h i s c o m b i n a t i o n i s a c c e p t a b l e f o r l a y o u t i n t h i s c a s e . L o a d i n g s e -quence a d o p t e d f o r D r i f t A and D r i f t B, g i v e n i n T a b l e 6 - A p p e n d i x IV , was g u i d e d by t h e p r o g r e s s i v e downward movement o f a band o f w a s t e r o c k ( w h i t e i n c o l o u r ) p l a c e d on the t o p o u t l i n e o f a s t a n d a r d r i n g a t the s t a r t o f l o a d i n g . P i c t u r e s were t a k e n a t d i f f e r e n t s t a g e s o f l o a d i n g and t h e y a r e g rouped under F i g u r e 15 i n A p p e n d i x V . P r o p o s e d l a y o u t i s shown as C o n f i g -u r a t i o n D f r o m S e r i a l No. 6 o f T a b l e 5. 5.642 A t 70° F.W. a n g l e , F.W. s l a s h i n D r i f t A (see C o n f i g u r a t i o n E) and L o a d i n g I n t e n s i t y (see T a b l e 7 i n A p p e n d i x I V ) . T e s t No . 32 (#89, 90, 91 and 9 2 ) . E x a c t l y t h e same p r o c e d u r e i s a d o p t e d as i n t h e c a s e o f T e s t No. 33, S e c t i o n 5-641. C a l c u l a t e d o r e r e -c o v e r i e s and t o t a l e x t r a c t i o n s a r e d e t e r m i n e d f o r 8 f t . and 6 f t . b . r . d . f o r D r i f t A and 6 f t . , 4 f t . b . r . d . f o r D r i f t B r e s p e c t i v e l y . From d i f f e r e n t c o m b i n a t i o n s o f b l a s t r e t r e a t d i s t a n c e s i n D r i f t A and D r i f t B (#97, 98, 99 and 100), an 8 f t . - 6 f t . c o m b i n a t i o n (#98) g i v e s t h e h i g h e s t o v e r a l l o r e r e c o v e r i e s . P r o p o s e d l a y o u t i s b a s e d on t h i s r e s u l t and i s shown as C o n -66. f i g u r a t i o n E f r o m S e r i a l No . 7 o f T a b l e 5. In t h e s e l e c t e d l a y o u t , c o m b i n a t i o n o f b l a s t r e t r e a t d i s t a n c e s c o v e r d i f f e r e n t d e p t h s i n D r i f t A and D r i f t B. T h e r e f o r e , p r o p e r s e q u e n c e o f b l a s t i n g w o u l d have t o be d e v e l o p e d i n a c t u a l p r a c t i c e . In any c a s e , i f d i f f e r e n t b l a s t r e t r e a t d i s t a n c e s a r e c h o s e n f o r D r i f t A and D r i f t B, t h e n r e t r e a t i n D r i f t B s h o u l d be k e p t a s t e p ahead o f r e t r e a t i n D r i f t A . The f o r e g o i n g i s s p e c i a l l y s i g n i f i c a n t w i t h o r e b o d i e s d i p p i n g a t a n g l e s l e s s t h a n 6 5 ° . L o a d i n g s e q u e n c e f r o m D r i f t A o r D r i f t B i s shown i n T a b l e 7, A p p e n d i x IV. In o r d e r t o f i n d t h e most s u i t a b l e l o c a t i o n f o r D r i f t 1 B 1 i n r e l a -t i o n t o D r i f t A , the f i r s t d e s i g n was made by t r a n s p o s i n g d i f f e r e n t c a v e f i g u r e s a l r e a d y o b t a i n e d on t h e s e c t i o n s o f t h e w i d e r o r e b o d y , so as t o o b t a i n t h e b e s t d r a w . As t h e t e s t i n g p r o g r e s s e d , a n o t e w o r t h y o b s e r v a t i o n was made i n t h e d e v e l o p m e n t o f a v e r t i c a l p l a n e o f draw w h i c h r e s u l t s f r o m t h e e x t e n s i o n o f s u r f a c e s o f s l i d i n g ( S e c t i o n 3-37) s t a r t i n g f r o m t h e i n n e r s i d e s o f t h e e x t r a c t i o n d r i f t s . T h e r e f o r e , i t i s f o u n d t h a t opt imum maximum c e n t r e t o c e n t r e d i s t a n c e between D r i f t A and D r i f t B i s d o u b l e the h o r i z o n -t a l d i s t a n c e between t h e c e n t r e l i n e o f e i t h e r d r i f t f r o m the v e r t i c a l p o s i -t i o n o f t h e s u r f a c e o f s l i d i n g . T h i s phenomenon i s o f c o n s i d e r a b l e v a l u e and can be used i n t h e q u a n t i t a t i v e d e s i g n o f l o c a t i n g m u l t i p l e e x t r a c t i o n d r i f t s i n t h e c a s e o f l o n g i t u d i n a l sub l e v e l c a v i n g methods t h u s e l i m i n a t i n g t h e guess work employed so f a r . A l o g i c a l e x t e n s i o n o f t h i s p r o c e d u r e c o u l d be a p p l i e d t o 60 f t . o r even b i g g e r o r e b o d y w i d t h s . 5.65 E s t i m a t e d Waste From t h e F o o t w a l1 S l a s h : -F o o t w a l l s l a s h t o be t a k e n i n t h e w a s t e r o c k f o r t h e p u r p o s e o f i m p r o v i n g t h e g r a v i t y f l o w i n l o n g i t u d i n a l sub l e v e l c a v i n g s t o p e s i s 67-r e c o r d e d b e l o w as a p e r c e n t a g e o f t h e t o t a l vo lume o f o r e b r o k e n i n a s t a n -d a r d r i n g : Orebody W i d t h . F.W. A n g l e E x t r a Waste i n t h e S l a s h . 20' 55° 13.7% 20' 65° 7-8% 30' 55° 9-0% 30' 65° 5-0% 40' 55° 6.7% h0' 65° 3-7% 50' 55° 2.8% 50' 70° 1.9% 5.66 20 f t . Orebody W i d t h , 65° F.W. A n g l e S 80° F .W. S l a s h T e s t e d W i t h 1:20 S c a l e M o d e l . . Towards t h e end o f t h e t e s t w o r k , one t e s t was c o n d u c t e d on a 1:20 s c a l e g e o m e t r i c a l l y r e d u c e d model w i t h s i m i l a r b a s i c p a r a m e t e r s as u s e d i n T e s t No. 37 a t 1:30 s c a l e . A l s o , t h e p a r a m e t e r s o f t e s t i n g were k e p t s i m i l a r i n b o t h c a s e s . The s w e l l f a c t o r o f t h e m a t e r i a l used i n t h i s t e s t was a r -ranged t o match w i t h the e q u i v a l e n t t e s t (No. 37) on 1:30 s c a l e . T h i s was a c h i e v e d by c h a n g i n g t h e s c r e e n a n a l y s i s o f t h e t e s t e d m a t e r i a l i n s t e p s u n t i l the d e s i r e d s w e l l f a c t o r was o b t a i n e d . From T e s t 35 (#30, 31. 32, 33), 60 S . L . I , w i t h 8 f t . b . r . d . g i v e s t h e h i g h e s t o r e r e c o v e r i e s amongst t h i s g r o u p . From t h i s i t i s c l e a r t h a t r e s u l t s o b t a i n e d f r o m 1:20 s c a l e and 1:30 s c a l e show a good agreement w i t h e a c h o t h e r . B a r n e s (39), i n h i s p a p e r " S i m i l i t u d e i n t h e S t u d i e s o f T i l l a g e Implements F o r c e s " , has used t h i s t e c h n i q u e o f c h e c k i n g t h e p r e d i c t i o n s made by s m a l l s c a l e d models w i t h a b i g g e r model t h a n b e f o r e and r e p e a t e d t h i s p r o c e d u r e a r e a s o n a b l e number o f t i m e s . T h i s e x e r c i s e h e l p e d show t h e i m p o r t a n t v a r i a b l e s t a k i n g p a r t i n t h e p r o c e s s a n d , as a r e s u l t , c l o s e p r e d i c t i o n s t o t h e p r o t o t y p e b e h a v i o u r w e r e made. S i m i l a r a p p r o a c h c a n be a d o p t e d i n t h e m i n e model w o r k t o f u r t h e r a d v a n t a g e . 5.7 D i s c u s s i o n on t h e T r a n s v e r s e Sub L e v e l C a v i n g T e s t s : -5.71 A t 79° s i d e s l o p e & 30 f t . S . L . I . T e s t No. 4 (#101 t o #105) show t h a t b l a s t r e t r e a t d i s t a n c e i n t h e r a n g e o f 7 f t . a n d 6 f t . (#103 £ #104) g i v e b e s t o r e r e c o v e r y v a l u e s . 5.72 A t 74° s i d e s l o p e & 30 f t . S . L . I . F rom t e s t No. 6 (#106 t o #109) i s f o u n d t h a t i n t h i s c a s e a l s o , b e s t r e c o v e r i e s a r e t o be f o u n d w i t h b l a s t r e t r e a t d i s t a n c e s o f 6 f t . t o 7 f t . 5-73 A t 84° s i d e s l o p e s & 30 f t . S . L . I . T e s t No. 11 (#114 £ 115), h e r e a l s o 6 f t . a n d 7 f t . b l a s t r e t r e a t d i s t a n c e s g i v e h i g h o r e r e c o v e r i e s . I t i s c l e a r , h o w e v e r , t h a t o p t i m u m s i d e s l o p e a n g l e m u s t be f o u n d somewhat a b o v e t h e a n g l e o f s l i d i n g , w h i c h was f o u n d t o be b e t w e e n 74° and 79° a s d e t e r m i n e d f r o m t h e c a v e f i g u r e t e s t s i n t h e o p e n m a s s . From S e c -t i o n s 5.71, 5.72 a n d 5-73 a b o v e , o r e r e c o v e r i e s show up b e t t e r w i t h 84° s i d e s l o p e a s c o m p a r e d t o e i t h e r 74° o r 79° s i d e s l o p e . H o w e v e r , l o w e r d e v e l o p -ment c o s t a n d o p e r a t i o n a l c o s t s r e q u i r e d w i t h a l a y o u t p a t t e r n o f 79° s i d e s l o p e s , as c o m p a r e d t o 84° s i d e s l o p e s , make i t a d e s i r a b l e c h o i c e e v e n t h o u g h somewhat b e t t e r o r e r e c o v e r i e s a r e o b t a i n a b l e w i t h 84° s i d e s l o p e . A 30 f t . S . L . I , a n d 79° s i d e s l o p e p a t t e r n h a s a l r e a d y b e e n u s e d i n t h e p l a n n i n g w o r k . T h i s i s shown by C o n f i g u r a t i o n H f r o m S e r i a l No.8 o f T a b l e 5. C o n f i g u r a t i o n 1 shows t h e p a t t e r n o f d r a w i n a v e r t i c a l s e c t i o n a l o n g t h e c e n t r e l i n e o f t h e e x t r a c t i o n d r i f t . 69. In conclusion, it can be said that the design of these proposed layouts permit adoption to the already existing development work, when flexi-bil ity is of great value for the first period of operation. 5-8 Change in the Angle of Sliding - Determined by Triaxial Compression Testing Equipment:- Table 2, attached in Appendix III - records some of the tests per-formed, which clearly show the change in the angle of sliding and thereby a change in cave figures upon varying the test conditions. These tests were carried out with the ore samples from one particular place in the mine, but samples of ore collected from various locations in the mine representing different composition, can be tested to determine the difference in the flow properties for the purposes of quantitative design work. To illustrate the importance of Triaxial tests in designing the blast retreat distance, attention is drawn to Test Nos. 10, 11, 12, 13 and 14 of Table 2, Appendix III. Test No. Moisture Content Angle of Sliding (M.C. %) (Degrees) 10 NIL 65° 11 1.8% 64° 12 3.6% 69° 13 7.2% 61° 14 10.8% 51° Figure 10 shows that the angle of sliding for the dry sample (Test No. 10) is 65°. A moisture content of 1.8% (Test No. 11) does alter the angle of sliding to 64°, but it is not very significant. 70. 60' ELLIPSOID OF MOTION ( 45 +<))-7-2) =65° ANGLE OF SLIDING II' FIGURE 10 ANGLE OF SLIDING WITH VARYING M O I S T U R E C O N T E N T D E T E R M I N E D BY T R I A X I A L T E S T 71 • M o i s t u r e c o n t e n t o f 3 .6 . ( T e s t No . 12) r e d u c e s t h e f l o w a b i l i t y o f t h e mass and t e n d s t o s t e e p e n t h e a n g l e o f s l i d i n g t o 69° - hence r e d u c e s t h e d e p t h o f e l l i p s o i d . W h e r e a s , m o i s t u r e c o n t e n t o f 1.2% and 1 0 . 0 . ( Tes t N o s . 13 and 14) show a p r o g r e s s i v e i n c r e a s e i n t h e f l o w a b i l i t y , and f l a t t e n t h e a n g l e o f s l i d i n g t o 61° and 51° r e s p e c t i v e l y - hence i n c r e a s e t h e d e p t h o f t h e e l l i p -s o i d o f m o t i o n . M a t e r i a l d e s c r i p t i o n " F " ( T a b l e 3, A p p e n d i x I I I ) was used i n t e s t s 10 t h r o u g h 1 4 , f o r t h e above c o m p a r i s o n . I t i s n o t e d t h a t J e n i k e (38) used an a r b i t r a r i l y c h o s e n No. 20 mesh m a t e r i a l i n h i s t e s t s , b e c a u s e t h e f l o w a -b i l i t y o f a s o l i d c o n t a i n i n g a range o f s i e v e s i z e s , w h i c h i n c l u d e s b o t h f i n e and c o a r s e p a r t i c l e s , i s i n v a r i a b l y g o v e r n e d by t h e f l o w p r o p e r t i e s o f t h e f i n e f r a c t i o n . T h i s i s e x p l a i n e d by the f a c t t h a t d u r i n g f l o w t h e s h e a r i n g t a k e s p l a c e a c r o s s t h e f i n e s . N e v e r t h e l e s s , t h e s e t e s t s do i n d i c a t e t h e i m p o r t a n c e o f e x t e n d e d s t u d y i n t h i s d i r e c t i o n , w i t h r e g a r d t o Granduc o r e and w a s t e . 72. CHAPTER 6 CONCLUSIONS W h i l e f u l l s c a l e t e s t i n g u n d e r n a t u r a l c o n d i t i o n s w o u l d r e m a i n e s s e n t i a l as f i n a l d e m o n s t r a t i o n o f t h e w o r t h o f t h e s e k i n d o f t e s t s , c e r -t a i n l y much p r e l i m i n a r y s c r e e n i n g o f t h e t r i a l l a y o u t s o f L o n g i t u d i n a l Sub L e v e l C a v i n g Method c o u l d be c o n d u c t e d on t h e m o d e l . Q u a l i t a t i v e o b s e r v a t i o n s a r e r e p o r t e d and t h e e f f e c t s t h a t w i l l have t o be d e a l t w i t h i n t h e o r e t i c a l t r e a t m e n t a r e d e s c r i b e d . The f o l l o w i n g c o n c l u s i o n s a r e b a s e d on t h e r e s u l t s o f a few most r e p r e s e n t a t i v e c o n f i g u r a -t i o n s o f o r e b o d i e s a t Granduc M i n e s , and h e n c e , e x t r a p o l a t i o n o f some o f t h e s e c o n c l u s i o n s s h o u l d be a v o i d e d u n t i l f u r t h e r d a t a on a l l p o s s i b l e c o n -f i g u r a t i o n s i s a v a i l a b l e . 1. From t h e t h e o r y o f m o d e l s , a n a l y s i s c o m p l e t e d a t t h e p r e s e n t s t a g e shows t h a t g e o m e t r i c a l r e d u c t i o n o f t h e model i s p e r m i s s i b l e , so t h a t o r e r e c o v e r y and t o t a l e x t r a c t i o n f i g u r e s o b t a i n e d f r o m t h e model t e s t s may a t l e a s t be used u s e f u l l y f o r c o m p a r i s o n p u r p o s e s . However , a c o r r e c t i o n f o r t h e c o n v e r s i o n o f r e s u l t s based m a i n l y on t h e c o n s o l i d a t i o n and b u l k d e n s i t y in t h e s t o p e i s r e q u i r e d . 2. T e s t s c o n d u c t e d on 20, 30, kO and 50 f t . o r e b o d y w i d t h s a t f o o t w a l 1 a n g l e s l e s s t h a n 70°, w i t h a f o o t w a l 1 s l a s h , w h i c h i s c o m p a t i b l e w i t h p r o d u c t i o n d r i l l Jumbos s p e c i f i c a t i o n s have shown improved r e c o v e r i e s a t 60 f t . sub l e v e l i n t e r v a l s . 3- H i g h e r sub l e v e l i n t e r v a l s o f 60' w i t h e i t h e r n a r r o w and s t e e p o r e -b o d i e s o r n a r r o w and medium d i p p i n g o r e b o d i e s w i t h p r o p e r F.W. 73. s l a s h show b e t t e r r e c o v e r i e s compared to a l o w e r sub l e v e l i n t e r v a l o f 30' o r hS'. However , w i d e and f l a t d i p p i n g o r e b o d i e s a r e more s u i t e d t o l o w e r sub l e v e l i n t e r v a l o f t h e o r d e r o f 30 f t . 4. I t has been o b s e r v e d , w i t h t h e a i d o f t r i a x i a l t e s t i n g e q u i p m e n t , t h a t t h e r e i s a change i n t h e c a v e f i g u r e s when t h e c o n f i n i n g p r e s -s u r e s o r t h e m o i s t u r e c o n t e n t s a r e v a r i e d . S t u d y o f t h e change i n a n g l e o f s l i d i n g c a n , t h e r e f o r e , be u s e f u l i n t h e d e s i g n o f opt imum b l a s t r e t r e a t d i s t a n c e , e t c . , on t h e q u a n t i t a t i v e b a s i s . 5. T e s t s on 50 f t . o r e b o d y w i d t h , w i t h two e x t r a c t i o n d r i f t s on t h e same l e v e l on a l o n g i t u d i n a l sub l e v e l c a v i n g m e t h o d , has r e v e a l e d t h a t o v e r a l l o r e r e c o v e r i e s a r e low a t low f o o t w a l l a n g l e s , b u t w i t h s t e e p e r f o o t w a l l a n g l e s (70° and a b o v e ) , a c c e p t a b l e o r e r e -c o v e r i e s a r e o b t a i n a b l e . A l a y o u t w i t h t w i n d r i f t s a t 60 f t . sub l e v e l i n t e r v a l w i t h l o n g i t u d i n a l sub l e v e l c a v i n g i s more e c o n o m i c a l i n te rms o f w a s t e d e v e l o p m e n t f o o t a g e p e r ton o f o r e mined and a l s o , o v e r a l l o r e r e c o v e r y a t s t e e p e r d i p s compared t o t r a n s v e r s e sub l e v e l c a v i n g method a t 30 f t . sub l e v e l i n t e r v a l . F u r t h e r , i t i s seen f r o m t h e draw f i g u r e s f o r 50 f t . o r e b o d i e s t h a t t h i s method can be e x t e n d e d t o 60 f t . o r e b o d i e s a l s o , w i t h p r o p e r c o n t r o l o f l o a d i n g i n t e n s i t y i n d r i f t s 'A' and T h i s i s where t h e r e i s much t o g a i n p r i m a r i l y f r o m t h e d e v e l o p m e n t c o s t s t a n d p o i n t by t h e p r o p e r s e l e c t i o n between the l o n g i t u d i n a l or t h e t r a n s v e r s e sub l e v e l c a v i n g method i n a p a r t i c u l a r s i t u a t i o n . 74. CHAPTER 7 RECOMMENDATION FOR FURTHER WORK AND DISCUSSION. 7• 1 Recommendat ions f o r F u t u r e Work : The l i t e r a t u r e r e v i e w c o n t a i n e d i n t h i s r e p o r t , w h i l e n o t a l l -i n c l u s i v e , r e v e a l s t h a t t h e p r e s e n t s t a t e o f u n d e r s t a n d i n g i n t h e f i e l d o f g r a v i t y f l o w as a p p l i e d t o t h e s t o p e d e s i g n i s v e r y l i m i t e d . I t may, t h e r e -f o r e , be c o n c l u d e d t h a t t h i s f i e l d has q u i t e a c h a l l e n g e i n t h e d e v e l o p m e n t o f modern sub l e v e l c a v i n g m e t h o d s . The r e s u l t s in t h e T a b l e 1, A p p e n d i x I I , a r e not c o n c l u s i v e , p r o -m a r i l y b e c a u s e o f s e v e r a l a s s u m p t i o n s made i n t h e c a l c u l a t i o n s o f o r e r e -c o v e r i e s and w a s t e d i l u t i o n s , e t c . However , t h e s e r e s u l t s a r e u s e f u l i n d e t e r m i n i n g t h e r e l a t i v e i m p o r t a n c e o f v a r i o u s l a y o u t s . I t i s a p p r o p r i a t e t o make r e c o m m e n d a t i o n s f o r o t h e r i n v e s t i g a t i o n s , i n t h e l i g h t o f what has been r e v e a l e d f r o m t h e work so f a r . W i t h t h i s i n m i n d , the f o l l o w i n g such r e c o m m e n d a t i o n s f o r f u r t h e r and a d v a n c e d work a r e o f f e r e d . 1. S t o p i n g l a y o u t s s h o u l d be d e s i g n e d on a q u a n t i t a t i v e b a s i s and use can be made o f J e n i k e and J o h n s o n and W a l k e r t h e o r i e s and a l s o t h e i r t e s t i n g e q u i p m e n t i n d e t e r m i n i n g t h e f l o w a b i l i t y o f t h e b r o k e n o r e and w a s t e . Based on such f l o w a b i l i t y t e s t d a t a , a mine model can be c o n s t r u c t e d t o c h e c k t h e p r e d i c t i o n s b e f o r e i m p l e m e n t -i n g t h e d e s i g n i n t h e m i n e . 2. F u r t h e r e x p e r i m e n t a l work c o u l d be d e v e l o p e d t o i n t r o d u c e t h e e f f e c t o f b l a s t i n g i n t h e m o d e l , o r some s c a l e d e f f e c t t h e r e o f . 75. This would mean that a n a l y s i s o f the model s c a l i n g laws has to be improved upon so that model p r e d i c t i o n s are at l eas t va r i ance w i t h r e a l i t y . It i s seen that mine model t e s t procedure adopted so f a r has been time consuming because o f the placement and recovery o f s p e c i a l l y numbered rocks in the model on three dimensional g r i d . The numbered rocks were used as i n d i c a t o r s in o rder to draw s e c t i o n a l diagrams o f the cave f i g u r e s . There is a scope f o r improvement here in i n -c r e a s i n g the e f f i c i e n c y o f the t e s t i n g procedure . Observat ions in the f i e l d s h a l l have to be made to check the mer i t o f any design adopted. T h i s , g e n e r a l l y , i s an extremely slow p ro -cess s i n c e each problem u s u a l l y has fea tures p e c u l i a r to i t s e l f . However, techniques and ins t rumenta t ion should be developed. (a .) To monitor the f low pa t t e rn in the stopes so as any c o r r e c -t i v e measures be taken based on measurement ra ther than on hunch (moni tor ing in the mass-flow bins can be e a s i l y i n s t a l -led and has been used w i t h some success , but fo r the p l u g -flow type bins proper moni to r ing has yet to be deve loped) . (b.) To determine the extent o f caving in the s t op ing area which i s important from the o p e r a t i o n a l as w e l l as the sa fe ty po in t of v iew, i . e . , in o rder to know i f there is an adequate mat o f waste rock on the top of a p a r t i c u l a r column o f ore at any time and a l s o in a s ses s ing a s i t u a t i o n beforehand when dangers from an a i r b l a s t areimminent . 76. ( c . ) F o r f l o w p r o m o t i o n and f l o w c o r r e c t i o n i n t h e s t o p e on e n -c o u n t e r i n g an a r e a w h i c h r e a c t s e x c e p t i o n a l l y u n f a v o u r a b l y t o t h e a v e r a g e c o n d i t i o n s f o r w h i c h t h e l a y o u t was d e s i g n e d . 5. On ly v e r t i c a l b l a s t / d r i l l f a n s have been t e s t e d i n t h e model so f a r , H o w e v e r , a few t e s t s s h o u l d be done w i t h i n c l i n e d f a n s , as t h i s may be t h e b e s t p r o p o s a l j u s t i n c a s e t h e f r a g m e n t a t i o n r e l a t i o n s h i p i s s u c h t h a t t h e caved w a s t e i s f i n e r than t h e b l a s t e d o r e i n t h e m i n e , 6. The model t e s t s c o u l d n o t g i v e e x a c t a n s w e r s t o t h e q u e s t i o n o f opt imum l a y o u t , b u t do p r o v i d e a v e r y c l o s e range f o r i t . The l a y -o u t s w h i c h have been p r o p o s e d p r o v i d e f o r a d j u s t m e n t s i n some p a r t s , For e x a m p l e , b l a s t r e t r e a t d i s t a n c e , i n c l i n a t i o n o f f a n s and t h e i n t e n s i t y o f l o a d i n g , e t c . , c a n be i m p r o v e d a c c o r d i n g t o t h e o p e r a -t i o n a l e x p e r i e n c e . T h e r e f o r e , a p r a c t i c a l f o l l o w - u p s h o u l d be t a k e n up i n t h e mine i n a s e l e c t e d t e s t a r e a . T h i s t e s t a r e a s h o u l d be so c h o s e n t h a t i t does not depend on t h e r e g u l a r p r o d u c -t i o n o p e r a t i o n . D r i l l i n g , b l a s t i n g and l o a d i n g must be c a r r i e d o u t w i t h a t t e n t i o n a n d , t h e r e f o r e , more s l o w l y t h a n normal so a good c o n t r o l can be k e p t by t h e p e r s o n i n c h a r g e o f t h i s o p e r a t i o n . 7.2 O p e r a t i o n a l & P r a c t i c a l D e t a i l : Some o f t h e p a r a m e t e r s o f sub l e v e l c a v i n g method a r e d i s c u s s e d h e r e i n t h e l i g h t o f o p e r a t i n g and p r a c t i c a l d e t a i l . 7-21 F r a g m e n t a t i o n : I t i s known t h a t f r a g m e n t a t i o n o f o r e and w a s t e i s t h e key t o o t h e r p a r a m e t e r s . How much f i n e o r e s h o u l d be b r o k e n , depends on t h e a p p e a r a n c e 77. o f w a s t e f r o m t h e c a v e . As t h e o r e i s c o s t l y t o b r e a k i t w o u l d , o f c o u r s e , be d e s i r a b l e t o a c c e p t a r a t h e r c o a r s e f r a g m e n t a t i o n . H o w e v e r , one s h o u l d n o t l o o k too s e r i o u s l y a t t h e b l a s t i n g c o s t s , b u t p e r m i t a f r a g m e n t a t i o n w h i c h w i l l be most p r o f i t a b l e f o r t h e e n t i r e o p e r a t i o n . 7.22 Sub L e v e l I n t e r v a l : One can f i n d f r o m t h e model t e s t s , t h e b e s t p o s s i b l e sub l e v e l i n -t e r v a l w i t h normal c o n d i t i o n s . But somet imes much a t t e n t i o n has t o be g i v e n t o t h e i r r e g u l a r shape o f t h e o r e b o d y as w e l l as t o i t s d i p and p i t c h on mak ing s u c h a d e c i s i o n . A n o t h e r f a c t o r i n t h i s r e g a r d i s t h e e a s e o f b l a s t i n g and f r a g m e n -t a t i o n o f o r e . H i g h e r sub l e v e l i n t e r v a l s r e q u i r e l o n g e r d r i l l h o l e s w h i c h i n c r e a s e s t h e d r i l l i n g c o s t s r a p i d l y , e s p e c i a l l y i f c l o s e r h o l e p l a c i n g has t o be used t o a c h i e v e a c c e p t a b l e f r a g m e n t a t i o n . T h u s , t h e r e i s an e c o n o m i -c a l and a l s o p r a c t i c a l l i m i t f o r each t y p e o f o r e , w h i c h must not be e x c e e d e d . 7.23 Fan 1 n c l i n a t i o n : Optimum f a n i n c l i n a t i o n i s d e t e r m i n e d w h i c h i s c o m p a t i b l e w i t h o r e r e c o v e r y , l o n g h o l e d r i l l i n g e f f i c i e n c y , s a f e t y and o t h e r o p e r a t i o n a l p r o -b lems . T h e o r e t i c a l l y , 90° r i n g s g i v e an o v e r a l l r e c o v e r y w h i c h i s b e t t e r compared w i t h t h e i n c l i n e d r i n g s . T h e r e f o r e , t h i s i n c l i n a t i o n s h o u l d be u s e d i n t h e f i r s t l a y o u t s . However , t h e r e seem t o be o t h e r r e a s o n s f o r h o l e f a n s i n c l i n e d f o r w a r d 10° - 20°. V e r t i c a l r i n g s have c e r t a i n p o t e n t i a l o p e r a t i o n a l d i s a d v a n t a g e s f r o m t h e d r i l l i n g p o i n t o f v i e w ; w h e r e a s , i n c l i n e d h o l e s have t h e a d v a n t a g e s as t h e c o l l a r i n g i s done f u r t h e r away f r o m t h e o p e r a t o r a n d , t h e r e f o r e , 7 8 . w a t e r and s l u d g e do not f a l l d i r e c t l y o n t o t h e machine o r the o p e r a t o r . I t i s a l s o e a s i e r t o charge the d r i l l f a n c l o s e s t t o the f r o n t i f the h o l e s a r e i n c l i n e d f o r w a r d as more room w i l l be a v a i l a b l e between the back and the muck p i l e . T h i s , a l s o , c r e a t e s a s t r o n g e r brow w h i c h i s most i m p o r t a n t t o have i n bad grounds. W i t h the H.W. r e t r e a t method ( i . e . , r e t r e a t i n g from F.W. t o H.W.), d r i l l f o o t a g e s a r e 2 0 - 25% l e s s w i t h i n c l i n e d h o l e s compared t o v e r t i c a l a n g l e s w i t h orebody d i p s i n the range o f 6 5 ° . T h i s p o i n t s h o u l d be s t r o n g l y c o n s i d e r e d i n the case o f Granduc Mines where the H.W. r e t r e a t method has been p l a n n e d . 7.2k B l a s t R e t r e a t D i s t a n c e : B l a s t r e t r e a t d i s t a n c e o r the b l a s t depth d e t e r m i n e d from the model t e s t s a r e o n l y v a l i d f o r v e r t i c a l h o l e f a n s . I f i n c l i n e d h o l e fans a r e t o be u s ed, the b l a s t depth w i l l be s m a l l e r . However, as soon as r e s u l t s from the f o l l o w - u p system ( S e c t i o n 7 - 1 ) a r e o b t a i n e d , t h e b l a s t r e t r e a t d i s t a n c e s h o u l d be a d j u s t e d i f n e c e s s a r y . 7 - 2 5 Time F a c t o r : I t i s known t h a t time has c e r t a i n e f f e c t s on t h e f l o w p r o p e r t i e s o f g r a n u l a r m a t e r i a l s . I f the b l a s t e d column o f o r e i s l e f t u n l o aded f o r some t i m e , the s o l i d s remain under a c t i o n o f s t a t i c p r e s s u r e and, t h e r e f o r e , con-s o l i d a t e d , which reduces t h e i r f l o w a b i l i t y . F u r t h e r , i f w a t e r i s p r e s e n t , the c o h e s i o n f o r c e s i n the b l a s t e d o r e s t i l l s t r e n g t h e n i t , a t w h i c h s e r i o u s hangups o r doming can o c c u r . T h e r e f o r e , the b l a s t s s h o u l d not be l e f t un-l o a d e d t o o l o n g . F i e l d i n v e s t i g a t i o n s w i l l be n e c e s s a r y t o s t u d y t h i s e f f e c t i n fu11. 79. 7.26 The f o l l o w i n g a d d i t i o n a l p o i n t s may be c o n s i d e r e d w i t h a v i e w t o p r a c t i c a l t r i a l : A . I t has been f o u n d n e c e s s a r y , a t some m i n e s , t o r e d u c e t h e f a n b u r -den t o f i v e f e e t and t h e t o e b u r d e n s t o 4,1/2 - 5 f t . d e p e n d i n g on how " t i g h t " the p o s i t i o n i s . I f b i g g e r b u r d e n s a r e t r i e d , i t w o u l d p r o b a b l y be n e c e s s a r y t o d r i l l e a s e r h o l e s as shown i n F i g u r e 12. B. One p r o b l e m t h a t a r i s e s f r o m d r i l l i n g a l l o f a s t o p e f r o m an o r e e x t r a c t i o n d r i f t i s t h a t t h e r e i s a t e n d e n c y t o g e t " t i g h t " c o r n e r s , o r i n o t h e r w o r d s , a s u c c e s s i v e n a r r o w i n g o f b r e a k . In a normal l o n g i t u d i n a l sub l e v e l c a v i n g l a y o u t ( F i g u r e 12), t h e c o n t a c t b e -tween t h e H.W. and t h e f a n s t e n d s t o be t i g h t . On t h e F.W. s i d e , t h i s c o r n e r i s not so t i g h t b e c a u s e i t i s normal t o d r i l l a l o n g t h e c o n t a c t thus e n s u r i n g a b r e a k . I t may be p o s s i b l e t o c o n s i d e r r e - o r i e n t a t i n g t h e f a n s ( i n p l a n ) as shown i n F i g u r e 13, to e a s e s l i g h t l y t h e b r e a k i n g o f t h e r i n g . A l t e r n a t i v e -l y , b u t p e r h a p s l e s s d e s i r a b l y f r o m t h e p o i n t o f v i e w o f r e c o v e r y , t h e f a n s c o u l d be d r i l l e d i n a v e e - s h a p e d normal t o t h e f o o t w a l 1 , but a t an o b t u s e a n g l e t o t h e h a n g i n g w a l l . 7.27 I n t e n s i t y o f L o a d i n g : L o a d i n g / m u c k i n g i n t e n s i t y i s e x p r e s s e d as a p r o p e r r a t i o o f l o a d -i n g e i t h e r f r o m t h e F.W. o r H.W. s i d e o f t h e e x t r a c t i o n d r i f t . T h i s i s e x t r e m e l y i m p o r t a n t i n the c a s e o f l o n g i t u d i n a l sub l e v e l c a v i n g m e t h o d . To e n s u r e p r o p e r f u n c t i o n i n g a t t h e o p e r a t i n g l e v e l , i t w o u l d r e q u i r e o p e r a t o r t r a i n i n g , c l o s e r s u p e r v i s i o n and i n t r o d u c t i o n o f a bonus s y s t e m b a s e d on t h e q u a l i t y o f much p r o d u c e d r a t h e r t h a n on t h e t o t a l t o n s o f r o c k removed f r o m t h e s t o p e . THE HOLES FOR THE EASER RING (BROKEN LINES) SHOULD BE DRILLED FROM THE SAME SET-UP AND ANGLED FORWARD SO THAT THE COLLARS ARE NOT DAMAGED BY THE PREVIOUS BLAST. ; ^- - - - ^ t a , „  VERTICAL SECTION ALONG THE LONGITUDINAL AXIS OF EXTRACTION DRIFT SECTION I-I FIGURE 12. LONGITUDINAL SUB L E V E L CAVING - P O S S I B L E POSITIONING OF E A S E R H O L E S . 8 1 . PLAN FIGURE 13 . LONGITUDINAL SUB LEVEL CAVING - V E E SHAPED LONG HOLE FANS. .3 Comments on t h e Q u a n t i t a t i v e D e s i g n o f t h e S t o p e s : 82. Q u a n t i t a t i v e d e s i g n o f b i n i s e a s i e r t o a c h i e v e t h a n t h e d e s i g n o f t o p e l a y o u t s f o r t h e f o l l o w i n g r e a s o n s : 1. The s l o p e s o f t h e h o p p e r p o r t i o n o f t h e b i n can be d e s i g n e d a c c o r d -i n g t o t h e f l o w p r o p e r t i e s o f m a t e r i a l i t i s c h a r g e d w i t h . Now, i n t h e c a s e o f s t o p e d e s i g n , f l o w p r o p e r t i e s o f t h e o r e and w a s t e r o c k can be d e t e r m i n e d and s i d e s l o p e s f o r t h e T r . sub l e v e l c a v i n g s t o p e s i t may be p o s s i b l e t o a c h i e v e t h e d e s i g n e d s l o p e on t h e F.W. s i d e o n l y by s l a s h i n g (when t h e d e s i g n e d s l o p e c a l l e d f o r i s s t e e p e r t h a n t h e d i p o f t h e o r e b o d y ) as l o n g as t h e s l a s h i s e c o n o m i c a l o v e r a l l , whereas t h e m a i n t e n a n c e o f s t e e p e r s l o p e s on t h e H.W. s i d e may not be p o s s i b l e m a i n l y b e c a u s e o f t h e p r o h i b i t i v e l e n g t h o f l o n g h o l e s t o be d r i l l e d f r o m t h e l e v e l b e l o w s p e c i a l l y on a sub l e v e l i n t e r v a l o f 60 1 o r h i g h e r . 2. C o n s o l i d a t i o n o f m a t e r i a l w h i c h o c c u r s i n t h e b i n s i s e i t h e r c a u s e d by t h e dead l o a d s o r due t o t h e f a l l i n g m a t e r i a l on t h e top o f t h e b i n . These c o n s o l i d a t i o n s can be s i m u l a t e d on t h e t e s t e d s a m p l e s f o r f l o w a b i l i t y t e s t s . W h e r e a s , t h e c o n s o l i d a t i n g e f f e c t o f b l a s t -i n g may not be c o m p l e t e l y r e p r o d u c i b l e on t h e t e s t e d s a m p l e meant to d e t e r m i n e t h e f l o w p r o p e r t i e s o f o r e and w a s t e i n t h e s t o p e . 3. In the q u a n t i t a t i v e d e s i g n o f b i n s , g e n e r a l l y t h e s t o r a g e and f l o w o f o n l y one t y p e o f b u l k s o l i d i s c o n s i d e r e d whose f l o w p r o p e r t i e s a r e d e t e r m i n e d b e f o r e h a n d . In t h e c a s e o f a s t o p e , e s p e c i a l l y where b r o k e n o r e and c a v e d w a s t e r o c k have d i f f e r e n t f l o w p r o p e r t i e s , c o n t i n u o u s i n t e r m i x i n g o f o r e and w a s t e i n t h e e l l i p s o i d o f m o t i o n 83. may p r o d u c e p r o d u c t s o f v a r i a b l e f l o w a b i l i t y . The d e s i g n o f modern sub l e v e l s t o p i n g methods w o u l d be c o n s i d e r e d f u l l y s u c c e s s -f u l o n l y when p r o b l e m s a r i s i n g f o r m a s p e c i a l l y changed s i t u a t i o n o f f l o w c a u s e d by f r a g m e n t a t i o n o r m o i s t u r e c o n t e n t , e t c . , i n a l a y -o u t d e s i g n e d f o r a v e r a g e c o n d i t i o n s c o u l d be d e a l t w i t h e f f e c t i v e l y so as t o e n s u r e t h e e x t r a c t i o n o f p l a n n e d o r e r e c o v e r i e s and w a s t e d i l u t i o n s . T h e r e i s a v a s t s c o p e f o r improvement w h i c h c o u l d be b r o u g h t i n t h e d e s i g n o f sub l e v e l c a v i n g methods and i t s i m p o r t -ance can e a s i l y be r e a l i z e d - say f o r e x a m p l e , even i f a 5% i n -c r e a s e i n t h e o v e r a l l o r e r e c o v e r i e s c o u l d be a c h i e v e d , t h e n f o r Granduc M i n e s a l o n e t h i s c o u l d mean an a d d i t i o n a l income o f a p p r o x i -m a t e l y $29-0 m i l l i o n . (5% o f a p p r o x i m a t e l y 36.0 m i l l i o n t o n s o f o r e e x p e c t e d t o be mined w i t h sub l e v e l c a v i n g methods (3> say $16.0 o r e ) . 84 LIST OF'REFERENCES 1. J e n i k e , A . W . , J o h a n s o n , J . R . - "On t h e T h e o r y o f B i n L o a d s " , J o u r n a l o f E n g i n e e r i n g f o r I n d u s t r y . V o l . 91, No . 2, T r a n s . ASME, S e r i e s B , May 1969, P P . 339-344. 2. P o t t e r , A . A . - " O p e n i n g Remarks a t t h e ASME Symposium on S t o r a g e , F low and H a n d l i n g o f S o l i d s " . J o u r n a l o f E n g i n e e r i n g f o r I n d u s t r y , V o l . 91, No. 2, T r a n s . ASME, S e r i e s B, May 1969- P P . 293"294. 3. J e n i k e , A .W. - " Q u a n t i t a t i v e D e s i g n o f M a s s - F l o w B i n s " , Powder T e c h n o l . , 1 (1967) P P . 237"244. 4. J e n i k e , A .W. - " G r a v i t y F low o f S o l i d s " , T r a n s . I n s t . C h e m i c a l E n g i n e e r s ( L o n d o n ) , 40 (5) (1962) P P . 264-271. 5. J e n i k e , A . W . , and S h i e l d , R . T . - "On t h e P l a s t i c F l o w o f Coulomb S o l i d s Beyond O r i g i n a l F a i l u r e " , J o u r n a l o f A p p l i e d M e c h a n i c s , V o l . 82, S e r i e s E . , D e c . 1959, P P . 599-602. 6. J e n i k e , A .W. - " D e s i g n Y o u r B i n s f o r F r e e F l o w " , Modern M a t e r i a l s H a n d l i n g , V o l . 19, No. 11, Nov . 1964, P P . 48 -51. 7. J o h a n s o n , J . R . - " E f f e c t o f I n i t i a l P r e s s u r e s on F l o w a b i l i t y o f B i n s " , J o u r n a l o f E n g i n e e r i n g f o r I n d u s t r y , V o l . 91, No . 2, T r a n s . ASME, S e r i e s B, May 1969, P P . 395~399-8. J o h a n s o n , J . R . - " S t r e s s and V e l o c i t y F i e l d s i n t h e G r a v i t y F low o f B u l k S o l i d s " , J o u r n a l o f A p p l i e d M e c h a n i c s , V o l . 31, T r a n s . ASME, V o l . 86, S e r i e s E, 1964, P P . 499~506. 9. J o h a n s o n , J . R . - "New D e s i g n C o n c e p t s f o r Coa l B i n s and H o p p e r s " , Coa l A g e , J a n . I966, P P . 104-108. 10. W a l k e r , D .M. - "An A p p r o x i m a t e Theory f o r P r e s s u r e s and A r c h i n g i n H o p p e r s " , C h e m i c a l E n g i n e e r i n g S c i e n c e . 1966. Volume 21, P P . 975-997-11. W a l k e r , D .M. - "A B a s i s f o r Bunker D e s i g n " , Powder T e c h n o l o g y , 1 (1967) P P . 228-236. 12. C a r r , J . F . and W a l k e r , D .M. - "An A n n u l a r S h e a r C e l l f o r G r a n u l a r M a t e r i a l s " , Powder T e c h n o l o g y , 1 (1967/68) P P . 369"373-85 13- K v a p i l , R. - " G r a v i t y F low o f G r a n u l a r M a t e r i a l s i n Hoppers and B i n s " , I n t . J . Rock M e c h . M i n i n g S c i . 1965, V o l . 2 , P P . 25-41. 14. K v a p i l , R. - " G r a v i t y F l o w o f G r a n u l a r M a t e r i a l s i n Hoppers and B i n s i n M i n e s - 11. C o u r s e M a t e r i a l s " , I n t . J . Rock M e c h . M i n i n g S c i . 1965, V o l . 2 , P P . 2 7 7 - 3 0 4 . 15. B e r n a c h e , P . L . - " F l o w o f Dry B u l k S o l i d s on B i n W a l l s " , J o u r n a l o f E n g i n e e r i n g f o r I n d u s t r y , V o l . 91, No. 2 T r a n s . ASME, S e r i e s B. May , 1969, P P . 489-496. 16. M r o z , Z . , and D r e s c h e r , A . - " L i m i t P l a s t i c i t y A p p r o a c h t o Some Cases o f F low o f B u l k S o l i d s " , J o u r n a l o f E n g i n e e r i n g f o r I n d u s t r y , V o l . 9 1 , No. 2 , T r a n s . ASME, S e r i e s B. May , 1969, P P . 357~364. 17- R o b e r t s , A .W. - "An I n v e s t i g a t i o n o f t h e G r a v i t y F l o w o f N o n - C o h e -s i v e G r a n u l a r M a t e r i a l s Th rough D i s c h a r g e C h u t e s " , J o u r n a l o f E n g i n -e e r i n g f o r I n d u s t r y , V o l . 91, No. 2 , T r a n s . ASME, S e r i e s B, May 1969, P P . 373-381. 18. D e l a p l a i n e , J . W . - " F o r c e s A c t i n g in F l o w i n g Beds o f S o l i d s " , A . I . C h . E. J o u r n a l , V o l . 2 , No . 1, March 1956, P P . 1 2 7 - 1 3 8 . 19- P e s c h l , I . A . S . Z . - " T h e o r y o f the F o r m a t i o n o f A r c h e s i n B i n s " , J o u r n a l o f E n g i n e e r i n g f o r I n d u s t r y , V o l . 91, No. 2 , T r a n s . ASME, S e r i e s B, May 1969, P P . 423-434. 2 0 . D e u t s c h , G . P . , and C l y d e , D . H . - " F l o w and P r e s s u r e o f G r a n u l a r M a t e r i a l s i n S i l o s " , J o u r n a l o f t h e E n g i n e e r i n g M e c h a n i c s D i v i s i o n , P r o c . A S C E , EM6, D e c . 1967, P P . 103 - 1 2 5 . 2 1 . R e t t i g , G. - " B u n k e r D e s i g n - The C i n d e r e l l a o f I n d u s t r i a l P r o -c e s s i n g " , B r i t i s h C h e m i c a l E n g i n e e r i n g , V o l . 11, No . 7 , J u l y 1966 , P P . 7 0 6 - 7 0 7 . 2 2 . A y t a m a n , V. - " C a u s e s o f ' H a n g i n g ' i n Ore C h u t e s " , C a n a d i a n M i n i n g J o u r n a l , No . i 9 6 0 , P P . 7 7 ~ 8 l . 2 3 . A y t a m a n , V . - " S t u d y o f P a r t i c l e A r c h e s Under E x e r t e d P r e s s u r e " , C a n a d i a n M i n i n g J o u r n a l , Dec . i 9 6 0 , P P . 7 1 _75-24. A y t a m a n , V . - " T h e o r y o f P a r t i c l e A r c h e s " , C a n a d i a n M i n i n g J o u r n a l , J a n . 1961, P P . 41-45-25- R o s c o e , K . H . - " S o i l s and Model T e s t s " , J o u r n a l o f S t r a i n A n a l y s i s , V o l . 3, No. 1, 1968, P P . 57-64. 86. 26. Matthee, H. - "Segregation Phenomena Relating to Bunkering of Bulk Materials: Theoretical Considerations and Experimental Investiga-tions", Powder Technol., 1 (1967/68) PP. 265-271 27. Reisner, W. - "The Behaviour of Granular Materials in Flow out of Hoppers", Powder Technol., 1 (l967/68) PP. 257-264. 28. Fowler, R.T., and Glastonbury, J.R. - "The Flow of Granular Solids Through Orifices", Chemical Engineering Science, 1959, Vol. 10, PP. 150-156. 29- Clough, R.W., and Rirtz, D. - "Earthquake Resistance of Rock-Fill Dams", Trans. ASCE, Paper No. 2939, PP. 792-811. 30. Johanson, J.R. - "The Placement of Inserts to Correct Flow in Bins", Powder Technol., 1 (1967/68) PP. 328-333-31. Handley, M.F., and Perry, M.G. - "Stresses in Granular Materials Flowing in Converging Hopper Sections", Powder Technol., 1 (1967/68) PP. 245-251-32. Bepco Canada Ltd. - "Monitoring Levels of Granular Solids", Canadian Chemical Processing, Dec. 1958, PP. 95~96. 33- Beck, M.S., and Wainwright, N. - "Current Industrial Methods of Solids Flow Detection and Measurement", Powder Technol., 2, (1967/68) PP. 189-197-34. Nicholls, H. - "A Case Study of the Validity of Scaling Laws for Explosion-Generated Motion", U.S. Bureau of Mines - Report of Investi-gation 6472, 1963, PP. 14. 35- Duncan, W.J. - "Physical Similarity and Dimensional Analysis, an Elementary Treatise", (1953)-36. Jenike, A.W., Elsey, P.J. , and Wooley, R.H. - "Flow of Bulk Solids. Progress Report:, Bulletin 96. Utah Engineering Experiment Station, University of Utah, July 1959-37. Jenike, A.W. - "Gravity Flow of Bulk Solids", Bulletin 108, Utah Engineering Experiment Station, University of Utah, Oct. 1961. 38. Jenike, A.W. - "Storage and Flow of Solids", Bulletin Engineering Experiment Station, University of Utah, Nov. 123, Utah 1964. 87-39- B a r n e s , K . K . , and o t h e r s - " S i m i l i t u d e i n t h e S t u d i e s o f T i l l a g e Implements F o r c e s " , J o u r n a l o f A g r i c u l t u r a l E n g i n e e r i n g . Jan.1960. kO. T e r z a g h i , K. - " T h e o r e t i c a l S o i l M e c h a n i c s " , John W i l e y , New Y o r k , 1943. 41. B i s h o p , A . W . , and H e n k e l , D . J . - "The Measurement o f S o i l P r o p e r t i e s i n t h e T r i a x i a l T e s t s " , 1962. Edward A r n o l d L t d . , P P . 200. kl. Lambe, T . W . , and W h i t m a n , R .V . - " S o i l M e c h a n i c s " , 1969, S e r i e s i n S o i l M e c h a n i c s , John W i l e y & Sons I n c . , New Y o r k . 43. K e t c h u m , M . S . - " W a l l s , B i n s and G r a i n E l e v a t o r s " , M c G r a w - H i l l , New Y o r k , 1911 . 44. J a n s s e n , H . A . Z . - " V e r . D t s c h . I n g . " 1895, 39, 1045. 45. S t e p a n o f f , A . J . - " G r a v i t y F low o f B u l k S o l i d s - Hopper F low C h a r a c t e r i s t i c " , P a p e r No. 68-MH-34, ASME Symposium on F low o f S o l i d s , O c t . 20-23, 1968. 46. K v a p i l , R. - " F l o w and E x t r a c t i o n o f S o l i d s From B i n s " , P a p e r No . 68-MH-32, ASME Symposium on F l o w o f S o l i d s , O c t . 20-23, 1968. 47. J a n e l i d , I; and K v a p i l , R. - "Sub L e v e l C a v i n g " , I n t . J . Rock M e c h . M i n . S c i . V o l . 3, P P . 129-153. Pergamon P r e s s L t d . , I966. 48. J a n e l i d , I . , and K v a p i l , R . , - "Sub L e v e l C a v i n g D e s i g n " . U n p u b l i s h e d p a p e r s . 49. J u s t , G . D . - " D e v e l o p m e n t o f Sub L e v e l C a v i n g P r i n c i p l e s and M i n i n g t h e 500 Copper O r e b o d y " . Mount I sa M i n e s L t d . , T e c h n i c a l R e p o r t No . RES. MIN . - 6. 50. J u s t , G . D . - "Sub L e v e l C a v i n g D e s i g n " , Mount I sa M i n e s L t d . ; T e c h n i c a l R e p o r t No. RES. MIN . - 1.2 51. "Draw C o n t r o l a t Mount I s a " . M i n e P l a n n i n g S t a f f o f Mount I s a M i n e s L t d . A p r i v a t e p u b l i c a t i o n . 52. S a n d s t r o m , P . O . - " M i n e Model T e s t s " . C r a i g m o n t M i n e s L i m i t e d -u n p u b l i s h e d r e p o r t . 53. M ine MOdel T e s t s , a t M u f u l i r a Copper M i n e s L i m i t e d - u n p u b l i s h e d r e p o r t . J u b e l i n , K . R . - "Sub L e v e l C a v i n g i n Sweden and A u s t r a l i a " . The Q u a r r y , M i n e and P i t - S e p t e m b e r , 1966. Cox , J . A . - " L a t e s t D e v e l o p m e n t s and Draw C o n t r o l i n Sub L e v e l C a v i n g " . P r i v a t e p u b l i c a t i o n o f M u f u l i r a , Zambia - S e p t e m b e r , 1 9 6 7 . A P P E N D I X THEORY OF MODELS 90. APPENDIX I The p e r t i n e n t v a r i a b l e s c o n s i d e r e d i n t h e a n a l y s i s o f t h e g r a v i t y f l o w i n t h e s t o p e , a r e as f o l l o w s : NOTATION DIMENSION VARIABLE : 1. Draw Volume 2. A s i g n i f i c a n t d i s t a n c e 3. Any p e r t i n e n t d i s t a n c e h. A r e a o f t h e o p e n i n g ( f r e e f l o w ) 5. H y d r a u l i c d i a m e t e r o f t h e o p e n i n g = 4 x f r e e a r e a - P e r i m e t e r 6. S p e c i f i c w e i g h t o f t h e m a t e r i a l (dead l o a d ) 7. A v e r a g e s i z e o f the p a r t i c l e 8. Head o f p a c k i n g above o p e n i n g 9. T rue d e n s i t y o f s o l i d s 10. B u l k d e n s i t y o f p a c k i n g 11. Volume o f t h e c o n t a i n e r 12. D i g g i n g d e p t h o f the scoop 13. V e l o c i t y o f d i s c h a r g e f r o m o p e n i n g 14. A n g l e o f i n t e r n a l f r i c t i o n 15. A n g l e o f s i d e s l o p e s ( a n g l e o f i n c l i n a t i o n o f t h e hopper bo t tom) 6 So t h e vo lume o f draw coming o u t o f t h e s t o p e i s a f u n c t i o n o f : V = f (1, A i , A , DL, W, d , H, f>s, / ° b , V c > d d , v , 0, 6) - ( l ) I t i s t o be n o t e d t h a t the f o l l o w i n g s i m p l i f y i n g a s s u m p t i o n s have been made b e f o r e p r o c e e d i n g w i t h t h e a n a l y s i s : V 1 Ai A % w d H A A dd v 0 L3 L L M L _ 2 T " 2 L L ML"3 ML"3 L 3 L L T - ' 9 1 • 1 . No e f f e c t o f m o i s t u r e has been c o n s i d e r e d . 2 . No o t h e r f o r c e s t h a n o f t h e mass o f b r o k e n r o c k above o r on t h e s i d e s o f t h e s t o p e s has been c o n s i d e r e d . 3. P'o o f t h e o r e and w a s t e i s assumed t o be t h e same i n t h e a r e a o f d r a w . k. C o n s o l i d a t i n g p r e s s u r e s o f f e r e d by t h e b l a s t i n g a c t i o n has n o t been c o n s i d e r e d . 5. G e n e r a l l y e q u a l l o a d i n g o f t h e m a t e r i a l has been done f r o m e i t h e r end o f t h e o p e n i n g f o r T r a n s v e r s e Sub L e v e l C a v i n g M e t h o d . From t h e t h e o r y o f m o d e l s , i f t h e g e n e r a l e q u a t i o n f o r t h e p r o t o t y p e i s : T T i = F ( T T 2 , T7 3, T T i , . T T S ) - (2A) Where a l l t h e P i (TT) te rms a r e d i m e n s i o n l e s s and i n d e p e n d e n t . S i n c e e q u a t i o n (2A) i s e n t i r e l y g e n e r a l , i t a p p l i e s t o any o t h e r s y s t e m w h i c h i s a f u n c t i o n o f the same v a r i a b l e s . H e n c e , i t a p p l i e s t o a s p e c i f i c s y s t e m c a l l e d the m o d e l . " ^ I m - F ( T T 2 m ' TTSm. ^ m " ^ J " (2B) An e q u a t i o n f o r p r e d i c t i n g TTi f r o m T T ] m may be f o u n d d i r e c t l y by d i v i d i n g e q u a t i o n (2A) by e q u a t i o n ( 2 B ) . T h e r e f o r e : T T , = F ( T T 2 > TT3, TT M T T S ) - (2C) TTi F ( n 2 m , T T - J , TTZi T T S m ) Now, i f t h e model i s d e s i g n e d and o p e r a t e d so t h a t T T 2 m = T T 2 n 3 m " ^ 3 TT S = TT S (2D) 92. I t f o l l o w s t h a t : F ( T T 2 , TT3, Tlli T T 5 ) = F ( T T 2 m » T T 3 m T T S m ) - (2E) The n a t u r e o f t h e f u n c t i o n i s i d e n t i c a l f o r t h e model and p r o t o t y p e b e c a u s e e q u a t i o n (2A) i s g e n e r a l . From e q u a t i o n (2C) and (2E) , i t i s a p p a r e n t t h a t : TTj = T T ] m ; t h i s 1 5 the p r e d i c t i o n e q u a t i o n . Now, r e w r i t i n g e q u a t i o n (1): V = F (1, M, A , D L , W, d, H ,/=s, / » b , V c , d d , v , 0, 6) - ( l ) To a p p l y d i m e n s i o n a l a n a l y s i s and t h e o r y o f m o d e l s , E q u a t i o n (1) may be w r i t t e n a s : V d l c 2 A i c3 AC 1 * D hc5 W c 6 dc7 HC8 ^ s c 9 / ^ b c l O v c ' l d d12 v c l 3 0cl4 e c l 5 = o - ( A ) The c o r r e s p o n d i n g d i m e n s i o n a l e q u a t i o n i s : (L3 ) c l L C2 L C 3 (L2)c4 L C5 (ML"2 T-2) LC7 LC8 (ML"3)c9 (ML"3 )c lO (L3)cll Lcl2 ( L T ~ 1 ) c l 3 (-)clA (-)cl5 = 0 From t h e a b o v e , t h e a u x i l i a r y e q u a t i o n s may be w r i t t e n a s : (B) - M: C6 + Cg + C]0 = 0 (C) - L : 3C] + C2 + C3 + 2C/, + C5 - 2Cg + C7 + C8 - 3Cg - 3C]0 + 3Ci ] + C12 ~ C13 = 0 ( D ) - T: - 2C6 Ci 3 = 0 S i n c e t h r e e e q u a t i o n s a r e a v a i l a b l e f o r s o l v i n g t h i r t e e n unknowns , a r b i t r a r y v a l u e s must be a s s i g n e d t o ten o f t h e unknowns , many c o m b i n a t i o n s a r e p o s s i b l e , o f t h e s e one i n v o l v i n g : C ] , C3, Cz,, C5, Cfc, C7, C8, C ]Q, C11, C12» t]k> C-|5, has been s e l e c t e d . The d e t e r m i n a n t o f t h e c o e f f i c i e n t s o f t h e r e m a i n i n g terms C2, C9 and C]3 I s : 0 1 0 * 0 1 1 -3 0 0 - 1 S i n c e t h i s i s not e q u a l t o z e r o , t h e r e s u l t i n g e q u a t i o n s a r e i n d e p e n d e n t and the s e l e c t i o n i s v a l i d . V a l u e s a r e a s s i g n e d a r b i t r a r i l y as f o l l o w s : Cl C3 c5 C6 C7 C8 c10 Cl 1 C12 1 0 0 0 0 0 0 0 0 0 S u b s t i t u t e t h e s e v a l u e s i n e q u a t i o n s ( B ) , ( C ) , (D) Cg = 0 3 + C 2 - 3Cg - C13 =• 0 - C 1 3 = 0 From e q u a t i o n s 3a, 3b and 3c: C 2 = "3 and f r o m a b o v e : C] •3a •3b •3c = 1 3k. From t h i s and e q u a t i o n (A) - d r o p p i n g TT, = v _ I 13 From t h e P i t h e o r e m , i t i s s e e n t h a t a t o t a l o f 10 P i te rms must be d e t e r -m i n e d . A n o t h e r t e r m may be f o u n d by s e l e c t i n g a d i f f e r e n t c o m b i n a t i o n o f a r b i t r a r y v a l u e s f o r the s e l e c t e d e x p o n e n t s ; f o r e x a m p l e : Cj = 0 C 3 - 1 Cz, = 0 c 5 = 0 c 6 = 0 c 7 = 0 C8 = 0 C 1 0 = 0 C l i = o c 1 2 = o S u b s t i t u t e above i n e q u a t i o n s ( B ) , ( C ) , (D) C 9 = 0 -ka C 2 + 1 " 3Cg - C | 3 = 0 -kb - C 1 3 = 0 -kc From E q u a t i o n s ha, kb, kc: C 2 = -1; and fpom a b o v e : C^ = 1 From t h i s and e q u a t i o n (A) d r o p p i n g C o , o r : T T o = Ai || 95. A n o t h e r P i t e r m may be f o u n d by l e t t i n g Cj, = I w i t h o t h e r s e l e c t e d e x p o n e n t s e q u a l l e d t o z e r o : TT3 = A _ I I I 12 S i m i l a r l y , s e v e n more i n d e p e n d e n t P i t e r m s a r e d e v e l o p e d by l e t t i n g C5, C5, C8, C g , C11, C]2 and C13 i n t u r n , e q u a l u n i t y , w i t h t h e o t h e r s e l e c t e d e x -p o n e n t s e q u a l t o z e r o , t h u s : TT 5 = w . l IV n 6 = 1 - VI 1 TT-, = H_ - VI I 1 T T 8 = A - V I I I TTg = V c - IX 13 TT 1 0 = £d - X 1 And a l s o f o r t h e d i m e n s i o n l e s s v a r i a b l e s 0, 6: n n = 0 - XI TT12 6 - X I I A g e n e r a l s o l u t i o n may, t h e r e f o r e , be w r i t t e n a s : V_ = F ( Ai , k_, Dh, w j _ , d , H_, A , ^ c , £ d , 0, 6) - (5) l3 1 l 2 1 />s v 2 1 1 /°s l3 1 A P P E N D I X II TABLES 1 and IA - RESULTS. T A B L E 1 ( L O N G I T U D I N A L SUB L E V E L C A V I N G ) H .W. LOADING P A T T E R N F.W. 1 2 3 4 5 6 7 8 9 10 1 1 12 13 14 15 16 17 18 19 1 19 20' 60° 60' 7' 1.46 1.50 G 0-125 SC = 1: 1 8736 125 125 83 59.5 NO F . W . S L A S H 2 26 20' 60° 60' 7' 1.68 1.60 1.35 D 0-85 SC = 0: 1 9163 132 132 134 85.0 80° F . W . S L A S H 85-200 SC = 1 : 1 3 22 20' 65° 60' 6' 1.68 1.60 1.35 D 0-100 SC = 1 : 1 7128 100 100 130 71 .0 NO F . W . S L A S H 4 24 20' 65° 60' 6' 1.68 1.60 1.35 D 0-120 SC = 0 : 1 7980 115 115 146 86.6 90° F . W . S L A S H 120-200 SC = 1::1 5 27 20' 65° 60' 8' 1.68 1.60 1.35 A II II 9944 142 142 130 86.3 33-9 80° F . W . S L A S H 6 27 20' 65° 60' 6' 1.68 1.60 1.35 A II II 7458 106 106 127 82.6 35-4 7 27 20' 65° 45' 8' 1.68 1.60 1.35 A II n 7216 103 103 129 80.7 37.4 • 1 8 27 20' 65° 45' 6' 1.68 1.60 1.35 A II II 5616 80 80 118 78.4 33-9 .. 9 27 20' 65° 30' 8' 1.68 1.60 1.35 A II II 4536 65 65 123 69.O 43.9 10 27 20' 65° 30' 6' 1.68 1.60 1.35 A II n 3726 52 52 120 69.4 35.5 i , 11 28 20' 65° 60' 8' 1.68 1.60 1.35 A 0-90 SC = 0::1 10048 144 144 144 90.8 37-1 85° F . W . S L A S H 90-200 SC = 1::1 V* N** - DRAW F I G U R E S P L O T T E D AND COLUMNS 1 6 , SC - SCOOPS DRAWN. VOLUME OF H E A P E D BUCKET OF SCOOP - 112 C U . F T . 1 7 , 18 C A L C U L A T E D FOR NO. OF SCOOPS DRAWN 1 N 1 U3 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 1 3 1 4 1 5 1 6 1 7 1 8 19 1 2 28 2 0 ' 65° 60' 7' 1.68 1.60 1 -35 A 9 0 - 2 0 0 S C = 1::1 8732 1 2 6 1 2 6 1 5 2 90.5 4 0 . 6 85° F . W . S L A S H 13 28 2 0 ' 65° 60' 6' 1.68 1.60 1.35 A I I I I 7536 1 0 6 1 0 6 1 138 8 4 . 6 38.8 1. 1 4 28 2 0 ' 65° 4 5 ' 8' 1.68 1.60 1.35 A 0-90 S C = 0::1 7 3 2 0 1 0 5 1 0 5 137 85.0 37.8 . 1 9 0 - 2 0 0 S C = 1::1 1 5 28 2 0 ' 65° 45' 7' 1.68 1.60 1.35 A I I I I 6405 92 92 1 4 0 86.3 38.2 ., 1 6 28 2 0 ' 65° 45' 6' 1.68 1.60 1.35 A I I 11 5430 78 78 1 1 4 80.5 39.4 .. 1 7 28 2 0 ' 65° 3 0 ' 8' 1.68 1.60 1.35 A I I n 4536 65 65 1 2 4 66.3 4 6 . 5 , , 18 28 2 0 ' 65° 3 0 ' 6' 1.68 1.60 1-35 A I I I I 3 4 0 2 49 54 1 3 1 73-0 44.6 , . 1 9 37 2 0 ' 65° 60' 1 0 ' 1.56 1.56 F I I I I 1 2 5 6 0 1 7 3 191 1 2 0 8 1 . 9 28.3 80° F . W . S L A S H 2 0 37 2 0 ' 65° 60' 8' 1.56 1.56 F I I n 1 0 0 4 8 1 4 0 154 1 2 1 86.1 28.4 . 1 2 1 37 2 0 ' 65° 60' 8' 1.56 1.56 F I I I I 10048 1 4 0 167 1 3 4 87.1 34.2 -22 37 20' 65° 60' 7' 1.56 1.56 F I I I I 8792 121 135 121 82.3 31.8 1 . 2 3 37 20' 65° 60' 6' 1.56 1.56 F I I I I 7536 103 115 125 79.7 35-9 2 4 37 20' 65° 60' 5' 1.56 1.56 F I I I I 6280 86 96 124 74.0 4 0 . 5 25 37 20' 65° 45' 8' 1.56 1.56 F I I I I 7520 1 0 4 115 1 2 4 83-5 3 2 . 5 26 37 20' 65° 45' 6' 1.56 1.56 F n I I 5395 74 82 115 81.1 29.2 .. 27 37 20' 65° 30' 8' 1.56 1.56 F I I n 5024 70 77 122 63.6 43.2 ' , . 28 37 20' 65° 30' 6' 1.56 1.56 F I I I I 3360 4 6 51 118 66.7 43.2 , , 23 37 20' 65° 30* 5' 1.56 1.56 F 11 I I 2800 39 43 120 59.3 50.5 . 1 30 35 2 0 ' 65° 60' 8' 1.56 1.56 E I I I I 1 0 0 4 8 1 4 0 154 112 74.9 33.0 80° F . W . S L A S H 3 1 35 2 0 ' 65° 60' 6' 1.56 1.56 E I I I I 7536 1 0 4 115 1 1 3 7 1 . 2 37.1 1 : 2 0 S C A L E T E S T 32 35 2 0 ' 65° 45' 6' 1.56 1.56 E I I I I 5652 72 79 1 1 3 71.3 37.1 11 11 33 35 2 0 ' 65° 30' 8' 1.56 1.56 E I I I I 5 0 2 4 70 77 1 0 7 54.0 49.1 11 11 34 9 30' 60° 60' 8' 1.80 1.80 B 0-230 S C = 1::3 15520 199 219 13 82.5 1 8 . 0 NO F . W . S L A S H 1 2 3 4 5 6 7 8 9 10 1 1 12 13 14 15 16 17 18 19 58 36 30' 6 5 ° 30' 5' 1.56 1.56 F 0-9- SC = 0::1 4430 6.2 68 123 55.4 54 .7 80° P.W. SLASH 90-275 SC = 1::1 59 25 30' 7 5 ° 60' 10' 1.68 1,60 1.35 A 0-110 SC = 0::1 1691 2 242 242 132 83 .5 NO F.W. SLASH 1 10-130 SC = 2:: 1 130-260 SC = 1 : : 1 60 25 30' 7 5 ° 60' 8' 1.68 1.60 1.35 A I I I I 13529 193 193 121 87 .4 27.9 .. 61 25 30' 7 5 ° 45' 8' 1.68 1.60 1.35 A I I I I 10150 145 145 126 80.3 36 .3 .. 62 25 30' 7 5 ° 45' 6' 1.68 1.60 1.35 A I I I I 7340 102 115 125 67 .0 46 .4 .. 63 25 30' 7 5 ° 30' 8' 1.68 1.60 1.35 A I I I I 6757 97 97 123 52 .4 57 .6 ., 64 25 30' 7 5 ° 30' 6' 1.68 1.60 1.35 A it I I 4650 65 72 125 52.2 58 .2 1, 65 14 40' 55° 60' 61 1.80 1.80 B 0-260 SC = 1::3 16260 261 261 102 73.0 28,4 . 1 1 . 66 14 40' 55° 60' 5' 1.80 1.80 B I I n 13550 218 218 127 68 .7 46 .2 .. 67 14 40' 55° 45' 6' 1.80 1.80 B I I I I 12198 196 196 102 75 .8 25 -5 . 1 68 14 40' 55° 45' 5' 1.80 1.80 B I I I I 10165 I63 I63 126 75 -7 39 .8 .. 69 14 40' 55° 30' 6' 1.80 1.80 B I I I I 8130 131 131 108 81 .4 24.9 ,. 70 14 40' 55° 30' 5' 1.80 1.80 B I I I I 6775 109 109 127 81 .4 35-6 . 1 71 13 40' 6 5 ° 60' 5" 1.80 1.80 B 0-210 SC = 1::3 12450 200 200 118 74.8 36 .7 , , 72 13 40' 6 5 ° 45 ' 8' 1.80 1.80 B I I I I 14888 239 239 105 82 .5 21 .7 11 73 13 40' 6 5 ° 45' 7' 1.80 1.80 B n I I 13027 209 209 121 84 .7 29 .5 1, 74 13 40' 6 5 ° 45' 5' 1.80 1.80 B I I I I 9305 131 131 115 77.6 32.1 1 , 75 13 40' 6 5 ° 30' 7' 1.80 1.80 B n I I 8547 137 137 117 70 .0 ., 76 13 40' 6 5 ° 30' 5' 1.80 1.80 B I I I I 6105 98 98 1 10 64 .9 ,i 77 31 40' 6 5 ° 60' 10' 1.56 1.56 F 0-180 SC = 0:: 1 25450 356 392 119 90 .0 25.4 80° F .W.SLASH 180-300 SC = 1 : : 1 1 2 3 k 5 6 7 8 9 10 1 1 12 13 14 15 16 17 18 19 35 9 30' 60° 60' 7' 1.80 1.80 B 0-230 SC = 1 : :3 13580 152 167 102 77.6 25 .0 NO F.W.SLASH 36 9 30' 60° 60' 6' 1.80 1.80 B I I I I 11640 112 123 110 74.8 32 .0 11 11 37 9 30' 60° 30' 8' 1.80 1.80 B I I I I 7440 114 126 117 68 .0 41.8 n in 38 9 30' 60° 30' 7" 1.80 1.80 B n I I 6510 101 111 109 59 .0 45.6 11 11 39 9 30' 60° 30' 6' 1.80 1.80 B I I I I 5580 86 95 108 71.0 25 .0 11 11 4o 7 30' 65° 60' 8' 1.80 1.80 B 0-260 SC = 1: : 1 14880 239 261 113 81.0 27.9 11 11 k] 10 30' 65° 60' 8' 1.80 1.80 B 0-260 SC = 3: : 1 14880 239 261 1 10 54.7 32.3 1 1 1 1 kl 21 30' 65° 60' 8' 1.68 1.60 1.35 A 0-210 SC = 1: 1 14720 210 210 118 80.1 32.1 NO F.W.SLASH k3 21 30' 65° 45' 8' 1.68 1.60 1.35 A I I I I 10792 154 154 117 84.7 27.7 n 1 1 kk 21 30' 65° k5' 6' 1.68 1.60 1.35 A I I I I 8145 116 128 134 84.1 37.4 n n 45 21 30' 65° 30' 8' 1.68 1.60 1.35 A I I I I 6832 98 98 132 83.O 37 .0 11 11 46 21 30' 65° 30' 6' 1.86 1.60 1.35 A n n 5045 71 78 132 73.4 44 .2 n 11 kl 36 30' 65° 60' 1 0' 1.56 1.56 F 0-90 SC = 0::1 19280 270 296 123 86.8 25-7 80° F .W.SLASH 90-275 SC = 1::1 48 36 30' 65° 60' 9' 1.56 1.56 F I I n 17352 242 266 122 88.1 27.5 11 1 1 k3 36 30' 65° 60' 8' 1.56 1.56 F I I I I 15424 215 237 124 89.3 28.0 1 1 1 1 50 36 30' 65° 60' 8' 1.56 1.56 F I I I I 15424 215 258 138 90.4 32.8 1 1 1 1 51 36 30' 65° 60' 7' 1.56 1.56 F I I I I 13496 188 207 122 85.9 29.5 11 11 52 36 30' 65° 60' 6' 1.56 1.56 F I I I I 11568 161 177 126 81 .0 35.4 11 1 1 53 36 30' 65° H 5 ' 8' 1.56 1.56 F ii I I 11252 157 173 120 73.5 39-4 n 1 1 5k 36 30' 65° k5' 6' 1.56 1.56 F I I I I 8250 115 127 123 77.5 36.8 1 1 1 1 55 36 30' 65° 45' 5' 1.56 1.56 F I I I I 6875 95 105 121 71.7 40.6 1 1 1 1 56 36 30' 65° 30' 8' 1.56 1.56 F I I I I 7499 104 115 122 57.7 53-3 1 1 1 1 57 36 30' 65° 30' 6' 1.56 1.56 F ti I I 5310 74 81 124 59.9 51.9 n 11 o o 1 2 3 4 5 6 7 8 9 10 1 1 12 13 14 15 16 17 18 13 78 31 40' 65° 60' 8' 1.56 1.56 F 0-180 SC = 0::1 20720 296 314 115 90.5 21.3 80° F .W.SLASH 180-300 SC = 1::1 79 31 40" 65° 60' 8' 1.56 1.56 F 20720 296 345 134 91 .2 32.1 1 1 11 80 31 40' 65° 60' 7' 1.56 1.56 F I I 11 n 17815 233 257 117 85-7 27.3 n 1 1 81 31 40' 65° 60' 6' 1.56 1.56 F ., 1 5270 212 236 120 76.4 36.6 11 1 1 82 31 40' 65° 45' 8' 1.56 1.56 F , , 14976 210 230 118 84 .6 31.0 83 31 40' 65° 45' 6' 1.56 1.56 F 11232 156 172 111 65-8 35.6 11 1 1 84 31 40' 65° 30' 5' 1.56 1.56 F „ 6100 85 94 99 45-5 53-9 11 11 85 33 50' 55° 60' 8' 1.46 1.50 G SEE TABLE 6 18624 246 270 110 59-8 48 .1 DRIFT ' A ' 86 33 50' 55° 60' 6' 1.46 1.50 G SEE TABLE 6 13968 184 203 111 62.0 50.6 DRIFT ' A ' 87 33 50' 55° 60' 6' 1.46 1.50 G SEE TABLE 6 673? 88 97 115 82.0 42 .0 DRIFT ' B ' 88 33 50' 55° 60' 4' 1.46 1.50 G SEE TABLE 6 4488 59 65 110 61 .0 44.1 DRIFT ' B ' 89 32 50' 70° 60' 8' 1.56 1.60 F SEE TABLE 7 14120 201 221 110 77-6 23.4 DRIFT ' A ' 90 32 50' 70° 60' 6' 1.56 1.60 F SEE TABLE 7 10590 151 1 166 1 11 67.1 42 . 0 DRIFT ' A ' 31 32 50' 70° 60' 6' 1.56 1.60 F SEE TABLE 7 9300 106 117 110 79-8 27.4 DRIFT ' B ' 92 32 50' 70° 60' 4' 1.56 1.60 F SEE TABLE 7 6200 71 78 110 62.5 43.0 DRIFT ' B ' DRIFT ' A ^ ' B ' 93 33 50' 55° 60' 8'-4' 1.46 1.50 23112 110 60.1 94 33 50' 55° 60' 8'_6' 1.46 1.50 25356 112 65-8 95 33 50' 55° 60' 6'-6' 1.46 1.50 20700 112 68.4 96 33 50' 55° 60' 6'_4' 1.46 1.50 18456 111 61 .7 o 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 DRIFT ' A ' - ' B 97 32 50' 70° 60' 8'-4' 1.56 1.60 20320 110 73.0 98 32 50' 70° 60' 8'-6' 1.56 1.60 23420 110 78.4 99 32 50' 70° 60' 6'-6' 1.56 1.60 19890 1 10 73-0 100 32 50' 70° 60" 6'-4' 1.56 1.60 16790 110 65-3 TABLE IA (TRANSVERSE SUB LEVEL CAVING) LOADING PATTERN W . : : F . W . 101 4 79° 30' 10' 1.80 1.80 B 0-200 SC = 1::1 10360 167 184 113 69-8 37-9 102 4 79° 30' 8' 1.80 1.80 B 8284 133 147 109 77-6 29.2 103 4 79° 30' 7' 1.80 1.80 B . , 7252 120 132 108 81.8 24.8 104 4 79° 30' 6' 1.80 1.80 B M 6216 102 113 109 87.3 20.1 105 4 79° 30' 5' 1.80 1.80 B .. 5180 85 94 114 80.0 29-7 106 6 74° 30' 8' 1.80 1.80 B . . 8912 144 158 110 80.0 27.2 107 6 74° 30' 7' 1.80 1.80 B . . 7252 128 128 114 86.4 24.1 108 6 74° 30' 6' 1.80 1.80 B . . 6216 101 111 111 86.6 20.0 109 6 74° 30' 5" 1.80 1.80 B . . 5180 84 92 111 80.4 27.4 1 10 20 79° 30' 8' 1.75 1.60 1.38 C 8272 118 118 138 83.4 39-6 11 1 20 79° 30' 7' 1.75 1.60 1.38 c " 7238 103 103 138 83.7 39-4 112 20 7 9 ° 30' 6' 1.75 1.60 1.38 c 6204 89 89 136 81.8 39.6 113 20 79° 30' 5' 1.75 1.60 1.38 r, ,1 II £.170 74 74 1 ?R 77 4 40 5 114 1 1 84° 30' 7' 1.80 1.80 B I. 6328 104 115 114 87.5 23.8 115 11 84° 30' 6' 1.80 1.80 B .1 5424 90 99 109 89.2 18.3 V* - VOLUME OF HEAPED BUCKET OF SCOOP - 112 CU .FT . N** - DRAW FIGURES PLOTTED AND COLUMNS 16 , 1 7 , 18 CALCULATED FOR NO. OF SCOOPS DRAWN ' N 1 . SC - SCOOPS DRAWN. o A P P E N D I X I I I T A B L E S 2 , 3 A N D k T A B L E 2. REMARKS: 1 A NIL - 130 40 3-12 2.5 1 .22 2.56 1.6 26 66 L o o s e l y P a c k e d t h e S a m p l e . 2 A NIL - 640 296 23.6 5.0 2.45 9.65 3.1 54 72 V i b r a t e d t h e S a m p l e . 3 B NIL - 950 530 42 .4 15-0 7.35 5.76 2.4 44 67 - d o -4 B 100 3-7 820 430 34.4 11.0 5.37 6.4 2.53 46 68 Tamped t h e Sample W h i l e F o r m i n g . 5 C NIL - 150 46 3.68 1.25 0.61 6.02 2.46 46 68 V i b . t h e Sample W h i l e F o r m i n g . 6 C 300 10.8 135 40 3-2 2.5 1 .22 2.62 1.618 26 58 - d o -7 C 300 10.8 260 80 6.4 5.0 2.45 2.62 1.618 26 58 - d o - REPEAT OF '6' EXACTLY. 8 D NIL - 420 130 10.4 5-0 2.45 4.24 2.06 38 64 - d o -9 E 50 1.76 650 300 24 .0 15.0 7.35 3.26 1.80 32 61 Tamped t h e S a m p l e . 10 F NIL - 640 290 23.2 10.0 4.90 4.74 2.2 40 65 Tamped t h e Sample W h i l e F o r m i n g . 11 F 50 1.8 620 280 22.4 11 .0 5-38 4.16 2.04 38 64 - d o -12 F 100 3.6 810 424 34.0 10.0 4.90 6.94 2.64 48 69 - d o -13 F 200 7-2 530 206 16.5 10.0 4.90 3-37 1.84 32 61 - d o -14 F 300 10.8 300 94 7-5 10.0 4.90 1.53 1 .24 12 51 - d o -T A B L E 3 . S I E V E A N A L Y S I S O F S A M P L E S U S E D I N T H E T R I A X I A L T E S T S ( I N T A B L E 2 , O F A P P E N D I X I I I ) \ % S I E V E \ A N A L Y S 1 S D E S C R . N . O F T E S T E D N . M A T E R I A L N . - 0 . 6 2 5 " + 0 . 5 2 5 " - 0 . 5 2 5 " + 0 . 3 7 1 " -0.371" + 0 . 2 6 3 " -O .263" + 0 . 1 8 5 " - 0 . 1 8 5 " + 0 . 0 6 5 " - 0 . 0 6 5 " +0.0328" -O.0328" -0 .0328" + 0 . 0 2 3 2 " -0 .0232" + 0 . 0 1 6 4 " - 0 . 0 1 6 4 " + 0 . 0 1 1 6 " - 0 . 0 1 1 6 " 1 0 0 % T O T A L W E I G H T I N G R A M S A 4 0 . 5 6 % 3 4 . 3 3 % 1 4 . 0 0 % 5.92% 4 . 0 5 % 0 . 5 8 % 0 . 5 6 % 2 8 5 8 . 6 0 B 4 5 - 7 4 % 35.03% 11 . 2 0 % 4.06% 3 . 0 0 % 0 . 5 2 % 0 . 4 5 % 2 6 6 9 . 7 0 C 5 . 2 6 % 6 . 6 2 % 1 5 - 0 9 % 1 7 . 1 0 % 32.87% 9 . 7 0 % 1 3 . 3 6 % 2 7 7 0 . 5 0 D 9-36% 1 3 - 9 4 % 1 5 . 9 0 % 1 5 . 1 2 % 2 7 - 5 5 % 7 . 9 7 % 1 0 . 1 6 % 2 8 8 5 - 4 0 E 2 . 8 1 % 6 . 2 2 % 1 6 . 2 0 % 1 8 . 8 2 % 3 2 . 7 3 % 9 . 5 2 % 1 3 . 6 9 % 2 8 4 1 . 4 0 F 72 .30% 1 1 . 0 0 % 9 . 6 5 % 7 . 0 5 % 2 7 7 2 . 8 0 T A B L E 4. (ORE MATERIAL USED IN MODEL) ' A ' 32 65 3 1.68 1 :30 SCALE ' B 1 13 27 60 1.80 1 :30 SCALE •c 25 60.6 14.4 1.75 1 :30 SCALE ' D ' 22.5 60.7 16.8 1.68 1 :30 SCALE •E1 10.0 24.6 23.7 11.0 21.8 7-7 1 .2 1.56 1:20 SCALE ' F' 0.7 45.6 25.5 17-4 6.7 4.1 1.56 1:30 SCALE 1 G 1 27.0 13-0 25.0 25.0 10.0 1.46 1:30 SCALE A P P E N D I X IV TABLE 5 " DESIGN DATA FOR THE RECOMMENDED LAYOUTS. SUMMARY T A B L E 5. DESIGN DATA FOR THE RECOMMENDED LAYOUTS, 23 As. to r i X - ^ AC tty Uj Co A. /3 Co to *NT "V. 03 AC A ? Av. to NT C? o\o Or A^ Co —i CO 10 A 20' 65c 60' 126 86. 28.4 0-90 SC = 0::1 80' 20 90-200 SC = 1::1 20' 65° 60' 112 74.9 33.0 80° 30 (1:20 SC) 30 1 65c 60' 124 89-3 28.0 0-90 SC = 0:1 80° 49 90-275 SC = 1:: 1 30' 75c 60' 121 87-4 27.9 0-110 SC = 0::1 NIL 60 110-130 SC = 2::1 130-260 SC = 1 40' 65° 60' 115 90.5 21.3 0-180 SC = 0::1 80' 78 180-300 SC = 1:1 50' 55c 60' 6' - 6' 112 68.5 SEE TABLE 6 80° 95 50' 70' 60' 8' 110 78.4 SEE TABLE 7 80< 98 T . S . L . C . 79° 30' 109 87-3 20. 1 0-200 SC 1 : :1 104 APPENDIX IV 110. CONFIGURATION - A STANDARD LAYOUT FOR 20-FT. ORE BODY - F.W. ANGLE 65° (TO 75°) (ITEM NO. 20 AND 30 TABLE 1 OF APPENDIX III) PRODUCTION JUMBO IN ORDER TO EQUALIZE THE WORK LOAD ON TWO BOOMS. 111. CONFIGURATION B STANDARD LAYOUT FOR 30 FT. ORE BODY - F.W. ANGLE 65° (TO 75°) (ITEM NO. 49 T A B L E 1 OF APPENDIX I I) 112. CONFIGURATION C STANDARD LAYOUT FOR kO FT. ORE BODY - F. W. ANGLE 65° (TO 75°) (ITEM NO 78 TABLE 1 OF APPENDIX l l ) 1 1 3 . CONFIGURATION D STANDARD LAYOUT FOR 50 FT. ORE BODY - F.W. ANGLE 55° (ITEM NO. 95 TABLE 1 OF APPENDIX l l ) CONFIGURATION E STANDARD LAYOUT FOR 50 FT. ORE BODY - F. W. ANGLE 70° ( ITEM NO. 98 TABLE 1 OF APPENDIX l l ) 115. CONFIGURATION F STANDARD' LAYOUT FOR 20 F T . , 30 FT. AND kO FT. ORE BODY F. W. ANGLE 75° AND ABOVE. 116. CONFIGURATION G STANDARD LAYOUT FOR 20 F T . , 30 FT. AND kO FT. ORE BODY -F. W. ANGLE 55° - 65°. CONFIGURATION H STANDARD LAYOUT FOR TRANSVERSE SUB LEVEL CAVING SUB LEVEL INTERVAL 30 FT. - S i p E SLOPES. 79° (ITEM NO 103TABLE IB OF APPENDIX I I ) 16' . 118. CONFIGURATION I STANDARD LAYOUT FOR TRANSVERSE SUB LEVEL CAVING SUB LEVEL INTERVAL 30 FT - SIDE SLOPES 79° VERTICAL SECTION ALONG THE CENTRE LINE OF THE EXTRACTION DRIFT. FROM CONFIGURATION 'H' CONFIGURATION J  COMPARISON OF LOADING INTENSITY 119 . 30 FT. ORE BODY - F. W. ANGLE 650 LOADING INTENSITY 3 : 1 : : F.W. : H.W. (ITEM NO. 41 TABLE 1 OF APPENDIX I I ) CONFIGURATION K 120. COMPARISON OF LOADING INTENSITY 30 FT. ORE BODY - F. W. ANGLE 65° LOADING INTENSITY 1:1 : : F.W. : H.W. (ITEM NOkO TABLE 1 OF APPENDIX I I ) TABLE 6. T e s t No . 33 (#85 t o #88 o f TABLE 1) C u m m u l a t i v e number o f s c o o p s drawn a r e t a b u l a t e d b e l o w : DRIFT B DRIFT A H.W. F .W. H.W. F.W. 0 - 250 251 - 350 351 - 380 TABLE 7. T e s t No. 32 (#89 t o #92 o f TABLE 1) C u m m u l a t i v e number o f s c o o p s drawn a r e t a b u l a t e d b e l o w : DRIFT B DRIFT A H.W. F.W. H.W. F.W. 171 - 290 351 - 360 366 - 370 376 - 380 386 - 390 396 - 400 0 - 1 7 0 291 - 350 361 - 365 371 - 375 381 - 385 391 - 395 401 - 450 APPENDIX V 122. FIGURE 14 L o n g i t u d i n a l Sub L e v e l C a v i n g - shows sequence o f draw w i t h s i n g l e e x t r a c t i o n d r i f t on each s u c c e s s i v e sub l e v e l . Ore body w i d t h 20', S . L . I . = 60', F.W. a n g l e 65° and F.W. s l a s h 80°. (PP 120 t o 124) FIGURE 15 L o n g i t u d i n a l Sub L e v e l C a v i n g - shows sequence o f draw w i t h two e x t r a c t i o n d r i f t s on a sub l e v e l . Orebody w i d t h 50', S . L . I . = 60', F.W. a n g l e 55° and F.W. s l a s h 80°. (PP 125 t o 127) 126. 14 M 14 0 14 P 1 2 7 . 1 4 S 1 4 T nniFT ii . C O U P S I) 11 AW H\V nv 0 D R I F T A s c o o l ' s II ii A W ; HW 0 0 15 A I1BIF scours II nw 0 • 0 1)111 F T \ S C O O P S 1) 1  A W N HW FW t 0 30 15 C 15 G 15 H 15 K 15 L A P P E N D I X VI 131. DETAILED GEOLOGY Granduc M i n e s ' o r e o c c u r s i n l o n g , i r r e g u l a r c o n f o r m a b l e t a b u l a r b o d i e s w i t h an a v e r a g e w i d t h o f kQ', combined s t r i k e l e n g t h o f 3,500' and v e r t i c a l e x t e n t o f a b o u t 2,500'. These l e n s e s a r e composed o f s t r i n g e r s and d i s -s e m i n a t i o n s o f p y r r h o t i t e , c h a l c o p y r i t e and m a g n e t i t e . They l i e i n a s e r i e s o f w e a k l y metamorphosed and s t r o n g l y f o l d e d p h y l l o n i t e s ( s i l i c i o u s m e t a s e d i m e n t s ) , i n a g r o u p c a l l e d the mine member, w h i c h i s a b o u t 500' t h i c k between t h e a n d i s i t i c f o o t w a l l and t h i n l i m e s t o n e h a n g i n g w a l l , w h i c h i s s u c c e e d e d by a l t e r e d g r e y w a c k e s . The s t r u c t u r a l o r e c o n t r o l i s f o l d s , f a u l t s and s h e a r e d c r u m p l e d z o n e s . The o r e b o d i e s a r e g e n e r a l l y d i p p i n g a t 70° a l t h o u g h some p a r t s d i p a t 50 - 55° and o t h e r s a t 90°. T h i c k p o r t i o n s i n " C " o r e b o d y a r e up t o 120 f e e t w i d e , whereas t h e w i n g s o f " C " o r e b o d y and o t h e r A , B and B] o r e b o d i e s v a r y between 15 f e e t t o 50 f e e t i n w i d t h . A l m o s t 50% o f t h e t o t a l m i n a b l e tonnages i n No. 1 M i n i n g Zone a r e t i e d up i n t h i n p o r t i o n s . G e o l o g i c a l p r e r e s e r v e s (1966) a r e 43 x lo6 t o n s a t a v e r a g e ].73% c u . W i t h 10% d i l u t i o n , o r e r e s e r v e s a r e a p p r o x i m a t e l y h7 x 106 t o n s a t 1.49% c u . A t y p i c a l s e c t i o n and p l a n o f t h e o r e b o d i e s a r e a t t a c h e d on Page 132. 11 0 00 E S4U 10 5 0 0 E c E n s0 0) c o 0> E o o 01 o o O o If) II 0 0 0 E 10 5 0 0 E O O o V o l c a n i c s HW, F 2 Vo 'cani-cs WTftlge \ y Mela sediments "Ch" M e l a sediments AS" Fault A L imeslone F W L E G E N D • ORE ZONES DYKE M E T A S E D I M E N T S V 0 L C AN ICS L I M E S T O N E A " Fau l t L imestone FW 3 6 3 0 P L A N 100 SURFACE 

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