-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
1/286
IN-PIT CRUSHING AND CONVEYING AS AN ALTERNATIVETO AN ALL TRUCK SYSTEM IN OPEN PI T MINES
by
JACEK K. RADLOWSKI
M . S c , The U n i v e r s i t y o f M i n i n g a nd M e t a l l u r g y , 1965Cracow, Po land
A THESIS SUBMITTED IN PARTI AL FU LFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE
OF MASTER OF APPLIED SCIENCE
i n
THE FACULTY OF GRADUATE STUDIES
Depar tmen t o f M i n i n g and M i n e r a l P r o c e s s E n g i n e e r i n g
We a c c e p t t h i s t h e s i s a s c o n f o r m i n gt 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 , 1988
J a c e k K. R a d l o w s k i , 1988
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
2/286
In presenting this thesis in partial fulfilment of the requirements for an advanced
degree at the University of British Columbia, I agree that the Library shall make it
freely available for reference and study. I further agree that permission for extensive
copying of this thesis for scholarly purposes may be granted by the head of my
department or by his or her representatives. It is understood that copying or
publication of this thesis for financial gain shall not be allowed without my written
permission.
Department of MlNMJ Cr * W\ KJ\ PfeOCSSS ^MG-KJcS
The University of British Columbia1956 Main MallVancouver, CanadaV6T 1Y3
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
3/286
i i
A B S T R A C T
The m a t e r i a l t r a n s p o r t s y s t e m i n a n open p i t
mine s i g n i f i c a n t l y a f f e c t s t h e c a p i t a l a n d o p e r a t i n g c o s t s .
A l l t r u c k h a u l a g e i s t h e most common a n d i s a r e l i a b l e and
f l e x i b l e t r a n s p o r t s y s t e m . On t h e o t h e r hand, t h i s s y s t em
i s v e r y e x p e n s i v e and ca n c o s t up t o 50% o f t o t a l m i n i n g
c o s t s . I t s c o s t i s c o n t i n u o u s l y i n c r e a s i n g due t o t h e
i n f l a t i o n o f t h e f u e l , t i r e , a n d l a b o u r e x p e n d i t u r e s .
I n - p i t c r u s h i n g a n d c o n v e y i n g i s a n a l t e r n a t i v e t r a n s p o r t
s y s t e m w h i c h r e g u i r e s a h i g h e r i n i t i a l i n v e s t m e n t b u t g i v e s
s u b s t a n t i a l s a v i n g s i n o p e r a t i n g c o s t s .
An e v a l u a t i o n o f t h e a l l t r u c k s y s t e m v e r s u s
t h e i n - p i t c r u s h i n g a nd c o n v e y i n g s y s t e m h a s been p e r f o r m e d
by means o f a s i m u l a t i o n o f b o th t r a n s p o r t s y s t e m s i n t h e same
mine mode l . R e s u l t s o f t h e s i m u l a t i o n a n d t h e d a t a o b t a i n e d
f r o m t h e f e a s i b i l i t y s t u d i e s p r o v i d e d i n p u t f o r an e conomic
c o m p a r i s o n o f t h e a l t e r n a t i v e t r a n s p o r t s y s t e m s .
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
4/286
i i i
A cash f low a n a l y s i s showed tha t the i n - p i t
crushing and conveying system was co mp et it iv e wi th the
a l l t r u c k system, g i v i n g a payback w i t hi n fou r yea rs and
r e s u l t i n g i n t o t a l c o s t s over 30% lower than tho se o f an
a l l t r u c k system.
Three computer programs, wr i t te n by the
au thor, have been used to analyse the mine model:
(1) Open P i t S i m u l at i o n Program - t o model a h y p o t h e t i c a l
mine and s imula te i t s haulage o p e r a t i o n over the
mine l i f e ,
(2) Off-Highway Truck S i m u l a t i o n Program - to si mu la te the
t r u c k haulage on average annual rou tes in terms of the
o p e r a t i n g t ime and f u e l consumption f o r t he e s t ima t i on
of the t ruck f l e e t s i z e and the f u e l co s t ,
(3) Cash Flow A n a l y s i s C a l c u l a t i o n Program - t o compare
costs of the a l t e r n a t i v e t r a n s p o r t systems over the
whole pe r iod of a mine l i f e .
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
5/286
i v
TABLE OF CONTENTS
Page
1. INTRODUCTION , 1
2. LITERATURE REVIEW 3
3. A L L TRUCK TRANSPORT SYSTEM 11
3.1 R e a r Dump O f f - H i g h w a y Tr u c k s 12
3.2 New D e v e l o p m e n t s i n O f f - H i gh w a y T r u c k s 12
3.3 D i r e c t i o n s o f Improvement o f T r u c k E f f i c i e n c y . 14
3.3.1 Improvements i n We i g h t t o Power R a t i o 14
3.3.2 A l t e r n a t i v e F u e l 15
3.3.3 I n c r e a s e i n T r u c k S i z e 16
3.3.4 T r o l l e y Power A s s i s t 17
3.3.5 A u t o m a t i c T r u c k C o n t r o l 2 0
3.3.6 We a t h e r C o n d i t i o n s 21
3.3.7 Ramp G r a d e . . . . ; 214. I N - P I T CRUSHING AND CONVEYING SYSTEM 22
4.1 A d v a n t a g e s o f t h e C o n v e y o r S y s t e m 24
4.2 D i s a d v a n t a g e s o f t h e C o n v e y o r S y s t e m 2 5
4.3. I n f l u e n c e o f Wea the r C o n d i t i o n s 2 6
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
6/286
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
7/286
v i
TABLE OF CONTENTS
(cont)
Page
8. HIGH ANGLE CONVEYORS 4 7
8.1 Pocket B e l t Conveyor 47
8.2 Sandwich B e l t Conveyor 4 8
9. COMPARISON OF CONVEYORS 51
10. IN-PIT CRUSHING PLANT 56
10.1 Crusher I n s t a l l a t i o n s 56
10.2 Hopper/Feeder Conf igura t ions 61
10.3 A u x i l i a r y Equipment 64
11. HYPOTHETICAL OPEN PIT MINE 66
11.1 General D e s c r i p t i o n : 66
11.2 Ex ca va ti on Procedur e 68
11.3 A l l Truck System 70
11.4 I n - P i t Crushing and Conveying System 72
11.4.1 Conveying across Benches 7711.4.2 Conveying with I n c l i n e 8 0
12. OPEN PIT SIMULATION PROGRAM 8 3
12.1 Model Algor i thm 84
12.2 Pro du ct io n Alg or it hm 89
12.3 Truc k Schedul e Al go ri th m 92
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
8/286
v i i
TABLE OF CONTENTS
(cont)
Page
13. SIMULATION OF THE MINE OPERATION 96
13.1 R e s u l t s and I n t e r p r e t a t i o n 98
13.2 Truck Demands 105
14. EQUIPMENT COST ESTIMATION 114
14.1 A l l Truck System 122
14.2 I n - P i t Crush ing and Convey ing System 124
14.2.1 Conveying across Benches 128
14.2.2 Conveying with I n c l i n e 130
15. CASH FLOW CALCULATION PROGRAM 133
15.1 Main Al go ri th ms 13 3
15.2 Formulae 137
16. DISCOUNTED CASH FLOW ANALYSIS 14 0
17 CONCLUSIONS 162
18. BIBLIOGRAPHY 166
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
9/286
v i i i
TABLE OF CONTENTS
(cont)
APPENDIX A Open P i t O p e r a t i o n S i m u l a t i o n Program
Program L i s t i n g and O u t p u t Ta b l e s
APPENDIX B O f f - H i g h w a y T r u c k S i m u l a t i o n Program
Program L i s t i n g and Out put Examples
APPENDIX C Cash Flow C a l c u l a t i o n Program
Program L i s t i n g
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
10/286
i x
LIST OF TABLES
Page
Table 1 Off-Highw ay Trucks - B a s i c Features 13
Table 2 C a p i t a l Costs of the Conveying System
I s l a n d Copper Mines 3 2
Tab le 3 Sandwich B e l t Conveyor - Te c h n i c a l Data
Majdanpek , Yugos lav ia 5 0
Table 4 I d l e r B e l t Conveyor vs. Cable B e l t Conveyor 52
Table 5 Sandwich B e l t Conveyor
vs . Pocket B e l t Conveyor 54
Table 6 Crusher P l a n t Requirements 57
Table 7 F i x e d Operating Delays 69
Table 8 C h a r a c t e r i s t i c s of Convey ors 76
Table 9 Computer Model - P i t C h a r a c t e r i s t i c s
Input Data Required 88Table 10 Computer Model - Product ion C h a r a c t e r i s t i c s
Input Data Required 94
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
11/286
X
LIST OF TABLES
(cont)
Page
Table 11 Open P i t S imula t ion Program
Input Parameters 9 6
Tab le 12 Open P i t S imula t ion Program
Reserves Table 99
Table 13 Open P i t S imula t ion Program - A l l Truck System
Ore Truck Haulage Schedule 102
Table 14 Open P i t S imula t ion Program - Con veyi ng System
Ore Truck Haulage Schedule 103
Table 15 Open P i t S imula t ion Program -
Waste Truck Haulage Schedule 104
Table 16 Off-Highway Truc k S imula t ion Program
Input - Truck C h a r a c t e r i s t i c s 107Table 17 Off-Highway Truck S imula t ion Program
A l l Truck System - Ore Truck Demands 108
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
12/286
x i
L I S T OF TABLES
(cont)
Page
Ta b l e 18 O f f - H i g h w a y Tr u c k S i m u l a t i o n Program
C o n v e y i n g Sys t em - Or e T r u c k Demands 110
Ta b l e 19 O f f - H i g h w a y Tr u c k S i m u l a t i o n Program
Was te T r u c k Demands I l l
Ta b l e 2 0 C o m p a r i s o n o f T r u c k F l e e t R e q u i r e m e n t s
A l l Tr u c k S y s t em v s . C o n v e y i n g S y s t e m 113
Ta b l e 21 E q u i p m en t R e q u i r e m e n t s f o r A l l T r u c k S ys te m 115
Ta b l e 22 E q u i p m en t R e q u i r e m e n t s f o r C o n v e y i n g S y s t e m 116
Ta b l e 23 Cash F low Program - I n p u t R e q u i r e m e n t s .. 134
Ta b l e 24 A l l T r u c k S ys te m - Cash F low A n a l y s i s
T r u c k s , 154 t o n n e c a p a c i t y 141
Ta b l e 25 A l l T r u c k S ys te m - Cash F low A n a l y s i s C r u s h e r ,
S t a t i o n a r y G y r a t o r y 14 2
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
13/286
x i i
L I S T OF TABLES
(cont)
Page
Ta b l e 26 A l l T r u c k Sy st em
C u m u l a t i v e Cash F low A n a l y s i s 14 3
Ta b l e 27 C o n v e y i n g a c r o s s Benches - Cash F low A n a l y s i s
Tr u c k s , 154 t o n n e c a p a c i t y 14 4
Ta b l e 28 C o n v e y i n g a c r o s s Benches - Cash F low A n a l y s i s
C r u sh e r , S t a t i o n a r y G y r a t o r y 145
Ta b l e ' 2 9 C o n v e y i n g a c r o s s Benches - Cash F low A n a l y s i s
C r u s h e r , P o r t a b l e
G y r a t o r y 146
Ta b l e 3 0 C o n v e y i n g a c r o s s Benches - Cash F low A n a l y s i s
M a i n Co n v ey o r , 700 m 14 7
Ta b l e 31 C o n v e y i n g a c r o s s Benches - Cash F low A n a l y s i s
S u r f a c e C o n v e y o r, 2200 m 14 8
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
14/286
x i i i
LIST OF TABLES
(cont)
Page
Ta b l e 32 C o n v e y i n g a c r o s s Benche s - Cash F low A n a l y s i s
E x t e n s i o n Co nv ey or , 300 m 149
Ta bl e 3 3 C o n v e y i n g a c r o s s Bench es - Cas h F lo w A n a l y s i s
C u m u l a t i v e Cash F low A n a l y s i s 150
Ta b l e 34 C o n v e y i n g i n I n c l i n e - Cash F low A n a l y s i s
T r u c k s , 154 tonne c a p a c i t y 151
Ta b l e 35 C o n v e y i n g i n I n c l i n e - Cas h F low A n a l y s i s
C r u s h er , S t a t i o n a r y G y r a t o r y 152
Ta b l e 36 C o n v e y i n g i n I n c l i n e - Cash Flow A n a l y s i s
C r u s h e r , P o r t a b l e
G y r a t o r y 153
Ta b l e 3 7 C o n v e y i n g i n I n c l i n e - Cas h Flow A n a l y s i s
M a i n C o n v e y o r , 700 m 154
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
15/286
x i v
LIST OF TABLES
(con t )
Page
Ta b l e 38 C o n v e y i n g i n I n c l i n e - Cash Flow A n a l y s i s
S u r f a c e Co nv ey or , 1800 m 155
Ta b l e 39 C o n v e y i n g i n I n c l i n e - Cash Flow A n a l y s i s
E x t e n s i o n o f Ma in Co nv ey or , 240 m 156
Ta b l e 40 C o n v e y i n g i n I n c l i n e - Cash Flow A n a l y s i s
D r i f t Co nv ey or , 80 m 157
Ta b l e 41 C o n v e y i n g i n I n c l i n e - Cash Flow A n a l y s i s
C u m u l a t i v e Cash F low A n a l y s i s 158
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
16/286
X V
LIST OF FIGURES
Page
F i g . 1 Convent ional Conveyors 53
F i g . 2 High Angle Conveyors 55
F i g . 3 A l l Truck System - S i t e P lan 71
F i g . 4 I n - P i t Crushing & Conveying - S i t e P lan .... 73
F i g . 5 I n - P i t Crushing and Conveying a cro ss Benches
Plan View 78
F i g . 6 I n - P i t Crushing and Conveying a cro ss Benches
Side View 79
F i g . 7 I n - P i t Crushing and Conveying with I n c l i n e
Plan View 81
F i g . 8 I n - P i t Crushing and Conveying with I n c l i n e
Side View 8 2
F i g . 9 Computer Model - P i t Geometry 85
F i g . 10 Computer Model - Mining Sequence 9 3
F i g . 11 Cumulative Costs v s. Time i n Years 161
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
17/286
x v i
ACKNOWLEDGEMENT
I w i s h t o acknowledge P r o f e s s o r A .E . H a l l f o r h i s
v a l u a b l e a d v i c e and t i m e t h a t he c o n t r i b u t e d .
I w i s h a l s o t o acknowledge Dr . H.D.S. M i l l e r who
i n s p i r e d t h i s t h e s i s and P r o f e s s o r s A .L . M u l a r,
G.W. P o l i n g and A . J . R ee d f o r p r o v i d i n g me w i t h
i n f o r m a t i o n I needed.
My s p e c i a l t h a n k s t o my w i f e Z o f i a f o r h e r p a t i e n c e ,
encouragement and s u b s t a n t i a l h e l p i n e d i t i n g t h i s
t h e s i s
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
18/286
- 1 -
1. INTRODUCTION
The c a p i t a l an d o p e r a t i n g c o s t s o f a n open p i t
mine a r e s i g n i f i c a n t l y i n f l u e n c e d b y t h e c o s t o f m a t e r i a l
h a u l a g e . T he u s u a l means o f m a t e r i a l h a u l a g e a t p r e s e n t i s
o f f - h i g h w a y t r u c k s , a l t h o u g h i t i s o f t e n t h e most e x p e n s i v e
s y s t e m due t o h i gh f u e l c o n s u m p t i o n , wear, a nd l a b o u r c o s t s .
C o s t s o f t h e t r u c k h a u l a g e ca n be as much a s a h a l f o f t he
t o t a l m i n i n g c o s t s , w i t h t h e m a j o r e x p e n d i t u r e s a t t r i b u t e d
t o f u e l , l u b r i c a t i o n , t i r e s and m a i n t e n a n c e .
T h e r e i s a n eed t o examine a l t e r n a t i v e
t r a n s p o r t s y s t e m s . The b e s t s o l u t i o n seems to be c o n v e y o r
t r a n s p o r t , a s i t i s e f f i c i e n t and e c o n o m i c a l i n power
c o n s u m p t i o n . The c o n v e y o r s y s t e m r e s u l t s i n a s i g n i f i c a n t
r e d u c t i o n i n t h e number o f t r u c k s , bu t i t r e q u i r e s t h e r o c k
to be c r u s h e d b e f o r e t r a n s p o r t a t i o n . T h i s i s a c h i e v e d by
t h e p r o v i s i o n o f an i n - p i t c r u s h i n g p l a n t , w h i c h can be more
e x p e n s i v e p e r t o n n e t h a n t h e s t a t i o n a r y o u t o f p i t c r u s h e r
n o r m a l l y u s e d w i t h a l l t r u c k h a u l a g e . The d i f f e r e n c e i n
c r u s h i n g c o s t s i s a t t r i b u t a b l e t o t h e c o s t s o f u s i n g a
c o n v e y o r t r a n s p o r t sy s t em .
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
19/286
- 2 -
A c o m p a r i s o n o f o p e r a t i n g c o s t s f o r t h e s e
t w o s y s t e m s f a v o u r s t h e c o n v e y o r t r a n s p o r t i n most c a s e s ,
a l t h o u g h t h e mine c o n f i g u r a t i o n i n some c a s e s may make
a c o n v e y o r t r a n s p o r t s y s t e m u n a t t r a c t i v e e c o n o m i c a l l y .
The i n i t i a l i n v e s t m e n t i s l o w e r f o r t h e a l l - t r u c k sys tem,
b e c a u s e o f t h e l o w e r c a p i t a l c o s t o f i t s s t a t i o n a r y c r u s h e r
compared t o t h e m o b i l e one u s e d w i t h c o n v e y o r s . Th e h i g h e r
i n v e s t m e n t w i l l be a m o r t i z e d q u i c k l y however b y s a v i n g s i n
t h e l o w e r o p e r a t i n g e x p e n s e s o f t h e con vey o r sy s t em .
I n a d d i t i o n , t h e c o s t s o f t r u c k t r a n s p o r t i n c r e a s e r a p i d l y
e a c h y e a r , a s a r e s u l t o f i n f l a t i o n o f w o r k i n g c o s t s and
t h e i n c r e a s e d h a u l a g e d i s t a n c e s f r om t h e d ee p er p i t .
The e v a l u a t i o n o f an a l l - t r u c k t r a n s p o r t
s y s t e m v e r s u s a c o n v e y o r t r a n s p o r t s y s t e m i s a v e r y complex
p r o b l e m . To p e r f o r m t h i s t a s k , a d e t a i l e d c o s t a n a l y s i s i s
r e q u i r e d , o v e r t h e whole p e r i o d o f a mine l i f e . T h i s t h e s i s
p r e s e n t s t h e r e s u l t s o f s u c h a c o s t a n a l y s i s a nd compares
t h e r e l a t i v e c o s t s , a d v a n t a g e s an d d i s a d v a n t a g e s o f t h e
two sys tems .
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
20/286
- 3 -
2. LITERATURE REVIEW
I n t h e p e r i o d 1980 - 1987 many t e c h n i c a l
p u b l i c a t i o n s r a i s e d t h e c o n c e r n s o f t h e h i g h o p e r a t i n g
c o s t s o f t r u c k h a u l a g e i n open p i t m i n e s , o f low m i n e r a l
p r i c e s , and r a p i d e s c a l a t i o n o f f u e l c o s t s .
E f f o r t s t o improve t r u c k e f f i c i e n c y a r e
l o g i c a l l y d i r e c t e d t o improvements i n t h e e n g i n e i t s e l f ,
improvements i n t h e power t o w e i g h t r a t i o and v a r i o u s
schemes a imed a t o p t i m i z i n g t r u c k u t i l i z a t i o n and m i n i m i z i n g
c o s t s . T h i s a c t i v i t y r e s u l t s i n m a r g i n a l improvements an d
n o s e r i o u s b r e a k t h r o u g h ca n be e x p e c t e d (A.K. B u r t o n , 1980) .
I n c r e a s i n g t h e t r u c k s i z e r e s u l t s i n o n l y
a s m a l l r e d u c t i o n o f o p e r a t i n g c o s t s p e r t o n n e a t a much
h i g h e r c a p i t a l c o s t f o r t h e l a r g e r u n i t . F o r exampl e,
t h e c o s t o f a 2 00 t o n n e t r u c k i s o v e r 50% h i g h e r t h a n t h a t
o f a 154 t o n n e model ( L . S . Lyon , 19 80) . L a rg e r t r u c k s a l s o
u s e tandem r e a r a x l e s w h i c h i n c r e a s e t i r e c o s t s .
V e r t i c a l t r u c k h a u l a g e i n e x c e s s o f 150 m
c r e a t e s t r a f f i c and m a i n t e n a n c e p r o b l e m s , t h e s e r e d u c e
e f f i c i e n c y and c o s t s r i s e ( C E . Huss e t a l . , 1983 ) .
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
21/286
- 4 -
There i s a t r end towards the use of hi gh speed,
l a rg e c a p a c i t y conveyor systems, and these i n s t a l l a t i o n s have
been h i g h l y p r o duc t i ve . C u r r en t l i m i t s o f technology are
a b e l t width maximum of 3.05 m and b e l t speeds o f 6.2 m/s f o r
coarse crushed ma te r i a l (T.W. Mar t in e t a l . , 1981). Higher
speeds are l i m i t e d t o f i n e m a t e r i a l s .
Seve ra l s t ud i e s performed on e x i s t i n g i n p i t
c r u s h i n g i n s t a l l a t i o n s (R.W. U tl e y , 1983) and on h y p o t h e t i c a l
models (T.W. Ma rt in et a l . , 1981) showed co st saving s ranging
from 2 6 to 50%.
Run of mine ma te ri al has t o be crushed to
a conveyable s i z e be fore loa d ing onto a conveyor.
Crushing has to be done i n t he p i t . There a re i n p i t
c r u s h e r c o n f i g u r a t i o n s , such as mobile, semi-mobile,
movable, modular, semi -f ix ed, and f i x e d (E.M. F r i z z e l l ,
1983) . Design of mobi le c rus hers has advanced to the point
where they are as rugged and r e l i a b l e a s s t a t i ona rycrushers . In Europe, owners who have operated both mobile
and s ta t i on ar y c rushers p re fe r the mobi le un i t s a s they are
more economical (H.G. Kok, 1982).
Crusher e l ev a t io n should be conv enie n t ly
c lose to the cen t ro id o f the mate r ia l s be ing mined.
Pr ef er ab ly , the i n p i t crush er should be loc at ed on a s i t e
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
22/286
- 5 -
t h a t w i l l not r e q u i r e mi ning f o r one or more years to avoid
f requent r e l o c a t i o n s . I n - p i t cru she r throughput i s up t o 2 0%
h igher than the throughput achie ved through the same c ru sher
l o c a t e d at the p i t r im and s u p p l i e d by haul t r u c k s ( C E . Huss
e t a l . , 1983). T h i s r e s u l t s from b e t t e r u t i l i z a t i o n of the
c rushe r by t r u c k s operat ing only w i t h i n the p i t and cont ino us
feed to the cr us he r by apron feeder.
Conventional l a r g e - c a p a c i t y conveyors are
widely used around th e wo rl d. One o f the l a r g e s t opera t ions
i s a t For tuna, West Germany, where over 14,000 tonnes of
l i g n i t e per hour are handled by conveyor b e l t s .
In North America, t he re a re s ix s i g n i f i c a n t
rock moving opera t ions which use conveyors f o r haulag e
i n open p i t mines. At the Twin Butt es i n Ar izona where
conveyors have been used s i n c e 1965. At the S e r r i t a open
p i t copper mine, a l s o i n Ar izona, conveyors moved over
58 m i l l i o n t onnes of or e and waste i n 1979 (T.M. Brady et
a l . , 1982). The Bingham Canyon Copper Mine produces 70,000
tonnes of ore a day us ing a semi-mobile 1.5x2.7m (60-109 in.)
gyra to ry cr us he r and s i x conveyor f l i g h t s of a t o t a l length
of abo ut 8.5 km. The c a p a c i t y of t h i s system i s 9,000 tonnes
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
23/286
- 6 -
p e r h o u r (D. K a e r s t , 1987) . I n Canada s o f a r t h r e e open p i t
mines u s e i n - p i t c r u s h i n g a nd c o n v e y i n g s y s t e m . T h e s e a r e
G i b r a l t a r M i n e s , I s l a n d C o p p e r M i n e s , a n d H i g h l a n d Va l l e y
C op pe r, a l l l o c a t e d i n B r i t i s h Columbia .
B a s i c c o n v e y o r d e s i g n p r o c e d u r e i s g i v e n i n
t h e CEMA book (1979 ) . Fo r a b e l t c a r r y i n g c o a r s e c r u s h e d
m a t e r i a l i t i s d e s i r a b l e t o keep t h e c r o s s s e c t i o n a l l o a d
t o l e s s t ha n 80% of t he CEMA s t a n d a r d s , when c a r r y i n g the
d e s i g n e d t o n n a g e t o a v o i d s p i l l a g e . F o r c o a r s e o r e
c o n v e y o r s , t h e recommended sp ee d i s 4 t o 5 m/s whereas f o r
ov er bu rd en c on ve yo rs i t i s 5 t o 8 m/s (A.D. F e r n i e , 1985).
The a l t e r n a t i v e C a b l e B e l t co nve yo r has
a maximum c a p a c i t y o f 4,600 ton nes pe r hour, wh ich l i m i t s
i t s a p p l i c a t i o n t o medium s i z e open p i t m i n e s . T h i s type
o f c o n v e y o r h a s f o u n d a p p l i c a t i o n i n s e v e r a l h a r d r o c k
o p e r a t i o n s a r o u n d t h e w o r l d , m o s t l y as o v e r l a n d i n s t a l l a t i o n s
(D.E. Brown, 1983 & 198 6) .
C o n v e n t i o n a l b e l t c o n v e y o r s c a n t r a n s p o r t m a t e r i a l s
a t a n g l e s a p p r o a c h i n g 1 8 . H i g h a n g l e b e l t c o n v e y o r s ,
l i k e th e sandwic h co nve yor and po ck e t con vey or, can t r a n s p o r t
m a t e r i a l a t h i g h a n g l e s u p t o 9 0 , w h i l e m a i n t a i n i n g
t h e most p o s i t i v e f e a t u r e s o f c o n v e n t i o n a l c o n v e y o r s
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
24/286
- 7 -
( J .A . do s S a nt os & E.M. F r i z z e l l , 1983) . Sandwich
b e l t c o n v e y o r s o f f e r : h i g h c a p a c i t y up to 9,000 t o n n e s / h ,
l i f t s t o 300 m, and a ng l es i n ex ce ss o f 45 . The co nv ey or
can be i n s t a l l e d a c r o s s t h e b e n c h e s w i t h r e l a t i v e l y s m a l l
p r e p a r a t i o n . I t c a n a l s o be e a s i l y r e l o c a t e d t o a n o t h e r
a r e a o f t h e mine. The a p p l i c a t i o n o f th e sandw ich b e l t
c o n v e y o r does n o t r e q u i r e a change i n mine p l a n n i n g
( J .A . Dos San to s , 1983) whi ch i s an im po rt an t c o n s i d e r a t i o n .
A n o t h e r h i g h a n g l e c o n v e y i n g method i s
t h e F l e x o w a l l p o c k e t c o n v e yo r. T h i s typ e o f con vey or can
be o f v a r i o u s c o n f i g u r a t i o n s : s t r a i g h t , i n c l i n e d , "L", "S",
and 1 1 C" sha pe s (J.W. P a e l k e , 1982) . B a s i c f e a t u r e s o f
t h e F l e x o w a l l c o n v e y o r a n d c u r r e n t i n s t a l l a t i o n s have
been d e s c r i b e d by U. Kunstmann & J.W. P a e l k e (19 84) , an d
J.W. P a e l k e e t a l . , ( 1 9 8 6) . C a p a c i t y o f t h e p o c k e t b e l t
c o n v e y o r i s l i m i t e d by the lump s i z e o f th e conv eyed
m a t e r i a l . The maximum o p e r a t i n g a n g l e , t h e r e f o r e , i s
d e t e r m i n e d b y a m a t e r i a l s i z e and t h i s must a lw ays be
c o n s i d e r e d i n t h e d e s i g n o f s u c h i n s t a l l a t i o n s .
S e l e c t i o n o f t h e most e c o n o m i c a l o p e r a t i o n
r e q u i r e s e v a l u a t i o n o f s e v e r a l m i n i n g schemes s i n c e a l l
open p i t mines a r e d i f f e r e n t , a nd p l a n n i n g a m u l t i - s y s t e m
method of ore and was te e x t r a c t i o n i s g e n e r a l l y more
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
25/286
- 8 -
complex than fo ll ow in g the t r a d i t i o n a l shove l / t ruck method
with i t s f l e x i b i l i t y . An ope rat ing mine, that is planning
to use i n - p i t crushing and conveying as a replacement for
the shovel / t ruck system, must deve lop c once pts t h a t can be
worked i n t o the e x i s t i n g p i t wi thout i n t e r f e r i n g wi th d a i l y
produc t ion .
Such pla nnin g may re qu ir e deve lopi ng se ve ra l
d i f f e r e n t schemes to f i n d the most p r a c t i c a l and cost
e f f e c t i v e method of t r an sp or t i ng the ore from p i t to p lan t .
For example:
I t may be de si r ab le to s t r i p overburden to the f i n a l
p i t perimeter before i n s t a l l i n g the a l t e r n a t i v e
system. Pushing back p i t wa l l s r equ i res r e l o c a t i o n
of the main conveying system and would be very
d i f f i c u l t during the p i t oper at io n.
When s e l e c t i v e mining i s r equ i red , mul t ip le working
fa ces may be needed, usi ng smal ler loa di ng and haul
equipment.
Operating layout can change with inc reas ed i n - p i t
h o r i z o n t a l haulage.
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
26/286
- 9 -
T he c r u s h i n g p l a n t b e n c h a r e a must be a d e q u a t e f o r
t h e c r u s h i n g p l a n t , a u x i l i a r i e s , t r a n s p o r t an d
s e r v i c e e q u i p m e n t , t r u c k dump h o p p e r and c r u s h e r
f e e d e r , d i s c h a r g e c o n v e y o r and ma in c o n v e y o r t a i l
s e c t i o n .
The dumping a r e a o f t h e c r u s h e r must h a v e a d e q u a t e
s p a c e f o r t r u c k manoeuvers.
When t h e c r u s h e r o r c o n v e y o r a r e t e m p o r a r i l y down,
t h e r e must be a d e q u a t e s p a c e t o a c c u m u l a t e a s u rg e
p i l e . P r e f e r a b l y t r u c k s s h o u ld be s w i t c h e d t o wast e
h a u l a g e t o p r e v e n t r e h a n d l e .
The s t a b i l i t y o f t h e dumping b e n c h may r e q u i r e
a s p e c i a l r e i n f o r c e m e n t o r e l s e a dumping h o p p e r
may b e n e c e s s a r y.
Ad equ a t e d i s t a n c e s h o u l d be p r o v i d e d t o p r e v e n t
f l y r o c k damaging t h e i n - p i t c r u s h i n g p l a n t an d
c o n v e y o r s d u r i n g b l a s t i n g . I n h a r d r o c k m i n i n g
t h i s d i s t a n c e u s u a l l y v a r i e s f r om 150 t o 300 m,
a l t h o u g h 120 m i s c o n s i d e r e d s a f e .
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
27/286
- 10 -
The o p e r a t i o n a l l a y o u t must p r o v i d e f o r moving
t h e c r u s h e r p l a n t , r e l a t e d equ ipment a nd e x t e n d i n g
t h e c o n v e y o r, t h u s t h e l a y o u t must p r o v i d e ramps
o f 7 t o 10% gra de, h au l ro ad s ap pr ox im at el y 30 m
w i d e , and the new s i t e f o r r e l o c a t i o n on a d e e p e r
b e n c h must be p re pa re d .
For a b e l t c o n v e y i n g s y s t e m a more d e t a i l e d d e s i g n
i s r e q u i r e d t h a n f o r c o n v e n t i o n a l t r u c k h a u l a g e .
I t i s t h e o r e t i c a l l y p o s s i b l e t o u se j u s t one b e l t
o r add a d d i t i o n a l s ec t ions (R .M. Hays , 1983)
T h e c r u s h e r s i t e s must b e p r e - p l a n n e d t o m i n i m i z e
t h e l o c k - u p o f t o n n a g e b y t h e c r u s h e r . T h i s a f f e c t s
t h e c r u s h e r moving s c h e d u l e a n d r e l o c a t i o n c o s t s .
C o n v e y o r t r a n s p o r t s y s t e m s r e d u c e t h e t r u c k
m a i n t e n a n c e p e r s o n n e l a nd i n f r a s t r u c t u r e
s i g n i f i c a n t l y .
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
28/286
- 11 -
3 . ALL TRUCK TRANSPORT SYSTEM
The a l l t r u c k t r a n s p o r t s y s t e m i s t h e mos t
common t r a n s p o r t a t i o n method and i s w e l l e s t a b l i s h e d i n
open p i t m i n i n g . I t p r o v i d e s h i g h r e l i a b i l i t y , e x c e l l e n t
f l e x i b i l i t y and f u l l y s a t i s f i e s needs f o r m a t e r i a l s
b l e n d i n g . I t s d i s a d v a n t a g e i s t h a t i t i s a l s o v e r y
e x p e n s i v e i n t e r m s o f o p e r a t i n g c o s t s and t r u c k s e r v i c e
f a c i l i t i e s . I n remote a r ea s d r i v e r s a nd m e c h a n i c s may
r e q u i r e h o u s i n g and t r a n s p o r t .
I n t h e a l l t r u c k s y s t e m , t h e m a t e r i a l i s
e n t i r e l y h a u l e d out o f th e p i t t o t h e s u r f a c e f a c i l i t i e s .
W i t h i n c r e a s e d p i t d e p t h , l o n g u p h i l l h a u l s c a u s e e x c e s s i v e
m a i n t e n a n c e p r o b l e m s and d e c r e a s e t r u c k a v a i l a b i l i t y .
I n t h i s c h a p t e r t h e t r u c k h a u l a g e s y s t e m i s
b r i e f l y d e s c r i b e d , and th e d i r e c t i o n o f p o s s i b l e improvements
i s d i s c u s s e d f u r t h e r .
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
29/286
- 12 -
3 .1 R e a r Dump O f f - H i g h w a y Tr u c k s
T h e r e a r dump t r u c k i s t h e most p o p u l a r t y p e
o f r u b b e r - t i r e d h a u l a g e v e h i c l e u s e d i n open p i t s and ca n
h a u l a l m o s t any t y p e o f m a t e r i a l . I t s body i s mounted ont h e t r u c k c h a s s i s and ca n be r a i s e d b y a h y d r a u l i c h o i s t
sy s t em.
The dump t r u c k i s e q u i p p e d w i t h an e l e c t r i c
whee l o r m e c h a n i c a l d r i v e , and ca n be d r i v e n by two a x l e s
o r r e a r a x l e o n l y . B a s i c f e a t u r e s o f t h i s t y p e o f t r u c k
a r e g i v e n i n Ta b l e 1.
3.2 New Deve lopments i n O f f - H i g h w a y Tr u c k s
I n t h e p a s t 25 y e a r s many c h a n g e s have been
made t o h a u l a g e t r u c k s and t h e y have had s i g n i f i c a n t impac t
i n t h e m i n i n g i n d u s t r y . I n th e 1960's p a y lo a d c a p a c i t i e s
i n c r e a s e d f r o m 60 t o 90 t o n n e s . The most i m p o r t a n t
t e c h n o l o g i c a l a c h i e v e m e n t was the e l e c t r i c d r i v e s y s t em
i n t r o d u c e d by G e n e r a l E l e c t r i c and U n i t R i g Equipme nt
Company. The b i g g e s t improvement i n t h e 1970's was t h e
d e v e l o p m e n t o f a 154- tonne d i e s e l e l e c t r i c t r u c k .
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
30/286
- 13 -
TABLE 1
OFF-HIGHWAY TRUCKS - BASIC FEATURES
C a p a c i t y 45 t o 320 t onnes
Pow er 300 t o 2,250 kW
V e h i c l e w e i g h t 26,000 t o 236,000 k g
D r i v e M e c h a n i c a l d r i v e sys tem,up t o 118 t o n n e s c a p a c i t y
E l e c t r i c a l wheel sys tem,77 t o 180 t onnes
E l e c t r i c a l a x l e d r i v e sys tem,210 t o 320 t onnes
Top speed 48 t o 72 km/h
A v e r a g e a v a i l a b i l i t y 75%
Payload/EVW a p p r o x . 1.5
P o w e r / P a y l o a d a p p r o x . 8.2 kW h/t onn e
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
31/286
- 14 -
Over 1400 o f t h e s e u n i t s have been b u i l t and t h e y a r e
i n o p e r a t i o n i n e v e r y a r e a o f t h e w o r l d . T h i s t r u c k i s
c o n s i d e r e d t o be t h e most p r o d u c t i v e , e f f i c i e n t and
e c o n o m i c a l , and i t s r e l i a b i l i t y and e a s e o f m a i n t e n a n c e
have been p r o v e n o v e r many y e a r s .
3.3 D i r e c t i o n s o f Improvement o f T r u c k E f f i c i e n c y
E f f o r t s t o improve t r u c k e f f i c i e n c y a r e
d i r e c t e d t o i m p r o v i n g t h e w e i g h t t o power r a t i o , t h e
e n g i n e i t s e l f , and v a r i o u s schemes a imed a t o p t i m i z i n g
t r u c k u t i l i z a t i o n and m i n i m i z i n g c o s t s .
3.3.1 Improvements i n Weigh t t o Power R a t i o
The w e i g h t t o power r a t i o i s b e i n g improved
by b o o s t i n g t h e power o f e x i s t i n g e n g i n e s . T h e r e a r e
p o t e n t i a l a p p l i c a t i o n s o f t w i n h i g h s p e e d d i e s e l s i n h i g h e r
power r a n g e s , t o compete w i t h t h e h e a v i e r l ow-speed
l o c o m o t i v e t y p e d i e s e l e n gi n es , c u r r e n t l y i n u s e . F u r t h e r
improvements a r e a l s o b e i n g made i n t u r b o c h a r g in g and h i g h
p r e s s u r e f u e l i n j e c t i o n .
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
32/286
- 1 5 -
3.3.2 A l t e r n a t i v e F u e l
T h e c o n v e r s i o n o f d i e s e l e n g i n e s t o a n a t u r a l
g a s / d i e s e l d u a l f u e l mode i s an a t t e m p t t o r e d u c e t r u c k
o p e r a t i n g c o s t s . I t i s e x p e c t e d , t h a t d u a l - f u e l o p e r a t i o n
w o u l d r e p l a c e up t o 80% o f d i e s e l f u e l c o n s u m p t i o n w i t h
n a t u r a l g a s w h i c h c o s t s h a l f as much as t h e d i e s e l .
N a t u r a l g a s w o u l d n o r m a l l y o n l y be u s e d f o r h a u l a g e up
t h e ramp t o m i n i m i z e c o n v e r s i o n p r o b l e m s o f low l o a d
o p e r a t i o n s .
To make the n a t u r a l ga s o p e r a t i o n f e a s i b l e ,
t h e f o l l o w i n g p r o b l e m s n e e d t o be s o l v e d :
A c o n v e r s i o n k i t needs t o be d e v e l o p e d t o o p e r a t e
t h e e n g i n e i n n a t u r a l g a s / d i e s e l d u a l f u e l mode
- S t o r a g e o f n a t u r a l ga s on b o a r d t h e t r u c k .
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
33/286
- 16 -
3.3.3 In c r ea se i n T r u c k S i z e
Man y m i n i n g companies a r e l o o k i n g f o r l a r g e r
t r u c k s t o r e d u c e t h e i r h a u l a g e c o s t s . An i n c r e a s e i n t h e
t r u c k s i z e l o w e r s t h e o p e r a t i n g c o s t p e r t o n n e , b e c a u s e :
T r u c k d r i v e r c o s t pe r t o n n e d e c r e a s e s ,
- R e p a i r c o s t s g r a d u a l l y d e c r e a s e , w i t h a f a i r l y l a r g e
d r o p between a 68- tonne t r u c k a nd a 109- tonne t r u c k ,
T i r e , f u e l and l u b r i c a t i o n c o s t s d e c r e a s e p e r t onne
h a u l e d .
The i n t r o d u c t i o n o f h e a v y t r u c k s e x c e e d i n g
180 t o n n e c a p a c i t y s i g n i f i c a n t l y i n c r e a s e s c a p i t a l c o s t s ,
b e c a u s e o f t h e p r o v i s i o n o f t w i n a x l e s y s t e m s .
T h e i n c r e a s e d t i r e wear a l s o e x p e r i e n c e d w i t h t h e s e models
h a s l i m i t e d t h e i r use by mine o p e r a t o r s .
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
34/286
- 17 -
3.3.4 T r o l l e y Power A s s i s t
The t r o l l e y a s s i s t s y s t e m c o n s i s t s of an
o v e r h e a d power l i n e , c u r r e n t c o l l e c t o r ( p a n t o g r a p h ) mounted
on the t r u c k , and add-on c o n t r o l equ ipme nt . The e x t e r n a l
e l e c t r i c power i s r o u t e d t h r o u g h t h e c o n t r o l equ ipment t o
t h e m o t o r i z e d w h e e l s . T he d i e s e l e n g i n e i s u s e d t o p r o p e l
t h e t r u c k on l e v e l s e c t i o n s o f the road . On i n c l i n e s , the
whee l moto rs o f th e t r u c k a r e c o u p l e d b y t h e c u r r e n t
c o l l e c t o r t o t h e o v e r h e a d power l i n e .
The c o n v e n t i o n a l d i e s e l e l e c t r i c t r u c k i s
e q u i p p e d w i t h t wo d . c . m o t o r s mounted on the r e a r a x l e .
They d r i v e t h e r e a r w h e e l s t h r o u g h p l a n e t a r y g e a r b o x e s .
N o r m a l l y t h e d i e s e l eng ine and an a l t e r n a t o r i s u s e d t o
power t h e whee l mot ors . The d i e s e l e n g i n e h a s l o w e r o u t p u t
t h a n t h e whee l m o t o r s w h i c h l i m i t s t h e t r u c k p e r f o r m a n c e .
When t h e t r o l l e y power a s s i s t i s a p p l i e d , t h e t r u c k
p e r f o r m a n c e i s s i g n i f i c a n t l y enhanced : t r u c k speed can
be i n c r e a s e d b y a p p r o x i m a t e l y 4 5% , a nd f u e l c o n s u m p t i o n
re du ce d by 75%.
I n t h e 1960's, t h e t r o l l e y power a s s i s t
was u t i l i z e d by Quebec C a r t i e r M i n i n g C o . u n t i l t h e mine
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
35/286
- 18 -
was c l o s e d . P r e s e n t l y , t h i s s y s t e m i s u s e d i n t h r e e Sou th
A f r i c a n m i n e s , P h a l a b o r w a Mi n i ng Co. , ISCOR S i sh en and
R o s s i n g Uran ium. T he S i s h e n i r o n o r e mine, of 60 m i l l i o n
t o n n e s a n n u a l p r o d u c t i o n , c l a i m s s a v i n g s on d i e s e l f u e l o f
20%, i n c r e a s e i n d i e s e l e n g i n e l i f e by 45%, and e x t en s io n
o f wheel motor l i f e by 88%. The t r u c k s p e e d on 8% g r ade
was i n c r e a s e d by 4 6% when u s i n g t r o l l e y a s s i s t . Siemens
a r e c u r r e n t l y e x t e n d i n g t h e R o s s i n g s y s t e m a t a cos t
o f $750,000 by i n s t a l l i n g a 3 MW r e c t i f i e r t o c o n v e r t t h e
11 kV a. c. s u p p l y t o 1200 V d. c. and i n s t a l l i n g a f u r t h e r
1 km o v e r h e a d e l e c t r i c l i n e s y s t e m c o m p r i s i n g d o u b l e c o n t a c t
w i r e s u p p o r t e d by f r e e s t a n d i n g s t e e l m a s t / c a n t i l e v e r
s t r u c t u r e s . A r e d u c t i o n o f f u e l c o n s u m p t i o n f r o m 24 1/km
t o l e s s tha n 4 1/km i s c l a i me d when t h e t r u c k s o p e r a t e o n
a 1200 V d. c. s u p p l y on a g r a d i e n t o f 8% and 1050 V d. c.
f o r 10% gra de. Speeds a r e a l m o s t d o u b l e d r e s u l t i n g i n b e t t e r
f l e e t u t i l i z a t i o n and i n c r e a s e d p r o d u c t i v i t y
(S .A. Min ing Wo r l d , Nov. 1987).
The t r o l l e y a s s i s t i s a v e r y p r o m i s i n g a p p r o a c h
t o l o w e r mine o p e r a t i n g c o s t s , and i n c r e a s e p r o d u c t i v i t y .
U n f o r t u n a t e l y , t h e c a p i t a l c o s t o f t h i s s y s t e m i s v e r y h i g h ,
and i t s a p p l i c a t i o n i s o n l y p r o f i t a b l e where f u e l i s v e r y
e x p e n s i v e compared t o e l e c t r i c e n e r g y. M o r e o v e r, i t r e d u c e s
t h e f l e x i b i l i t y o f t h e t r u c k f l e e t and imposes t r a f f i c
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
36/286
- 19 -
p r o b l e m s and l i m i t a t i o n s . Th e c l e a r a n c e between t h e t r u c k
and the t r o l l e y w i r e i s c r i t i c a l and t he p a n t o g r a p h can
u s u a l l y o n l y c a t e r f o r 0.3 m change. The p a n t o g r a p h t h e n
l o s e s c o n t a c t a nd t h e t r u c k l o s e s power. T h i s s l o w s t he
t r u c k a nd d e l a y s a l l o t h e r t r u c k s b e h i n d i t on t h e h a u l
r o a d . T h e h e a v y r a i n f a l l and f r o s t heave e x p e r i e n c e d i n
W e s t e r n C a n a d i a n M i n e s make t h e c o n t r o l o f c l e a r a n c e t o
t h i s t o l e r a n c e i m p o s s i b l e u n l e s s t h e h a u l r o a d i s paved .
T h e s e f a c t o r s have r e s u l t e d i n t h e t r o l l e y a s s i s t s y s t e m no t
b e i n g a d o p t e d by any We s t e r n C a n a d i a n open p i t o p e r a t i o n s .
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
37/286
- 20 -
3.3.5 Au to ma t i c Tr u c k C o n t r o l
T h e c o n c e p t o f A u t o m a t i c T r u c k C o n t r o l (ATC)
i s t h e r emo te c o n t r o l a nd d i s p a t c h o f t h e t r u c k . A d r i v e r ' s
a s s i s t a n c e i s o n l y neede d t o e n t e r o r e x i t t h e s y s t e m .
The b a s i c s y s t e m c o n s i s t s o f t h e o n - b o a r d
c o n t r o l e q u i p m e n t a n d t h e w a y s i d e c o n t r o l equ ipmen t .
Th e wa ys ide equ ipmen t c o n s i s t s o f a b u r i e d g u i d e w i r e ,
b l o c k c o n t r o l u n i t s , an d a c e n t r a l c o n t r o l l e r w h i c h p r o v i d e s
p r e d e t e r m i n e d s i g n a l s t o t h e o n - b o a r d e q u i p m e n t f o r spee d
c o n t r o l , s t e e r i n g , a nd f o r a u x i l i a r y f u n c t i o n s t h r o u g h t h e
g u i d e w i r e l o c a t e d i n t h e t r u c k p a t h .
T h e A u t o m a t i c Tr u c k C o n t r o l s y s t e m i s s t i l l
u n d e r d e v e l o p m e n t , b u t a n e c o n o m i c a n a l y s i s showed t h a t
t h e u s e o f ATC c o u l d r e d u c e d r i v e r s ' l a bo u r by 50% .
A d d i t i o n a l l y , t h e s h o v e l u t i l i z a t i o n wou ld improve a s t h e
s h o v e l w o u l d c o n t i n u e t o work a t s h i f t c h a n g e s , l u n c h t i m e
an d o t h e r b r e a k s p r e s e n t l y r e q u i r e d by d r i v e r s .
The a p p l i c a t i o n o f ATC may a l s o r e s u l t i n a s a f e r m i n i n g
o p e r a t i o n , b y r e d u c i n g human e r r o r s an d human e x p o s u r e
t o l a r g e e qu ip men t .
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
38/286
- .21 -
3 . 3 . 6 Weather C o n d i t i o n s
T r u c k o p e r a t i o n s a r e a d v e r s e l y a f f e c t e d by
wet c o n d i t i o n s , low t e m p e r a t u r e s and p a r t i c u l a r l y by fo gs .
A l l t h e s e c o n d i t i o n s o c c u r i n We s t e r n C a n a d i a n open p i t
o p e r a t i o n s .
3 . 3 . 7 . Ramp Grade
W h i l s t g r a d e s o f 10 t o 12% a r e more e c o n o m i c
f o r t r u c k o p e r a t i o n i n s h a l l o w p i t s , o v e r h e a t i n g o f wheel
m ot o r s o n l o n g ramps o f t h i s g r a d e l i m i t s deep p i t o p e r a t o r s
t o u s i n g 8 % maximum g r a d e s .
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
39/286
- 22 -
4. IN-PIT CRUSHING AND CONVEYING SYSTEM
I n - p i t c r u s h i n g and c o n v e y i n g i s a n a l t e r n a t i v e
s y s t e m f o r t r a n s p o r t i n open p i t m i n e s . The b i g g e s t
a d v a n t a g e o f t h i s s y s t e m i s a s i g n i f i c a n t r e d u c t i o n o f t he
t r u c k h a u l a g e by i n t r o d u c i n g t h e i n - p i t c o n v e y o r . I f a mine
p r o v i d e s two c o n v e y o r s , b o t h o r e and was te a r e c o n v e y e d ou t
o f t h e p i t . T h i s way, the t r u c k t r a n s p o r t on l o n g u p h i l l
d i s t a n c e s i s e l i m i n a t e d . When t h e mine s u p p l i e s o n l y one
c o n v e y o r , i t c o n v e y s o r e and was te on d i f f e r e n t s h i f t s , o r
a l l t h e w a s t e i s t r a n s p o r t e d by t r u c k s t o t h e s u r f a c e .
The i n - p i t c r u s h e r i s moved down e v e r y one
o r two y e a r s , t o keep t h e t r u c k h a u l a g e t o a minimum.
The r e l o c a t i o n t a k e s 2-3 d a y s . F o r s h o r t moving t i m e s t h e
p r o c e s s i n g p l a n t c a n b e f e d f r om a s t o c k p i l e . I n l o n g e r
s t o p p a g e s , u s u a l l y i n E u r o p e a n o p e r a t i o n s , t h e move c o i n c i d e s
w i t h a g e n e r a l mine h o l i d a y p e r i o d .
T h e c r u s h e r i s l o c a t e d n e x t t o an embankment,
s o t h a t t r u c k s a r e a b l e t o dump t h e m a t e r i a l d i r e c t l y f rom
t h e embankment i n t o t h e h o p p e r / f e e d e r above t h e c r u s h e r .
Under an a l t e r n a t i v e a r r a n g e m e n t , t h e c r u s h e r i s l o c a t e d
c l o s e r t o t h e p i t c e n t r e and ha s a s e p a r a t e f e e d e r w i t h
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
40/286
- 23 -
t h e f e e d e r t a i l - e n d l o c a t e d i n t h e r e c e s s i n t h e p i t f l o o r .
T h e t r u c k s dump t h e m a t e r i a l f ro m t h e p i t f l o o r i n t o t he
h o p p e r on t h e f e e d e r .
B e l t co nv ey or s ca n be one of th e most
e f f i c i e n t means o f t r a n s p o r t i n g m a t e r i a l o u t o f t h e p i t .
They have been s u c c e s s f u l l y p r o v e n i n c o a l m i n i n g , b u t
t h e y a r e n o t s o p o p u l a r i n m e t a l m i n i n g .
T h e r e a r e t h r e e t y p e s o f b e l t c o n v e y o r s
t h a t ca n be use d i n ha rd roc k mi n i ng : i d l e r s u p p o r t e d
c o n v e y o r, c a b l e s u p p o r t e d c o n v e y o r an d h i g h a n g l e c o n v e y o r.
T h e s e a r e d e s c r i b e d i n d e t a i l i n c h a p t e r s 5, 6 and 7.
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
41/286
- 24 -
4.1 A d v a n t a g e s o f t he Conveyor Sys t em
The i n - p i t t r a n s p o r t s y s t e m i s more
e c o n o m i c a l t h a n a l l t r u c k t r a n s p o r t , a nd c an s i g n i f i c a n t l y
l o w e r m i n i n g c o s t s . The f o l l o w i n g a s p e c t s o f t he sy s t em
c o n t r i b u t e t o t h e s a v i n g s :
R e d u c t i o n o f t h e t r u c k f l e e t , and c o n s e q u e n t r e d u c t i o n
o f t h e d r i v i n g a nd m a i n t e n a n c e p e r s o n n e l , m a i n t e n a n c e
f a c i l i t i e s and f u e l s t o r a g e ,
- R e d u c t i o n o f t h e t r a n s p o r t d i s t a n c e f rom t h e p i t s i n c e
c o n v e y o r s c a n o p e r a t e s a f e l y u p t o a 2 5% g r a d e c a r r y i n g
lumps o f 2 50 mm i n s i z e v e r s u s 12% maximum e c o n o m i c
g r a d e f o r t r u c k s ,
T h r o u g h p u t c a p a c i t y o f t h e i n - p i t m o b i l e c r u s h e r i s
a p p r o x i m a t e l y 2 0% h i g h e r t h a n t h a t o f a s t a t i o n a r y
c r u s h e r , b e c a u s e o f i m p r o v e d u t i l i z a t i o n ,
L e s s f u e l and l u b r i c a n t c o n s u m p t i o n , l e s s t i r e wear,
C o s t o f e l e c t r i c e n e r g y i s more s t a b l e t h a n t h a t o f
d i e s e l f u e l ,
Dependence on w o r l d a v a i l a b i l i t y o f f u e l i s g r e a t l y
r e d u c e d .
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
42/286
- 25 -
4.2 Di sa dv an ta ge s o f th e Convey or Sys tem
The i n - p i t c o n v e y o r s y s t e m a l s o h a s some
d r a w b ac k s . T h e s e d i s a d v a n t a g e s a r e a s f o l l o w s :
The i n i t i a l c o s t o f t h e s y s t e m i s n o r m a l l y h i g h e r
t h a n t h a t o f t h e t r u c k h a u l a g e s y s t e m , b e c a u s e t h e
c o m p l e t e c o n v e y o r a nd c r u s h e r a r e b o u g h t t o s t a r t
p r o d u c t i o n whereas t h e t r u c k f l e e t ca n be bou ght
i n s t a g e s t o s t e p up p r o d u c t i o n ,
T h e m i n i n g o p e r a t i o n i s c o m p l e t e l y d e p e n d en t o n
a v a i l a b i l i t y o f t h e c o n v e y o r s ; t h i s a v a i l a b i l i t y
i s over 95% but a shutdown of one b e l t c a n s t o p t h e
e n t i r e p r o d u c t i o n ,
R e l o c a t i o n o f t h e c r u s h e r a nd e x t e n s i o n o f t h e
c o n v e y o r i s e x p e n s i v e an d r e q u i r e s a shutdown o f
t h e m i n i n g o p e r a t i o n f o r a p e r i o d fro m 2-3 da ys ,
M a t e r i a l must b e c r u s h e d t o a s i z e o f minus 2 50 mm
b e f o r e l o a d i n g o n t o t h e c o n v e y o r.
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
43/286
- 26 -
4.3 Inf lue nce of Weather Cond i t ions
In low temperatures of l e s s th an -4 5C,
some o p e r a t i o n a l problems a re cre ate d:
The conveyor system must operate without i n t e r r u p t i o n ;
otherwise , b e l t s f r e e z e t o p u l l e y s and i d l e r s , which
leads t o b e l t damage dur i ng the r e - s t a r t ,
Maintenance has to be reduced t o a minimum.
Repair welding i s har dly p o s s i b l e and c l e a n i n g work
i s imposs ib le un less automated,
The power r a t i n g in cr ea se s with decrease of temperature.
Gear r educers have to be heated by heater rods i n s i d e
gear housings, or heating p l a t e s at the bottom of the
gears of conveyors,
B e l t c r y s t a l i z a t i o n occurs at -55C.
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
44/286
- 27 -
5. CASE STUDIES - IN-PIT CRUSHING AND CONVEYING SYSTEM
5.1 Twin B u t t e s
T h i s open p i t o p e r a t i o n i n Pima County,
A r i z o n a u s e s a n o v e r b u r d e n h a n d l i n g s y s t em, c o n s i s t i n g o f
t h r e e 1.5 m w ide b e l t c o n v e y o r s , w i t h a c a p a c i t y o f 7,2 00
t o n n e s / h e a c h . T he mine a l s o employs a few k i l o m e t r e s o f
c o n v e y o r s t o move c rushed ore f rom two i n - p i t c r u s h e r s t o
s t o c k p i l e s on the s u r f a c e (C.R. S t J o h n & J.W. Kr on ke , 19 75 ).
5.2 Duval C o r p o r a t i o n - S i e r r i t a Coppe r Mine
T h i s l a r g e open p i t i n S a h u a r i t a , A r i z o n a ,
U.S.A. p r o d u c e s 83,000 t o n n e s d a i l y o f co pp er o r e and
150,000 t o n n e s o f w a s t e . D u r i n g 1982-83, t h e mine d e v e l o p e d
an e x i s t i n g h au l age sy s t em ba s e d on s t a t i o n a r y i n - p i t o r e
c r u s h i n g a n d c o n v e y i n g i n t o movable i n - p i t c r u s h i n g w i t h
e x t e n d a b l e co n ve yi ng f o r o r e and was te . The new sys tem
c o n s i s t s o f t h r e e movable 1.5x2.2 m (60-89 in . ) g y r a t o r y
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
45/286
- 28 -
c r u s h e r s , t r a n s p o r t e r u n i t , movable s t a c k e r , and 7.3 km o f
c o n v e y o r s w i t h i n s t a l l e d power o f 14,000 kW. The t o t a l
c a p i t a l i n v e s t m e n t was e s t i ma te d a t 32 m i l l i o n U.S. d o l l a r s .
A v e r a g e c o s t s a v i n g s a r e $.32/tonne a t a n o m i n a l m i n i n g c o s t
o f $1 .10/ tonne. T h i s new s y s t e m a l l o w e d t h e mine t o r educe
t h e t r u c k f l e e t by 25%. M o r e o v e r, a v e r a g e t r u c k r e q u i r e m e n t s
were r e d u c e d by 37%, w h i c h e l i m i n a t e s a l l t r u c k c a p i t a l
e x p e n d i t u r e s o v e r t h e n e x t t e n y e a r p e r i o d . I t i s e s t i m a t e d
t h a t a r e d u c t i o n i n a v e r t i c a l t r u c k l i f t o f o n l y 30 m e t r e s
c a n s a v e one m i l l i o n d o l l a r s o f o p e r a t i n g c o s t s p e r c r u s h e r
a n n u a l l y .
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
46/286
- 29 -
5.3 Bingham Canyon Copp e r Mine
T h i s open p i t i n U t a h , U.S.A i s c u r r e n t l y
u n d e r m o d e r n i z a t i o n t o a c h i e v e a p r o d u c t i o n o f 70,000
to nn es o f o r e pe r d ay u s i n g i n - p i t c r u s h i n g and co nv ey o r
t r a n s p o r t . The s y s t em c o n s i s t s o f a s e m i - m o b i l e 1.5x2.7 m
(60-109 in . ) g y r a t o r y c r u s h e r a nd s i x b e l t c o n v e y o r s .
T he c r u s h e r we ighs 1,200 t on ne s and i s
i n s t a l l e d o n c o n c r e t e f o u n d a t i o n s i n a r e c e s s on a be nc h a t
t h e c o n v e y o r t u n n e l p o r t a l e l e v a t i o n . I t i s f e d by 154 ton ne
t r u c k s f rom two s i d e s . To t a l h e i g h t o f t h e i n s t a l l a t i o n i s
a p p r o x i m a t e l y 30 m. Ore i s c ru sh ed t o a s i z e o f 250 mm a t
a t h r o u g h p u t r a t e o f 9,000 t o nne s pe r hou r. The f e e d hoppe r
has a c a p a c i t y o f 600 m 3. T he d i s c h a r g e b e l t i s 3 m wide
and 26 m l o n g , w i t h i n f i n i t e l y a d j u s t a b l e s p e e d be tween z e r o
an d 0.5 m/s. Th e p l a n t i s e q u i p p e d w i t h a h y d r a u l i c c r a n e
o f 110 tonne l i f t i n g c a p a c i t y and a h y d r a u l i c r o c k b r e a k e r .
The mine u s e s s i x c o n v e y o r s o f a t o t a l l e n g t h
o f a b o u t 8.5 km. Th e l o n g e s t co nve yo r, wh i ch i s 6 km l o n g ,
r u n s t h r o u g h a t u n n e l e x c a v a t e d i n t h e p i t w a l l t o t he
s u r f a c e . A l l c on v ey o r b e l t s are 1.8 m wide. T o t a l i n s t a l l e d
d r i v e power i s 12,900 kW.
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
47/286
- 30 -
5.4 G i b r a l t a r Mines
T h i s open p i t mine i n McLeese La ke , B.C.
p r o d u c e s 37,000 t o n n e s o f copper-molybdenum o r e d a i l y
f r o m f o u r p i t s . I n 1980, an i n - p i t c r u s h i n g a n d c o n v e y i n g
sys tem was i n s t a l l e d i n t h e E a s t P i t . Th e s y s t e m c o m p r i s e s
a 1.4x1.9 m (54-74 i n . ) g y r a t o r y c r u s h e r a nd t h r e e f l i g h t s
o f c o n v e y o r s o f a t o t a l l e n g t h o f ab ou t 10 km and l i f t o f
145 m. Cr us he d or e i s l o ad ed on to a s lo w spe ed 2.13 m wide
d i s c h a r g e c o n v e y o r , t h e n t r a n s f e r r e d onto a 1.5 m wide
t w o - f l i g h t o v e r l a n d c o n v e y o r t r a n s p o r t i n g o r e t o t h e
p r o c e s s i n g p l a n t . Av e r a g e c a p a c i t y o f t h e sys te m i s 1,8 00
to nn es p e r ho u r , and d u r i n g t h e l a s t f i v e y e a r s t h e s y s t e m
h a n d l e d 4 5 m i l l i o n t o n n e s o f o r e .
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
48/286
- 31 -
5.5 I s l a n d Copp er Mi nes
T h i s open p i t a t P o r t Hardy, B.C., Canada
p r o d u c e s 43,000 t o n n e s o f c o p p e r o r e d a i l y a t a s t r i p p i n g
r a t i o o f 2 :1. I t i s a mine w hi ch c o n v e r t e d i t s a l l - t r u c k
s y s t e m i n t o i n - p i t c r u s h i n g a n d c o n v e y i n g .
The new system, i n s t a l l e d i n 1985, empl oys
a p o r t a b l e c r u s h e r s t a t i o n , and o u t - o f - p i t c o n v e y o r w h i c h
t r a n s p o r t s o r e t h r o u g h a n i n c l i n e d t u n n e l t o t h e s u r f a c e
f a c i l i t i e s . Was te i s s t i l l h a n d l e d b y t r u c k s .
T o t a l i n v e s t m e n t i n t h e e n t i r e system was
24.3 m i l l i o n CDN d o l l a r s ( s e e Ta b l e 2 ) , w i t h e x p e c t e d
s a v i n g s o f $ 0.19/tonne. The pay bac k p e r i o d i s 4 y e a r s
an d t h e t r u c k f l e e t was re du ce d fro m 25 t o 14 u n i t s .
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
49/286
- 32 -
TABLE 2
CAPITAL COSTS OF THE CONVEYING SYSTEM
I s l a n d C o p p e r Mines
$ CDN
CRUSHER STA TIO N 7.6 m i l l i o n1.4x1.9 m (54-74 i n . ) g y r a t o r y p o r t a b l ec r u s h e r , r a t e d t h r o u g h p u t 2,550 tonne /h ;e q u i p p e d w i t h a h y d r a u l i c r o c k b r e a k e r,h o p p e r / f e e d e r , 50 t o n n e s l e w i n g c r a n e ,a nd d i s c h a rg e c o n v e y o r 30 m l o n gand 2 . 1 m w ide .
CONVEYOR TUNNEL 4.2 m i l l i o nl e n g t h 850 m, s i z e 4.25x3.65 m,i n c l i n e d a t 2 5%, l i n e d w i t h f i b r er e i n f o r c e d c o n c r e t e .
CONVEYOR 9.4 m i l l i o n1.37 m w ide b e l t , c a p a c i t y 4,500 tonne /h ;e q u i p p e d w i t h m a g n e t i c s e p a r a t o r ,v e r t i c a l t a k e - u p , an d 2980 kW d r i v e .
OTHER COSTS:D e s i g n E n g i n e e r i n g 0.4 m i l l i o nP r o j e c t Mana geme nt 0.5 m i l l i o nC o n t i n g e n c y 2.2 m i l l i o n
TOT AL COSTS: $ 24.3 m i l l i o n
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
50/286
- 33 -
5.6 H i g h l a n d Va l l e y Copper
T h i s open p i t mine, l o c a t e d i n t h e H i g h l a n d
V a l l e y , B.C., p r o d u c e s 120,000 t o n n e s o f copp er /molybdenum
o r e p e r d a y f r o m two p i t s . R e c e n t l y , t h e Company h as
i n s t a l l e d two i n - p i t 1.5x2.2 m (60-89 i n . ) g y r a t o r y
c r u s h e r s f o r o r e c r u s h i n g , a t a c o s t o f $20 m i l l i o n .
E a c h c r u s h e r has a c a p a c i t y o f 6,000 t o n n e s / h a n d h a s i t s
own c o n v e y o r s y s t e m t r a n s p o r t i n g o r e t o t h e L o r n e x m i l l
o v e r a d i s t a n c e o f 2.5 km.
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
51/286
- 34 -
6. IDLER SUPPORTED BELT CONVEYOR
The p r o p e r t i e s and c h a r a c t e r i s t i c s o f m a t e r i a l s
be ing conveyed have a major i n f l u e n c e on conveyor de si gn .
For a b e t t e r unders tanding o f problems a s s o c i a t e d with
conveyors, the f o l l o w i n g p r o p e r t i e s r e q u i r e d e f i n i t i o n :
The angle o f repose o f a m a t e r i a l i s t h e angle which
the s u r f a c e o f a normal, f r e e l y formed p i l e makes t o
the h o r i z o n t a l ,
The angle o f surcharge o f a m a t e r i a l i s t h e angle t o
the h o r i z o n t a l which the s u r f a c e of the m a t e r i a l assumes
whi l e t he m a t e r i a l i s a t r e s t on a moving conveyor b e l t .
T h i s angle u s u a l l y i s 5 t o 15 l e s s than t he ang le
of repose,
The f l o w a b i l i t y o f a m a t e r i a l as measured by i t s
angle o f repose and angle o f surcha rge, determine s the
c r o s s - s e c t i o n of the m a t e r i a l l o a d which can be c a r r i e d
s a f e l y on a b e l t . I t i s a l s o an index of the sa f e
angle o f i n c l i n e of the b e l t conveyor.
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
52/286
- 35 -
The above p r o p e r t i e s a r e d e t e r m i n e d by
t h e c h a r a c t e r i s t i c s o f a m a t e r i a l , s u c h a s : b u l k d e n s i t y ,
maximum lump s i z e , m o i s t u r e c o n t e n t , a b r a s i v e n e s s ,
s t i c k i n e s s , t e m p e r a t u r e , and c o r r o s i v e n e s s .
B a s i c components o f t h e c o n v e y o r a r e :
b e l t , h e a d and t a i l p u l l e y s , c a r r y i n g and r e t u r n i d l e r s ,
t a k e up , d r i v e s , m o t o r s and b r a k e s .
6.1 B e l t
A c o n v e y o r b e l t c o n s i s t s o f t h r e e e l e m e n t s :
c a r r y s i d e c o v e r , c a r c a s s , and b a c k c o v e r . The p r i m a r y
p u r p o s e o f t h e c o v e r s i s t o p r o t e c t t h e b e l t c a r c a s s a g a i n s t
damage. B o t h c o v e r s a r e made f rom n a t u r a l r u b b e r s o r
e l a s t o m e r s . The c a r r y s i d e c o v e r , t h a t i s i n c o n t a c t w i t h
t h e m a t e r i a l , i s u s u a l l y t h i c k e r t h a n t h e b o t t o m c o v e r
( f o r c o a r s e o r e , 14 and 6 mm, r e s p e c t i v e l y ) .
The b e l t c a r c a s s c a r r i e s t h e t e n s i o n f o r c e s
when a c o n v e y o r s t a r t s and o p e r a t e s , a b s o r b s t h e impact
e n er g y d u r i n g l o a d i n g , and p r o v i d e s t h e n e c e s s a r y s t a b i l i t y
f o r p r o p e r a l i g n m e n t and l o a d s u p p o r t o v e r i d l e r s .
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
53/286
- 36 -
High t en s io n ca r ca s se s employ a s i n g l e l a y e r o f s t e e l
c a b l e s . The s t e e l c ab l e s run th e l eng th of th e b e l t and
are he ld i n p l a c e by th e rubber .
The be l t width should be s e l e c t e d t o avo id
s p i l l a g e whi le l o a d i n g and conveying the m a t e r i a l .
For coarse ore b e l t s , i t i s d e s i r a b l e t o keep t he c ro ss
s e c t i o n a l l o a d t o l e s s than 80% of th e Conveyor Equipment
Manufacturers A s s o c i a t i o n (CEMA) s tandards ( F e r n i e , A.D.,
1985). T h i s means t h a t f lowsheet tonnage w i l l be 65 t o
70% o f CEMA. Peak tonnage can be as h igh as 85% of CEMA.
The c ros s s e c t i o na l l oad shou ld then be c a l c u l a t e d a t a 20
surcharge angle f o r 35 equal l eng th i d l e r r o l l s .
The maximum recommended b e l t speed i s 4 - 5 m/s t o avoid
m a t e r i a l s p i l l a g e .
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
54/286
- 37 -
6.2 Pulleys
The pu l l ey s are of va r io us s i ze s and te xt ur es ,
but should be wider than the width of the b e l t . The pu l l ey s
are cons t ruc ted from s t e e l s h e l l s , e i t h e r bare or lagged,
f i t t e d wi th hubs and sea led bear ings . There a re d r i ve
p u l l e y s , snub pu l l ey s , and take-up p u l l e y s .
For high tension conveyors, the d r iv e pu l le ys
should have a heavy duty diamond lag gin g, and non -dr ivi ng
p u l l e y s a p l a i n l a g g i ng . A l l p u l l e y s f o r b e l t speed
exceeding 5 m/s should be turned, dynamically balanced,
and s t r e s s r e l i e v ed .
6.3 Idlers
I d l e r un i t s a re c l a s s i f i e d a s e i t he r c a r ry ing ,
r e tu rn , o r impact. The ca r r y i ng i d l e r s support a loaded
run of the conveyor b e l t , and re t u rn i d l e r s support the empty
re tu rn run of the b e l t . The impact i d l e r s support the bel t
dur in g mat e r i a l load ing . The i d l e r s may be the second or
t h i r d l a r g e s t investment i n a be l t conveyor system.
A t y p i c a l i d l e r system co ns i s t s o f th ree
r o l l s . One i s p lac ed h o r i z o n t a l l y i n the cen tre and the
other two are on the s i d es at opposing angles.
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
55/286
- 38 -
The troughing angles can range from 5 to 4 5, depending
upon the angle of surcharge and the types of material being
handle d. In North America, a 35 angle i s ap pl ie d f o r
coarse ore handling.
An i d l e r which i s common on the con ven tio nal
conveyor b e l t system i s the t r a i n i n g i d l e r . Th i s i d l e r
i s a troughing i d l e r equipped on both si de s wit h sm al le r,
v e r t i c a l , s p r i n g mounted i d l e r s which keep the b e l t a l igned.
The fu nc ti on of the i d l e r u n i t determ ines the
spacing of the u n i t . In ge ne ra l, impact i d l e r u n i t s have
the c l o s e s t spacing, whereas re tu rn i d l e r u n i ts are widel y
spaced. Spacing of ca rr yi ng i d l e r s l i m i t s the catenary sag.
The suspended (garland) i d l e r system, very
popular i n Europe, i s used on lon g ov er la nd convey ors, but
on slopes over 20% causes b e l t misalignment and exce ss iv e
wear, because the i d l e r s have a tendency t o change t h e i r
p o s i t i o n f req uent ly. I t i s a b a l l bearing, non greasable
i d l e r c o n s i s t i n g of three or f i v e r o l l p r o f i l e s .
The suspended i d l e r i s t o l e r a n t of both poor ali gnment and
abuse by lumps because of the f l e x i b l e connections between
i d l e r s . I t can be fur ni sh ed wit h a qui ck re le as e type
of mounting which permits the e n t i r e i d l e r to be replaced
whi le the conveyor i s opera t ing.
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
56/286
- 39 -
6 . 4 Dr ive Uni t s
The dr ive equipment b a s i c a l l y c o n s i s t s
of a motor, speed reducer and d r i v e wi th torque c o n t r o l
d e v i c e s . The d r i v e u n i t s are u s u a l l y l o c a t e d i n the r eg ion
of maximum t e n s i o n at the d ischarge end, but i n th e case ofa s teep d e c l i n e they are p l a ced at the f eed po i n t and act
as a brake .
The tandem d r i v e which comprises two d r i ve
p u l l e y s at the head i s t he most common arrangement for long,
h igh capa c i t y conveyors . Each p u l l e y i s powered by one or
two motors . The tandem d r i v e reduces b e l t s t r e s s e s and the
p o s s i b i l i t y o f a b e l t s l i p . A t t e n t i o n must be p a i d to the
e l e c t r o n i c s y n c h r o n i z a t i o n of the tandem d r i v e t o preven t
damage to the system.
I t i s very important t o c o n t r o l the motor
torque a p p l i e d t o the b e l t wh i le s t a r t i n g the conveyor .
An exces s ive torque adverse ly a ff ec t s the. mat e r i a l s t a b i l i t y
on an i n c l i n e d b e l t , the b e l t i t s e l f , mechanical p a r t s and
motor. The wound r o t o r motor and f l u i d c o u p l i n g are two
most commonly used systems t o ob t a in a s o f t s t a r t for long
conveyors.
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
57/286
- 40 -
The wound r o t o r motors e n s u r e a m u l t i s t a g e a c c e l e r a t i o n t h a t
p r e v e n t s o v e r t e n s i o n i n g o f a l o a d e d b e l t when s t a r t i n g t h e
c o n v e y o r.
C o n v e y o r b r a k e s a r e u s e d w i t h i n t h e motor
o r i n c o n j u n c t i o n w i t h t h e moto r. Dynamic b r a k e s u s e t h e
motor i t s e l f a s a g e n e r a t o r o r a t t e m p t t o r e v e r s e t h e
d i r e c t i o n o f t h e motor movement. D o w n h i l l c o n v e y o r s use
motor f o r dynamic b r a k i n g , backed-up by a f u l l m e c h a n i c a l
b r a k e f o r emergency u s e . U p h i l l c o n v e y o r s us e t h e one-way
b a c k - s t o p and b r a k e s a r e o n l y u s e d i f t h e r e i s a f o l l o w i n g
c o n v e y o r.
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
58/286
- 41 -
6.5 A c c e s s o r i e s
The a c c e s s o r i e s t h a t ca n be u s ed w i th
an y conv ey o r b e l t s y s t e m i n c l u d e b e l t c l e a n e r s , v a r i o u s
d e t e c t i o n d e v i c e s , and e n v i r o n m e n t a l p r o t e c t i o n c o v e r s .
The b e l t c l e a n e r s ca n be o b t a i n e d i n v a r i o u s t y p e s
and s t y l e s . The most common a r e b l a d e c l e a n e r s and b r u s h
c l e a n e r s .
A l a r g e s e l e c t i o n o f w a r n i n g and d e t e c t i o n d e v i c e s
i s a v a i l a b l e , s u c h a s : b r e a k d e t e c t o r s , o v e r t r a v e l d e t e c t o r s ,
p u n c t u r e d e t e c t o r s , o v e r l o a d d e t e c t o r s , and numerous t y p e s
o f w e i g h i n g and random s a m p l i n g e q u i p m e n t .
T he cov e r s u se d on con vey or sys tems rang e
f r o m w i n d s c r e e n s t o f u l l y e n c l o s e d c o n c r e t e s t r u c t u r e s .
T he t ype o f c o v e r depends on t h e c l i m a t e and t y p e o f t h e
m a t e r i a l moved.
L o n g d i s t a n c e c o n v e y o r s a r e e q u i p p e d w i t h
s a f e t y d e v i c e s w h ic h a l l o w t h e c o n v e y o r t o be s t o p p e d
i n c a s e o f emergency. The most common a r e p u l l c o r d
emergency s w i t c h e s . I n t h e c a s e o f power f a i l u r e th e
c o n v e y o r i s s t o p p e d by immedia te engagement o f t h e
b r a k i n g sys tem.
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
59/286
- 42 -
7. CABLE SUPPORTED BELT CONVEYOR
T he c a b l e s u p p o r t e d b e l t c o n v e y o r s e p a r a t e s
t h e d r i v i n g an d c a r r y i n g f u n c t i o n s . I n t h e s y s t e m , t h e
d r i v i n g t e n s i o n s a r e t r a n s m i t t e d t h r o u g h two p a r a l l e l s t e e l
c a b l e s i n t h e f o rm o f e n d l e s s l o o p s , w h i c h c o n t i n u o u s l y
s u p p o r t a n d c a r r y t h e b e l t n e a r i t s e d g e s . The b e l t ,
t h e r e f o r e , i s n o t a f f e c t e d b y d r i v e t e n s i o n s a nd i s o n l y
d e s i g n e d t o c a r r y m a t e r i a l . The t w i n c a b l e s a r e s u p p o r t e d
by g r o o v e d l i n e p u l l e y s a l o n g t h e l e n g t h o f t h e c o n v e y o r,
w h i c h g i v e s t h e s y s t e m a p o s i t i v e t r a c k i n g .
7.1 B e l t
The b e l t c o v e r s have g r o o v e s f o r t h e c a b l e s .
T h e s e g r o o v e s r u n t h e t o t a l l e n g t h o f t h e b e l t and a r e
u s e d a s g u i d e s f o r t h e c a b l e . Due t o t h i s f e a t u r e t h e b e l t
needs no e x t r a a l i g n m e n t u n i t s .
The b e l t c a r c a s s c o n s i s t s o f t r a n s v e r s e s t e e l
w i r e s and w i r e mesh. R e c e n t l y , s t e e l w i r e s a r e u s e d i n
p l a c e o f s t e e l s t r a p s . T h i s a r r a n g e m e n t p r o v i d e s t h e b e l t
w i t h c a r r y i n g s t r e n g t h and f l e x i b i l i t y .
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
60/286
- 43 -
7.2 C a b l e P u l l e y s
Th e c a b l e p u l l e y a s s e m b l i e s a r e mounted
o n l i n e s t a n d s a n d a r r a n g e d i n t w i n c o n f i g u r a t i o n u s i n g
r o c k e r b a r s . The r o c k e r b a r s c an p i v o t h o r i z o n t a l l y and
v e r t i c a l l y t o f a c i l i t a t e c o r r e c t s e l f a l i g n m e n t w i t h the
d r i v e c a b l e s . A t e i t h e r e nd o f t h e c o n v e y o r , t h e b e l t i s
t r a n s f e r r e d f r o m c a r r y i n g t o r e t u r n an d v i c e v e r s a by a
s i m p l e d e f l e c t i n g u n i t .
A t t h e h e a d and t he t a i l , t h e C a b l e B e l t
c o n v e y o r ha s b e l t p u l l e y s s i m i l a r t o t h o s e u s e d w i t h the
i d l e r b e l t c o n v e y o r . A t t h e t u r n i n g p o i n t t h e c a b l e s a r e
removed f r o m t h e i r g r o o v e s and r e ve r s ed by s e p a r a t e v e r t i c a l
d e f l e c t i o n c a b l e p u l l e y s w h i c h d e f l e c t t h e c a b l e s i n t o t h e
g r o o v e s on the o p p o s i t e s i d e o f t h e b e l t .
F o r e a s y m a i n t e n a n c e , t he p u l l e y a s s e m b l i e s
c a n b e q u i c k l y removed and a re p r o v i d e d w i t h r e n e w a b l e
p o l y u r e t h a n e l i n e d r i m s known as p o l y r i m s .
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
61/286
- 44 -
7.3 D r i v e U n i t s
One o f th e main f e a t u r e s o f c a b l e s u p p o r t e d
b e l t c o n v e y o r s i s t h a t t h e r e i s o n l y one d r i v e u n i t f o r
e a c h c o n v e y o r r e g a r d l e s s o f t h e l e n g t h . A d r i v e u n i t
c o m p r i s e s a t o t a l l y e n c l o s e d r e d u c t i o n g e a r b o x i n c o r p o r a t i n g
t h e d i f f e r e n t i a l g e a r a r r a n g e m e n t t o e q u a l i z e c a b l e speeds
a n d t e n s i o n s .
Twin c a b l e d r i v i n g w h e e l s , e i t h e r s u rge
o r Koepe whee l t y p e , p r o v i d e t h e d r i v e t o t h e c a b l e s .
C o n t r o l a nd b r a k i n g f u n c t i o n s a r e a c c o m p l i s h e d by
c o n v e n t i o n a l me thods . The d r i v i n g c a b l e s a r e t e n s i o n e d
i n d e p e n d e n t l y t o c a t e r f o r any v a r i a t i o n s i n s t r e t c h .
T h e t e n s i o n i n g a r r a n g e m e n t e n s u r e s t h a t t h e t e n s i o n s i n
e a c h c a b l e a r e t h e same. The b e l t i s t e n s i o n e d s e p a r a t e l y
f r o m t h e c a b l e s .
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
62/286
- 45 -
7.4 S p e c i a l F e a t u r e s o f t h e Sys tem
T h e C a b l e B e l t c o n v e y o r h a s t h e a b i l i t y t o
n e g o t i a t e s udden changes i n t h e h o r i z o n t a l d i r e c t i o n , b y
means o f a n a n g l e t r a n s f e r s t a t i o n . T h i s s t a t i o n c o m p r i s e s
a d i s c h a r g e and f e e d a r r angemen t combined a t t h e i n t e r s e c t i o n
o f two f l i g h t s o f t h e b e l t . M a t e r i a l i s t r a n s f e r r e d f rom
one b e l t t o a n o t h e r b u t t h e d r i v i n g c a b l e s r e m a i n t h e same
f o r b o t h f l i g h t s and t h e i r d i r e c t i o n i s c h a n g e d by a s e t
o f h o r i z o n t a l c a b l e d e f l e c t i o n p u l l e y s mounted o n t h e a n g l e
t r a n s f e r s t a t i o n . O n l y one d r i v e u n i t i s n e e d e d f o r t h e
whole c o n v e y o r s y s t e m when t h i s a r r a n g e m e n t i s u s e d .
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
63/286
- 46 -
7.5 H a r d Rock I n s t a l l a t i o n s
C a b l e B e l t c o n v e y o r s o p e r a t e w o r l d w i d e ,
b o t h o v e r l a n d a n d u n d e r g r o u n d , c o n v e y in g v a r i o u s m a t e r i a l s
i n d i f f e r e n t c l i m a t i c e n v i r o n m e n t s . Many a p p l i c a t i o n s hav e
been c o n s i d e r e d f o r ext reme l ow t e m p e r a t u r e c o n d i t i o n s ,
down t o -45C .
I n Canada, a t Algoma ' s George McLeod Mine
i n Wawa, O n t a r i o , a 4570 me t re l o n g c a b l e b e l t c o n v e y s t h e
c r u s h e d i r o n o r e f r om t h e u n d e r g r o u n d mine t o a p r o c e s s i n g
p l a n t o n t h e s u r f a c e .
A t Newmont M i n i n g Company, S i m i l k a m e e n ,
a 1980 me t re l o n g c a b l e b e l t c r o s s e s a 25% s l o p e down
t h e s i d e o f a c a n y o n , a n d t h e n t a k e s a r i g h t a n g l e t u r n
a c r o s s a 490 m s u s p e n s i o n b r i d g e t o t h e p r o c e s s i n g p l a n t .
T h e b r i d g e was s p e c i f i c a l l y d e s i g n e d t o c a r r y a c o n v e y o r
o f a c a p a c i t y o f 153 0 t o n n e / h o f c o p p e r o r e .
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
64/286
- 47 -
8. HIGH ANGLE CONVEYORS
Over t h e l a s t f i f t e e n y e a r s , d i f f e r e n t
t y p e s o f s t e e p a n g l e c o n v e y i n g s y s t e m s have been d e v e l o p e d .
T h e p o c k e t b e l t c o n v e y o r and sandwich b e l t c o n v e y o r have
f o u n d a p p l i c a t i o n i n open p i t m i n i n g .
8.1 P o c k e t B e l t Conveyor
A p o c k e t b e l t c o n v e y o r was d e v e l o p e d by
K o n r a d S c h o l t z AG Hamburg, W est Germ any. H i g h a n g l e p o c k e t
c o n v e y o r s u s e c o n t i n u o u s c o r r u g a t e d s i d e s k i r t s and r u b b e r
c r o s s c l e a t s v u l c a n i z e d t o a f l a t r u b b e r b e l t t o fo rm box
compartments f o r m a t e r i a l a l o n g t h e l e n g t h o f t h e b e l t .
The s p e c i a l s k i r t d e s i g n p e r m i t s c o n t i n u o u s b e n d i n g a r o u n d
p u l l e y s w i t h o u t f a t i g u e o f t h e c o r r u g a t i o n s . The s i d e w a l l s
r a n g e i n h e i g h t f r om 40 t o 400 mm. A c r o s s - r i g i d i z i n g o f th e
f l a t b e l t m i n i m i z e s d i s h i n g and r e d u c e s a g i t a t i o n o f t h e
c o n v e y e d m a t e r i a l . The b e l t i s s u p p o r t e d by c l o s e l y spaced
f l a t i d l e r s .
-
8/11/2019 Thesis In-Pit Crushing as an alternative UBC_1988_A7 R32.pdf
65/286
- 48 -
So f a r , p o c k e t b e l t i n s t a l l a t i o n s a r e l i m i t e d
t o c a p a c i t i e s l e s s th an 1,000 to nn e/ h. The o n l y e x c e p t i o n
i s t h e Algoma C e n t r a l R a i l w a y ' s s e l f u n l o a d i n g v e s s e l MV
"Agava Canyon", w i t h i t s new e l e v a t i n g sys t em. The sys tem