1. Venkat

2. Geometrical Considerations
Cumulative frequency
distribution of measured
Parts of a bench bench face angles (Call, 1986).
2

3. Geometrical Considerations
Functioning of catch benches.
Section through a working bench.
3

4. Geometrical Considerations
Double benches at final pit limits. Catch bench geometry (Call, 1986).
Typical catch bench design dimensions (Call, 1986).
Bench height Impact zone Berm height Berm width Minimum bench width
(m) (m) (m) (m) (m)
15 3.5 1.5 4 7.5
30 4.5 2 5.5 10
45 5 3 8 13
4

5. Geometrical Considerations
Safety berms at bench edge
5

6. Geometrical Considerations
Height of reach as a
function of bucket
size.
6

7. Geometrical Considerations
Ramp access for the example orebody.
Example orebody geometry.
Blast design for
the ramp
excavation.
7

8. Shovel Working Range
8

9. Geometrical Considerations
Minimum width drop cut
geometry with shovel
alternating from side to side.
9

10. Geometrical Considerations
Minimum width drop cut
geometry with shovel
alternating from side to side.
10

11. Geometrical Considerations
Diagrammatic
representation of the
expanding mining front.
Isometric view of the ramp in
waste approaching the
orebody.
11

12. Geometrical Considerations
Dropcut / ramp placement in ore. Expansion of the mining front.
12

13. Geometrical Considerations
Plan view of an actual pit bottom
Showing drop cut and mining
Expansion (McWilliams, 1959).
13

14. Geometrical Considerations
Extension of the current
Ramp close to the pit wall
(McWilliams, 1959).
14

15. Geometrical Considerations
Creating initial access /
benches.
Shovel cut sequence when
initiating benching in a hilly
Sidehill cut with a shovel. terrain (Nichols, 1956).
15

16. Geometrical Considerations
Detailed steps in the
development of a
new production level.
16

17. Geometrical Considerations
Parallel cut
with drive by.
17

18. Geometrical Considerations
Parallel cut with
the double
spotting of trucks.
18

19. Geometrical Considerations
Parallel cut with
the single spotting
of trucks.
19

20. Geometrical Considerations
Time sequence
showing shovel
loading with single
spotting.
20

21. Geometrical Considerations
Time sequence
showing shovel
loading with double
spotting.
22

22. Geometrical Considerations
(Continued).
23

23. Geometrical Considerations
(Continued).
24

24. Geometrical Considerations
Section and plan views through a working bench.
Simplified presentation of a safety berm.
25

25. Geometrical Considerations
Initial geometry for the push back example.
Cut mining from bench 1.
Cut mining from bench 2.
26

26. Geometrical Considerations
Safety bench geometry
showing bench face angle.
Overall slope angle.
27

27. Geometrical Considerations
Overall slope angle with ramp included.
Interramp slope angles.
28

28. Geometrical Considerations
Overall slope angle with
Working bench included.
Interramp angles associated with
the working bench.
29

29. Geometrical Considerations
Overall slope angle with
one working bench an a ramp section.
Interramp slope angles for a slope containing
a working bench and a ramp.
30

30. Geometrical Considerations
Overall slope angle for a
slope containing two
working benches.
31

31. Geometrical Considerations
Slopes for each working group.
32

32. Geometrical Considerations
Final overall
pit slope.
33

33. THANKS