The document defines key mining terminology used in open pit mine design including: bench, bench height, bench slope, berm, overall pit slope angle, haul roads, angle of repose, subcrop/ore depth, pre-production stripping, ultimate pit limits, pit scheduling, stripping ratio, single working bench, shovel in working bench, two working benches, pit sequence, and section of pit sequence. It provides illustrations of these concepts and how an example mine may develop its pit over time through sequential pushbacks.

1. Venkat

2. Terminology
BENCH: Ledge that forms a single level
of operation above which mineral or
waste materials are mined from the
bench face.
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3. Terminology
BENCH HEIGHT: Vertical distance between the
highest point on the bench (crest) and the lowest
point or the bench (toe). It is influenced by size of
the equipment, mining selectivity, government
regulations and safety.
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4. Terminology
BENCH SLOPE or BANK ANGLE :
Horizontal angle of the line connecting
bench toe to the bench crest.
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5. Terminology
BERM: Horizontal shelf or ledge within the ultimate pit
wall slope left to enhance the stability of the a slope
within the pit and improve the safety. Berm interval,
berm width and berm slope angle are determined by the
geotechnical investigation.
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6. Terminology
OVERALL PIT SLOPE ANGLE: The angle measured
from the bottom bench toe to the top bench crest. It is
the angle at which the wall of an open pit stands and it
is determined by rock strength, geologic structures and
water conditions.
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7. Terminology
The overall pit slope angle is affected by the width and
grade of the haul road.
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8. Terminology
HAUL ROADS: During the
life of the pit a haul road
must be maintained for
access.
HAUL ROAD - SPIRAL
SYSTEM: Haul road is
arranged spirally along the
perimeter walls of the pit.
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9. Terminology
HAUL ROAD – SWITCH BACK SYSTEM: Zigzag pattern on
one side of the pit.
HAUL ROAD WIDTH:
Function of capacity of
the road and the size
of the equipment. Haul
road width must be
considered in the
overall pit design.
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10. Haul Road Effect on Pit Limits
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11. Terminology
ANGLE OF REPOSE: Maximum slope of the
broken material.
SUBCROP OR ORE DEPTH: Depth of waste
removed to reach initial ore.
PRE-PRODUCTION STRIPPING: Stripping
done to reach initial ore.
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12. Terminology
ULTIMATE PIT LIMITS: Vertical and lateral extend of
the economically mineable pit boundary. Determined on
the basis of cost of removing overburden or waste
material vs. the mineable value of the ore.
PIT SCHEDULING: Material may be mined from the pit
either in:
1) sequential push backs
2) conventional push backs.
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13. Terminology
STRIPPING RATIO: Expressed in tons of waste to tons
of ore in hard rock open pit operations. Critical and
important parameter in pit design and scheduling.
AVERAGE STRIP RATIO: Total waste divided by total
ore within the ultimate pit.
CUTOFF STRIPPING RATIO: Costs of mining a ton of
ore and associated waste equals to net revenue from the
ton of Ore.

14. Single Working Bench
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15. Shovel in Working Bench
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16. Two Working Benches
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17. Final
Pit
Limit
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18. Example Mine
2001 2007 2011
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19. Pit
Sequence
(1)
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20. Pit
Sequence
(2)
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21. Pit
Sequence
(3)
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22. Pit
Sequence
(4)
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23. Section of Pit Sequence
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