Venkat

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Terminology

BENCH: Ledge that forms a single levelof operation above which mineral orwaste materials are mined from thebench face.

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Terminology

BENCH HEIGHT: Vertical distance between thehighest point on the bench (crest) and the lowestpoint or the bench (toe). It is influenced by size ofthe equipment, mining selectivity, governmentregulations and safety.

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Terminology

BENCH SLOPE or BANK ANGLE :Horizontal angle of the line connectingbench toe to the bench crest.

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BERM: Horizontal shelf or ledge within the ultimate pitwall slope left to enhance the stability of the a slopewithin the pit and improve the safety. Berm interval,berm width and berm slope angle are determined by thegeotechnical investigation.

Terminology

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OVERALL PIT SLOPE ANGLE: The angle measuredfrom the bottom bench toe to the top bench crest. It isthe angle at which the wall of an open pit stands and itis determined by rock strength, geologic structures andwater conditions.

Terminology

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The overall pit slope angle is affected by the width andgrade of the haul road.

Terminology

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HAUL ROADS: During thelife of the pit a haul roadmust be maintained foraccess.

HAUL ROAD - SPIRALSYSTEM: Haul road isarranged spirally along theperimeter walls of the pit.

Terminology

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HAUL ROAD – SWITCH BACK SYSTEM: Zigzag pattern onone side of the pit.

HAUL ROAD WIDTH:Function of capacity ofthe road and the sizeof the equipment. Haulroad width must beconsidered in theoverall pit design.

Terminology

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Haul Road Effect on Pit Limits

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ANGLE OF REPOSE: Maximum slope of thebroken material.

SUBCROP OR ORE DEPTH: Depth of wasteremoved to reach initial ore.

PRE-PRODUCTION STRIPPING: Strippingdone to reach initial ore.

Terminology

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ULTIMATE PIT LIMITS: Vertical and lateral extend ofthe economically mineable pit boundary. Determined onthe basis of cost of removing overburden or wastematerial vs. the mineable value of the ore.

PIT SCHEDULING: Material may be mined from the piteither in:1) sequential push backs2) conventional push backs.

Terminology

STRIPPING RATIO: Expressed in tons of waste to tonsof ore in hard rock open pit operations. Critical andimportant parameter in pit design and scheduling.

AVERAGE STRIP RATIO: Total waste divided by totalore within the ultimate pit.

CUTOFF STRIPPING RATIO: Costs of mining a ton ofore and associated waste equals to net revenue from theton of Ore.

Terminology

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Single Working Bench

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Shovel in Working Bench

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Two Working Benches

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FinalPit

Limit

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Example Mine

2001 2007 2011

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PitSequence

(1)

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PitSequence

(2)

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PitSequence

(3)

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PitSequence

(4)

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Section of Pit Sequence

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