Zambia copper pit: is a 1.9 m³ bucket too small for a 21 t excavator?
Mwila K.
Verified member · Mine equipment manager
Bench height is 10 m, the material is weathered copper ore, bulk density about 2.1 t per cubic metre.
Our 21 t machine runs a 1.9 m³ bucket; a 40 t truck takes nine passes and waits 40 seconds.
Should we move to 2.3 m³ or add a 30 t machine? Anyone on similar ground, please share numbers.
Discussion (3)
Grace W.Verified member · Project chief engineer2026-10-29
At the same bench height we ran 2.3 m³: cycle time fell from 26 to 24 seconds, but teeth wore about 30% faster and the face had to stay level.
Chanda M.Verified member · Service engineer2026-10-30
Check pump flow first. With a bigger bucket the relief valve stays open longer, and rising oil temperature is the first sign of a mismatch.
Ade O.Verified member · Procurement lead2026-10-31
Do not look only at shift output: 40 seconds of waiting costs about 30 bucket loads a day. A second machine pays back in roughly 14 months, if the roads hold.
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