Miners use this fundamental gravity separation method to extract dense precious metals or gemstones from loose alluvial deposits. Flowing water carries away the lighter sands and clays, leaving the heavier target minerals trapped in riffles or mats. It forms the basis of both historic panning and large-scale mechanized sluicing operations.
We need to wash that new gravel pile before the water truck runs dry.
Washing requires a significant water supply, making water management a major logistical challenge for dryland placer operations.
Related terms
Washdirt
Placer gravel or earth that contains enough precious metal to be worth processing.
Washing stuff
An informal term for alluvial deposits containing enough valuable mineral to process.
Sluice
An artificial channel or trough used to separate heavy minerals from lighter dirt using flowing water.
Trommel
A rotating cylindrical screen used to sort crushed ore or aggregate by size.