A sluice relies on a steady flow of water to wash gravel and dirt over a series of raised obstructions called riffles. The water current carries the lighter waste material away while the heavier precious minerals, like gold or platinum, drop out of suspension and get trapped in the bottom. Miners scale this basic gravity separation principle from small portable boxes to massive industrial flumes.
Make sure the sluice has enough water flow to keep the gravel moving without blowing out the fine gold.
The angle of the trough dictates the water velocity; set it too steep and you wash away the fine gold, but set it too flat and the box just packs full of barren gravel.
Also heard as
- sluice box
Related terms
Riffle
A raised cleat or groove in a sluice box designed to trap heavy precious metals.
Long Tom
A historic inclined wooden trough used to wash placer gold from gravel.
Miner's moss
A woven vinyl matting used in sluice boxes to trap fine gold particles.
Washdirt
Placer gravel or earth that contains enough precious metal to be worth processing.