sluice box

A sluice box is a long, inclined trough used in placer mining to recover heavy minerals, most notably gold. It is typically constructed of lumber and features a bottom lined with riffles – raised bars that create eddies in the flowing water.12

In placer mining, water and mineral-rich dirt are introduced at the upper end of the sluice box. As the mixture flows down, the riffles agitate the current. This action prevents lighter materials from settling while effectively trapping heavier, valuable minerals like gold due to their higher density. A sluice box is essentially a single section, often about 12 feet long, of a larger gold-mining sluice.324