Sluice box setup: getting the angle and flow right

A sluice box relies on water flow doing the same sorting work a gold pan does by hand, but it only works well if the flow and angle are actually tuned correctly. Too steep an angle or too fast a flow will wash gold straight through along with everything else, while too shallow an angle or too slow a flow will let the box clog with material and stop separating anything effectively. Most operators start with a moderate angle and adjust based on watching how material moves through the riffles, material should tumble and roll through rather than either sitting still or shooting straight through untouched. Periodically checking the riffles for buildup and clearing accumulated material is also part of running a sluice properly, a clogged riffle stops trapping anything new.