From the earliest gold rushes to the present day, the sluice box has remained a staple tool for prospectors and placer miners. Despite advancements in engineering over the years, gold sluices have changed very little since they first became popular – after all, “if it ain’t broke, don’t fix it!” This is due in part to the solid design philosophy that gold sluices are based on.
While early prospectors were panning for alluvial gold, they soon noticed that the best places to search were the inside bends of rivers and creeks; in natural hollows and rock crevices; and at the base of escarpments, waterfalls, or other minor impediments to the water’s flow. What all these areas have in common is that they accumulate gold by “catching” it as it flows past while dirt and gravel are pushed further on by the current. This happens because the gold is heavier and harder for the current to push. In the lab, this process is called “gravity separation.”
Sluice boxes are designed to mimic this naturally occurring gravity separation. As water carries gold-laden sediment through the box, small obstructions called riffles block the free flow of material. These tiny flow restrictions form low pressure pockets where the gold collects.
Sluices are an effective tool for collecting gold, but they don’t work without water. They can also miss gold if the water flow through the box is not carefully regulated. If you want to learn more about how sluice boxes are used to find gold, check out our infographic below.