Keys to History

Here some miners are making sluice boxes. Sluice-boxes were square, three-sided troughs of the length shown in the picture. Small strips of wood called riffles were nailed across the inside bottom of the box. Dirt and gravel containing gold were shovelled into one end of the box, and it was tilted up slightly. Then water was let into that end. The water washed the dirt and gravel out the other end, but the gold sank to the bottom and was caught in the riffles. When the water was stopped, the gold was scraped off the riffles, and the process repeated. Some gold was lost, of course, but the process was simple and cheap.

Source : Off to the Klondike! The Search for Gold [Web tour], by William R. Morrison, University of Northern British Columbia (see Links)