Placer Mining at Coloma

When quartz decomposes, small gold particles are freed, washed downstream, and collected as placer gold in sand and gravel bars along Sierra rivers. At Coloma, miners found gold mainly in the American River’s gravelly bed and in gravel terraces along the banks, then washed tons of sand, gravel, and dirt to recover ounces of gold. Depending on the size of an operation, they used pans, cradles, long toms, or sluice boxes, with the heavy placer gold settling to the bottom of a pan or catching in the riffles of a sluice. Sluices and long toms were man-made channels set next to or in flowing water to process large amounts of placer material more quickly, while cradles used screens and bottom riffles to separate larger rocks and trap gold, and simple pans could be improvised from ordinary household items. People from many nations came to mine the bed of the American River.

Coloma, California · United States