“Placer” is the name given to gold (and certain other minerals) that are near the surface when found in alluvial deposits of sand and gravel, whether in modern or ancient stream beds. During the California Gold Rush from the late 1840s to the early 1850s, prospectors used ordinary American-made, shallow metal kitchenware pans with sloping sides—or native California Indian-made, water-tight reed-baskets—to mine placer gold.
After filling the receptacle with mud, sand, gravels, and a generous amount of water, the miner swirled the pan from side to side in a constant circular motion. He removed the larger river pebbles by hand, carefully rinsed away smaller particles, then (hoping all the while) allowed the heavier gold particles, if any, to sink to the bottom. This all-day-long, numbingly-repetitious task—called “panning”—was slow and, to be effective, required experience and skill. An experienced panner could process one-half to three-fourths of a cubic yard in ten hours. Most of the time, for most of the eager prospectors, it meant a very long, wet, discouraging day.
Improvements to the individual gold pan included the rocker, which allowed small groups working together to increase the amount of gravels processed, which in turn led to the larger “Long Tom,” an extended version of a sluice box. Over 64% of the gold produced in California came from placer deposits.