Placer mining is a method of extracting valuable minerals from alluvial deposits, which are materials that have been deposited by water. This technique often targets precious metals like gold and silver, as well as gemstones. Miners typically use simple tools such as pans, sluices, and dredges to separate the minerals from the surrounding sediment. The process involves washing the sediment to allow heavier materials to settle at the bottom, while lighter materials are washed away. Placer mining is often done in riverbeds, beaches, or other areas where water has eroded and concentrated valuable minerals over time.