Thursday, February 14, 2008

Panning

Gold panning is a mostly manual technique of sorting gold. Wide, shallow pans are filled with sand and gravel that may contain gold. Water is added and the pans are shaken, sorting the gold from the gravel and other material. Gold being much denser than rock, quickly settles to the bottom of the pan. The silt is usually removed from stream beds, often at a bend in the stream, or resting on the bedrock bed of the stream, where the weight of gold causes it to separate out of the water flow. This type of gold found in streams or dry streams are called placer deposits.

The simplest technique to extract gold from placer ore is panning. In panning, some mined ore is placed in a large metal or plastic pan, combined with a generous amount of water, and agitated so that the gold particles, being of higher density than the other material, settle to the bottom of the pan. The lighter ore material such as sand, mud and gravel are then washed over the side of the pan, leaving the gold behind. Once a placer deposit is located by gold panning, the miner usually shifts to equipment that can treat volumes of sand and gravel more quickly and efficiently.

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