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Gold panning, or simply ''panning'', is a form of placer mining and traditional mining that extracts gold from a placer deposit using a pan. The process is one of the simplest ways to extract gold, and is popular with geology enthusiasts especially because of its cheap cost and the relatively simple and easy process. It is the oldest method of mining gold. The first recorded instances of placer mining are from ancient Rome, where gold and other precious metals were extracted from streams and mountainsides using sluices and panning. However, the productivity rate is comparably smaller compared to other methods such as the rocker box or a large extractor such as in 'The Pit', in Kalgoorlie, which have led to it largely being replaced in areas with capital for more sophisticated equipment. ==Process== Gold panning is a simple process. Once a suitable placer deposit is located, some gravel from it is scooped into a pan, where it is then gently agitated in water and the gold sinks to the bottom of the pan. Materials with a low specific gravity are allowed to spill out of the pan, whereas materials with a high specific gravity sink to the bottom of the sediment during agitation and remain within the pan for examination and collection by the gold panner. These dense materials usually consist primarily of a black, magnetite sand with whatever gemstones or metal dust that may be found in the deposit that is used for source material. While an effective method with certain kinds of deposits, and essential for prospecting, even skilled panners can work but a limited amount of material, significantly less than the other methods which have replaced it in larger operation. Pans remain in use in places where there is limited capital or infrastructure, as well as in recreational gold mining. In many situations, gold panning usually turns up only minor gold dust that is usually collected as a souvenir in small clear tubes. Nuggets and considerable amounts of dust are occasionally found, but panning mining is not generally lucrative. Panning for gold can be used to locate the parent gold veins which are the source of most placer deposits. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Gold panning」の詳細全文を読む スポンサード リンク
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