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Quartz reef mining played an important role in 19th Century gold-mining districts such as Bendigo, Victoria, Central Otago in New Zealand, and the California mother lode. In at least the shallow, oxidized zones of quartz reef deposits, the gold occurs in its metallic state, and is easily recovered with simple equipment. A "quartz reef" is another term for a vein of quartz, and has nothing to do with biological reefs (bioherms), such as coral reefs. Quartz is one of the most common minerals in the earth's crust, and most quartz veins do not carry metallic gold, but those that have gold are avidly hunted by prospectors. ==Mining== Mining the ore usually required mine shafts sunk to mine quartz from the reefs, sometimes deep underground. Horizontal tunnels called drifts were dug out from the shaft at different levels to find the gold-bearing rock. All the ore was hoisted to the surface for processing. Water had to be removed by pumping. Big hoisting engines were installed to hoist lifts and buckets up the shafts. On the surface above the shaft stands a building known as the headframe. This contained a wheel called a gin wheel which lifted buckets of rock up to a raised platform called a Brace. Wheeled buckets then carried the rock along elevated tracks to waste dumps or processing works. The steel cable that hoisted the bucket passed over the gin wheel. 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「Quartz reef mining」の詳細全文を読む スポンサード リンク
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