Science Fair Project Encyclopedia
Tailings, also called gangue, are the rejected material from mining and screening operations. Tailings are the uneconomic remainders from mining; as mining techniques and the price of minerals improve it is not unusual for tailings to be reprocessed using new methods or more throughly with old methods, perhaps to recover minerals other than those originally mined.
Large-scale operations often leave huge piles of this material on site. Often, as in the case of riverbed metal extraction, this has buried valuable river-flat soils under the largely worthless and often contaminated tailings. Modern extraction methods have resulted in less damage but land rehabilitation continues to be a major problem and costly consideration.
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