至尊木虫 (知名作家)
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书剑如风: 金币+150, 翻译EPI+1, ★★★很有帮助 2015-07-09 16:05:54
1. Mineral resource is one of the important means of production for human survival, its main feature is non-renewable and irreplaceable in the short term.
2. The exploitation of mineral resources must include crushing, grinding, sorting and other procedures to elect concentrates and a large amounts of tailings are inevitably discharged in this process.
3. Up to more than 10 billion tons of metal ore, non-metallic minerals, coal, clay are mined, and about 5 billion tons of tailings are discharged by various countries in the world every year.
4. For example, the accumulated stockpiles of tailings of non-ferrous metal mines in the United States and the former Soviet Union are up to 8 and 4.1 billion tons, respectively.
5. In our country, more than 150 kinds of minerals have been found and more than 8,000 mines have been developed so far, which cover an area of more than 80,000 ha, with the cumulative production of tailings of 5.97 billion tons and an annual growth rate of 300 million tons.
6. Tailings not only occupy a lot of land, but also cause serious pollution and hazards to the human production and life, it has gotten widespread concern in the whole society.
7. With the substantial development and utilization of mineral resources, minerals are becoming increasingly scarce. Therefore, recycling of tailings as the secondary resources has been of more and more concern. |
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