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一、世界铝工业根据美国地质调查局和美国矿业局联合制定的矿产资源分级系统,来确定“已证实的”冶金级铝土矿储量和资源的估计吨数。所谓
First, the world aluminum industry determines the estimated tonnage of “proven” metallurgical grade bauxite reserves and resources based on a mineral resource classification system jointly established by the United States Geological Survey and the U.S. Bureau of Mines. So-called