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为了满足美国国内黄金生产的需要,矿业局按照1966～1970重金属发展计划在全国范围内进行了金矿的勘探。通过初步勘探发现,加利福尼亚州大面积的第三纪河床砾石层蕴藏着美国最大的金矿。这种金矿可用砂矿开采新技术或改进的砂矿开采技术进行快
In order to meet the needs of domestic gold production in the United States, the Bureau of Mines conducted gold exploration in the whole country in accordance with the heavy metal development plan from 1966 to 1970. Preliminary exploration revealed that the gravel bed of a large area of the tertiary river bed in California contains the largest gold mine in the United States. This gold mine can be exploited with new technology for sand mining or improved sand mining technology