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▲1969年美国金属和非金属矿产钻探进尺达924万米，其中与铀矿有关的矿产达718万米。苏联1971年地质部系统岩心钻探总进尺达1664万米。
▲ In 1969, the U.S. drilling of metal and non-metallic minerals reached 9.24 million meters, of which 7.18 million meters were related to uranium deposits. In 1971, the total drilling footage of the core drilling system of the Department of Geology in the Soviet Union reached 16.64 million meters.