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1984年6月11日至13日,由地质矿产部探矿工程装备工业公司在天津宾馆主持召开了,天津探矿机械厂研制的GJC-40HF型泵吸反循环大口径施工钻机
June 11, 1984 to 13, by the Ministry of Geology and Mineral Resources Exploration Engineering Equipment Industry Company hosted the Tianjin Hotel, Tianjin Prospecting Machinery Factory developed GJC-40HF pump reverse circulation large-diameter construction rig