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我队新设计的78—DDA型采煤管,在郃阳、韩城两个矿区的六个钻孔的不同深度、不同煤层中进行了二十二个回次的取芯试验。平均采取率达到93％,与同时试验的原采煤管的十二个回次相比,采取率有较大幅度的提高(见表)。
Our newly designed 78-DDA coal mining tube has undergone 22 core coring tests in different coal seams at different depths of six boreholes in two mining areas in Shenyang and Hancheng. The average adoption rate reached 93%. Compared with the 12 times of the original coal-mining pipes tested at the same time, the adoption rate has been greatly improved (see table).