用露天法开采硬岩矿床时,穿孔工作是最繁重、低效和高耗的工序。黑色冶金工业各采选公司露天矿最不利的情况是所采矿岩的普氏坚固性系数一般都在16以上。用国产牙轮钻机在这类矿岩中穿凿直径250mm 的炮孔时,穿孔速度一般不超过7～8m/h,牙轮钻头的最大寿命为80m。在这些条件下,牙轮钻头的平均价格为220卢布时,每米炮孔的穿孔成本约10卢布,而1m~3矿岩的穿孔成本达0.4卢布。由于苏联硬质合金和牙轮钻头十分短 When exploiting opencast mining hard rock deposits, perforation work is the heaviest, inefficient and expensive process. The most unfavorable situation for the mining companies in the mining sector of the black metallurgical industry is that Platts’ solidity coefficient of the ore is usually above 16. With domestic roller cone drilling in such ore rock drilling diameter of 250mm, the perforation speed is generally not more than 7 ~ 8m / h, the maximum life of the cone bit is 80m. Under these conditions, the average cost of a roller cone bit is 220 rubles, the perforation cost per meter hole is about 10 rubles, and the perforation cost for a 1m-3 ore rock is 0.4 rubles. Because the Soviet Union cemented carbide and roller cone bit is very short