穿孔工作的改进炮孔直径的演变自1964年帕拉博拉矿开始采矿以来,穿孔参数有了很大变化。初期用旋转冲击式钻机钻进直径171mm 的炮孔。1970年引进了牙轮钻机,开始采用直径251mm 的炮孔。随着牙轮穿孔技术的发展,帕拉博拉矿进行了研究,以确定钻进更大直径炮孔的经济合理性。1980年的试验表明,311mm 钻头的性能已达到改用这种直径的炮孔是正确的程度,到1981年所有钻机均已改用311mm的钻头。由于钻机效率的提高,已有可能将 Improvements in perforation The evolution of the diameter of the hole has changed considerably since the Parapola Mine started mining in 1964. Early use of rotary impact drilling machine diameter hole 171mm. 1970 introduced a cone drill, began using the diameter of 251mm hole. With the development of cone penetration technology, the Parabora mine was studied to determine the economic justification for drilling larger diameter holes. Tests conducted in 1980 showed that the performance of the 311mm drill bit had reached the correct level by changing the borehole diameter to this diameter. By 1981, all drill rigs had been converted to 311mm drill bits. Due to the increased rig efficiency it has been possible