地质、冶金和煤田钻探,我国过去几乎全部采用大口经钢粒钻头和硬质合金钻头,钢材消耗多、劳动强度大、成本高、效率低和钻井质量差。虽有少部分地区也用过小口经金刚石钻关,但这些钻头几乎全是国外进口的,价格昂贵,(一只含量20克拉的天然金刚石钻头需要12.5吨大米换取,我厂生产的每只合400元左右)质量还不能保证。我 Geology, metallurgy and coalfield drilling, almost all of our past, the use of large-diameter drills and carbide drill bit, steel consumption, labor-intensive, high cost, low efficiency and poor drilling quality. Although a small part of the area has also used a small hole through the diamond drill off, but almost all of these drill bits are imported, expensive, (a content of 20 karats of natural diamond drill requires 12.5 tons of rice in exchange for each plant I produced 400 yuan) quality can not be guaranteed. I