凡存在煤和瓦斯突出动力现象的矿井,特别是用石门揭煤时,煤和瓦斯的突出常常造成严重的自然灾害。为了防止煤和瓦斯的突出,实践证明采用大直径钻孔排放瓦斯和形成泄压带,能够获得比较理想的技术经济效果。但是,目前我国适用的岩石钻机,一般只能钻直径150毫米的钻孔,不能满足这种抽放钻孔施工的需要。因此,我们于1971至 Where mines with gas and gas outburst phenomena occur, especially when exposing coal with stone gates, the prominence of coal and gas often cause serious natural disasters. In order to prevent the prominence of coal and gas, practice has proved that the use of large diameter borehole drainage gas and the formation of pressure relief zone, can obtain the ideal technical and economic results. However, at present, rock drilling rigs suitable for use in China generally can only drill holes with a diameter of 150 mm, which can not meet the requirement of such drainage drilling. So we came in 1971