一、空区概况攀枝花冶金矿山公司兰家火山露天矿2号矿石溜井,自1970年2月投产后,于同年12月就发现有局部塌方,并日趋严重。1974年6月开始用钻孔透测、开拓平峒观察、激光经纬仪测绘等多种方法调查(参见图1)。所获资料表明:由井口起向下90米一段主要 First, the empty area overview Panzhihua Metallurgical Mine Company Lanjia volcanic open pit ore No. 2 ore slide, put into operation in February 1970, in December the same year found that there are partial landslides, and increasingly serious. In 1974 June began drilling with penetration testing, development of flat ridge observation, laser theodolite mapping and other methods of investigation (see Figure 1). The information obtained indicates that the section headed 90 meters downwards from the well head