极软中厚煤层越界开采区老空水害防治技术

小煤窑越界开采是我国煤炭行业极为普遍的现象。由于越界开采范围、积水量等条件不明，老空水严重威胁着毗邻大型煤矿的安全采掘工作。为快速准确地探查小煤窑越界开采边界并预防老空水的威胁，运用地面定向钻孔轨迹可控、定位精确的特点，提出了以极软中厚煤层精准钻进、不同岩性钻井液配比和采空区井漏预防与封堵为主的极软中厚煤层中地面顺层孔长距离钻进技术，并提出了越界开采区老空水害防治流程。以华北型煤田某煤矿Ⅲ63采区右翼为研究区，应用越界开采区老空水害防治技术体系，通过工程示范准确查明了越界开采边界与越界开采方向，为合理留设矿界防隔水煤柱提供依据。该方法的成功应用为同类矿井的老空水害防治提供了科学的技术，并且为地面顺层孔在探查越界开采边界与极软煤层抽取瓦斯等领域中的应用提供宝贵经验。 

Prevention and control technology of goaf water hazard in unauthorized mining areas of extremely soft and medium-thick coal seams

Unauthorized mining in coal pit is common in China's coal industry. As the scope of unauthorized mining and the amount of accumulated water are hard to determine, the goaf water seriously threatens the safety of mining in adjacent large coal mines. In order to explore the unauthorized boundary of coalpits quickly and accurately and prevent the threat of goaf water, the long distance drilling technology of ground bedding borehole in medium and thick coal seam is proposed based on the controllable trajectory and accurate positioning of ground directional drilling, which mainly includes precise drilling in extremely soft and medium-thick coal seam, drilling fluid ratio of different lithology, prevention and plugging of lost circulation in goaf. In addition, the prevention and control process of water disaster in the goaf of the unauthorized mining area is put forward. Taking the right side of Ⅲ63 mining area of a coal mine in North China coalfield as the research area, adopting the goaf water disaster prevention technology system in the unauthorized mining area, the unauthorized mining boundary and direction are accurately identified through engineering demonstration, which provides a basis for reasonably retaining the waterproof coal pillar in the mine boundary. The successful application of the method provides a scientific technique for the prevention and control of goaf water disaster in similar mines, and provides valuable experience for the ground bedding borehole in the field of detecting the unauthorized mining boundary and gas extraction from extremely soft coal seam.