基于抽采半径考察的回采工作面瓦斯预抽钻孔优化设计

为了解决高瓦斯长推进距离回采工作面各区域瓦斯预抽时间极不均衡的问题，提出了基于抽采半径考察的回采工作面瓦斯预抽钻孔优化设计方案：采用瓦斯储量法对回采工作面瓦斯预抽钻孔有效抽采半径进行考察，得出工作面瓦斯预抽钻孔不同预抽时间的有效抽采半径，将高瓦斯长推进距离回采工作面按瓦斯预抽时间长短的不同划分为若干个区块，每个区块瓦斯预抽钻孔根据其有效抽采半径设计钻孔间距，预抽时间长的区块钻孔间距较大，预抽时间短的区块钻孔间距较小，实现工作面瓦斯抽采达标的同时最大限度的减少钻孔工程量。现场应用结果表明，2311回采工作面采用优化的瓦斯预抽钻孔设计方案，钻孔工程量减少约7万m，节约工作面瓦斯预抽时间约15d，并且在开采期间实现了瓦斯抽采达标和安全回采，高瓦斯长推进距离回采工作面采用基于抽采半径考察的回采工作面瓦斯预抽钻孔优化设计方案，取得了良好的技术经济效益。

Optimal Design of Gas Pre-drainage Boreholes in Coal Mining Face Based on Investigation of Drainage Radius

In order to solve the problem of extremely uneven gas pre-drainage time in various areas of high gas long distance mining face. Based on investigation of drainage radius, the optimum design plan for gas pre-drainage boreholes in coal mining face was put forward. The effective drainage radius of gas pre-drainage boreholes in coal mining face was investigated by gas reserve method. The effective drainage radius of gas pre-drainage borehole for different pre-drainage time in coal mining face was obtained. The high gas long advancing distance mining face was divided into several blocks according to the length of gas pre-drainage time. Each block of gas pre-drainage borehole was designed according to its effective drainage radius. The longer the pre-drainage time was, the larger the distance between the pre-drainage boreholes. The shorter the pre-drainage time was, the smaller the distance between the pre-drainage boreholes. Achieve the standard of gas drainage at the coal face mining and minimize drilling works at the same time. The results of field application showed that, the optimized design of gas pre-drainage borehole was adopted in the 2311 mining face, the amount of drilling engineering was reduced by about 70 thousand M, and the gas pre-drainage time of coal face mining was about 15d, and during the mining period, gas drainage standard and safe mining were achieved. The optimal design of gas pre-drainage borehole in the mining face based on investigation of drainage radius was adopted in the high gas long advancing distance mining face, and good technical and economic benefits had been obtained.