Gas emission quantity prediction and drainage technology of steeply inclined and extremely thick coal seams

Gas emissions of workfaces in steeply inclined and extremely thick coal seams differ from those under normal geological conditions, which usually feature a high gas concentration and a large emission quantity. This study took the Wudong coal mine in Xinjiang province of China as a typical case. The gas occurrence of the coal seam and the pressure-relief range of the surrounding rock(coal) were studied by experiments and numerical simulations. Then, a new method to calculate the gas emission quantity for this special geological condition was provided. Based on the calculated quantity, a further gas drainage plan, as well as the evaluation of it with field drainage data, was finally given. The results are important for engineers to reasonably plan the gas drainage boreholes of steeply inclined and extremely thick coal seams.

顺层平行钻孔预抽回采区域煤层瓦斯数值模拟

为了得到采取顺层长钻孔措施和顺层交错钻孔措施的瓦斯抽放效果,建立了顺层平行钻孔预抽煤层瓦斯数学模型,并采用有限体积法模拟计算出不同时刻钻孔周围煤体瓦斯压力分布与钻孔累计抽放瓦斯量。模拟结果表明,合理的顺层单向钻孔和顺层交错钻孔布置,对于预抽回采区域煤层瓦斯均取得良好效果;顺层钻孔抽放瓦斯效果与煤层渗透率、煤层原始瓦斯压力及煤层钻孔布置密切相关。