彬长低阶煤高瓦斯矿区瓦斯地质及其涌出特征

针对近年来低煤阶煤矿区高瓦斯矿井数量增多,但瓦斯赋存规律及涌出特征知之甚少的问题,以陕西省黄陇煤田彬长矿区为例,依据勘查阶段和煤矿生产过程中测试的瓦斯参数及抽采数据,总结分析低煤阶煤矿区矿井瓦斯参数及瓦斯富集规律,讨论地质因素对低煤阶煤矿区瓦斯涌出特征的影响及其机理。研究表明,低阶煤煤化程度低,孔隙度较高,游离气含量高,煤层透气性好,瓦斯富集规律和涌出特征明显区别于中、高阶煤。彬长矿区发育大佛寺瓦斯富集区、小庄-亭南瓦斯富集区、胡家河瓦斯富集区3个瓦斯富集区。地质构造是控制低煤阶煤矿区矿井瓦斯富集的主要因素,煤质特征决定了低煤阶矿区瓦斯赋存状态。瓦斯涌出量同时受控于开采层瓦斯含量、煤厚、煤层底板标高、地质构造等地质因素。开采煤层原位瓦斯含量越高,煤层厚度越大,煤层底板标高越大,回采工作面瓦斯涌出量越大。褶曲翼部瓦斯涌出量明显要大于向斜轴部宽缓区域,翼部地层倾角越大,回采工作面瓦斯涌出量越大,褶曲对煤层倾角的影响控制了低阶煤瓦斯涌出特征。断层附近受游离气含量的影响,易造成回采工作面瓦斯涌出量突然增大。综采放顶煤采煤工艺在显著提高煤炭产量的同时,也造成了近年来低煤阶煤矿区高瓦斯矿井数量增多。

Geology and emission of mine gas in Binchang mining area with low rank coal and high mine gas

In recent years,the number of high gas mines in low rank coal mining area has increased,but the law of gas occurrence and emission characteristics are not well understood.In this study,taking the Binchang mining area in Huanglong coalfield of Shaanxi Province as an example,the gas parameters and gas enrichment rules of low coal rank mines were studied based on the exploration stage and the test in the coal mine production process.At the same time,the influence of geological factors on the gas emission characteristics of low rank coal mining area and its mechanism were discussed.The research shows that the low rank coal has a low degree of coalification,high porosity,high free gas content,good coal seam permeability,and the gas enrichment law and emission characteristics are obviously different from that of medium and high rank coals.There are three gas enrichment areas in Binchang mining area:Dafosi gas enrichment area,Xiaozhuang Tingnan gas enrichment area and Hujiahe gas enrichment area.The geological structure is the main factor controlling the gas enrichment in low coal rank coal mines.The coal quality characteristics determine the gas occurrence state of low coal rank mining areas.The gas emission is controlled by the geological factors such as gas content,coal thickness,coal seam floor elevation and geological structure.The higher the in situ gas content of the coal seam is,the larger the coal seam thickness is.The larger the coal seam floor elevation is,and the larger the gas emission from the mining face is.The gas emission at the folded wing is obviously larger than that at the wide area in the shaft of syncline.The larger the inclination dip angle of the wing formation,the larger the gas emission from the mining area.The influence of the fold on the dip angle of the coal seam controls the low rank coal gas emission characteristics.Because of the high free gas content near the fault,it is easy to cause a sudden increase in the amount of gas emission from the mining face.The fully mechanized top coal caving mining process has significantly increased the coal production,and also caused an increase in the number of high gas mines in the low coal rank mining area in recent years.