宁东煤炭基地煤炭开采对地下水的影响预测

宁东煤炭基地生态环境脆弱,水资源匮乏,煤炭开采过程中的水资源保护备受关注。采用公式法及现有3个工作面实测数据研究,确定了首采煤层开采导水裂缝带发育的最大高度,对比首采煤层至主要含水层之间的距离与导水裂缝带发育的高度差值,预测首采煤层开采对含水层结构的影响程度。研究结果表明,宁东煤炭基地首采煤层开采的导水裂缝带发育高度一般为20～80m,其中大于180m的区域面积约5.9km2,集中于西北部灵武矿区;石炭纪—二叠纪煤矿区横城矿区7个钻孔导水裂缝带突破石盒子组达主要含水层(新生界含水层)底部,侏罗纪煤矿区灵武矿区9个钻孔的导水裂缝带已经沟通地表。将首采煤层开采影响含水层的程度划分为影响大、影响较大、影响一般、影响微弱4种类型,各种类型所占比例分别为14.7%、40.31%、18.65%、26.34%。

The prediction of the influence of coal mining on the groundwater in Eastern Ningxia coal production base

The protection of water resources in mining has aroused much concern in Eastern Ningxia coal production base which is characterized by the fragile ecological environment and scarce water resources relatively. The authors calculated the maximum height of water flowing fractured zone in the first coal seam mining using the formula method and the three measured data. The difference value between the computations comprising the first coal seam, the main aquifer and the height of water flowing fractured zone could be used to predict influence of coal mining on the groundwater. According to the results obtained, the height of water flowing fractured zone is generally 20~80m, and the northwest Lingwu mining area of more than 180m possesses an area of about 5.9km²; in the Carboniferous-Permian coal mine area, the water flowing fractured zone has penetrated the Shihezi Formation and reached the main aquifer (Cenozoic aquifer) with 7 drill holes, such as 2808 and 2809; in the Jurassic coal mine area, the water flowing fractured zone has communicated the surface with 9 drill holes, such as 2702 and Yan1. The influence degree of the first coal seam mining for the aquifer has been divided into four types, i.e., large, larger, affected and weak, with the proportion being14.7%, 40.31%, 18.65% and 26.34%, respectively.