沙漠地区露天煤矿疏干水回灌包气带影响分析

Analysis on influence of water drainage and recharge of huge thick vadose zone in open-pit coal mines of desert areas

巴基斯坦塔尔煤田Ⅰ区块露天煤矿位于巴基斯坦塔尔沙漠南端,气候干燥,降雨量少,蒸发量大,露天煤矿疏干水外排系统短期内无法建成;为保障露天矿安全生产,亟需解决疏干水外排问题。通过分析当地地质条件,拟利用表土覆盖层的强渗透性进行回灌,将疏干水排至巨厚包气带内,缓解疏干水外排压力;采用modflow建立水文地质数值模型,分析入渗量及回流疏干水对露天矿疏干系统的影响,同时对库容、蒸发量及同时对露天矿第四系潜水涌水量进行了定量分析。结果表明:入渗量及蒸发量可以满足露天矿排水要求。

The open-pit coal mine in Block I of Thar Coalfield in Pakistan is located at the southern end of the Thar Desert in Pakistan,with a dry climate,low rainfall and large evaporation.The drainage system for open-pit coal mines cannot be built in a short period of time.In order to ensure the safe production of open-pit mines,it is urgent to solve the problem of draining water.By analyzing the local geological conditions,the article proposes to use the strong permeability of the topsoil cover to recharge,and to discharge the drained water into the huge thick vadose zone to relieve the pressure of the drained water to drain out.We use modflow to establish a numerical model of hydrogeology,to analyze the influence of infiltration amount and backflow drainage water on the drainage system of open pit mines,and to quantitatively analyze storage capacity and evaporation.At the same time,the article carries out the quantitative analysis of the quaternary submerged water inflow of the open-pit mine,proposes a new idea of draining water from open pit mines with similar geological conditions in foreign countries.The results show that the infiltration and evaporation can meet the drainage requirements of the open-pit mine.