某酸法地浸铀矿山全采区地下水流场变化数值模拟

区域流场是地下水中溶质迁移的基础，其形态特征是判断地浸铀矿山地下水环境影响范围的前提，准确预测区域流场的变化情况对指导地浸铀矿山生产实践有着极其重要的作用。本文以我国北方某地浸铀矿山为研究对象，利用数值模拟方法再现了该地浸铀矿山生产以来全采区地下水流场变化情况。模拟结果表明，生产井的抽注活动是区域地下水流场变化的根本原因，采区内部由于生产井的抽注活动，注液井周围会形成小范围的水头升高区，形成点源，抽液井周围则形成水头下降区，成为点汇；但生产期间总抽液量大于总注液量，全采区整体上形成了明显的水头下降区，区域降落漏斗的形成可以有效控制浸出液中溶解组分的迁移范围。结合含矿含水层地下水pH、铀、硫酸根背景值及采区监测井监测数据，进一步证实了区域流场形态对地下水中溶解组分迁移范围的控制作用，得出该地浸铀矿山的地下水环境影响控制在了150 m以内。

Numerical simulation of regional groundwater flow field change in an acid in-situ leaching uranium mine

Regional groundwater flow field is the basis of solute transport in groundwater and its distribution is the premise of judging the influence range of groundwater environment in in-situ leaching uranium mine. It is very important to accurately predict the change of regional flow field for guiding mine production practice. Taking an in-situ leaching uranium mine in northern China as the research object, this paper reproduces the variations of groundwater flow field in the whole mining area since its production by using numerical simulation method. The simulation results show that the pumping and injection activities of production wells are the fundamental reason for the changes of the regional groundwater flow field. Due to the pumping and injection activities of production wells, a small range of water head rising area will be formed around the injection wells and the injection wells form point sources, while the water head drop area around the pumping wells will become point sinks. However, the total pumping volume during production is greater than the total injection volume, and the whole mining area has formed obvious water head drop zone. The regional cone depression can effectively control the migration range of dissolved components in the leaching solution. Combined with the background values and monitoring data of pH, uranium and sulfate in groundwater in mining area, the control effect of regional groundwater flow field on the migration range of dissolved components in groundwater is further confirmed. It is concluded that the environmental impact of groundwater in the in-situ leaching uranium mine is controlled within 150 m.