应用粒子示踪模拟技术确定地浸采铀溶浸范围

溶浸范围是铀矿地浸开采经济技术评价的重要考量要素之一。由于溶浸过程发生在地下矿层,溶浸范围的确定往往比较困难。本文以我国某砂岩铀矿地浸单元为例,根据研究区水文地质条件和实际地浸抽注液流量数据,运用地下水模拟软件Visual Modflow粒子示踪技术对溶浸液渗流路径和范围进行了模拟,模拟结果的示踪迹线指示出了溶浸液从注液孔进入矿层后的不同渗流方向、速度及运移路径,沿该迹线的溶浸液流量有所不同,对抽液总流量的贡献率也不同。按贡献率大小从低到高剔除占总贡献率5%的那些低效率的迹线,保留占总贡献率95%的迹线,以此圈定了该地浸条件下的有效溶浸范围,计算得出有效溶浸面积是钻孔所围几何面积的1.51倍。

Application study of particle tracer technique to calculate the in-situ leaching areaof uranium mining

Leaching area is one of the important factors that must be considered in economic and technical evaluation of in-situ leaching of uranium. Because the leaching process is taken place in the ore bed underground, it is difficult to determine the leaching area. In this paper, based on study of the in-situ leaching process of a mining unit at a sandstone type uranium deposit in northwest China, a new method for leaching area calculation by using particle tracer technique which is employed in Modpath as a model integrated in Visual Modflow was explored. According to the hydrogeological conditions and leaching flux data, lixiviant flow was simulated by using Visual Modlfow and the flow distribution was showed by the tracer paths, which gave us information about the flow directions, velocities and paths of lixiviant. Different path had different contribution to the total extraction flux, so, the contribution of each path had been calculated and ordered from low to high, and the lowers of which cumulative contribution ratio achieved 5% were wiped off, thus, the leaching area was determined by the highers of 95%. According to this method, the calculated leaching area was 1.51 times to geometric area of enclosure of mining wells.