砂岩型铀矿地浸开采过程中电法勘查技术的应用

原地浸出采铀是一种利用砂岩型矿层对水的渗透性，采用注、抽液孔向含矿岩层注入“溶浸液”和抽取“浸出溶液”而获得铀的先进采矿技术。研究井场下方 “浸出液”分布范围，不仅能掌握矿体的被覆盖程度和矿床开采率，且对于地下水体污染监控具有重要意义。对内蒙古二连盆地某铀矿地浸开采试验基地进行电法勘查，以对铀矿地浸开采过程进行监测试验。具体采用可控源音频大地电磁测深法(CSAMT)和时间域激发极化法对试验井场进行探测试验。试验区以抽孔为中心布设一个18×18的测网，测网的线距和点距均为10 m。电法探测试验时，对穿过抽、注井的5条纵向和4条横向测线进行了CSAMT观测，并对全区进行中间梯度激发极化测量。经过数据处理和反演得到了中梯装置视极化率平面等值线图及CSAMT二维电阻率模型，并结合研究区域已知资料进行解释，认为电阻率断面上井场区域下方的低阻异常带反映了地浸开采过程“溶浸液”的地下分布状态；视极化率平面等值线图上显示的抽注单元下方的大片低极化率异常，可能是由地下浸出液与岩层组成的离子导电体系“薄膜极化”效应产生的异常带。

Application of Electrical Prospecting Technology in Extraction Process of In situ Leaching in Uranium Deposit

In situ leaching for uranium is an advanced technology which extracts uranium by injecting leaching solution into the ore bearing formation and pumping lixiviate out from the ore bearing formation based on the water permeability of the sandstone orebed.Studying the distribution range of the leaching solution below well field will not only help to learn the coverage range of the orebody covered by leaching solution and mining rate, but also be significance to monitoring the underground water pollution. Electrical prospecting methods were carried out in the Uranium In Situ Leaching(ISL) Test Base in Erlian Basin of Inner Mongolia in order to perform a monitoring test on the course of ISL for uranium. The monitoring tests consist of controlling source audio magneto telluric method (CSAMT) and time domain induced polarization method (TDIP).The test area was divided by an 18×18 survey grid with the both line line and dot dot space of 10 m apart. During the test, CSAMT was performed on 5 longitudinal and 4 transverse prospecting lines which crossed through the well unit and TDIP was conducted on the whole well field. A plane polarizability contour map of TDIP and a 2 dimensional apparent resistivity model were obtained after data processing and inversion. Combining the result with the geological information known in the test area, it is considered that the low resistivity anomaly region in the apparent resistivity profile below the pumping well unit is the reflection of the distribution state of the leaching solution underground during the in situ leaching process, meanwhile,a massive low polarizability anomaly region in the plane apparent polarizability contour map below the pumping well unit is caused by film polarization effect occurring within the ionic conduction system which consists of leaching solution and rock formation.