含矿自流盆地的放射性环境地质和地浸法开采铀矿床

层间 渗入型铀矿床不同的现代水文地质环境对采用地浸方法采矿过程中保护环境不受污染的程度不同。根据水文地质特征 ,特别是水动力指标可将铀矿床分为有利的、不利的和非常不利的 3类 :有利的铀矿床指矿区的水流从矿带两侧分别从氧化带和原生灰色岩石带以斜交形式向矿带方向流动 ,并沿矿带走向方向相互作用。这样的水文地质条件下工艺溶液不可能流到矿带范围以外 ,故环境将不受污染。完全不利的水文地质条件是指水流垂直穿透矿带从氧化带向原生灰色岩石带流动 ,它们能将有毒元素和重金属带到矿带以外的相邻地区。不利的水文地质条件是指同时具有上述两种特征的铀矿床。实践证明 ,水文地质条件有利于地浸方法开采和有关工艺流程时 ,开采工作对现场造成的污染要比天然放射性污染低。

RADIOACTIVE ENVIRONMENTAL GEOLOGY OF ORE-BEARING ARTESIAN BASIN AND IN-SITU LEACH MINING OF URANIUM DEPOSIT

The recent hydrogeological environments of interlayer infiltration type uranium deposits exert different influence in protecting the environment pollution during in situ leach mining process. According to the hydrogeologic characteristics, especially the hydrodynamic parameters, uranium deposits may be divided into 3 groups: favorable, unfavorable and extremely unfavorable. Favo rable uranium deposits are those in which ground water diagonally flows from oxidation zone and unaltered rock zone to the ore zone interacting along the trending of the ore zone. Under such hydrogeologic conditions leaching solution is not able to flow beyond the ore zone, protecting the environment from pollution. Completely unfavorable hydrogeologic conditions are those under which ground water perpendicularly passes through the ore zone flowing from the oxidation zone towards the zone of grey rocks. In this case ground water may carry poisonous elements and heavy metals out of the ore zone to neighbouring areas. Uranium deposits of unfavorable hydrogeologic conditions are those in which the above two situations coexist. Practice demonstrates that the pollution caused by in situ leach mining is lower than that of the natural radioactive pollution when hydrogeologic conditions are favorable for in situ leach mining.