401矿区铀矿床地质地球化学特征及其地下堆浸评价

40 1矿区贫铀花岗岩成岩后经过三期水溶液流体的改造作用 :早期高温热液的碱交代作用使花岗岩中的铀活化转移 ,此活性铀是形成铀矿床的物质基础 ;中期中低温热液是沿断裂上升的深源富 CO2 流体与大气降水的混合产物 ,它浸出了花岗岩中的活性铀 ,并迁移至有利的断裂构造部位 ,富集成脉状热液铀矿床 ;晚期地表水沿控矿断裂向下渗滤 ,铀矿床遭受表生淋滤 ,其矿石的物理化学性质发生改变 ,为地下堆浸创造了有利条件

GEOLOGICAL-GEOCHEMICAL CHARACTERISTICS AND UNDERGROUND LEACHING APPRECIATION OF URANIUM DEPOSITS IN OREFIELD 401

In this paper, the geological-geochemical characteristics and underground leachability of the uranium deposits in the uranium-barren granite of Orefield 401 are studied. The orefield's granite has experienced reformation of post-diagenetic aqueous fluids for three periods. In early period, the uranium of granite was remobilized by the alkali-metasomatism of hydrothermal with high-temperature, and the actived uranium is the material base forming uranium deposits. In medium period, the mid-epithermal solution was a mixture of the precipitated water and abyssal fluid containing CO2 that rose along abyssal fault, and it leached the actived uranium from the granite, then migrated to favorable location of fault structure, and concentrated hydrothermal vein uranium deposits. In late period, the surface water permeated down along ore-forming faults, then the uranium deposits has illuviated, and the physicochemical nature of ore was changed, all that provided the favorable conditions for underground leaching.