紫木凼金矿开采过程中的环境效应:1.污染状况对比

ENVIRONMENTAL EFFECT DURING THE EXPLOITATION PROCESSES OF ZHIMUDANG GOLD DEPOSIT: Ⅰ. COMPARISON OF POLLUTION SITUATIONS

金矿开采具有其独特的环境效应 ,特别是贵州等地的卡林型金矿 ,因为这种金矿富含As、Tl、Hg、Sb、Pb等有毒元素 ,而且矿区发育喀斯特地形 ,使这类金矿的开采具有“毒上加毒”的污染特征和“明暗相间”的污染扩散迁移特征。本文通过对紫木凼金矿从1 989年到 1 995年开采六年间土壤、地表水、地下水的监测项目的变化对比 ,证明了黄金生产造成了矿区土壤、地表水、地下水中CN- 、As、Hg、Pb、Zn等的增高 ,其中以对地表水的影响最大 ;确定了主要的污染源有采矿废石、矿渣及废液 ,主要污染物有CN- 、As、Hg、Pb和Zn ,由于矿区Tl的区域背景值较低 ,未造成Tl的二次污染。

Exploitation of gold deposits has caused a unique environmental effect, especially for the Carlin\|type gold deposits located in Guizhou, Guangxi and Yunnan provinces because those deposits developed in karst areas are enriched in toxic elements such as As, Tl, Hg, As and Pb, which are mobile in supracrustal conditions and easy to diffuse and transport over a significant distance, especially in karst areas. Hence, environmental pollution induced by the exploitation of those gold deposits is more serious than that by other activities. This paper addresses the environmental pollution in the exploitation of the Zhimudang gold deposit, Guizhou Province, based on comparative research on six\|year monitored data of soil, surface and underground waters from 1989 to 1995. It is proved that the exploitation activity led to an increase in concentrations of CN\+-, As, Hg, Pb, Zn, etc. in soil, surface and underground waters, especially in surface waters; and that the main pollution sources and materials are wall rocks, mine waste and waste liquid and CN\+-, As, Hg, Pb and Zn, respectively. Because of the low regional background value of Tl in the ore field, the secondary pollution of Tl does not happen.\;