Research On Establishment Of Risk Assessment System On Metal Tailings Reservoir

The composition of metallic tailings is very complex.It contains many kinds of heavy metals and mineral processing reagents left during the processing procedure of metallic mineral,such as sulfide,chloride,cyanide, and so on.If tailings reservoir accidents take place,for example,dam fracture,dam leakage,landslide,subsidence,dam break,it can pollute farmland,increase the content of heavy metals in crops and groundwater,damage the regional ecosystem and human health.Therefore,it is signality to establish a system of environmental risk assessment of metal tailings reservoir for quantitative and standardized environmental risk evaluation,and decreasing the damage caused by metallic tailings on human health and environment.It can provide theoretical foundation and scientific basis for the prevention,surveillance and control of environmental pollution caused by metal tailings reservoir.Based on the theories and technologies,combining with the characteristics of the metal tailings pollution, the risk assessment system on metal tailings reservoir was set up from the acute pollution accident risk and the health risk two aspects.The main works and results are listed as following:(1)As the data of mine tailings discharge showing, the phenomenon of mine tailings emissions has been very serious. The safety situation and existing environmental problems of our tailings was analyzed. Besides the related concepts of environmental risk assessment, the differences between it with environmental impact assessment and safety evaluation were introduced in details.Moreover,the domestic and foreign research status on environmental risk assessment of tailings reservoir were deeply analyzed.(2)Based on the analysis of tailings reservoir pollution accident, combining with the characteristics of the metal tailings pollution, the risk assessment system on metal tailings reservoir was set up from two aspects,that is,the acute pollution accident risk and the health risk.This system explained the concrete evaluation content and ways,and puted forward corresponding evaluation standard and risk management measures.The acute pollution accident risk includs water and atmospheric contamination risk assessment.(3)According to the metal tailings reservoir water and atmospheric contamination risk assessment methods and frameworks, the potential risk factors and risk source term in metal tailings can be identifed scientifically,and the aximum credible accident effect on the surrounding environment is represented more intuitively.Then through the comparison for dangers of accidents and the standard, the acceptable risk degree is gained.(4)According to the metal tailings reservoir health risk assessment methods and frameworks, the ralation between the crowd exposure degree of pollutant and the possibility of negative effect is estimated, and the size, frequency, duration and route of exposure is determined.And then, the size of the risk can be characterized by all ways of the health risk values.(5)Finally,the above discribed method is applied to Paishanlou gold mine tailings reservoir pollution and health risk assessment, and the results have confirmed that the risk criterion and its integrated system were practical and reasonable on the whole.