The Environment Geochemistry of Gold Mining and Ecological Effects in upper Biliu River
|Course||Mineral prospecting and exploration|
|Keywords||Gold deposits Hazardous minor and trace elements distributions and occurrences Ecological environment effects Acid productionexperiments Leaching experiment.|
From the point of view of geology, geochemistry, mineralogy, pedology, ecology, environ-chemistry, environmental geochemistry of gold deposits and the effects of gold mining on ecological environment in upper Biliu River area have been studied for the first time. The distributions and occurrences of minor and trace elements,especially hazardous elements in gold-bearing rocks have been studied,and comparaed with those of Chinese gold-bearing rocks.Especially,the occurrences of hazardous elements in discarded rocks and tailings were researched directly and quantitatively using sequential chemical extract of six stepes ,and surface activity of elements were discussed based on the occurrences of elements. Acid neutralization potential test, acid production potential test, net acid production test,column leatching experiment and mineralogy study were done for the purpose of study and prediction the ecological envronment effects of gold mining. The results show that discarded rocks and tailings will produce acid during piling ,and that the net acid production of discard rocks is medium to high and the that of tailings is low. The inspects of the filtered water of discarded rocks, the poculated water of tailings pool,the water of mining lane and the altered mineral studies of discarded rocks and tailings indicate the acid production of discarded rocks and tailings.The oxidation and buffering of the sulfides and the activity and migration of elements in discarded rocks and tailings were discussed. The oxidation of sulfides, buffering of carbonates and silicates,the activity and migration of trace elements in discarded rocks and tailings and affecting factors were discussed and the oxidation sequences of sulfides and activity coefficients of elements were determined.The acid production of the discarded rocks is more than that of tailings.121 day leaching test at the 6.5 of pH show that total leached concentrations of As、 Hg、 Pb、 Zn、 Cd、 Cr、 SO42- are evidently beyoand of the criterions on surface water of the nation and on life drinking water of the nation which indicate that the environment effects of gold mining are not ignored.The ecological environment appraise of the soils first Using blurred mathematics, plant of the soils, microorganism of the soils and geochemistry of the soils in Wolongquan river area indicated that gold mining have caused the complex pollution of the siols and plants, especiallyusing phospholipid fatty acid as microbial biomass, with urine enzyme and hydrogen peroxide enzyme, studied the relations of soils compound pollution to gold mining, and that the pollution level increased with mining intensity. The ocuurences of hazardous elements in the soils were determined using sequential chemical extract and ecological effectives of the hazardous elements in soils and influence factors were discussed. The studies of absorption and desorption test and soil profile section show that the hazardous elements of soils largely move downwords, and that pollution of hazardous elements are more than 1 miter deep and Cu> PK Zm As> Cd have been moving downwords.The environment quanlity and the function of surface water and subsurface water were appraised using environmental model and geochemical methods in upper Biliu river,and the heavy metals pollution and ecological endanger of water sediments were appraised using geo-accumulative index ,ecological endanger coefficienets and endanger index .The studies on environmental geochemistry of water and the origin of pollution indicated that water environment was largerly relatived to gold mining ,partly to water-rocks reaction.pollutes mainly come from the discarded rocks and poculating water of tailing pools,which are relation to poorly poculateproof of tailings pools, poorly wastes administration and gold mining in disorder.