HEAVY METALS IN SOIL AROUND THE GANGUE TAILINGS OF THE PINGDINGSHAN COAL MINE AREA

摘要

During the process of coal mining, large amounts of gangue produced. It is estimated that the discharge-rate of gangue is about 15 to 30 % that of the production of raw coal. The total amount cumulated in China is about 40 × 10~9 tons presently, occupying 70 km~2 of soil, and the gangue stones are still being discharged with a rate of 15 × 10~6 to 200 × 10~6 tons per year. As the total synthetic utilization rate is less than 40%, most of these coal wastes are being piled naturally and form gangue hills without any engineering treatment. After the interaction with physical, chemical and biological processes such as wind, rain and spontaneous combustion in rather a long time, the compositions of these coal wastes will change accordingly. As a result, some components of the coal wastes will be discharged and transferred into soil, leading to geochemical abnormaly in coal mining area, and eventually leading to environmental pollution and ecological damages. Soil around those gangue tailings are now commonly polluted by these solid coal wastes, and the study in this field becomes very important and timely.