KARST WATER CONTROL AND MANAGEMENT IN THE HANXING MINING AREA OF NORTH CHINA

The Hanxing mining area of North China includes three coalfields: Feng feng, Handan and Xingtai. Six or seven coal seams can be commercially mined in Permo-Carboniferous strata, among which the lower three, acco unting for 37% of the total reserves, are threatened with karst water from the underlain Ordovician limestone. Hundreds of water inrush acci dents have occurred and over 30 mines have been flooded, resulting in heavy economic losses and casualties. In order to avoid water inrushes and keep the mines safely operational, dewatering in the karst aquife r was considered an essential measure. Unfortunately, this practice ha s caused serious environmental problems such as surface subsidence (si nkhole), dry spring, and water supply shortage. On the basis of a seri es of investigations and tests in the last 20 years, an alternative me thod, mining with water pressure, has been proposed and is the main fo cus of this paper. By using this method, the karst water in the limest one can be preserved to some extent and the coals can be mined in a re latively safe way.