HYDROGEOCHEMICAL CHARACTERISTICS AND SOURCE IDENTIFICATION OF DEEP GEOTHERMAL WATER IN QINGDONG COAL MINE, HUAIBEI, ANHUI PROVINCE

The abnormal geo-temperature in coal mine is a warning factor of geological disaster. Study on the hydrogeochemistry and source of geothermal water is an effective method of prevention on mine water and heat disaster. In this study,we collected 13 samples of geothermal water and 11 samples of common groundwater from draining hole at the same depth (-585^￣￣m). Based on the hydrochemistry characteristics,the hydrochemical process and sources of geothermal water were analyzed. Compared with the common groundwater,geothermal water had higher content of TDS,Ca²⁺,Cl^-. The hydrochemical facies of geothermal water were SO₄ ·Cl-Ca ·Mg type in weak alkaline environment. The chemical composition of geothermal water was dominated by both ion-exchange interaction and dissolution of silicate and evaporates. The oxidation of pyrite in coal,the geothermal water possessed fine hydrodynamic condition and the more intense ion-exchange interactions are more active than those in common groundwater. The formation of geothermal water was supplied by deep Ordovician limestone water and mixed with Taiyuan limestone water through the fracture. The mixing proportion of Ordovician limestone water was higher. The outcomes of this paper can provide guidance for mine water prevention and control.