HAZARD IDENTIFICATION AND RISK ASSESSMENT OF WATER INRUSH IN DEEP MINING OF METAL MINES: A CASE STUDY OF MAOPING LEAD-ZINC MINE IN NORTHEAST YUNNAN, CHINA

After it enters deep mining, the metal mine will face the complex geological conditions of "three highs and one disturbance". The disturbance of ore body mining can easily induce water inrush disasters. In this paper, the systematic hazard identification and risk assessment of water inrush were carried out on the basis of the hydrogeological structure investigation of the Maoping lead-zinc mine in Northeast Yunnan Province. The control measures of water inrush hazard sources were determined in the deep mining process. According to the geological, tectonic and hydrogeological conditions of the Maoping lead-zinc mine, two types of hydrogeological structures were classified, namely, the strongly water-rich aquifer lateral filling water-steep dip type on the west flank of the Shimenkan anticline and the medium Karst aquifer roof-floor filling water-gentle type on the east flank of the Shimenkan anticline. From the three aspects of tectonic development, aquifer/aquiclude and mining disturbance, a detailed analysis of the hazard identification and risk assessment of water inrush in deep mining of the Maoping lead-zinc mine was conducted. An analytic hierarchy process evaluation model was established to obtain the evaluation map of water inrush risk in the main mining level. The five area types of safe, relatively safe, transitional, relatively dangerous and dangerous area were divided. The evaluation results show that the drainage center of the inverted triangular cone of the mine is the area with less risk of water inrush, i.e., the safe area. The Permian Qixia and Maokou Formation Karst fissure strong water-rich aquifer in the north is the area with the greatest risk of water inrush in the deep mining, i.e., the dangerous area. The zoning maps of the 490 m and 310 m levels show that the dangerous area and the relatively dangerous area are striped in a north-east and north-west direction, which is consistent with the development direction of the main hydraulic conductivity structures. This research provides a scientific basis for the establishment of a five-in-one integrated water control key technology system of "exploration, prevention, blocking, dredging and monitoring" in the deep mining of metal mines.