Some scientific issues in water-preserved coal mining

In Yushenfu mining area,the concept of water-preserved coal mining is based on the groundwater level de- cline and vegetation degradation caused by coal mining in the early stage. After theoretical research and engineering practice in many years,a key technical system for water-preserved coal mining has been initially established,which ef- fectively guides the exploitation of coal resources and ecological environment protection in the ecological fragile mining areas. Under the high standards for the construction of national ecological civilization,the ecological environment pro- tection of coal-water resources symbiosis areas in the arid and semi-arid regions of western China is facing a historical test. This paper reviewed the achievements of water-preserved coal mining technology,and concluded that the research on geological conditions,rock movement and water-preserved coal mining methods had basically solved the outstanding problems in single coal seam mining,while the investigation on water and ecological constraints on coal mining,and ecological restoration and reconstruction lagged slightly behind. By combing the relevant contributions,this paper ex- plores the scientific issues in the study of five water-preserved coal mining and related fields. This includes the ecologi- cal constraints identification,the quantification and monitoring of the groundwater dependent on the mining area,the detection and prediction of the water conducting fissure zone under the conditions of large mining height and repeated mining,the quantification and evaluation of the thickness of the effective aquiclude,the overburden control and ecolog- ical reconstruction and restoration. Under the new situation,the responsibility and tasks of ecological protection in min- ing areas are significant. More research is needed to support the water-preserved coal mining in western China and pro- mote the construction of green mining areas.