Framework of the theory and technology for simultaneous extraction of coal and geothermal resources

Simultaneous extraction of coal and geothermal resources is an active investigation on the simultaneous ex- traction of coal and its associated resources,and it is also a combination of coal mining and geothermal energy utiliza- tion. To take advantage of the geothermal resources in the underground mines makes some contributions to the con- struction of green mines and the development of geothermal energy. The types and the causes of high temperature mines in China are summarized,the statistics of the dis-tribution of high temperature mines in China are presented,and the necessity and feasibility of the development and utilization of geothermal resources in mines are discussed. The bas- ic concept of simultaneous extraction of coal and geothermal resources is put forward,and the framework of simultane- ous extraction of coal and geothermal resources is described from the aspects of engineering background,scientific is- sues,key technologies and practices. The scientific issues are discussed,including coal reservoir geomechanics,tem- perature distribution law of deep section in high temperature mines,technical and economic evaluation method of mine geothermal resources,and multi-field coupling and its evolution laws. Based on the study,the key technical issues of simultaneous extraction of coal and geothermal resources are analyzed,including the process of resources simultaneous mining,high efficient heat pump technology,the process of drilling and well completion in underground mines,the ex- traction and reinjection technology in underground mines,the high efficient gathering and transportation and indirect heat exchange technology,dynamic monitoring and intelligent peaking technology.