Numerical simulation of mine heat hazard governance and geothermal resource exploitation using extraction-ventilation collaborative method

As the mining depth of coal mines continues to increase, the problem of mine heat damage becomes increasingly prominent. In response to the heat damage problem in deep mines, this paper presents a novel approach of mine heat damage control and geothermal resource exploitation under the collaborative effect of extraction and ventilation. Taking Sanhejian Coal Mine in Xuzhou as the research object, numerical simulation is conducted using finite element simulation analysis software to analyze the evolution law of the temperature field of roadway surrounding rock and air in the roadway during the variation of different key factors. Additionally, in the process of continuous tunneling, the optimal cooling scheme for roadways at different locations is obtained. The conclusions are as follows: (1) Treating mine heat damage under pure ventilation has the advantage of rapid cooling speed. The temperature at the observation point in the roadway can be reduced to approximately 283 K at its lowest. However, the disadvantage lies in the large temperature difference before and after the roadway (no less than 7 K) and the need for continuous ventilation. (2) During the extraction process, reducing the average injection water temperature and decreasing the distance from the roadway can effectively enhance the effectiveness of mine heat damage control. Nevertheless, under pure extraction, the temperature reduction rate of roadway surrounding rock is relatively slow. When the distance between the roadway and the injection well does not exceed 30 m and the average injection water temperature does not exceed 190 K, the surrounding rock temperature can be reduced to below 303.15 K within one year. (3) The extraction-ventilation synergy method not only can effectively narrow the temperature difference before and after the roadway but also can improve the temperature reduction speed in the roadway to a certain extent. Moreover, the geothermal resources generated by extraction can also yield certain economic benefits. This research provides a new perspective for cooling the coal mining face of coal mines.