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With the development of coal resources to the deep, the mine heat damage has become increasingly serious. In this work, we proposed a comprehensive airflow temperature prediction model considering the coupling effect of multiple heat sources in coal mining face. The model was then discretized and a coupled solution simulator was developed independently. Finally, we conducted field test to verify the simulation results, and carried out a multi-factor sensitivity analysis affecting the thermal environment of coal mining face. The results show that:(i) The maximum relative error of prediction results is less than 4 %, which verifies the reliability of the prediction model. (ii) Heat dissipation from electrical equipment, surrounding rock and hot airflow leakage of gob area account for 43.8 %, 28.8 % and 17.4 % of the total heat load, which are the main causes of heat damage. (iii) The maximum airflow temperature in coal mining face increases in a parabolic trend with average advance speed. (iv) As the original rock temperature increases, the thermal environment of coal mining face deteriorates rapidly. (v) Cooling the inlet airflow or increasing the airflow volume can alleviate the high temperature problem. This research can provide guidance for the treatment of deep mine heat damage.

As the depth of mines continues to increase, the problems of high temperature and potential heat damage become more prominent. In this study, the characteristics of natural and industrial heat sources in mines were reviewed, and then mainstream heat hazard governance technologies and corresponding utilization methods were discussed and compared. The first category of technologies comprises the optimization of ventilation systems, the insulation of roc heat, and artificial refrigeration. These cooling approaches are limited because the heat resources cannot be recovered. The second category is the utilization of waste industrial heat in mines, including the use of waste heat from the air compressors, drainage water, and foul airflow, but the current applications of these approaches have limited effectiveness in cooling the underground space. The third category is the application of geo-structures to recover natural heat in mines. Based on the principles of the chiller/heat pump cycle and the characteristics of heat sources and sinks in mines, the potential and constraints of each technology were discussed and summarized. This study provides a scientific reference for the selection of suitable heat governance and utilization technologies. [ABSTRACT FROM AUTHOR]

In the present scenario, the underground chambers of deep metal mines are plagued by excessively high temperatures, and the existing adiabatic materials have proven to be inadequate in addressing this challenge. Considering these issues, this study introduces an innovative adiabatic and flame-retardant SiO 2 aerogel-based fibrous composite designed specifically for underground applications. The optimal preparation method for SiO 2 aerogel preparation was identified through monomer and orthogonal experiments, ultimately achieving a low thermal conductivity coefficient of 0.028 W/(m·K). Subsequently, through integral moulding, a composite material was developed, incorporating the optimal SiO 2 aerogel as a precursor along with ceramic fibres. The resulting ceramic fibre/SiO 2 aerogel exhibited an increased thermal conductivity coefficient of 0.061 W/(m·K). When subjected to a high-temperature combustion source of approximately 700 °C, the temperature of the upper surface of the sample was maintained at 131.9 °C and its mass loss rate was a mere 1.2%, exhibiting strong adiabatic and flame-retardant capabilities of the composite material. Moreover, the composite material exhibited good hydrophobic, adsorbent, and mechanical properties, making it well-suited for underground chamber applications. The research conducted on SiO 2 aerogel and its adiabatic ceramic fibre composite not only holds theoretical significance by guiding the development of improved adiabatic materials but also provides practical engineering solutions for mitigating heat transfer through raw rock and reducing chamber temperatures in underground mining environments. [ABSTRACT FROM AUTHOR]

In order to alleviate the problem of mine thermal damage, this paper proposes to put cold water pipe into the surrounding rock of roadway, and reduce the temperature of surrounding rock by intercepting the high temperature through the cold water pipe. According to the similarity principle, a cold water interception and cooling experimental system for high temperature surrounding rock was built. Experiments were conducted by changing cold water velocity, inlet time and surrounding rock temperature, etc. Combined with COMSOL simulation, the influence of different diameters and spacing layouts of cold water pipe on cold water interception and cooling effect of roadway surrounding rock was analyzed. The results show that when other conditions remain unchanged, the cooling range of surrounding rock increases with the increase of cold water velocity, inlet time and temperature difference between surrounding rock and cold water. When the diameter of the cold water pipe is 10 cm and the vertical distance is 2.5 m, the average temperature of the roadway wall after cooling is 23.4 ℃.

In this paper, the deep hole and shallow hole temperature measurement technology is used to measure the rock temperature in No.13 mining area of Yangchangwan Coal Mine, and the cooling circle range of 937 m elevation roadway for the return air downhill in No.13 mining area and 430 m elevation roadway for the auxiliary transportation downhill in No.13 mining area are determined. The COMSOL software is used to analyze the surrounding rock temperature distribution, and the reliability of the surface borehole temperature measurement data is verified according to the temperature measurement results. Combined with the ground borehole temperature measurement data and the deep hole and shallow hole temperature measurement results, the ground temperature gradient and the heat damage area are defined, which provides a basis for the subsequent heat damage treatment.

As the depth of mines continues to increase, the problems of high temperature and potential heat damage become more prominent. In this study, the characteristics of natural and industrial heat sources in mines were reviewed, and then mainstream heat hazard governance technologies and corresponding utilization methods were discussed and compared. The first category of technologies comprises the optimization of ventilation systems, the insulation of roc heat, and artificial refrigeration. These cooling approaches are limited because the heat resources cannot be recovered. The second category is the utilization of waste industrial heat in mines, including the use of waste heat from the air compressors, drainage water, and foul airflow, but the current applications of these approaches have limited effectiveness in cooling the underground space. The third category is the application of geo-structures to recover natural heat in mines. Based on the principles of the chiller/heat pump cycle and the characteristics of heat sources and sinks in mines, the potential and constraints of each technology were discussed and summarized. This study provides a scientific reference for the selection of suitable heat governance and utilization technologies.

Taking Xinjulong Mine in Juye Mining Area as the object, the ventilation difficulties and cooling difficulties were analyzed, and a graded cooling method combining the full air volume cooling at the wellhead and the underground centralized cooling was proposed. The air flow temperature was studied to study its cooling effect. The ventilation route of the mine is extended, the cross section and direction of the tunnel and the bifurcation or convergence point increase, the resistance and local resistance of the wind flow increase, and the heat production of air compression increases. The heat exchange between wind flow and surrounding rock is strengthened, which aggravates the heat damage of high-temperature mines. The full air volume cooling system at the wellhead is used to reduce the air flow temperature at the air inlet of the mine, leaving the high temperature air flow heat on the ground. The underground centralized cooling system is used to solve the air flow cooling of the underground working face. After cooling, the temperature of the air flow at the entrance of the wellbore is kept below 19 ℃. After the air flow enters the bottom of the well, the temperature along the ventilation route is relatively stable, and the overall variation range is within 2 ℃. After adopting the underground centralized cooling system, the temperature difference between the inlet and return air of the working face is 4 ℃. The combination of wellhead cooling and downhole cooling can effectively improve the underground environment.

Aiming at the thermal hazards of mining face in Mengcun Coal Mine, a movable air chilled refrigeration system for coal mining face is studied based on the mine water supply and drainage system to reject heat. According to the present situation of thermal hazards in Mengcun Coal Mine, the chilling requirement of coal mining face is calculated. The applicability of two local refrigeration systems, water cooling and air cooling, in coal mining face is analyzed. The characteristics of water gushing from coal seam roof and low water temperature are analyzed. The technology of moving air-chilled refrigeration system in coal mining face is proposed, where the cooling water of refrigeration unit is taken from mine water supply pipeline and discharged to tunnel water ditch. A ZLF-450 movable air-chilled refrigeration unit was selected to test in the first mining face. The results show that: the return water temperature of the cooling water from the refrigerator is slightly higher than that of the mine water, and the water temperature rising after mixing with the water from the mining face in the ditch is only 0.4 ℃; the refrigeration unit operates normally, energy efficiency ratio reaches 3.05 and average temperature of the working face reduces by 2.8 ℃; the system uses mine water supply and drainage system to reject heat without laying any special pipeline for refrigeration system, which greatly reduces the cost of the refrigeration system.