Analyze the causes and propose solutions to prevent an increased temperature of the longwall in Khe Cham III coal mine

Abstract

During the coal mining period in the fourth quarter of 2020, the air temperature increased in mining areas and the survey results on the current state of the longwall 14.5.20 at Khe Cham III coal mine, showed that the air temperature rises to 320C and exceeded the permit regulation (300C) of QCVN 01/2011/BCT. To a nalyze the relationship between oxygen adsorption capacity and temperature in coal samples, coal samples were taken at the head and bottom of the coalface. The result shows that the oxygen adsorption constant U25 = 0.0032 is the largest in the coal samples, while the Russian standard for self-ignition of coal is U25 ≥ 0.016. Therefore, the coal samples of Khe Cham III coal mine are low self-ignition. Thus, it can be seen that the causes leading to the increase in temperature in the longwall 14.5.20 due to the compression of the road ventilation, the only measured airflow is 7.68 m3/s, while the required airflow is 16 m3/s. On the other hand, due to the influence of thermal radiation from the surrounding rock, the area has finished mining on the longwall and the road is narrow lead to the airflow is not small enough to carry this heat out. To ensure safety in the mining process when there are signs of increasing temperature from the mining areas. The article proposed solutions to complete the ventilation system; drilling and pumping water into the coal face; construct walls to isolate the exploited area to prevent oxidation of coal and temperature in the goaf spread to longwall.