Prediction of gas emission from floor coalbed of steeply inclined and extremely thick coal seams mined using the horizontal sublevel top-coal caving method

Abstract

ABSTRACTIn the steeply inclined and extremely thick coal seams (SIETCS) mined using the horizontal sublevel top-coal caving (HSTCC) method, the uncertainty of gas emission is a safety threat to the mining operations. In order to reduce the occurrence of accidents, the determination of gas emission is crucial. In this paper, we first proposed a prediction model for workers at the floor coalbed to calculate gas emission on site. We then put forward a finite-element numerical simulation for researchers to predict gas emission from the floor coalbed. At last, we measured gas emitted from the floor coalbed of SIETCS in Wudong Coal Mine in a specific mining period and used the data to verify the applicability and accuracy of these two gas-emission prediction methods. The results showed that the gas emission from Wudong Coal Mine was 1.0802 m3/min calculated based on the prediction model and 1.07 m3/min obtained using the user-defined integration method. According to the field measurement, the gas emission amount is 1.032 m3/min, and the error analysis of the two preceding prediction methods is 4.67% and 3.68%, respectively. The two methods are thus beneficial and worthy of widespread use, and they have advantages and disadvantages from the perspective of application and academic research. In future production, targeted countermeasures can be implemented to achieve safe and efficient production of coal mines.