Effect of Mining Height on Shield Resistance in Shallow Buried Longwall Panel

Abstract

Based on the field conditions of Huojitu Coal Mine of Shendong coal field in Northern China, eight dynamic numerical models are developed to examine the interaction between the shield and surrounding rock of the longwall panel. The models take into consideration the actual mining process and are developed to simulate the change in the working resistance of the shield for the same shallow burial but with different mining height conditions, ranging from 2.5 to 7 m. The results show that the average shield resistance during the basic roof initial and periodic weighting is 7 to 20 times the weight load of the mining height under the same shallow stratum conditions. By means of dimensional analysis, a relation between mining height and shield resistance in longwall panels is derived theoretically and is fitted by using the shield resistance data under different mining heights monitored in the numerical simulations. This work has led to a new method for the selection of shield support in shallow coal seams.