Study on Regional Strata Movement during Deep Mining of Erdos Coal Field and Its Control.

Abstract

Disasters such as rock bursts and mine earthquakes became increasingly serious with the increase in mining depth in Erdos Coal Field and became serious problems that restrict high-strength continuous mining of coal mines. In this study, strata movement and energy polling distribution of ultrathick weak-bonding sandstone layers were controlled by the local filling-caving multi-faces coordinated mining technique, which was based on the analysis of subsidence and overlying structural characteristics in the Yingpanhao mining area. Moreover, the influencing factors and the control effect laws were investigated. Surface subsidence and energy polling distribution control effects of different mining modes were compared, which confirmed the superiority of local filling based on the main key stratum. According to the results, the maximum surface subsidence velocity of the first mining face was 1.24 mm/d, which indicates the presence of a logistic functional relationship between the mining degree and subsidence factors. When the mining degree was close to full mining, the practical surface subsidence was smaller than the corresponding logistic functional value. The largest influencing factor for the strata movement control effect of partial filling mining based on the main key stratum was the width of the caving face, followed by the filling ratio, section pillar width, and width of the filling face, successively. With respect to the influencing degree on the energy polling distribution of partial filling mining based on the main key stratum, the order followed as section pillar width > filling ratio > caving working face > width of backfilling working face. Additionally, the comparative analysis from the perspectives of control effect, resource utilization, and cost-effectiveness demonstrated that partial filling mining based on the main key stratum was one of the techniques with high cost-effectiveness in controlling strata movement and relieving rock bursts, mining earthquakes, and subsidence disasters.