Strata behaviour during depillaring in Blasting Gallery panel by field instrumentation and numerical study

Abstract

Selection of a suitable mining method for economical and safe underground extraction of a thick coal seam is an extremely delicate process and brings a number of geotechnical parameters into consideration. Charbonnage de France (CdF) proposed Blasting Gallery (BG) for the extraction of virgin thick seams as well as developed pillars in thick seams in a single lift. The method was very successful resulting in 85 % of extraction with high productivity. But this method experienced strata control problems during final extraction at East Katras Colliery in Jharia Coalfield, Coal India Ltd., and also at GDK No. 8 Incline, Singareni Collieries Company Ltd. In this paper, the role of different parameters influencing development of mining-induced vertical stress, and maximum roof deformation in a BG 1/12 panel (GDK No. 8 Incline, SCCL) during depillaring in specific geomining conditions was visualized through numerical simulation models using ANSYS software. In this study, extensive field monitoring is carried out using modern instruments such as vibrating wire stress gauges, extensometers, load cells, and telescopic convergence rods to understand the strata behaviour during depillaring in the BG panel. Salient findings of field instrumentation data analysis such as mining-induced vertical stress development over the pillars, load over the support, bed separation at different horizons, and convergence of roof in rooms with face advance are presented in this paper. The results of induced stress, deformation, and factor of safety of pillar obtained by the finite element method (FEM) analysis are validated with the results of field instrumentation data analysis.

Study on overburden failure characteristics in deep thick loose seam and thick coal seam mining

“…The significant findings from the field instrument data analysis were presented, such as the vertical stress development on the column caused by mining, load on the support, and bed separation under different observation conditions. The induced stress, deformation, and safety factor of coal pillars were obtained using finite element method (FEM) analysis, which were consistent with the field data (Satyanarayana et al 2015). Numerical simulation software was used to analyze the failure of surrounding rock during caving mining in a thick coal seam.…”

“…Some experts and scholars have achieved good results in addressing the above problems related to thick loose layers and thick coal seams. Satyanarayana et al Satyanarayana et al Satyanarayana et al (2015) conducted extensive on-site monitoring and used modern instruments such as vibrating wire strain gauges, extensometers, load cells, and telescopic gathering rods to probe formation forces under load. The significant findings from the field instrument data analysis were presented, such as the vertical stress development on the column caused by mining, load on the support, and bed separation under different observation conditions.…”

Gray algebraic curve model-based roof separation prediction method for the warning of roof fall accidents

“…The underground roadway roof separation was monitored in time by fiber Bragg grating sensors . Salient findings of field instrumentation data analysis such as mining-induced vertical stress development over the pillars, load over the support, roof separation at different horizons, and convergence of roof in rooms with face advance were presented (Satyanarayana et al 2015). Khan et al (2015) use wireless sensor networks to determine cluster breakage by sudden disruptions caused by roof falls.…”