Role of convergence behaviour for superior recovery of thick coal seams in underground mines by blasting gallery

摘要

Indian coal mining industry is starving for want of a technology which can extract deep seated thick coal seams. Blasting gallery (BG) method is applied for thick coal seam in underground. This technology ensures better percentage of extraction, ease of management, more safety and cost efficient. Though, it has limited applications in gassy coal seams still it yields an excellent result in a few Indian underground coal mines. Caving characteristics of overlying roof strata during liquidation of a coal seam vary from place to place depending upon the depositional condition of the site. Coal mining with caving has always an edge over partial extraction or a stowing face due to technical simplicity, favourable economics and high production and productivity. Unfortunately, Indian geo-mining conditions make it very difficult for a mine planner to opt for a caving coal mining face mainly due to the presence of massive overlying strata. In this paper prerequisites, development conditions, detailed extraction procedure and study of convergence of strata as the working progresses considering all the operational variables to designing a site-specific model of relevance to current days mining have been discussed thoroughly. Having control on strata by such scientific approach, the extraction of thick seam mining by blasting gallery method will yield highest percentage of recovery with utmost safety.