Coal pillar loading in shallow mining conditions

Finite element modeling of stress distributions and problems for multi-slice longwall mining in Bangladesh, with special reference to the Barapukuria coal mine

“…"Hydraulic sand stowing" can be considered as a remedial shield to reduce fracture development, roof subsidence, and the associated potential for water inflow hazards by reducing mininginduced stress from 13.3 MPa to 6.5 MPa. This practice is welldeveloped in some Indian coal mines such as the Lachhipur, Samla, and Madhusundanpur collieries (Singh et al, 1996).…”

Longwall chock sudden closure incident below coal pillar of adjacent upper mined coal seam under shallow cover in the Shendong coalfield

“…The traditional standpoint, however, failed to explain the sudden closure of the supports (may arguably explain gradual closure) and the reason why failure occurs merely when LW face leaves pillar instead of entering it. After conducting critical literature review it is noticed that the previous studies mainly focus on optimizing layout of maingate (MG) and tailgate (TG) under coal pillars [6], estimation and numerical simulation of pillar load and strength [7][8][9][10][11][12], coal pillar stability evaluation [13], and coal pillar recover techniques [14], etc. Nevertheless, few studies regarding the strata behavior control and roof management during the face mining through the upper coal pillar can be referred and all of them are limited to the statistics analysis and summarization of the strata behavior in the mining process [15][16][17], lacking the revelation of the mechanism and regulation of according preventative measurements.…”

Evaluation of induced vertical stress during depillaring in blasting gallery panel workings

“…Jayanthu et al (2004) found that the maximum vertical stress over rib and stook decreases with increase in working height during depillaring. Field investigations (Singh et al 1996) showed that the nature of development of mining induced stress over pillar/stook at different stages of depillaring, for a nearly flat coal seam, is influenced by different parameters like depth of cover, characteristics of overlying strata, distance from face line, extraction height and goaf treatment.…”

“…Safe and efficient underground extraction of coal pillars under competent roof strata needs information about amount and nature of the mining induced vertical stress over pillars in and around the Blasting Gallery (BG) panel workings. However, the performance of these workings is highly dependent upon two types of stresses; mining induced stresses (Singh et al 1996) and in situ stress (Sheorey 1994). For a given site, the in situ stress is more or less static in nature but the mining induced stresses over pillars/stooks keeps changing and is highly influenced by the strata equilibrium dynamics during different stages of the underground coal mining activity.…”