Estimation of rock load height during development operation in bord and pillar coal mine using numerical simulation method

Abstract

Bord and pillar mining is the predominant method for extraction of coal from underground in India. Strata control is a major problem affecting safety and productivity of the mine. In conventional method of extraction worked by LHD/SDL has gallery width up to 4.8 m. However, in mechanized mining operation, gallery width goes up to 6.6 m. As per the Director General of Mine Safety (DGMS) guidelines, suggested support pattern is given for gallery width up to 4.8m. In this paper, the study focused to develop generalized equation of roof failure height during development working for wider gallery operation. The input parameters have taken into consideration are rock mass rating (RMR), uniaxial compressive strength (UCS), in - situ stress ratio, depth of working, ratio of gallery width to height. The immediate roof of the model has considered as elasto - plastic in nature. By, considering all these parameters rock load height has been estimated at gallery and junction of the mine during development operation. A generalized equation has been made for gallery as well as junction with the help of regression analysis based on numbers of model results, considering all the input parameters. The required support load density has been estimating with the help of generalized equation. For calibration of the model results, number of case studies has been solved and analyzed. © 2018 AMSE Press. All rights reserved.