Development of pillar extraction strategy for a coal panel and rib pillar stability index under the influence of the goaved-out panels

Generally, a goaved-out panel develops high stress concentration in and around the panel, which results in deterioration of pillar stability and enhance roof stability issues of the surrounding workings. The effect of goaved-out panels in terms of the abutment load needs to be considered for the design of different parameters of an underground mining method to be adopted in the surrounding areas. In this study, the impact of an overlying and three surrounding goaved-out panels, which is a rare mining condition for a developed working, is analyzed. Also, a suitable manner of extraction for the coal pillars of the panel under the influence of the goaved-out panels is designed. A systematic parametric study, varying geological strength index (GSI), width of the rib pillar, height of extraction, and mining depth, is conducted using numerical modeling technique to develop rib pillar stability index for the rib pillars, formed in the designed manner of pillar extraction.