Wide stall mining for optimal recovery of coal from a thick seam under surface features

Abstract

The conventional method, splitting and stooking of a pillar, to optimise recovery of coal under built-up surface structures has limited scope for a multisection-developed thick seam under massive, immediate, roof strata and shallow depth cover. Taking advantage of the rapid increase of pillar strength with increase in its size, the conventional method to optimise recovery under built-up surface structures is replaced by widening of the existing galleries using the method called wide stall mining. The first field trial of the method was conducted under the geomining conditions of East Bhuggatdih colliery. Successful application of this method at East Bhuggatdih colliery provided nearly 42% coal from a multisection-developed 17 m thick coal seam without endangering the surface and subsurface structures. This paper describes the principles of wide stall mining together with the results of laboratory and field investigations.