Comparing the “Modified Split and Fender” and “Shortwall” Methods for the Pillar Recovery in Room and Pillar Coal Mining Using A 3D Finite Difference Modeling in Tabas Central Coal Mine, Iran

Abstract

Selecting a suitable pillar recovery method is one of the most important issues in the room and pillar mining. The main purpose of this study is to compare two methods for pillar recovery in Tabas central coal mine (TCM). Among the existing methods, the two methods, “Modified split and fender" and “Shortwall" are chosen for the numerical modeling. The three dimensional finite difference method (FLAC3D software) is used to model these methods. In the next step, the vertical stress and displacement, the plastic zone condition and the safety factor during each stage of pillar recovery were compared for each method. The results of this modeling show that the percentages of coal recovery for two methods of “modified split and fender" and “shortwall" are around 70% and 82% respectively. Comparing the percentage recovery of coal for these two methods, exhibits that the shortwall method is more suitable than modified split and fender, for this mine.