Principles and technology for the substitution of strip coal pillars with coal refuse

Abstract

This paper analyzes the fundamental principles of the substitution of strip coal pillars with coal refuse through the combination of theoretical analysis, physical simulation and numerical calculation with engineering practice. We propose to lay out roadways through strip coal pillars in a reasonable manner so as to produce a coal-rock bearing mass consisting of stowboards (i.e., roadways backfilled with coal refuse) and coal pillars that substitute the original strip coal pillars. The bearing mass bears the roof pressure and preserves the stable structure of overlying strata during extraction. This paper systematically studies the process of the substitution of strip coal pillars with coal refuse, mainly focusing on the selection of the position of the roadway for backfilling, excavation and support of the roadway, haulage of the coal refuse, design of the coal refuse bin and the backfilling and compacting technology of the coal refuse. Engineering application shows that surface deformation is controlled within the Level I deformation band of national regulations, and the proposed technology yields remarkable economic benefits at the experiment site.