Methods and applications of coal seam destress-A comprehensive literature review

Coal mine and other type of mine workings continue to face the challenges, as mining activities are extending to deeper subsurface, the ever increasing stress conditions mostly ground stress is anticipated to result in much coal bumps, floor heave, roadway stability, roof failure, cutter failure and coalbursts/rockbursts etc, due to high overburden pressures associated with the extraction of brittle, low strength coal seams. Destress applications has been applied for almost a century to control these challenges or remove the stresses from the coal seam. The main goals of destress applications are the softening of competent rock layers, the reduction of strain energy storage, and rock mass stress release, which together contribute to minimizing rockburst occurrence and risk. This paper presents a comprehensive literature review of methods and applications of coal seam destress such as hydraulic fracturing techniques, destress blasting and drilling and discuss distribution of destress application in the past 100 years around the world. Almost every country use destressing methods for mining operations where high stress conditions have been an issue but there are some countries such as China, Australia, Canada, South Africa and United states they used mostly because of their adverse geomechanical and geological conditions and deep mining conditions. The paper discusses the main destress applications, methods and the evaluation of its effectiveness as a measure to overcome the challenges of high ground stresses causing different problems. Based on data collected from literature review both surface and underground coal mines and other types of mines, the work presented herein uses destress applications to show the coal seam destress associated with various parameters and geomechanical conditions.