Abstract
The main constrain for effective gas drainage in coal mines is the low permeability nature of coal reservoirs. As coal mining activities are extending to deeper subsurface, the ever-increasing in situ stress conditions is anticipated to result in much lower permeability and more challenges for gas emission control in coal mines. In recent years, hydraulic slotting using high-pressure waterjet along underground gas drainage boreholes, as a general solution to stimulate low permeability coal seams, has become increasingly favourable. This paper presents a systematic investigation into the sensitivity of borehole slotting performance to a number of field and operational parameters. A wide range of geomechanical properties, in situ stress conditions, slot geometry and spacing of multiple slots were considered in a series of numerical simulations. The relations between these key parameters and the failure zone size/volume induced by slotting were quantified. The effect of different parameters in improving slotting performance has also been ranked, which provides theoretical base for mine operators to optimise slotting operations.
Highlights
Coal mining is extending to deeper and deeper levels, facing ever increasing coal seam methane contents, higher methane emissions and gas outburst risks at production districts
The tectonosedimentary evolution of the Central Asturian coal basin results in a high friable and foliated 8# coal seam, and the coal is subject to the sudden variations in thickness and bed-parallel shearing, which largely increase the outburst risk at the mine (Aguado and Nicieza 2007)
The importance of slot diameter was noted by Lu et al (2011), in which they concluded that the increasing of slot diameter can
Summary
Coal mining is extending to deeper and deeper levels, facing ever increasing coal seam methane contents, higher methane emissions and gas outburst risks at production districts. Increased gas content of coal seams with depth, and the concentration of coal exploitation in fewer high productivity faces in recent years, have been the major cause of. The work was conducted at the Imperial College when he was a Research Associate there. In December 2017, Guangyao moved to Australia to take the Lecturer position at the School of Minerals and Energy Resources Engineering, the University of New South Wales
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