Abstract
The 8939 working face in Xinzhouyao coal mine is a high coal bump proneness panel. For coal bump prevention, rib holes are drilled for pressure relief purpose. The deformational behaviour of the pressure relief borehole is studied using distributed optical fiber sensing technology. The strain of the surrounding coal and the pressure relief range were measured from 0 hrs to 402 hrs after hole drilling. Based on the analysis of pressure relief procedure, combining with borehole observation, the crack development, limited equilibrium, collapse, and compaction stages of the borehole were estimated as 0∼72 h, 72∼190 h, 190∼402 h, and greater than 402 h, respectively. Consequently, the hole drilling is modified to 110 m ahead of the working face to achieve better pressure relief effect. Microseismic monitoring shows that, after hole drilling optimisation, the high-energy microseismic events and average energy of microseismic events are reduced significantly.
Highlights
Along with increasing mining depth, geodynamic disasters, such as coal bump and coal and gas outburst, become one major issue that threaten mining safety and economy for underground coal mining industry [1,2,3,4]
Coal bump occurred at 132 underground coal mines in China
Is geodynamic disaster is closely relative to high ground stress and stress concentration around the coal pillar in the case of mulitseam mining [5,6,7]
Summary
Along with increasing mining depth, geodynamic disasters, such as coal bump and coal and gas outburst, become one major issue that threaten mining safety and economy for underground coal mining industry [1,2,3,4]. Pressure relief measures are often employed, which mainly include borehole drilling, injection, coal seam blasting, roof blasting, and floor blasting [12,13,14,15,16]. Distributed optical fiber sensing is one of them based on spontaneous Brillouin scattering principle It is being used in geotechnical engineering such as overburden subsidence measurement in coal mining industry [32,33,34]. BOTDR distributed optical fiber sensing technology is being used to monitoring the effect of pressure relief of drilling hole. Is study investigates borehole deformation and technical aspects of application of distributed optical fiber sensing technology in coal bump prevention Regular measurement of the deformation of surrounding coal was undertaken, combining with observation of the crushing procedure of the drilling holes. is study investigates borehole deformation and technical aspects of application of distributed optical fiber sensing technology in coal bump prevention
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