Optimization of Drilling Layouts Based on Controlled Presplitting Blasting through Strata for Gas Drainage in Coal Roadway Strips

Zhicheng Xie, Dongming Zhang, Zhenlong Song, Minghui Li, Chao Liu and Dongling Sun
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Zhicheng Xie: State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400030, China
Dongming Zhang: State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400030, China
Zhenlong Song: State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400030, China
Minghui Li: State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400030, China
Chao Liu: State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400030, China
Dongling Sun: Gas Research Institute, Chongqing Research Institute of China Coal Technology and Engineering Group Corp, Chongqing 400037, China

Energies, 2017, vol. 10, issue 8, 1-13

Abstract: The controlled presplitting blasting technique is widely used in mining engineering to improve the permeability and gas extraction efficiency of coal seams. One of the key factors is the appropriate arrangement of the blasting and drainage holes, which can help improve the gas drainage quantity. To optimize the drilling layout to enhance gas-drainage efficiency, a series of controlled presplitting blasting tests were conducted at the Pingdingshan No. 8 coal mine. Based on the analysis of variations in stress and longitudinal-wave velocity of the coal in different blasting ranges, the results show that the stress on the coal at a distance of 1 m from the blasting hole decreased significantly after blasting; thus, the coal exhibited negligible bearing capacity and the longitudinal-wave velocity decreased by 56%. However, the coal exhibited particular bearing capacity at a distance of 3 m away from the blasting hole, and the longitudinal-wave velocity decreased by 35%. The stress and longitudinal-wave velocity at a distance of 5 m from the blasting hole were unaffected by the blasting. The blasting integrity rate of coal k v was defined to characterize the effect of blasting on the coal-seam fracture. The effective cracking and effective influence radii of blasting under these working conditions were predicted to be in the ranges 3.3–3.4 m and 7.2–7.3 m, respectively. According to the test results, the borehole layout was optimized in the field testes for gas drainage in coal roadway strips, and the amounts of pure gas extracted after blasting were thus increased by 1.54–2.24 times the amount before blasting.

Keywords: mining engineering; controlled presplitting blasting; gas pre-drainage; longitudinal-wave velocity; drilling layout (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2017
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (3)

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