Blasting-enhanced water injection for coal and gas out-burst control

Yang, Wei; Lin, Minghua; Walton, Gabriel; Lin, Baiquan; Sinha, Sankhaneel; Lu, Changzheng; Guangtao, LI

doi:10.1016/j.psep.2020.05.013

Cited by 28 publications

(13 citation statements)

References 36 publications

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“…Mining activities must be stopped immediately if the coal temperature becomes abnormal—namely, if the coal temperature rise or temperature gradient exceeds the critical values. If the danger is identified, then outburst prevention measures, such as gas drainage, protective seam mining, and water injection [ 37 , 38 , 39 ], must be applied until the threat of an outburst is eliminated.…”

Section: Resultsmentioning

confidence: 99%

Research on Temperature Variation during Coal and Gas Outbursts: Implications for Outburst Prediction in Coal Mines

Zhang

Wang

et al. 2020

Sensors

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Coal and gas outbursts are among the most severe disasters threatening the safety of coal mines around the world. They are dynamic phenomena characterized by large quantities of coal and gas ejected from working faces within a short time. Numerous researchers have conducted studies on outburst prediction, and a variety of indices have been developed to this end. However, these indices are usually empirical or based on local experience, and the accurate prediction of outbursts is not feasible due to the complicated mechanisms of outbursts. This study conducts outburst experiments using large-scale multifunctional equipment developed in the laboratory to develop a more robust outburst prediction method. In this study, the coal temperature during the outburst process was monitored using temperature sensors. The results show that the coal temperature decreased rapidly as the outburst progressed. Meanwhile, the coal temperature in locations far from the outburst mouth increased. The coal broken in the stress concentration state is the main factor causing the abnormal temperature rise. The discovery of these phenomena lays a theoretical foundation and provides an experimental basis for an effective outburst prediction method. An outburst prediction method based on monitoring temperature was proposed, and has a simpler and faster operation process and is not easily disturbed by coal mining activities. What is more, the critical values of coal temperature rises or temperature gradients can be flexibly adjusted according to the actual situations of different coal mines to predict outbursts more effectively and accurately.

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Section: Resultsmentioning

confidence: 99%

Research on Temperature Variation during Coal and Gas Outbursts: Implications for Outburst Prediction in Coal Mines

Zhang

Wang

et al. 2020

Sensors

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“…Numerous previous studies have referred to the injection radii as equivalent radii. 36,47,48 However, the abovementioned simulation results and field data revealed that the wetting radii (r) were a function of the diffusion time, borehole length (l z ), and critical values (M ar ≥ 4.0% and W vf ≥ 0.7). Therefore, in the current study, the wetting radii of the CSWI were calculated by the ratio of S AUC to the length of the boreholes or eq 11, and the details are shown in Table 5.…”

Section: Mathematical and Physical Modelsmentioning

confidence: 98%

“…At the present time, three water injection methods have mainly been developed: face infusion, flank gate-road infusion, and remote infusion . Although the former two processes are considered to be simple and easy to implement, they were found to have inadequate effects in the previously examined coal seams. , In addition, longer boreholes have outstanding advantages in terms of wetting areas, process convergence, economy, and so on . Therefore, this study adopted the third method to perform related research.…”

Section: Materials and Experimental Processesmentioning

confidence: 99%

A Feasibility Study of Coal Seam Water Injection Processes: The Effects of Coal Porosity and Mass Flow Rates of Injected Water on Wetting Radii

et al. 2020

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Various effective methods of water injections for coal seams, which have been implemented in order to control coalmine disasters, have attracted substantial renewed interest in the fields related to water injection process parameters and the physical properties of coal seams. The water injection parameters, typically the mass flow rates of the water injections, are known to significantly affect the osmotic pressure levels and saturated wetting times. However, there remains a lack of effective evidence for wetting efficiency, such as wetting radii, infiltration regions, and diffusion times. In this study, the effects of porosity and mass flow rates were investigated using both numerical simulation and field application methods. The test results revealed that the moisture content, natural moisture absorption, firmness coefficients, and contact angles of the coal samples have satisfied the criteria for the identification of the feasibility of water injections in coal seams. In addition, the simulated results highlighted and quantified the wetting radii in different porosity and mass flow scenarios. The influencing effects of the wetting radii were mainly attributed to the constant flow rates of the water injections with the increased osmotic pressure, rather than the porosity levels. Moreover, as the porosity of the coal seams decreased, it was found that the water injection radii tended to increase. In comparison with the simulated results, the field measured results were also observed to demonstrate that there were remarkable improvements in the wetting radii when the porosity level equaled 7.2% combined with 3.88 m 3 /h. The findings obtained in this study will potentially be helpful in guiding and improving actual field applications.

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“…After blasting, gas extraction boreholes were arranged and the drilling field was utilized again to extract gas from top coal. It must be ensured that there should be one extraction borehole every other compound drilling field and bottom of each extraction borehole should be made to face the goaf (Figure 14), and the gases in current drilling and blasting area and the last neighboring drilling and blasting area will be mainly extracted while interaction between gas extraction in current field and blasting in the next drilling field [21,28,49] should be prevented from borehole connection.…”

Section: Rapid Gas Extractionmentioning

confidence: 99%

“…e conventional top coal weakening process by blasting was redesigned and set up again, and the arranged blast drilling field was repeatedly utilized to conduct gas extraction [20][21][22] and top coal weakening by water injection [23][24][25][26], resulting in a multifunctional, mutually promoting, and cyclic top coal weakening process, in order to maximize the economic benefit and optimize the top coal weakening performance. While increasing economic benefit of a mine and preventing it from mine fire [27] and gas explosion [28,29], this process enabled less waste of coal resource and sustainable mine development.…”

Section: Introductionmentioning

confidence: 99%

A Case Study of Cyclic Top Coal Weakening Process Based on Highly Tough Coal Seam with Partings

Wang

Wan

et al. 2021

Shock and Vibration

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The top coal weakening process is an effective mean to increase the coal output, reduce the coal resource waste, and promote the sustainable development in a mine. The conventional blast weakening process and water injection weakening process are more widely applied in fully mechanized caving mining of hard thick coal seams, but under some special complex geological conditions, no desirable performance has been achieved in top coal weakening by one weakening process alone after substantial investment in capital and equipment. In the context of highly tough top coal with partings at working face 110501 for fully mechanized top coal caving mining in Yushutian Coal Mine, effects of parting band and high toughness on top coal breaking were studied in terms of mechanism and extent, a multifunctional compound drilling field integrating blast weakening, water injection weakening, and gas extraction was purposefully designed, and a cyclic top coal weakening process for highly tough coal seams with partings was proposed. Engineering practice and performance testing show that degree of fragmentation and mobility of top coal was improved, mean top coal recovery ratio at the working face increased by about 35%, coal resource waste decreased, and potential risks of gas explosion and mine fire were eliminated, which provides reference for top coal weakening process under similarly complex engineering conditions.

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Blasting-enhanced water injection for coal and gas out-burst control

Cited by 28 publications

References 36 publications

Research on Temperature Variation during Coal and Gas Outbursts: Implications for Outburst Prediction in Coal Mines

Research on Temperature Variation during Coal and Gas Outbursts: Implications for Outburst Prediction in Coal Mines

A Feasibility Study of Coal Seam Water Injection Processes: The Effects of Coal Porosity and Mass Flow Rates of Injected Water on Wetting Radii

A Case Study of Cyclic Top Coal Weakening Process Based on Highly Tough Coal Seam with Partings

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