Identification Model and Indicator of Outburst-Prone Coal Seams

Jiang, Cheng‐Lin; Xu, Lehua; Li, Xiaowei; Tang, Jun; Chen, Yujia; Tian, Shixiang; Liu, Huihui

doi:10.1007/s00603-014-0558-0

Cited by 82 publications

(26 citation statements)

References 12 publications

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“…In particular, gaso-geodynamic hazards (including outburst hazards), linked to the co-occurrence of a solid and gaseous resource, are predominantly connected with the coal-methane system. During an outburst, the gas accumulated in the pore structure of a rock does work by comminuting the rock material and transporting it down the excavation (Beamish and Crosdale 1998;Cao et al 2001;Topolnicki et al 2004;Skoczylas 2012;Wang et al 2013;Jiang et al 2015). With the specific needs of the coal mining industry in mind, various research methods have been developed, which make it possible to evaluate the methane content of a given coal seam (Szlązak and Korzec 2016).…”

Section: Introductionmentioning

confidence: 99%

Balancing the amount and composition of gas contained in the pore space of cupriferous rocks

Kudasik

Skoczylas

2018

Environ Earth Sci

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From the perspective of economy and safety, balancing gas contained in the pore space of rocks is extremely essential, predominantly to establishments dealing with extraction of mineral resources. One of the main methods of evaluating the amount and composition of gas contained in the pore space of a rock is releasing the gas as a result of comminuting the investigated rock material. In the case of cupriferous rocks, effective comminution is a very difficult task, due to the strength properties of these rocks. The present paper discusses the results of studies into the gas content of cupriferous rocks, obtained by means of an original device named the GPR analyzer. The research was done on 41 samples of dolomites and anhydrites from various areas of two copper mines located in Poland: "Rudna" and "Polkowice-Sieroszowice." For all samples, on the basis of microscope analyses performed on cuts and polished sections, the open porosity, closed porosity, and total porosity were determined. In the case of the dolomite samples, the total porosity variability fell in the range of 4.75-23.05%, and in the case of the anhydrite samples-in the range of 3.87-16.60%. The maximum gas content of the dolomite samples was 166.67 cm 3 /kg, and of the anhydrite samples-84.66 cm 3 /kg. In some of the studied samples, the presence of methane was confirmed. Toxic gases, such as H 2 S, were not found. The main gas in the pore space of the investigated rocks was nitrogen. Knowing the amount of the released gas and the value of the closed porosity in the investigated samples, the authors were able to estimate the pore pressure of the gas, whose maximum value was 0.583 MPa.

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Section: Introductionmentioning

confidence: 99%

Balancing the amount and composition of gas contained in the pore space of cupriferous rocks

Kudasik

Skoczylas

2018

Environ Earth Sci

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“…Based on the cast distance and particle separation appearance of the scattered pulverized coal, Jiang divided the outburst results into three types: strong outburst (C-type), weak outburst (B-type), and no outburst (A-type): In C-type, the pulverized coal was cast to a greater distance of 5~6 m with apparent separation of the scattered pulverized coal; in B-type, the pulverized coal was cast to a distance of less than 2 m with no particle separation found; in A-type, only a small amount of flow was found when opening the rapid exposure device [5,26]. The outburst results in this work were divided into three types by the above indicators, as shown in Table 1.…”

Section: Outburst Experimental Phenomenamentioning

confidence: 99%

“…The understanding of the impact mechanism of in situ stress on outbursts is constantly being enriched with existing studies, but it has yet to be comprehensive. According to theoretical analysis, the released gas may vary for coal under different stresses [23][24][25], which could exert an influence on the outburst risk due to its potential energy contribution in the outburst [26][27][28]. In other words, the in situ stress may influence the outburst by affecting the intensity of the gas release.…”

Section: Introductionmentioning

confidence: 99%

Gas Release Characteristics in Coal under Different Stresses and Their Impact on Outbursts

et al. 2018

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The impact mechanism of in situ stress on outbursts plays a key role in the prevention of outbursts during deep coal mining. The in situ stress may influence the outburst by affecting the gas release intensity according to theoretical analysis, but none of the existing studies have taken into consideration this perspective. To explore whether the influence of in situ stress on gas release in coal is an important reason for stress-induced outbursts, experiments on gas release in coal under different axial stresses and on exposure-induced outbursts with different gases were conducted to respectively study the influence of in situ stress on gas release and the impact of gas release on outburst. The results show that with the increase of stress, the methane release intensity rises by 1~2.4 times and shows an obvious periodicity due to different degrees of fracture development. A small increase in gas release intensity can lead to huge increase in the outburst intensity based on an energy analysis of the outburst experiments, indicating that the gas release intensity is a sensitive physical quantity that influences outbursts. The differences in gas release in coal with different stresses will result in differences in the outburst results based on data from the two experiments, proving that the change in gas release intensity during variations of in situ stress is an important factor for in situ stress-induced outbursts. The research achievements can enrich the impact mechanism of in situ stress on outbursts.

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“…23,24 Although these theories commonly link the propensity for outbursting to the presence and action of "outburst-prone coal" (Figure 1), the key features of its dynamic failure characteristics under impact loading remain poorly understood and constrained. [25][26][27][28][29][30][31][32] Although the quasi-static physical properties of coal and rock have been studied widely, the dynamic failure characteristics of coal and rock are less fully constrained. 5 Dynamic properties of interest include the following: density, wave velocity, porosity, strength, scale effect, bedding effect, the influence of moisture, and energy dissipation.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation on dynamic strength and energy dissipation characteristics of gas outburst‐prone coal

Fan

Elsworth

et al. 2019

Energy Science & Engineering

113

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We report laboratory experiments to investigate the dynamic failure characteristics of outburst‐prone coal using a split Hopkinson pressure bar (SHPB). For comparison, two groups of experiments are completed on contrasting coals—the first outburst‐prone and the second outburst‐resistant. The dynamic mechanical properties, failure processes, and energy dissipation of both outburst‐prone and outburst‐resistant coals are comparatively analyzed according to the obtained dynamic compressive and tensile stress‐strain curves. Results show that the dynamic stress‐strain response of both outburst‐prone and outburst‐resistant coal specimens comprises stages of compression, linear elastic deformation, then microfracture evolution, followed by unstable fracture propagation culminating in rapid unloading. The mechanical properties of both outburst‐prone and outburst‐resistant coal specimens exhibit similar features: The uniaxial compressive strength and indirect tensile strength increase linearly with the applied strain rate, and the peak strain increases nonlinearly with the strain rate, whereas the elastic modulus does not exhibit any clear strain rate dependency. Differences in the dynamic failure characteristics between outburst‐prone and outburst‐resistant coals also exist. The hardening effect of strain rate on outburst‐prone coal is more apparent than on outburst‐resistant coal, which is reflected in the dynamic increase factor at the same strain rate. However, the dynamic strength of outburst‐prone coals is still lower than that of outburst‐resistant coals due to its low quasi‐static strength. The dissipated energy of outburst‐prone coal is smaller than that of outburst‐resistant coal. Therefore, the outburst‐prone coal, characterized by low strength, high deformability, and small energy dissipation when dynamically loaded to failure, is more favorably disposed to the triggering and propagation of gas outbursts.

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Identification Model and Indicator of Outburst-Prone Coal Seams

Cited by 82 publications

References 12 publications

Balancing the amount and composition of gas contained in the pore space of cupriferous rocks

Balancing the amount and composition of gas contained in the pore space of cupriferous rocks

Gas Release Characteristics in Coal under Different Stresses and Their Impact on Outbursts

Experimental investigation on dynamic strength and energy dissipation characteristics of gas outburst‐prone coal

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