Classification of coal seam outburst hazards and evaluation of the importance of influencing factors

Abstract

Coal and gas outbursts are the result of several geological factors related to coal seam gas (coal seam gas pressureTo classify the outburst hazard level of a coal seam by means of statistical methods, this study considered the geological parameters of coal seam gas and statistical data on the amount of material involved in coal outbursts. Through multivariate regression analysis, a multivariate regression equation between the outburst coal quantity andUsing a significance evaluation of the aforementioned factors, the relative contributions of the gas-related geological parameters to the outburst hazard level of a coal seam were found to follow the orderThis work provides a scientific basis for evaluating the outburst hazard level of a coal seam and adopting feasible and economical outburst-prevention measures.

Problems in the Classification of Mine Gas Grades and Classification of Coal and Gas Outburst Mine Types

“…Based on the analysis of relevant factors causing coal seam outburst, the material basis of outburst is the structural coal bed containing gas, and the major factors causing outburst are coal seam gas pressure (ground stress) and so on [11] . When the gas-bearing capacity of coal seam is low (for example, the local gas-bearing capacity of coal bed in the outburst location of Chensilou Coal Mine is 4.98m 3 /t), the outburst can occur as long as the tectonic coal and gas pressure (geostress) reach a certain value (the statistical data show that the minimum gas pressure causing the outburst occurs in Sijiazhuang coal mine of Yangmei, and the gas pressure causing the outburst is 0.4MPa [7] .…”

“…Therefore, mine types can be divided into low gas coal mine and high gas coal mine according to quantity of gas emission and other indicators [1][2][3][4][5] , and non outburst mine and outburst mine can be divided according to whether the coal seam is outburst or not [6] , as shown in Table 2. of in-situ stress in the structural coal bed with gas occurrence [11] . In case of coal mine outburst accident or when the coal seam dynamic phenomenon characteristics are not obvious or there is no dynamic phenomenon, according to the actual measured coal firmness coefficient f, maximum gas pressure P, damage type of soft layered of coal bed and initial gas emission velocity of coal ΔP, If all indexes reach or exceed the critical value listed in next table, it is determined as outburst coal bed, and the mine is outburst coal mine [6] .…”

“…Therefore, coal seam outburst risk can be evaluated by coal seam firmness coefficient f, coal seam gas content W and coal seam gas pressure P; Combined with the quantity of coal outburst in coal seam, the outburst risk classification of outburst coal seam (i.e. the classification of outburst risk degree of outburst coal seam) is carried out, and the outburst strength of coal seam is predicted [11] , and then classify the outburst wells. Combined with coal seam outburst intensity, statistical data and production practice, according to the amount of outburst coal, using three single indexes of coal seam gas pressure, coal seam gas content and coal seam firmness coefficient, the outburst risk degree of outburst coal seam is divided into four categories: weak outburst risk, medium outburst risk, strong outburst risk and extremely strong outburst risk [11] , as shown in Table 4.…”

“…the classification of outburst risk degree of outburst coal seam) is carried out, and the outburst strength of coal seam is predicted [11] , and then classify the outburst wells. Combined with coal seam outburst intensity, statistical data and production practice, according to the amount of outburst coal, using three single indexes of coal seam gas pressure, coal seam gas content and coal seam firmness coefficient, the outburst risk degree of outburst coal seam is divided into four categories: weak outburst risk, medium outburst risk, strong outburst risk and extremely strong outburst risk [11] , as shown in Table 4. According to the actual outburst coal quantity, the outburst mines are divided into weak outburst mines, medium outburst mines, strong (serious) and extremely strong (extremely serious) outburst mines [11][12][13] , as shown in Table 5.…”

MLP-Based Model for Estimation of Methane Seam Pressure

“…One of the key indicators of the outburst hazard used currently for the forecasts is the methane seam pressure [2,[8][9][10][11][12]. This corresponds to the pressure generated by free methane contained in macropores and fractures of coal.…”