Evolution of cracks in selvedge of the coal bed during its stationary working
E. Feldman1, N. Kalugina2, O. Chesnokova1
1Coal and Rock Physics Department, Institute for Physics of Mining Processes of the National Academy of Sciences of Ukraine, Dnipro, Ukraine
2Institute for Physics of Mining Processes of the National Academy of Sciences of Ukraine, Dnipro, Ukraine
Min. miner. depos. 2017, 11(2):41-45
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Purpose.To study rupturing of the coal/rock seam selvedge by natural gas-filled cracks as phenomena that prepare and initiate sudden outbursts of coal, rock, and gas during the steady movement of the face.
Methods. The work is based on theoretical studies, including methods of thermodynamics, statistical physics, and asymptotic analysis.
Findings. A generalized Griffith’s criterion for the material rupture by a crack is applied to the selvedge part of a gas-saturated coal/rock seam during its stationary unloading.
Originality. The kinetic theory describing processes of gas-containing materials destruction is developed using the example of rupturing the selvedge part of a coal/rock seam by natural gas-filled cracks.
Practical implications. The criterion for changing the control parameters (reservoir gas pressure, crack dimensions, rock pressure, surface coal/rock energy, elastic modulus) is found at which spontaneous failure of the seam becomes possible. This allows to discuss the possibility of predicting sudden outbursts of coal, rock and gas.
Keywords: main crack, gas, coal bed, face advance
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