A calculation method of gas emission zone in a coal mine considering main controlling factors

Abstract

The gas emission zone is an important parameter for the space–time effect of coal excavation and gas emission. In this paper, according to the effect of roadway excavation, a numerical model of gas emission zone based on the evolution of stress and permeability was established to obtain the width of gas emission zone with different pressure and permeability coefficient. Then the numerical simulation results were verified by measuring the gas content at different depths. Through numerical simulation and field measured data, the theoretical calculation formula is established on the basis of comprehensive consideration of the influencing factors of gas emission zone. The results showed that the gas emission zone increases with the increase of coal seam gas pressure and permeability coefficient when the roadway section and exposure time are the same. The measured gas emission zone, when taking gas content as the index with the same logistic function growth curve, matches the measured results with a relative error of 1.3 to 6%. The validity of the model is also verified by field experiments. The results can provide guidance for mine gas emission and gas drainage design.

Technogenic Reservoirs Resources of Mine Methane When Implementing the Circular Waste Management Concept

“…This means that the formed new crack system, after planting the main roof, leads to establishing more favorable conditions suitable for draining gas from the massif. In similar cases, analytical studies on the distribution of air and gas flows are most often used [64] based on known laws of aerodynamics, and/or the actual parameters of the ventilation network are introduced into the DEM model followed by the subsequent use of CFD modeling application software packages. For example, in the conditions of the Daxing mine (Liaoning Province), namely the "Y"-type ventilation scheme, the degassing parameters of the mined-out space were modeled using FLAC3D and FLUENT software [65].…”

Studies on the Influencing Factors of Gas Emission in a Steeply Inclined and Ultrathick Coal Seam Working Face

“…Chen et al 11 constructed a dynamic gas emission prediction model by comprehensively considering the parameters affecting the gas emission quantity. Chen et al 12 established a gas emission zone on the basis of the evolution law of stress and permeability and obtained a gas emission prediction model by the numerical simulation and field measurement of the gas emission zone. The accuracy of the prediction model was verified with a relative error of 1.3–1.6%.…”