Managing methane and preventing methane layering is of paramount significance for safety in gassy underground coal mines. Methane layering behaviour and dispersion of methane in underground coal mines are influenced by several geo-mining parameters. In this paper, we investigate the effects of five important geo-mining parameters, such as air velocity, methane emission rate, width, surface roughness and inclination of mine gallery on methane layering and dispersion of methane in tailgate of a retreating longwall mine. The main objectives are to examine the effects of these parameters on variation of methane concentration and identify the critical parameters significantly affecting methane dispersion to a safer level in hard coal underground mines. Three-dimensional CFD simulations were performed using standard k-ε turbulence model taking into account the actual mine geometry and methane emission data of a gassy underground coal mine of India. The study revealed that air velocity plays a vital role on turbulent dispersion of methane and breaking methane layering in underground coal mines. Air velocity of 3.0 m/s was found adequate for dispersing methane to a safer level in the tailgate with 7.26 m³/min methane emission rate. Methane dispersion in the tailgate decreased with increase in methane emission rate and gallery width at a particular airflow rate. Increase in surface roughness and inclination of mine galley eased methane dispersion, nevertheless, their effects on methane dispersion found negligible.

管理甲烷和防止甲烷分层对瓦斯地下煤矿的安全至关重要。地下煤矿中甲烷的分层行为和甲烷的扩散受几个采矿参数的影响。在本文中，我们研究了五个重要的地质开采参数，如风速，甲烷排放速率，宽度，表面粗糙度和矿井倾角对后撤长壁矿井瓦斯中甲烷分层和甲烷扩散的影响。主要目的是检查这些参数对甲烷浓度变化的影响，并确定在硬煤地下煤矿中显着影响甲烷扩散至更安全水平的关键参数。考虑到印度瓦斯地下煤矿的实际矿井几何形状和甲烷排放数据，使用标准k-ε湍流模型进行了三维CFD模拟。研究表明，空气速度对地下煤矿瓦斯的湍流扩散和破坏甲烷分层起着至关重要的作用。发现3.0 m / s的空气速度足以在7.26 m的后挡板中将甲烷分散到更安全的水平³ / min的甲烷排放速率。在特定的气流速率下，后挡板中的甲烷分散度随甲烷排放速率和通道宽度的增加而降低。表面粗糙度和矿井厨房倾斜度的增加缓解了甲烷的弥散，尽管如此，它们对甲烷弥散的影响可忽略不计。