Methane migration patterns in the goaf of a Y-type ventilated working face with gob-side entry.

Abstract

Methane accumulation in the upper corners of coal mine working faces poses significant safety risks. Y-type ventilation combined with gob-side entry retaining has been applied to improve gas dispersion; however, airflow convergence can still result in high methane concentrations near the return airway. To address this, a computational fluid dynamics (CFD) model was developed to simulate methane migration in the goaf under different drainage strategies. Results indicate that methane concentration increases with elevation and distance from the working face, and is consistently higher along the gob-side entry than on the intake side. Buried pipelines effectively reduced methane levels near the floor and along the gob-side, while high-level boreholes were more effective in the caved zone but less so in the overlying fractured zone. A combined drainage approach was found to yield the most comprehensive reduction across all regions of the goaf. These findings provide valuable insights for optimizing methane control in Y-type ventilated mining operations.