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

Area of Science:

• Mining Engineering
• Safety Science
• Environmental Engineering

Background:

• Methane accumulation in coal mine working faces presents significant safety hazards.
• Y-type ventilation with gob-side entry retaining aims to improve gas dispersion but can lead to high methane concentrations.
• Airflow convergence in goaf areas exacerbates methane buildup, particularly near return airways.

Purpose of the Study:

• To develop and validate a computational fluid dynamics (CFD) model for simulating methane migration in goaf.
• To evaluate the effectiveness of different methane drainage strategies in Y-type ventilated coal mines.
• To identify optimal strategies for mitigating methane hazards in complex mining environments.

Main Methods:

• Development of a computational fluid dynamics (CFD) model to simulate gas flow and methane dispersion.
• Parametric study of various methane drainage techniques, including buried pipelines and high-level boreholes.
• Analysis of methane concentration distribution under different ventilation and drainage scenarios.

Main Results:

• Methane concentration increases with elevation and distance from the working face.
• Gob-side entry methane levels are consistently higher than on the intake side.
• Buried pipelines reduced floor and gob-side methane; high-level boreholes were effective in caved zones but less so in fractured zones.

Conclusions:

• A combined methane drainage approach, integrating buried pipelines and high-level boreholes, offers the most comprehensive reduction in methane concentration across the goaf.
• Optimized drainage strategies are crucial for mitigating safety risks associated with methane accumulation in Y-type ventilated coal mines.
• CFD modeling provides valuable insights for designing effective gas control measures in underground coal mining operations.