Influence of airflow movement on methane migration in coal mine goafs with spontaneous coal combustion

Spontaneous coal combustion was proved to cause methane accumulation and methane explosions in coal mine goafs. To avoid possible methane explosions, the empirical engineering measure, ventilation dilution, is proposed in coal mines though its disaster prevention mechanism has not been well understood. Through experimental and numerical simulations, the superposition effect of the air leakage and coal combustion induced chimney effect was studied to reveal disaster prevention effect of ventilation dilution. Research results show that the high temperature area of coal combustion is steady and can provide continuous buoyancy force to form upward airflow even under ventilation dilution; the drifting methane accumulation is observed under the superposition effect of air leakage and upward airflow; ventilation dilution can weaken and even eliminate methane accumulation by overcoming chimney effect, but an increase in coal combustion temperature will enhance the upward airflow of chimney effect to cause methane accumulation again. The competitive relationship between the coal combustion-induced chimney effect and air leakage provides a new insight to study methane migration for the disaster formation and prevention mechanism. (c) 2021 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Automated summary

Spontaneous coal combustion in coal mines can lead to methane accumulation and explosions. Ventilation dilution is an empirical engineering measure proposed to prevent disasters, and it can weaken methane accumulation but an increase in coal combustion temperature may cause methane accumulation again. The competitive relationship between coal combustion-induced chimney effect and air leakage provides new insights for studying methane migration in disaster formation and prevention mechanisms.