Numerical investigations of ventilation and methane flow behaviour around the longwall shearer

Gas management in underground coal

mines remains a challenging issue for

mine operators. Computational Fluid

Dynamics (CFD) models of typical

longwall faces have been developed and

validated using field ventilation survey

data. The models were then used to study

both airflow and methane dispersion

patterns as a result of different shearer

cutting sequence. Modelling results show

that shearer cutting sequence has a

significant influence on the face

ventilation airflow and hence gas

accumulation around the shearer. When

the shearer is cutting from MG towards

TG, the maximum gas concentration

close to the coal face can reach as high as

2.00%, a situation which may not be

detected timely by gas sensors currently

mounted on the shearer. The

accumulation of methane is more

significant in the MG-TG pass, where the

methane-air mixture may fall in the

explosive range around cutting drum.