36 / 2021-08-09 19:40:18

Explosion Prevention Strategies in Indian Coal Mine: A CFD Modelling Approach

Coal mine,Methane,Methane layering,Explosion,Dilution,CFD

The history of coal mining is marred by disasters causing huge loss of human life. Since 1901 Indian coal mining industry alone has experienced about 60 disasters resulting in more than 2222 fatalities. Occurrences of disasters at frequent intervals are still a matter of serious concern. Coal mine disasters in India had been caused mainly due to explosion, fire, inundation and ground movement (Bhattacharjee et al., 2019; Dash et al., 2019). Explosion in mine, mainly due to methane or coal dust or a combination of methane explosion followed by coal dust explosion had created havoc all over the world in the past.  In the list of top ten worst coal mine disasters in the recorded history, 9 disasters were due to explosion with a fatality range of 376 to 1549. The second worst disaster in Indian mining industry is also due to explosion.

Methane is more readily ignitable than coal dust. In most of the cases, coal dust explosions are first initiated by methane explosions. The strategy of explosion prevention in Indian mines is mainly rule based where the Coal Mines Regulation provides certain specific provisions for prevention and mitigation of explosion, methane and coal dust. However, the past and present experience shows that there remain lots of limitations and deficiencies in the existing rule based safety management system. The controls are either inadequate or ineffective. The explosion prevention strategy has not been developed so far as a strategy for improvement in the system, rather it is dealt on case to case basis.

Mine explosions remain a major threat to underground coal mine workers, requiring continuous awareness to prevent accumulations of combustible gasses and coal dusts. Accumulations of methane in coal mines create the risk of large-scale explosions that can result in disaster with high consequences. The explosion hazard can be effectively controlled by diluting the methane concentration during the mining operation. Ventilation in underground mine has long been the primary means of controlling methane emissions or methane concentration in underground coal mines by diluting it (Hjertager, 1992; Hjertager, 1982). In this research article Computational Fluid Dynamics (CFD) modeling and simulation has been carried out for detailed analysis of gas explosions and its propagation in mines. In particular, CFD modeling based approach has been developed to understand the flow migration dynamics of methane with different ventilation scenarios. This approach also provides an in-depth knowledge about the accumulation of the methane and its dilution to eliminate an explosion hazard inside the mine making the mine safer.