Backgrounder
Some coal seams of Bharat Coking Coal Limited (BCCL) and Central Coalfields Limited (CCL) are on fire since the beginning of the century due to un-scientific mining activities by the erstwhile mine owners. The genesis of the fire in the coal seams is attributed to spontaneous heating of coal in contact with oxygen resulting in fire.
In BCCL 70 number of fire of different seams have been inherited from private mine owners at the time of nationalization. Since then lot of efforts have been made by BCCL to control the fire. Ten fires were quenched and other fires were kept under control. Four new fires were identified after nationalization.
In Central Coalfields Limited (CCL), 4 seams at 3 collieries are under fire which are about 15-30 years old. It is difficult to exactly estimate the quantity of coal getting destroyed by mine fire.
The following steps have been taken to extinguish fire in coal mines:
Sand flushing into active fire zone from surface to underground through boreholes.
Surface blanketing to prevent breathing in of air to the fire area.
Inert gas flushing from surface through boreholes to extinguish fire.
Quenching of spot fire and mining out the quenched coal.
Sealing of the part of the mine under fire by construction of fire stoppings/isolation stoppings.
Application of fire resistant sealant in and around the isolation stopping/fire stoppings.
Regular monitoring with the help of co-detectors, toximeter, air sampling and analysis of the same at colliery level.
Trench cutting by mechanised means to excavate fire and to prevent spread of the same; and
In some the mines intentional flooding by water has been done to quench the fire.