Coal Mine gas emission

Context :- 

Increased emission of carbon dioxide and methane from an abandoned mine at BCCL's Tisra Colliery in Lodna, around 15km from here, has made the life of over five hundred families living in the adjoining slums difficult.The socio-economic survey, is a prerequisite to rehabilitation, has already been carried out by Jharia Rehabilitation and Development Authority (JRDA), but only one or two families out of total 500 had so far been shifted to safer places.

The coal mine gas causes burning sensation in the eyes and is determental in health of residents.

Coal Mine Gas :- 

Firedamp is flammable gas found in coal mines. It is the name given to a number of flammable gases, especially methane. It is particularly found in areas where the coal is bituminous. The gas accumulates in pockets in the coal and adjacent strata, and when they are penetrated, the release can trigger explosions. Historically, if such a pocket was highly pressurized, it was termed a "bag of foulness".

Firedamp is explosive at concentrations between 4% and 16%, with most explosions occurring at around 10%. It caused much loss of life in coal mines before the invention of the Geordie lamp and Davy lamp.Even after the safety lamps were brought into common use, firedamp explosions could still occur from sparks produced when coal contaminated with pyrites was struck with metal tools. The presence of coal dust in the air increased the risk of explosion with firedamp, and indeed could cause explosions itself.

The Tyneside coal mines in England had the deadly combination of bituminous coal contaminated with pyrites, and a great number of lives were lost in accidents due to firedamp explosions, including 102 dead at Wallsend in 1835.

CMM typically has an oxygen content of 5-12%. The methane content ranges from 25-60%. However, the methane/air proportion can change suddenly, thus complicating its use in gas engines. The methane recovered from working mines is done so thanks to two main concerns, these are mine safety and energy production benefits.Methane is released as a direct result of the physical process of coal extraction. Coal is extracted through mining which in turn releases methane previously trapped within the coal seam into the air supply of the mine as layers of the coal face are removed, thus creating a potential safety hazard. Methane emissions also arise from the collapse of the surrounding rock after a section of the coal seam has been mined and the artificial roof and wall supports are removed as mining progresses to another section. The debris resulting from the collapse is known as gob and also releases methane or ‘gob gas’ into the mine