Methane in Coal (CO-11)
When plants are converted into coal, natural gas (mostly methane) is released. In many places the plant material is buried by impermeable rocks, such as shale, and methane may be left in the pores and fractures of the coal. Some of this gas is released when coal is mined.

Methane is colorless, odorless and tasteless, so it is difficult to detect. When 5 to 10 percent of methane is mixed with air, it becomes highly combustible. Many of Indiana's worst mine disasters were caused by explosions of ignited methane gas.

In some places experimental drilling has removed methane from the coal before it is mined. The recovered methane can be used if the volume is large and a need or a market exists. Some of Indiana's coal has about 90 cubic feet of gas per ton. Large mines may release more than a million cubic feet of gas each day -enough to supply heat for 3,000 homes if it could be collected.

Our Hoosier State Beneath Us: Coal

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