Firedamp is any flammable gas found in coal mines, typically coalbed 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".

Coal mining is the process of extracting coal from the ground or from a mine. Coal is valued for its energy content and since the 1880s has been widely used to generate electricity. Steel and cement industries use coal as a fuel for extraction of iron from iron ore and for cement production. In the United Kingdom and South Africa, a coal mine and its structures are a colliery, a coal mine is called a "pit", and above-ground mining structures are referred to as a "pit head". In Australia, "colliery" generally refers to an underground coal mine.