Mining also releases coalmine methane, a greenhouse gas twenty times more powerful than carbon dioxide. The coalmine was one of the highly productive mines in Germany. In 1905 another coalmine was founded in Marl. The coalmine, unlike those in other regions, also had underground workings. The Blakeburn coalmine, near Princeton and Coalmont, was another of Burns' ventures. He left Temuka for the coalmine at Nightcaps, Southland, in August 1903. Sinha's "Kalamati" was the first film to deal with life in creches in coalmine areas. When in operation, the coalmine was the most northerly coalmine in the UK. The film begins in a coalmine in Pennsylvania in the 1876. It is based on an English folk song, "Down in the Coalmine". "Everything Must Go" which was resurrected for the second Velvet Coalmine festival. The coalmine that employed him paid for his medical care and rehabilitation. The coalmine is one of the largest in the country.