The coal miners are in hospital after the explosion at Gramoteinskaya pit near town of Belovo in Kemerovo region.
Two men died but miraculously more than 100 reach the surface safely.
New purchase's total reserves are put at 2.2 billion tonnes of coking coal, and around 50 billion cubic metres of methane gas.
Bulging bumps in the Yamal and Gydan peninsulas believed to be caused by thawing permafrost releasing methane.
Fisherman keeps warm when his ice hole erupts in flames but he still netted a good catch
Local reindeer herder witnessed the tundra explosion that led to birth of new hole in river.
200 metres wide thermocirque seen weeks after scientists find funnel in the Yamal peninsula, caused by build up of methane.
Scientists say a 'fountain of gas' poured from jelly-like trembling earth in tundra on Belyy Island in northern Siberia.
Pipes are built over bulging and unstable Arctic pingos prone to violent eruptions caused by 'thawing methane gas', as seen twice on the Yamal peninsula this year.
Vital for making its waters so 'pure', one theory is that rising underwater methane leaks are killing off the sponge, but is there a silver lining?