It was done deliberately in the USSR, in a process known as Underground Coal Gasification. Oxygen and steam are injected to convert the coal to syngas (CO + H2) which is brought up to the surface. This allows exploitation of coal deposits that are not suitable for conventional mining.

https://en.wikipedia.org/wiki/Underground_coal_gasification

I mean there is this that happened in the USSRS: https://en.wikipedia.org/wiki/Darvaza_gas_crater so indeed it happens in socialist/communist countries too.

There's only one explicit reference to capitalism.

Also a comparison to Chernobyl (which no one would ever think they were anywhere near related.). Clearly the author wanted to communicate “something” more than the interesting takeover by nature.

I would agree that the root cause analysis of these two disasters is pretty different, and not super related to capitalism. But I don't think they were really trying to push that connection.