Most of the coal mines in the northern area of North Korea stopped producing coal months ago, mainly due to old machinery and poor mine pillars, Radio Free Asia reported Thursday.

There are more than a hundred mines in North Hamgyong province but only two mines are still able to produce coal, an anonymous source was quoted in the report as saying.

Even these two mines now produce much less than they used to in the ’80s.

According to the source, Obong mine in Eundeok district used to produce 1.3 million tons of coal per year in the ’80s but