DPRK traders made more money selling in coal in November than in any other month in 2016, with revenues hitting highs not seen for over three years, Chinese customs data compiled by the Korea International Trade Association (KITA) shows.

But North Korean coal miners and exporters were not moving volumes of coal significantly above average monthly DPRK exports: the North’s trade revenues benefited from a sharp uptick in the commodity’s price.

The DPRK struggled to maintain its coal revenues in the face of falling prices, which hit a record low in January 2016.