N.Korean coal piles up as Russian product sails away For years the coal trade was a lucrative earner for North Korea -- its main ally and key economic partner China imported 22 million tonnes worth nearly $1.2 billion in 2016, now mountains of the fuel are piled up in the port of Rason near the Chinese border unable to be traded due to UN sanctions. And while Pyongyang struggles to shift the commodity, business is booming for a Russian company operating further down the quayside.IMAGES AND SOUNDBITES