Mongolia will ship 25,000 tons of coal to North Korea’s Rajin port this year as part of a trial export project, the chairman of the Mongolian Railroad Authority said.

Mongolia has a thriving coal industry, but its lack of coastline and undeveloped rail infrastructure limit its export options. North Korea’s Rajin port in the country’s far northeast was recently upgraded to handle larger volumes of coal exports, as part of a Russian-backed infrastructure project.