The mining city of Jixi, Northeast China's Heilongjiang Province, bears the scars of China's slowing economy and ailing heavy industry.

Giant mounds of unsold coal sprout weeds in the makeshift depots marking nearly every junction, and bitter Siberian winds blow sulfurous dust through streets peopled by laid-off mining workers.

"This is a coal city and there is nothing else," said Xin Qinling, a former miner from Jixi's depleted Zhengyang coalmine.

State-owned Longmay Group has been making losses since 2012.

With Chinese economic growth dipping to a 25-year-low and government waging a "war on pollution," the plight of Jixi, near the border with Russia, is echoed across the coal production belt in China.

The Luan Group in Shanxi province, another of China's big state miners, said in October that it had no choice but to cut output and put some workers on extended unpaid leave.