Russia's invasion has thrown up huge challenges for Ukraine's coal mines, from the danger posed by air strikes to the departure of miners for the front to fight.
But pits are still producing coal in parts of eastern Ukraine that are not occupied by Russia, an act of defiance that the miners see as vital to the war effort.
"We are faced with new challenges, new problems...Last year there were several times when we had to stop production," Viktor Kuznetsov, chief engineer at a large mine in east Ukraine, told Reuters. He asked for the mine not to be named for security reasons.
"But nevertheless ... we plan to increase coal production at our enterprise, even in relation to the past (before the war)."
Kuznetsov said that more than 400 staff had been mobilised since Russia's full-scale invasion in February, 2022, and a total of about 700 since just before the start of hostilities involving Russian separatist proxies in eastern Ukraine in 2014.
Some, he said, had been replaced by other workers, including 436 displaced by the war.
Other problems caused by the war included difficulties with supplies of equipment, missile strikes and the damage caused by Russian attacks.
On one occasion, work at the mine was halted because a local substation was struck during a Russian attack and power to the area was lost while miners were underground.
"During one of the shifts, when we were working underground, there was a hit on the power plant, and the mine lost power. And we had to go out though emergency exits," said miner Andrii Yurkov.
Yurkov worked in another mine in the Donetsk region before fleeing his home in the city of Maryinka last year with his pregnant wife.
"Well, as they say, the war has come here too...No matter how we try to get away from the war, it slowly gets here," he said.
He underlined the need to keep working to prevent the mine coming to a standstill.
"Despite the shelling, we continued to work, because we understand that the enterprise will not work without (our) work. And, of course, there will be no light and energy, which is very necessary for our country."
Kuznetsov said the mine had managed to keep going because it had prepared for various scenarios including the loss of power when miners were underground.
"We were preparing for this. That is, from the moment the war began, probably literally the first two months were just spent on developing all those measures, possible situations that could somehow affect the work of our enterprise because of the hostilities," he said.
