The conflict in Donbass has disrupted one of the pillars of the region's economy: coal. Eighty percent of the Donbass area's coal mines have closed because of the fighting, and just about 20 remain operational.. That has bestowed an increased importance upon the small, illegal mines known as kopankas During the winter, many in rural Ukraine use coal as a heating source, which is considerably cheaper than other energy forms. Thousands of such mines, some as deep as 300m, are now believed to operate in the region - providing a source of employment and coal for locals.