57-year-old Artur, who did not want to give his full name, drove 18 miles to get to the mine in eastern Poland hoping to buy several tons of coal for himself and his family.

Artur's household is one of the 3.8 million in Poland that rely on coal for heating and now face shortages and price hikes, after Poland and the European Union imposed an embargo on Russian coal following Moscow's invasion of Ukraine in February.

Poland banned purchases with an immediate effect in April, while the bloc mandated fading them out by August.

While Poland produces over 55 million tons from its own mines every year, imported coal, much of it from Russia, is a household staple due to its competitive price and the fact that Russian coal is sold in lumps more suitable for home use.

Soaring demand has forced state-controlled mines to ration sales or offer the fuel to individual buyers via online platforms, in limited amounts.

Dorota Choma, spokeswoman for the Bogdanka mine.

"Yesterday, on Thursday (August 25) we launched a point for small coal buyers, up to 6 tonnes, but it is also needed to mention the formalities. We have introduced a two-step formal path in order to eliminate situations where people were coming here, taking a spot in the queue and selling it to someone else or trading the coal illegally later."

In recent years, Poland has been the most vocal critic of EU climate policy and a staunch defender of coal that generates as much as 80% of its electricity. But coal output has steadily declined as the cost of mining at deeper levels increases.