PGG asked the unions earlier this week to accept a cut in hours and pay of up to 20% for three months, which would make the company eligible for government help.
The trade unions rejected the offer and instead proposed that PGG stopped production for four days a month when workers would be entitled to 60% of their regular salary.
"The trade unions' proposal is unacceptable as it will not rescue the company...We are in a deep crisis," PGG Chief Executive Tomasz Rogala said in a statement.
He added that unless the company took the emergency action it had planned and the demand for coal continued to fall, PGG would start making a loss of 240 million zlotys ($57.56 million) a month.
"We must also take into account that there will be nowhere to store the coal. And the worst will begin, which is uncoordinated stopping of individual mines," Rogala also said.
Poland relies on coal for almost 80% of its electricity production, but lockdown measures, which have included closing schools, restaurants, cinemas, some factories and reduced railway transportation, have led to a decrease in electricity usage that the company puts at 10-12%.
(Reporting by Agnieszka Barteczko and Wojciech Zurawski; editing by Barbara Lewis)