Workers in the most powerful industry in Serbia have swung against President Milosevic, threatening to throttle Serbia's electricity system and plunge the country into darkness.
The 7,500 miners at the massive Kolubera opencast mine, 40 miles south of Belgrade, walked out on strike at the weekend in support of opposition challenger, Dr Vojislav Kostunica, who claims outright victory against Mr Milosevic in the Yugoslav presidential poll.
And the chief of opencast mining at Kolubara, Mr Slobadan Acimovic, resigned last night in support of the workers. However, the local TV station in Lazarevac was unable to broadcast the news because of a transmission problem.
Unofficial reports emerged last night that a local police chief refused a request by the mine management to intervene against strikers.
Serbia' opposition leaders have called for a general strike from 5.00 a.m. today but the miners at Kolubera were out all day yesterday. Many of the other 900 workers who work at the complex - which sprawls for at least 10 square miles - are expected to join the boycott today.
"Kolubera is the single most powerful industrial weapon in the whole country," said Mr Milovan Rankovic, from the Union of Serbian Electrical Industry.
Fearful of the consequences of a shutdown, Serbian government ministers were urgently meeting miners' strike leaders yesterday, and electrical industry officials were also seeking to persuade the strikers to stop the action. Two smart cars with Belgrade licence plates - one a black Audi, the hallmark of a government minister and the second, a green Lancia - sped through the rutted roads and desolate-looking communities close to the mine buildings, on their mission.
Serbian energy minister Mr Slobodan Tomovic met strikers in the early afternoon. The complex's director for coal, Mr Milovan Zunic, had previously threatened strikers, said one worker. "They said they would kick us out with the help of police and then bring people from Kosovo to work instead," he said.
More than half of Serbia's energy depends on Kolubera and its sister power plant, Obrenovac. Prof Srbijanka Turajlic, an expert on Serbia's electrical system, explained: "Obrenovac electricity station provides power for Belgrade and the surrounding region. Kolubera provides the coal for Obrenovac, which is a thermonuclear plant.
The support of the miners is a significant political gain for Dr Kostunica, for the region of Lazarevac, where Kolubera is based, was in the past a stronghold of Socialist support.
But that backing has disintegrated. "If Kolubera goes on strike, the electrical system for the whole of Serbia is damaged," said Mr Rankovic. "But people in positions of power in this country have to accept responsibility for the whole situation here."
Experts suggest the effect of an all-out strike at Kolubera could be felt on electrical power supplies across the country within a week.
Meanwhile, in the central Serbian town of Cacak, a bundle of official candidate ballot papers, with votes for non-regime candidates, were found by lorry drivers with a batch of paper for recycling at the Cacak Diva company.
All ballots were supposed to have been transported from polling stations under escort and should now be with the state election commission.