CARBO, VA., SEPT. 20 -- Striking miners ended their illegal occupation of a coal processing plant here tonight, 2 1/2 hours after the deadline for their forcible removal set by a federal judge. Under cover of darkness, the 98 miners and one clergyman walked from the eight-story plant structure without prior announcement and mingled with a crowd of 5,000 miners holding a vigil at the plant's entrance. "We've got a plan to stay a step ahead of the law, a step ahead of Pittston, a step ahead of the state court," said Cecil Roberts, international vice president of the United Mine Workers, who have been on strike against the Pittston Coal Group since April 5. "We are going to have another target for you," he told a cheering crowd at 9:30 tonight. "When we call you, you come on." The union move averted mass arrests of picketers who, despite a June court injunction, had been blocking the plant's entrance since Sunday afternoon, when some of the miners occupied the building. Although the mood was tense as the 7 p.m. deadline set by U.S. District Judge Glen Williams passed and night fell, only four State Police cars ventured into the road crowded with miners outside the plant, and then only to drive by. Before learning that the miners had left the plant, their supporters outside sang songs and watched as miners on an outside balcony spelled the letters UMWA, for United Mine Workers of America, with dozens of flashlights on the side of the building. Few eyes were dry after miners who had been in the plant came out to announce their decision to leave. "There is a time to plan and there is a time to react," said Eddie Burke, one of those who had occupied the plant for four days. In a federal court hearing in Abingdon this morning, Judge Williams had ordered the miners to vacate the property by 7 p.m. or face arrest and fines reaching into the hundreds of thousands of dollars to the union and individual protesters for each day the occupation continued. In his order, Williams found the union and its members in contempt of the June order prohibiting them from obstructing the entrance to Pittston's facilities, including the Moss No. 3 preparation plant, which had been the target of the sit-in. The order also said the union would be prohibited from paying the protesters $200 strike benefits weekly or from providing them bail bond or legal expenses if they were arrested. Williams said he acted because the occupation "is not achieving anything now. It's created a hardening of the hearts and is making this matter more difficult to settle." He said he wasn't sure what the consequences of defying his order would be, but added: "I can visualize a lot of things that are unpleasant." About 1,900 miners in Virginia, West Virginia and Kentucky are on strike. They have been joined in this isolated part of the country by increasingly large numbers of people from other unions nationwide. Since the strike began, about 3,000 miners and supporters have been arrested for nonviolent civil disobedience, mainly sit-ins or slow moving caravans meant to impede the movement of the coal trucks. Pittston Coal Group President Michael Odom today repeated earlier statements indicating that the company viewed the miners as "terrorists" and criticizing their takeover of the processing plant. Speaking to reporters today, Virginia Gov. Gerald L. Baliles said the union's actions would only escalate the level of confrontation. "I don't see how this helps anyone," he said. On Sunday, 98 miners and the Rev. Jim Sessions, executive director of the Commission on Religion in Appalachia, took advantage of a shift change among security guards at the plant and took over the building, stopping the company from processing 22,000 tons of coal a day. Among the supporters at tonight's rally was Kim Butler, a nurse from Salem, Va., representing the American Federation of Government Workers. "It's wonderful, it's what unionism is all about," she said of the miners' rally. " . . . We're all part of the same labor movement. One goes down the toilet and we all go down the toilet."