The labor board said the UMWA prevailed, 219 to 206, in the election to determine a possible successor to the International Brotherhood of Boilermakers union, which had represented miners at Willow Lake for several years. The Boilermakers “disclaimed interest” in continuing to serve the mine’s work force, according to the NLRB.

In July, the labor board was reviewing Peabody’s accusations that UMWA supporters resorted to “intimidation and threats, coercion and fraudulent conduct” in an attempt to interfere with the rights of Willow Lake miners. On several occasions, union backers also threatened mine employees with “bodily harm, contributing to an atmosphere of coercion that interfered with employees’ free choice,” the company said.

Peabody also accused the union of distributing “false and fabricated documents” during the organizing campaign. “All of these acts contributed to fear and confusion that prevented employees from exercising their rights to choose and speak for themselves regarding their working conditions.”

UMWA spokesman Phil Smith said the company’s charges were without merit. “We expect the NLRB will agree and certify this election.”

If upheld by the labor board, the Willow Lake victory would be the UMWA’s biggest in years in the high-sulfur Illinois Basin. Once a fixture in the region, the union currently represents only one mine in the state—Springfield Coal’s Crown III underground mine near Farmersville in Montgomery County.

Willow Lake, which has more than 440 hourly workers who would be represented by the UMWA, produced nearly 3 million tons of steam coal in 2010.