Article content This will be a critical week as negotiators for Steelworkers Local 6500 and Vale try to work out a new contract by May 31. That’s when the current labour contract expires. We apologize, but this video has failed to load. Try refreshing your browser. Steelworkers seek gains in new contract Back to video USW Local 6500 represents more than 2,500 production and maintenance workers in mining, milling, smelting and refining at Vale’s Sudbury operations. Vale, with almost 4,000 workers, is Sudbury’s largest employer. In Sudbury, it operates five mines, a mill, a smelter and a refinery from one of the largest integrated mining complexes in the world. Sudbury products include nickel, copper, cobalt, platinum group metals, gold and silver.