An agreement has been reached to end a labor-management dispute at Mallinckrodt in St. Louis. Members of the United Auto Workers Local 1887 will be back on the job today after a four-year contract was approved. The contract provides for a three percent annual wage increase and better pension benefits. Workers have been on strike for six weeks, forcing non-union managers and supervisors to work 12-hour shifts to keep the factory going. The factory manufacturers bulk active ingrediants for generic pharmaceuticals. Mallinckrodt is a subsidiary of Tyco International.