Complex sentence: The United Mine Workers of America (UMW or UMWA) is a North American labor union that represents not only coal miners, but also clean coal technicians, health care workers, truck drivers, manufacturing workers and public employees throughout the United States and Canada.
Split into simpler sentences: The United Mine Workers of America (UMW or UMWA) is a North American labor union. Although best known for representing coal miners and coal technicians, the union also represents health care workers, truck drivers, manufacturing workers and public employees in the United States and Canada.