PORTAGE, Ind. — An environmental group that sued a steelmaker in December for allegedly violating the Clean Water Act at its northwestern Indiana facility says the company continues to release excess amounts of chemicals into a Lake Michigan tributary.The Environmental Law & Policy Center said ArcelorMittal has had many self-reported violations for chronic toxicity and discharging excess ammonia into the Burns Waterway. The Indiana Department of Environmental Management has reported a total of 13 violations this …