SILVER BAY — State regulators fined Northshore Mining after the taconite processing plant released nearly half a million gallons of water over the course of more than two years. In a news release Wednesday, the Minnesota Pollution Control Agency said the Cleveland-Cliffs-owned facility in Silver Bay must pay $19,000 for 11 unpermitted releases of recycled and process water. According to the Jan. 9 stipulation agreement between MCPA and Northshor…