Rio Tinto Kennecott will shut down three of its four coal-fired power generation units in Magna after closing a deal to purchase power from Rocky Mountain Power. Kyle Bennett, a spokesman for Kennecott, said the deal will eliminate 3,500 tons of particulates — and the pollutants that contribute to the formation of particulates during inversions — from the company’s power-generation operation in Magna. All three units were slated for closure before the Jan. 1, 2018, deadline required by the sta...