U.S. Steel Corp. Thursday announced more layoffs as it struggles to contend with surging imports and declining demand for the energy sector, saying it will temporarily idle one of its iron ore operations in Minnesota, affecting 412 workers. The move is the latest in a series of retrenchments by the 114-year-old steelmaker as it attempts to navigate rough waters for the industry in the U.S., and pursue a longer-term strategy of repositioning itself as a smaller, more nimble steel company. U.S. Steel last year posted its first annual profit since 2008, but like other steelmakers is now having to cope with the triple whammy of a strong dollar that makes imports cheaper, weak oil prices that are killing the market for energy-related steel, and a surge in exports from China. The idling of the plant in Keewatin, Minn., which directly ships to U.S. Steel mills, will take place […]