sentences:  Cleveland-Cliffs shrank its operations, closing the Mather B Mine and the Pioneer Pellet Plant and associated Ore Improvement Plant in 1979.The Humboldt Pellet Plant closed in 1981 and the Republic Mine was idled in 1981 and closed for good in 1996, when Cliffs began turning the associated tailings ponds into compensatory wetlands for its other properties.Over half of the Marquette Iron Range employees were laid off and, in 1984, Cliffs withdrew from the Great Lakes shipping industry.