LONDON, June 12 (Reuters) - Glencore (GLEN.L) on Monday offered to buy Teck Resources' (TECKb.TO) steelmaking coal business as a standalone unit, after the Canadian miner twice rebuffed its $22.5 billon offer to combine the two companies. "It would provide Teck with a cleaner exit from coal and allow Glencore to split its own business into CoalCo and MetalsCo." Glencore's CEO Gary Nagle in May said buying Teck's coal business as a standalone unit was a "distant second" for the Swiss mining company, as it still pursues its merger plans. Teck's steelmaking coal mines are among few left in the world, making them attractive to Glencore, as global efforts to phase out coal-fired power generation gather momentum. As part of its original proposal, Glencore offered up to $8.2 billion in cash to Teck shareholders who may not want exposure to thermal coal.

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Persons: Teck, Gary Nagle, May, Pierre Lassonde, Glencore, Clara Denina, Eva Mathews, Dhanya Ann, Kirsten Donovan, Barbara Lewis Organizations: Teck Resources, Teck Metals, Deutsche Bank, Nippon Steel Corporation, Thomson Locations: Teck, CoalCo, Swiss