The chances that Teck will reinvest their profit into Rio's Iron Ore Co. is becoming less and less likely. See related links, demonstrating Teck losing interest. And China Minmetals are looking at Glencore's Las Bambas Copper project instead of Iron Ore.

http://www.fool.com/investing/general/2013/10/24/rio-tinto-is-running-out-of-room-to-maneuver.aspx

Bloomberg reported the other day that China Minmetals is likely withdrawing from the bidding process for Rio's Canadian iron ore mines while Teck Resources (NYSE: TCK ) , which has already said its interest is "grossly overblown," has hinted it may do so as well.

http://business.financialpost.com/2013/10/22/china-minmetals-said-to-likely-abandon-bid-for-rio-tintos-iron-ore-unit/

Teck Resources Ltd., Canada’s second-largest mining company, is also considering abandoning its bid for the Rio unit because of a wide valuation gap, two people familiar with the matter said earlier this month.

For those that think Teck would not accumulate CUU stock prior to making a bid, think again. From this story they accumulated up to 3% in anticipation of a buyout.

The 3 percent stake is being sold down through a book-build underwritten and run by CIMB, according to a term sheet seen by Reuters.

Vancouver-based Teck, a large copper, zinc and metallurgical coal miner, has long said it wanted to expand into iron ore, and speculation mounted last year it might bid for Fortescue after accumulating a small stake in the miner in early 2012.