There are two miners that have expressed interest in purchasing Rio Tinto's (ASX: RIO) $4 billion iron ore operations in Canada.

The first one is state-controlled China Minmetals Corp., one of Beijing's favoured vehicle for cross-border mining deals. The firm is watching developments, said Minmetals Assistant President Wang Jionghui on Tuesday/

"We have invested in the neighbourhood before and we are familiar with the area," The Wall Street Journal quoted Mr Wang. But he stressed that Rio's iron ore operations in Canada is just one asset among the many that Minmetals is looking into.

If Minmetals would pursue and succeed in its bid, it would add to the growing list of Chinese buy-ins into Canadian resources firm following the $15.1-billion purchase in February by Cnooc of oil and gas producer Nexen.

Canada is the seventh-largest supplier of iron ore to China, the world's biggest steelmaker.

Bloomberg reported that Apollo Global Management had made an offer for Rio's Iron Ore Co of Canada. Apollo is owned by billionaire Leon Block.

Rio had hired Credit Suisse and the Canadian Imperial Bank of Commerce to sell all or part of its 59 per cent stake in Iron Ore.

Other companies reportedly interested in buying the iron ore operations, despite the dropping price of the key steelmaking ingredient in global markets, include KKK, Glencore Xstrata of Switzerland and the Blackstone Group, a U.S.-based private equity company.