The opponents include the prominent Swiss-based (but Russia-linked) Trans World Group, which says that a ban on tolling is impractical, because Russian firms cannot be sure of always having the hard currency to pay for the continuous supply of imported ore they need.
After months of negotiations, China's steelmakers agreed to pay up to double the price for the iron ore they buy from Rio Tinto, the biggest-ever annual rise in the cost of the commodity.
Rio instead raised cash to pay down hefty debts with a rights issue and also announced an iron ore tie-up with BHP (which itself had tried, and failed, to acquire Rio in 2008).