UPDATE 2-Rio Tinto promises big returns in February despite iron ore rout
* New mine deferred amid tough near-term outlook
* Rio underscores vow to "materially increase" returns
* Sees iron ore margins at 56 pct even in weak market
* Rio shares rise 1.8 pct in weaker market (Adds CEO comments)
By Sonali Paul
MELBOURNE, Nov 28 (Reuters) - Global miner Rio Tinto deferred plans to build a $1 billion mine in Australia, stepping up cost cuts amid a plunge in iron ore prices so it can deliver on a vow to boost returns to shareholders.
The move to delay an investment decision on its proposed Silvergrass iron ore mine until at least the third quarter of 2015 follows a 50 percent slide in iron ore prices this year as Rio and its main rivals have flooded the market with new supply.
"While the long-term outlook remains sound, the near term is undoubtedly more challenging," Rio Tinto Chief Executive Sam Walsh said.
But he said that was not affecting Rio's promise to raise shareholder returns substantially come February 2015, when the company reports its full-year results. Continuación...