Rio boss Sam Walsh promises $US5bn in cost savings RIO Tinto's new boss Sam Walsh has told investors he will focus on costs savings and disciplined investments as he aims to build a more focused and accountable business. Mr Walsh outlined at the miner's annual meeting in London overnight that he aimed to cut $US5 billion ($4.8bn) out of the business across the next two years through a "relentless" focus on cost reduction and productivity improvement across all aspects of its business.