Also, aggregate productivity of petroleum slipped 7% year over year to 99 barrels of oil equivalent (MMboe) in the first half. We believe further inflation in iron-ore prices will likely benefit mining giants like BHP Billiton, Vale S. A., VALE , Rio Tinto plc RIO and Kumba Iron Ore Limited KIROY . Click to get this free report VALE S.A. (VALE): Free Stock Analysis Report BHP Billiton Limited (BHP): Free Stock Analysis Report Rio Tinto PLC (RIO): Free Stock Analysis Report To read this article on Zacks.com click here.