Brazilian mining giant Vale's second-quarter profits soared more than four-fold from a year earlier on higher iron prices and a new pricing system that let the company get higher prices for its ore. Vale, the world's largest iron ore producer, in the second quarter boosted prices for its ore by moving to a quarterly pricing system after the aging annual benchmark mechanism unraveled amid quarrels with China -- the world's largest buyer of the metal.

Iron ore and coal producer Cliffs Natural Resources Inc said much of its iron ore volume is subject to fluctuating prices on the spot market, after the world's three biggest miners abandoned their decades-old system of setting fixed prices once a year. "Final pricing and the replacement of what has historically been the annual benchmarking system continues to evolve," Chief Executive Joseph Carrabba told a conference call.

Demand for potash could come close to global supply capabilities next year, especially if China returns to the market as expected, Potash Corp CEO Bill Doyle said on Thursday. The company, like other crop nutrient producers, has weathered a difficult couple of years, after farmers around the world responded to the financial crisis by deferring the use of fertiliser.