Rio warning on commodities

Mining giant Rio Tinto warned yesterday that it expects to see high levels of volatility in commodity markets continue, pointing to risks to prices from monetary tightening in the developing world as well as European sovereign debt crises.

The warning, in a report published alongside its first-half results, comes as worries over the strength of global demand battered base metals prices and equity markets.

Rio said yesterday that its underlying profit rose by 35 per cent to $7.8bn (£4.5bn) during the first six months of the year – though the increase of a third was slightly below the expectations of mining company analysts,