Anglo American, the world's second-biggest mining company, yesterday reported a 21% increase in second-half profit on record platinum prices and higher production of copper and iron ore.

Anglo, which is based in South Africa and listed on the London Stock Exchange, said its operating profit from core operations rose by 12% to $8.9bn (£4.6bn) during 2007.

Anglo American also said it had postponed the sale of UK building materials arm Tarmac because of poor credit market conditons.

Anglo put the company up for sale last August as part of a restructuring to focus on its main mining operations.

The coal-to-metals group said Tarmac had enjoyed a "very strong" 2007 and the sale marketing process would not be launched "until current credit market conditions improve".

Operating profits at Tarmac climbed by 38% to $474m (£243m), it said.

Anglo bought Tarmac in 1999 for £1.2bn. The firm was established in 1903 and has operations throughout the UK, particularly in the Midlands, with a major office in Wolverhampton.

Anglo said strong metals demand helped boost the group's overall performance last year.

Its mining operations for platinum contributed $2.7bn (£1.4bn) of the group's operating profits. Platinum prices have soard to record levels in recent days.

In a statement accompanying the results, chief executive Cynthia Carroll made no reference to the bid talk that has been dominating the sector recently. Earlier this month, BHP Billiton made a hostile takeover for rival Rio Tinto.

Commenting on Anglo's results, Richard Hunter, head of UK equities at Hargreaves Lansdown, said: "Today's strong numbers are re-affirmation that the long-term demand story is not going away any time soon. Its diversification between commodities leaves it well placed to enjoy differently spiking prices as they occur."

Shares in Anglo American closed 14p higher at £31.61 in London dealing.