LONDON MARKETS: Miners Lift FTSE 100 To One-month High

By Sara Sjolin, MarketWatch

LONDON (MarketWatch) -- Mining firms posted solid gains in London on Thursday on an increase in commodity prices, while Associated British Foods PLC rallied after a well-received trading update.

The FTSE 100 index rose 0.6% to 6,543.41, closing at the highest level since June 4.

Among biggest gainers in the index, shares of Associated British Foods PLC jumped 5.1% after the food ingredients maker and owner of Primark clothing stores said revenue for the 40 weeks to June 22 was up 9%. Additionally, the company said it is on track to achieve good progress in full-year earnings.

Mining firms also showed positive moves as most metals prices rallied. Gold and silver had good days, after U.S. Federal Reserve Chairman Ben Bernanke said interest rates will remain low to boost economic growth. The comments sent the greenback lower, which helped dollar-denominated commodities such as gold.

Among London's precious miners, Randgold Resources Ltd. jumped 7.2% and Polymetal International PLC surged 8.3%, while silver miner Fresnillo PLC soared 13%.

Among other miners, Anglo American PLC gained 5.4%, Rio Tinto PLC (RIO) added 4.6% and BHP Billiton PLC (BHP) climbed 4.6%.

On a more downbeat note in London, shares of G4S PLC dropped 5.6% after U.K. Justice Secretary Chris Grayling asked the Serious Fraud Office to investigate the security firm for overcharging the government for electronic tagging for criminals.

G4S said in a statement that it is conducting its own review with external advisers and "is not aware of any indications of dishonesty or misconduct."

Serco Group PLC was also suspected of overcharging, but agreed to take part in a forensic audit. The shares slumped 7.9%.

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