LONDON - Raw material prices diverged this week on mixed US and Chinese economic data and an easing of geopolitical concerns, analysts said.

On Friday, all eyes were on Janet Yellen as the head of the US central bank said that the American jobs market has not yet fully recovered. In a speech to leading central bankers in Jackson Hole, Wyoming, the Federal Reserve chief gave no clear new signs for the outlook on US interest rates.

Midweek, minutes from the July 29-30 Fed meeting showed an intensifying debate on how much the labour market had tightened and how that would impact inflation and the timing of the US central bank’s plan to raise benchmark borrowing costs.

OIL: New York benchmark crude dropped to stand below $95 a barrel this week for the first time since January as a healthy supply situation offsets unrest in key producing regions.

The price was affected also by technical reasons as speculative traders sold off ahead of Wednesday’s expiry of the contract for September delivery.

Markets, meanwhile, reacted to the demand situations in the United States, the world’s biggest crude consumer, and in China, the largest user of energy overall.

The US Department of Energy revealed that American crude oil stockpiles slumped 4.5 million barrels in the week ending August 15, which was far heavier than expectations for a drop of 900,000 barrels.

But in China, manufacturing data came in weaker-than-forecast.

The HSBC preliminary purchasing managers index for China’s manufacturing sector slipped to 50.3 in August, down from a final reading of 51.7 in July. The figure, released Thursday, was the lowest for three months, the British banking giant said in a statement.  The indicator is a closely watched gauge of the health of the Asian economic powerhouse, with a reading above 50 indicating the sector is expanding.

Traders continued to track political developments in crude producers Libya and Iraq, as well as Ukraine, a key conduit for Russian gas exports to Europe.

“Prices are perhaps also under pressure as dealers stand on the sidelines tracking the various geopolitical crises going on right now,” Fat Prophets resources analyst David Lennox told AFP.

“The likelihood of significant disruptions is low for now,” he said.

In Iraq, the OPEC oil cartel’s second-biggest producer, Islamist militants who have overrun large swathes of the country’s north and west are now being pinned back by US military strikes that began on August 8. In Libya, another OPEC member, crude exports are steadily increasing after a deal between Tripoli and rebels ended a year-long blockade of terminals.

“Supply fears stemming from conflicts in both Iraq and Ukraine have recently diminished,” said Dorian Lucas, an analyst at energy consultancy Inenco.

“Supply fears have also been quelled by an increased export volume from Libya. Exports have resumed from Libya’s largest port following the end of the year-long blockade.”

By Friday on London’s Intercontinental Exchange, Brent North Sea crude for delivery in October dropped to $102.15 a barrel from $102.32 one week earlier.

On the New York Mercantile Exchange, West Texas Intermediate or light sweet crude for October stood at $93.11 a barrel compared with $95.63 for the September contract one week earlier.

- Palladium hits peak -

PRECIOUS METALS: Palladium prices struck a 13-year peak on expectations that strong global demand would continue to outpace supply, analysts said.

The price of palladium on Monday advanced to $901.45 an ounce, reaching the highest level since February 2001, before pulling back by the end of the week.

“Palladium climbed to a 13-year nominal high in the longest run of gains in more than a month on concern supply will lag demand and add to shortages,” said analyst Mark O’Byrne at bullion dealer GoldCore. Prices have hit several multi-year highs since a rally started in March, fuelled by concerns about industrial unrest in South Africa and the uncertain economic outlook in sanctions-hit Russia, two key suppliers. Palladium and its sister metal platinum are used to make jewellery as well as catalytic converters in vehicles.

Gold prices meanwhile slid this week owing to a stronger dollar, traders said.

By Friday on the London Bullion Market, the price of gold fell to $1,277.25 an ounce from $1,296 a week earlier.

Silver slid to $19.49 an ounce from $19.86. On the London Platinum and Palladium Market, platinum dropped to $1,416 an ounce from $1,446.

Palladium climbed to $883 an ounce from $878.

BASE METALS: Prices mainly rebounded thanks to solid US data, as aluminium hit an 18-month high at $2,083.75 a tonne supported by technical factors, according to traders.

By Friday on the London Metal Exchange, copper for delivery in three months rose to $7,058 a tonne from $6,845 a week earlier.

Three-month aluminium climbed to $2,064 a tonne from $2,003.25.

Three-month lead gained to $2,254 a tonne from $2,199.

Three-month tin dropped to $22,225 a tonne from $22,400.

Three-month nickel increased to $18,832 a tonne from $18,700.

Three-month zinc advanced to $2,359.75 a tonne from $2,272.

- Cocoa off highs -

COCOA: The key chocolate ingredient reached new three-year highs at the start of the week on strong demand before succumbing to profit-taking.

Cocoa struck the highest peaks since mid-2011, reaching £2,050 a tonne in London and $3,269 a tonne in New York.

By Friday on LIFFE, London’s futures exchange, cocoa for delivery in December had inched down to £2,028 a tonne compared with £2,029 a week earlier.

On the ICE Futures US exchange, cocoa for December fell to $3,212 a tonne from $3,233 a week earlier.

COFFEE: Prices advanced, spurred by supplies tight in main producer Brazil.

“There have been increasing reports in recent days that this year’s coffee crop in Brazil is set to fall short of last year’s crop volume by around 30 percent,” Commerzbank analysts said in a note to clients.

By Friday on ICE Futures US, Arabica for delivery in December rose to 188.55 US cents a pound compared with 184.50 cents for the September contract a week earlier.

On LIFFE, Robusta for November reached $1,993 a tonne compared with $1,943 for the September contract a week earlier.

SUGAR: Futures nudged higher following recent falls caused by robust supplies of the commodity.

By Friday on LIFFE, the price of a tonne of white sugar for delivery in October edged up to $432.60 from $431.30 a week earlier.

On ICE Futures US, the price of unrefined sugar for October inched higher to 15.97 US cents a pound from 15.95 US cents a week earlier.

RUBBER: Prices in Kuala Lumpur edged higher as Malaysia’s ringgit currency weakened against the dollar.

The Malaysian Rubber Board’s benchmark SMR20 rose to 166.65 US cent a kilo from 166.05 cents a week earlier.