Copper climbed on Thursday underpinned by expectations of returning demand from top consumer China, but caution over measures that may be unveiled by the U.S. monetary authorities in Wyoming this week kept gains in check.
Three-month copper on the London Metal Exchange traded up half a percent at $8,925 in official rings , compared with a close of $8,875 on Wednesday.
Copper has failed to break convincingly above the $9,000 mark since a U.S. credit downgrade reignited concerns over global economic growth earlier this month.
The metal used in power and construction remains some 13 percent from record highs of $10,190 a tonne hit in February with nagging concerns it might not revisit this level.
"There's still this expectation that China is going to surge in and buy lots of metal -- but we haven't seen much buying this week," analyst David Wilson of Societe Generale said.
"The macro picture is no consumption growth in Europe and stalling growth in the U.S. If I was a Chinese trader, I would be thinking prices should be going lower," he added.
"Also, everyone is waiting for Friday -- it all hinges on Bernanke."
U.S. Federal Reserve chief Ben Bernanke is due to address central bankers at an annual symposium in Jackson Hole, Wyoming, on Friday. His speech last year laid the groundwork for the Fed's $600 billion bond-buying program, to revive a sputtering U.S. economy.
Investors have taken an optimistic view of how strongly the Fed will commit to supporting the economy at a gathering this week, with risk appetite in Europe up, boosting stockmarkets and underpinning metals, Wilson added.
"The equity markets seem to be pricing in some form of relief from the Fed, so a complete rejection of further stimulus will likely be taken as a negative by all markets," RBC Capital said in a note.
In other news, commodity giant Glencore posted a 50 percent rise in first-half profit despite tough trading markets and said it saw potential opportunities merging from current market turbulence as commodity demand remains strong.
There are signs the global market for battery material lead is softening, given building unreported stocks in China and figures that suggest primary lead consumption is outpacing growth in China's key end-use automotive sector, said Macquarie in a note.
"This can be attributed, in part at least, to reduced purchases by lead-acid battery makers as a result of the government's ongoing crackdown on operations suspected of causing environmental pollution," it said.
Beijing ordered local governments to phase out 660,900 tonnes of lead smelting capacity this year as part of a multi-year plan to crack down on energy-intensive and polluting industries, in an announcement last month.
China is the world's top consumer and producer of lead. World lead consumption totalled 9.581 million tonnes in 2010.
Three-month l ead was untraded but bid at $2,3 91/2,395 a tonne in official rings from $2,348 on Wednesday. Tin was at $23,450 from $23,250 while zinc, used in galvanizing was at $2, 214 from $2,177.50 on Wednesday's close.
Aluminium was at $2,36 8 and little changed from $2,364 while nickel was bid at $21,050/21,100 from $20,825.
Metal Prices at 1218 GMT Comex copper in cents/lb, LME prices in $/T and SHFE prices in yuan/T Metal Last Change Pct Move End 2010 Ytd Pct
move COMEX Cu 406.45 6.65 +1.66 444.70 -8.60 LME Alum 2368.50 4.50 +0.19 2470.00 -4.11 LME Cu 8924.00 49.00 +0.55 9600.00 -7.04 LME Lead 2391.00 43.00 +1.83 2550.00 -6.24 LME Nickel 21050.00 225.00 +1.08 24750.00 -14.95 LME Tin 23450.00 200.00 +0.86 26900.00 -12.83 LME Zinc 2214.00 36.50 +1.68 2454.00 -9.78 SHFE Alu 17320.00 45.00 +0.26 16840.00 2.85 SHFE Cu* 66790.00 320.00 +0.48 71850.00 -7.04 SHFE Zin 17085.00 175.00 +1.03 19475.00 -12.27 ** Benchmark month for COMEX copper * 3rd contract month for SHFE AL, CU and ZN SHFE ZN began trading on 26/3/07