Metals-Supply fears boost copper ahead of US inflation data

Copper edged up on Wednesday as a temporary shutdown at a major Indonesian smelter added to the pressure on global red metal stocks, while investors prepared to parse through key U.S. inflation data.

Benchmark three-month copper CMCU3 on the London Metal Exchange was up 0.18% at $14,182 a metric ton by 0300 GMT.

The most-traded copper contract on the Shanghai Futures Exchange SCFcv1 edged 0.26% higher to 108,240 yuan ($16,044.83) a ton.

Signs of lower physical demand in the metal's biggest consumer, China, capped gains.

Freeport Indonesia suspended operations at its Smelting Gresik subsidiary for repairs.

That added to pressure on copper stocks. Available LME copper inventories have fallen to their lowest since January as the metal is shipped into the U.S., with traders hoping to get ahead of potential tariffs.

In China, the Yangshan copper premium SMM-CUYP-CN, a barometer for the country's demand for imported copper, fell to $99 a ton on Tuesday, from a peak of $115 a ton in July.

Traders of the red metal, nicknamed Dr Copper for its use as an indicator of wider macroeconomic health, will be closely watching the U.S. consumer inflation data when it is released later today for signs on the Federal Reserve's likely interest rate path.

Elsewhere, aluminium stayed firm and was set for an eighth straight daily increase, also supported by continued supply concerns and lower stocks.

Up by 0.18% on the LME CMAL3, it was nonetheless down from the seven-week high reached a day earlier after Norsk Hydro NHY.OL said it had cut output to 50% of capacity at its Alunorte alumina refinery.

On the SHFE SAFcv1 the light metal increased 1.01% to its highest in nearly 10 weeks.