Copper prices in Shanghai and London ticked higher on Tuesday, boosted by the extension of a U.S.-China trade truce deadline, which outweighed expectations of increasing supply that curbed further gains.

The most-traded copper contract on the Shanghai Futures Exchange closed daytime trade 0.13% higher at 79,020 yuan ($10,991.33) per metric ton.

The benchmark three-month LME copper on the London Metal Exchange rose 0.44% to $9,769 a ton, as of 0712 GMT.

On Monday, the United States and China extended a tariff truce deadline for another 90 days, easing concerns over near-term trade friction and supporting demand prospects ahead of the seasonal autumn import surge for goods such as electronics.

However, expectations of rising supply of the red metal, used in power and construction, kept prices in check on Tuesday.

Copper production from Chilean state-run miner Codelco rose 17% year-on-year in June to 120,200 tons. It also said its regulators have approved the reopening of parts of the El Teniente mine not affected by the July 31 collapse that killed six workers.

In China, refined copper output is expected to jump to record highs in July and August with new smelting capacity going online amid lower equipment maintenance work, analysts at consultancy Mysteel said in a note.

SHFE aluminium rose 0.29%, nickel added 0.67%, lead ticked up 0.18%, tin climbed 0.84%, and zinc advanced 0.31%.

LME aluminium advanced 0.7%, lead rose 0.35%, tin added 0.22% and zinc grew 0.75% while nickel eased 0.2%.
Source: Reuters