It was previously last above the benchmark in February 2011.

It closed down 0.18% on the London Metal Exchange yesterday to $9,949/t.

Nickel also gained, heading back towards $20,000/t as doubt grows about the environmental credentials of Tsingshan Group's recently-announced new technology designed to produce battery-grade metal from nickel matte.

Nickel closed up 1.3% to $17,872.50/t.

Trafigura's chief economist Saad Rahim has predicted a strong outlook for commodities amid improving economic optimism.

"Demand is extraordinarily strong across the globe and it's not limited to one sector," he told Bloomberg this week.

Copper major Freeport-McMoRan reached a fresh multi-year high of $41.74 intraday, before closing up 5.86% to $41.54.

Diversified miner Teck Resources (TSX: TECK.B) gained 7.1% in Toronto and Rio Tinto rose 4.6% in London.

Finally, US Treasury Secretary Janet Yellen yesterday clarified her earlier remarks about a possible interest rate rise to ensure the economy didn't overheat, telling a separate event she was not predicting or recommending a rate rise and did not anticipate inflation being a problem. 

Gold is subsequently about $10 an ounce higher than this point yesterday at $1,786/oz.