“We continue to see concerns about the deficit in the copper market,” Bart Melek, head of global commodity strategy at TD Securities in Toronto, said in a telephone interview. “We could have a significant deficit if this strike continues for a while.”

Copper for delivery in three months climbed 4.6 percent to settle at $6,090 a metric ton at 5:50 p.m. on the London Metal Exchange. That’s the biggest gain since May 2013. Aluminum, lead, nickel, tin and zinc also advanced on the LME.

An index of 18 base-metal producers climbed as much as 3.4 percent, with shares of Freeport-McMoRan Inc. and Rio Tinto Plc among the biggest increases.

Eoin Treacy's view

Strike action at the world’s largest copper mine is the catalyst which has spurred interest in copper prices over the last couple of days. However the bigger picture is that global economic growth is picking up following a lengthy period of disappointment and commodity producers are cautious about investing in new supply following the trauma of a significant bear market. 

Copper prices broke out to new recovery highs today and a clear downward dynamic wold be required to question medium-term scope for additional upside. 

BHP Billiton rallied today to hold the progression of higher reaction lows and a sustained move below 1340p would now be required to question the consistency of the more than yearlong uptrend.