London Metal Exchange (LME) base metals ended higher on Thursday as technical factors, fresh dollar weakness and supply concerns combined to lift the market, traders said.
"Essentially, it was a technical action in copper," a trader said.
"Then, other micro factors added to its momentum with weaker-than-expected US data causing a relapse in the dollar and supply concerns in South American, although that mostly affected COMEX rather than London," he added.
The dollar weakened broadly on Thursday, reflecting reactions in currency markets to deadly violence in Iraq and Turkey and mostly weak US economic data. The dollar suffered on disappointing data on US durable goods orders and initial jobless claims.
In industry news, workers at the Collahuasi copper mine in Chile planned to reject the company's wage offer in a vote next Tuesday, paving the way for a strike to begin on July 2, a union leader said.
A strike at Collahuasi, jointly controlled by Falconbridge Ltd and Anglo-American Plc, would squeeze an already tight copper market and could drive prices higher.
The metals market is expected to be volatile in the near term, sparked by poor liquidity during the traditionally thin trading conditions of the northern hemisphere summer.
Copper closed at $2,677 from $2,585.
"Overall, metals volumes were better today but still fairly thin," the trader said.
"Stops in copper were triggered at the 40-day moving average around $2,640 and then at the 50-day around $2,672. There was also some option-related buying and some short covering and the close suggests a move higher towards $2,700/720."
Aluminium ended at $1,729 from $1,703 and while traders said noted room to move up towards $1,740/750 on a technical level, the market had attracted trade hedge selling almost in isolation to cap firmer advances.
Zinc closed at $1000.50 a tonne from $982 at Wednesday's close.
Lead closed at $833 from $802, while nickel was at $14,710 from $14,525 and targeting a move higher towards $15,000, traders said.
Tin was untraded, closing at $8,550/590 from $8,520/550.
"Tin was out on its own today * very quiet but steady," the trader said.