Base metals had a mixed end to a turbulent day on the London Metal Exchange (LME) with aluminium and zinc higher, copper steady and nickel and tin down, traders said on Thursday.
"It's been a wild day," one LME trader said.
"First copper was down $50, then it was up again and after all that it's closed more-or-less steady," a second trader said.
Traders and analysts said that funds had been behind most of the price movement.
"They have half an eye on the dollar, half an on gold, and then they are also watching for strike news," the first trader said.
Copper initially fell overnight on news that a strike at the Collahuasi copper mine in Chile had been averted.
"I am surprised that copper came off so much on Collahuasi. Nobody really expected a strike to last," the first trader said.
However he said that the possibility remained that workers at Grupo Mexico subsidiary Asarco's North American copper facilities could walk out.
Talks between management and union were expected to be re-convened by the end of this week.
Three-months copper ended open outcry trade on Thursday at $2,744 a tonne, down from $2,751 at Wednesday's kerb close.
Overnight Chinese selling had driven the price to around $2,690.
"I am still bearish on the market at these levels, but we seem to have had quite a good run," Man Financial analyst Edward Meir said.
Aluminium pushed higher on steady technical buying and the prospect of supply disruptions at a Canadian smelter.
It ended $13 higher at $1,758.
On Thursday afternoon, Alcoa Inc said it may close one of three potlines at its 400,000 tonne aluminium smelter in Becancour, Quebec, as 800 workers walked out over labour contracts.
A company spokesman said that about 100 management staff were running the plant at normal capacity, but that tempo could not be maintained.
"The strike is supportive for aluminium, as is the stock situation. It was not that long ago we were well above one million tonnes. Now we are down to 929,500 tonnes," Meir said
Traders said they had seen substantial volumes of aluminium going through.
"Producers selling forward, but the funds keep buying," first trader said.
Nickel was $300 easier at $15,450, while lead fell $11 to $864.
Zinc rose $6 to $1,021, while tin was down 4.4 percent to $8,480.