London Metal Exchange three-month copper prices remained reasonably steady throughout Wednesday's session despite uncertainty about the outcome of talks over potential strike action at Chile's Escondida copper mine, market participants said.

Three-month copper prices climbed as high as $7,910 a metric ton during Wednesday's session, unable to surmount key resistance at $8,000/ton. Prices closed up $50 at $7,815/ton at the late kerb in London.

Although the latest new indicates both the company and workers at Escondida are optimistic a deal can be reached, many people are "nervous either way and there's not a lot of people willing to sell at the moment," said a trader.

The possibility of a deal being struck would result in fresh liquidation because the possibility of a strike has been largely priced in to copper prices, another trader said.

"If there's no industrial action or strike action ends earlier than anticipated, the question is: Does that take one of the major price forces away from the market or not?" he said.

Escondida workers are continuing talks with management at majority owner BHP Billiton in an attempt to head-off a strike due to start next Monday.

The strongest intraday gains on the LME were in lead, which touched a two-week high of $1,157.50/ton. Prices closed just shy of that level at late kerb in London at $1,140/ton, up $30 or 2.7% on previous PM kerb levels.

Traders said a recent pattern of reasonably large stock drawdowns in LME warehouse stocks, including a further 3,300-ton outflow Wednesday, helped to support lead prices while there was "not much material around." A trader said volumes traded in lead had been double the average in the last few days.

Zinc prices were slightly higher at $3,420/ton at the late kerb, seemingly unmoved by news labor talks at Canada's Inmet Mining may result in a disruption to output at its Cayeli mine in Turkey. The mine produces around 42,000 tons of zinc each year.

Nickel fell, closing the late kerb down $275 at $25,550/ton, still within its recent range. Despite fresh inflows of material into LME warehouses Wednesday, total LME nickel inventories remain at their lowest level since July 1991, Barclays Capital said.

3 months metal (prices in dollars a ton)
Bid – Ask, Change from Tuesday PM kerb

Copper 7815.00-7820.00, Up 50.00
Lead 1140.00-1145.00, Up 30.00
Zinc 3420.00-3425.00, Up 16.00
Aluminium 2554.00-2555.00, Up 21.00
Nickel 25550.00-25600.00, Dn 275.00
Tin 8325.00-8350.00, Dn 25.00