Base metals held mostly firm in Wednesday London Metal Exchange (LME) open-outcry trading, notching up fresh highs on continued fund buying, traders said.
Option-related business after February traded option declarations at late morning aided the trend, although conditions were not very active.
"The market today was just a continuation of strong support we've been seeing recently," a trader said.
Resistance was seen around the highs in copper, aluminium, lead and zinc, but might only represent a temporary pause.
Lead rose above $800 a tonne for the first time since May 1996, underpinned by overnight news that Teck Cominco lead output at Trail in Canada would be curbed due to a furnace explosion.
"There was trade selling around $810, but technically it's still very strong and we expect it to mount a test of the $820/830 area in the coming sessions," the trader said. Prices ended the rings at $809, up $12 from Tuesday's firm kerb close of $797.
Zinc foundered at tough resistance near three-year highs at $1,070 to close untraded in the kerb at $1,067/068, down $2.
Traders said the market would probably move in its current range in the next couple of days and was then seen challenging $1,080.
Falconbridge denied on Wednesday reports that it is planning to shut down its Kidd Creek lead-zinc refinery in Canada for eight weeks starting in March. Confusion surrounded a notice about a closure posted on the website of the Canadian Auto Workers union, but a union spokeswoman told Reuters the February message related to last year's production.
However, a company spokesman said it plans to shut down its Kidd Creek zinc and copper operations for maintenance during the summer.
"....we are planning a two-month shutdown for the zinc refinery...we are planning a 5-week combined maintenance and vacation shutdown as we did last time for the copper (smelter and) refinery in July, August and September," Dale Coffin said.
Copper earlier hit fresh 6-1/2 year highs around $2,560, but again stalled at firm resistance, ending at $2,553, up $9.
"There was further speculative buying this morning and there is a little resistance at around $2,555/560," the trader said.
Supply worries, falling inventories and a wide backwardation will prevail over technical factors and support prices, analysts said.
Aluminium tested resistance above $1,660, setting a four-year high at $1,680 at one stage before ending $12 higher at $1,671.
"Aluminium needed the option declarations out of the way as there was some capping ahead of that," the trader said.
"There were reports of call buying - there's a feeling sinking in that maybe aluminium isn't a laggard after all and is catching up with the firmer trend in other metals," he said.
Nickel was nervy ahead of any developments at Falconbridge's strike-bound Sudbury facilities. Prices eased $100 to $14,850.
Traders said the market remained vulnerable, especially around the 50-day moving average on the charts.
Tin was untraded in the kerb, standing at $6,430/450, down $10.