Shanghai copper rallied 1.4 percent on Thursday, lifted by a wave of strikes and strike threats at major producers after falling by its 4-percent daily limit in the previous session.
The most-active September copper contract on the Shanghai Futures Exchange rose 840 yuan or 1.4 percent to 61,280 yuan ($8,045). On Tuesday, prices dropped 4 percent to 60,420 yuan.
Copper for delivery in three months on the London Metal Exchange was $35 lower at $7,345 after gaining $20 in the previous session. When Shanghai closed on Tuesday, LME copper stood at $7,240.
"All the news is strike-related and people are waiting for developments," an LME dealer in New York said. "The market has lurched from strike threat to strike threat, which has helped maintain prices. Once all these issues are resolved, it will be interesting to see what happens," he added. A wave of strikes at major producers in North and South America has helped underpin prices, and could help lift copper once more, dealers said. Overnight, workers at Chile's Collahuasi copper mine were voting whether to strike in support of a new wage deal.
Union President Herman Fairies told Reuters that 600 of 689 workers had already cast their votes. He said he expected the votes to weigh in favour of a strike.
The tally should be complete. LME stocks fell 1,500 tonnes to 117,450 tonnes on Tuesday, while dealers expect a decline in Shanghai inventories in excess of 3,000 tonnes when weekly data is revealed on Friday.
Dealers will also be watching for the outcome of a Federal Reserve meeting. The Fed is widely expected to leave its benchmark federal funds rate on hold at 5.25 percent.
But only a minority of analysts now expects a rate cut by year-end, a dramatic turnaround from this year. Three-month LME lead was up $5 at $2,600 a tonne, but remained short of the record $2,745 hit on Tuesday. At their peak, three-month lead futures overtook aluminium prices for the first time.