Shanghai Futures Exchange copper edged down 0.5 percent to 47,740 yuan ($6,916) a tonne on Friday. "Base metals were broadly supported by the weaker USD and positive fundamentals. Supply side issues continue to support copper prices," ANZ said in a report.
Striking workers at BHP Billiton's Escondida copper mine in Chile are blocking attempts by the company to renew operations at a key port nearby as the stoppage enters its sixth week.
Union members said they would return to the negotiating table if the company gave a written guarantee that it would only discuss the union's three key demands.
Goldman Sachs said fees to China copper were falling close to break-even costs of $50-$60 a tonne, at $60-$70 a tonne.
"Should (treatment charges) fall substantially below this level in the coming weeks, we expect this will be an important catalyst for physical tightening and for the next leg higher in copper prices," it said. But so far, the shortfall has not eroded Asian stocks, a trader said.
"I have heard concentrates are getting tighter, which obviously makes sense but no tightness has fed through to the refined market whatsoever," he said.
"The best bids in Asia are the warehouses. Seems the end users in China were well stocked before Chinese New Year and have no appetite to buy more at these high LME numbers."