Arrivals jumped 78 percent from a year ago to 406,937 metric tons, rising for a seventh month, according to an e- mailed statement from the General Administration of Customs today. That was the highest on record, according to Wang Zhouyi, an analyst at Shanghai CIFCO Futures Co.

Surging imports, coupled with a rebound in domestic production, have swelled inventories in Shanghai for a seventh week and widened the local cash discount. Three-month copper on the London Metal Exchange advanced to $8,428.5 a ton yesterday, the highest in four months, after retreating 21 percent in 2011.

"There are wide expectations that the market will warm up after the Chinese New Year holiday, as spring is usually when demand picks up," said Wang. Still, "as prices continue to climb, we'll have to wait to see how downstream demand reacts."

Refined copper imports fell 3 percent to 2.84 million tons last year, after dropping 8.4 percent to 2.92 million tons in 2010, data from the customs office showed.

Output in the world's largest user gained for the first time in four months in December, rising 8 percent from a year ago to 457,000 tons, as more raw material supplies prompted smelters to meet their yearly production targets.

Surging Inventories

Copper stockpiles monitored by the Shanghai Futures Exchange climbed 11,193 this week to 131,645 tons, a nine-month high, bourse data showed yesterday.

"A strong set of preliminary Chinese trade data helped to soften market concerns regarding a slowing in demand, and recent economic data have suggested that the probability of a hard landing is declining at a fast pace," said Barclays Capital in a research report yesterday.

China reported better-than-expected fourth-quarter economic data last week. Gross domestic product expanded 8.9 percent in the fourth quarter, more than a Bloomberg News survey for 8.7 percent. Industrial production climbed 12.8 percent from a year ago in December, exceeding a forecast of 12.3 percent.

"Concerns remain regarding whether copper imports in particular will contract sharply in early 2012," analysts at Barclays said in the report.

The metal for immediate delivery on Shanghai's Changjiang market was quoted at a discount of about 350 yuan a ton yesterday to the front-month Shanghai futures contract. Markets in China will be closed during the week of Jan. 23 for the Chinese New Year holidays.

Scrap imports in December climbed 2.7 percent from a year ago to 446,819 tons, and full year arrivals gained 7.4 percent to 4.69 million tons, according to the customs.

Chinamining