Refined copper exports by China, the world's largest consumer, jumped for a second month in October as higher overseas prices encouraged outbound shipments. Imports declined for the third time in four months.

Exports reached 18,508 metric tons last month, the customs office said in an e-mailed statement today. That's up 73 percent from September and the highest level since August 2008, according to data compiled by Bloomberg. Inbound shipments fell 40 percent to 169,374 tons in October, customs data showed.

Copper, used in pipes and power cables, has more than doubled in London this year as China's 4 trillion yuan ($586 billion) stimulus spending, state stockpiling and a lack of scrap material boosted imports to a record.

"Companies have been attempting to ship their copper stocks to London Metal Exchange warehouses abroad because of higher overseas prices," Zhao Kai, an analyst at Jinrui Futures Co. said today. Chinese exports of the metal are "more likely to relieve pressure on domestic prices than to send London prices lower" amid a global recovery, Zhao added.

Xi'an Maike Metal International Group, a top Chinese copper trader, said earlier this month it has had to re-route some bonded copper to LME warehouses in South Korea because the company was unable to find buyers in China. A bonded zone holds imported goods before the duty has been paid.

Refined copper imports surged 149 percent to 2.7 million tons in the first 10 months of the year, customs data showed.