The price of copper held steady just off more than four year highs on Friday after customs data showed imports of raw materials by China rising sharply in May.
In brisk trading New York Comex copper for delivery in July traded at $3.3050 a pound ($7,286 per tonne), up 7.8% over the last week and on track for its highest close since January 2014.
Concentrate imports for January to May now total 7.8 million tonnes, the highest for the period since at least 2000May customs data from China showed import volumes of unwrought copper up nearly 22% compared to the same month last year at 475,000 tonnes.
It was the the highest May figure for refined copper for at least a decade according to Reuters calculations. The numbers suggest buyers are facing a shortfall in scrap copper, said an analyst at Antaike, the research arm of the China Nonferrous Metals Industry Association.
The demand for copper concentrate is surging. Concentrate cargoes landing at Chinese ports increased 37% from May 2017 to total 1.58m tonnes in January.
Concentrate imports for January to May now total 7.8 million tonnes, the highest for the period since at least 2000.
Copper's rally this week was spurred by renewed fears about disruption to supply from top producers Chile and Peru as workers at Escondida, the world's largest copper mine by a wide margin, enter wage talks with owner BHP.
Negotiations still left to resolve - including Escondida - represent about 2.6 million tonnes out of global copper supply.