In afternoon trading in New York, copper for delivery in March continued to climb, hitting $2.7620 a pound ($6,070 a tonne), a 20-week high and up 5.2% over four straight sessions of gains.

China consumes half the world’s copper, and trade data released on Sunday showed the country’s imports of unwrought copper increased to the highest since September 2018. Shipment totalled 483,000 tonnes in November, nearly 6% higher than the same month last year.

For the first 11 months of 2019, imports of unwrought copper are still down 8.5% from a year earlier at 4.45 million tonnes. Last year China imported a record 5.3m tonnes of refined copper.

Copper stocks in warehouses in China have been declining since June and were at 245,500 tonnes at the end of last month, the lowest since at least June 2013, according to Refinitiv Eikon data.

Imports of copper concentrate continued to rise sharply, up 27% from a year ago to a new record of 2.16m tonnes last month. November cargoes boosted year-to-date volumes to 20.1 million tonnes, a gain of just over 10% compared to the first 11 months of 2018. Concentrate imports are already above the record set in 2018 of 19.7m tonnes.

China put in place a complete ban on certain types of scrap copper imports at the start of 2019 on top of a 25% tariff on imports from the United States, one of its main suppliers, instituted in August.

Smelter expansions have increased demand and competition for copper ore in China, with spot treatment and refining charges (TC/RCs) — paid to smelters to process copper concentrate into refined metal — falling sharply this year as a result.