Copper for delivery in March hit a low of $2.7535 per pound ($6,070 a tonne) in early trading on the Comex market in New York, down more than 3% in a week.
China consumes half the world's copper, and trade data released on Thursday showed the country's copper imports were up sharply in January.
Shipments of unwrought copper came in at 479,000 tonnes last month, up 14% from December and nearly 9% from a year ago. At the current pace annual imports of refined copper are on course to top 2018's record 5.3m tonnes.
Imports of copper concentrate surged 17% from a year ago to 1.9m tonnes last month. January cargoes were the second-highest monthly total on record and on an annualized basis concentrate imports could exceed 22m tonnes in 2019, beating the record set last year 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.
Copper has declined by 17% from its June 2018 high over worries of a slowdown in China and the impact of a trade war with the US, but the longer term prospects for the metal remain rosy.
A panel of analysts polled by FocusEconomics sees copper averaging $6,500 a tonne in the final quarter of 2019, before rising to $6,824 a year later.