Copper for December settlement on the Comex division of the NYMEX closed Thursday down 5.45 cents or 2.5% to $2.1220 per pound. Earlier, the contract slid to $2.1165 per pound, the lowest since September 13.
The red metal's performance has been lacklustre managing only a 2.2% gain in 2016, following a drop of 26% last year.
The recent fall is the consequence of China's September trade data, which showed a decline of 10% in exports compared to the previous year. Analysts worry about the health of the world's No.2 economy and biggest user of metals.
China's copper imports fell to 340,000 tonnes in September from 350,000 tonnes in August. Its concentrate imports declined last month by 4.1% to 1.39 million tonnes.
On the London Metal Exchange, three-month copper declined 0.8% to $4,776 a tonne, after ending flat in the previous session.