Three-month copper on the London Metal Exchange fell 0.4% to $7,993 a tonne by 0229 GMT, while the most-traded March copper contract on the Shanghai Futures Exchange declined 0.4% to 58,920 yuan ($9,113.55) a tonne.
Copper concentrate imports from all countries were 1.89 million tonnes in December and 21.77 million tonnes in 2020 overall, data released on Jan. 14 showed.
Three-month copper on the London Metal Exchange rose 0.2% to $7,963.50 a tonne by 0318 GMT, while aluminium advanced 0.1% to $1,993 a tonne and nickel increased 1.2% to $18,125 a tonne.
Benchmark copper on the London Metal Exchange (LME) was up 0.7pc at $8,065 a tonne at 1703 GMT, a little below last week's peak of $8,238, the highest since February 2013.
The dollar extended its rebound from near three-year lows against major peers, supported by higher US yields, as President-elect Joe Biden prepared to outline his plans for massive fiscal stimulus.
On a full-year basis, concentrate imports missed a new record, with shipments totalling 21.77 million tonnes amid tight mine supply due to coronavirus-related curbs even as China's copper smelting capacity continued to expand.
Three-month copper on the London Metal Exchange was down 0.1% at $8,169.50 a tonne.
I think the market was just looking for positive news and the outcome of Georgia elections fits, but from a fundamental point of view it doesn't really change things.
China, the United States and Europe showed expansion in their factory activities in December, signalling some economic recovery from coronavirus-induced slumps.
However, US Senate leader Mitch McConnell's rejection to schedule a swift vote on whether to raise the country's coronavirus relief checks to $2,000 from $600 dampened sentiment.
The dollar slumped to multi-year lows against many currencies as traders looked past a new delay in US stimulus checks and maintained bets additional financial aid was still likely.
Shipments of Australian copper concentrate had fallen more than 50% in October from the previous month, although this was before the reported restrictions were to take effect.