Copper steadied on Friday but was set to end the week almost 2 percent lower as workers agreed to resume work at the world's top copper mine in Chile.
Investors this week were also jittery on prospects that President Donald Trump's health-care bill would not pass, suggesting he may not be able to muster the backing needed to push through fiscal measures central to the U.S. government's economic agenda.
"The market is beginning to price out the probability that we could get this big infrastructure spend from Trump," said Jens Pedersen, commodities analyst at Danske Bank.
"If he had such a difficult time getting this through, how will it go when things turn to the budget, infrastructure spending and tax."
Commodity markets have soared since November on expectations that Trump will increase spending on infrastructure.