London Metal Exchange (LME) prices were mostly lower by Friday's kerb close, dragged down by lead and zinc responding to news of a smelter restart, traders said.
On Friday morning officials at Glencore International's Portovesme confirmed the plant was operating and was heading towards full capacity.
"We are now producing lead and zinc," Carlo Lolliri, Portovesme s.r.l's general manager, told Reuters.
"We expect to reach full capacity by the end of the year," he added in an interview which traders said had clarified the situation regarding Portovesme.
Zinc fell by $23.50 to $1,000.50, while lead dropped from $873 to $860.
A series of conflicting news reports had left the market confused, but traders said the clarification had made holders of long positions consider reducing their exposure.
"The news about Portovesme is definitely moving things around. It has made people on the long side think twice about their positions," one senior London trader said.
The prospect of increased lead availability took pressure off the cash to three months spread for lead, which fell from $76/86 on Thursday morning to $25/35 on Friday afternoon.
A fall in the value of the dollar following weaker than expected US jobless data was not enough to lift prices.
The euro was up 1.3 percent to about $1.2269 by 1549 GMT.
The market will now look forward to the Federal Open Market Committee's meeting on August 10 for changes in US interest.
Copper fell to $2,784 from $2,787 as last minute buying helped shore up the metal, while aluminium fell $4 to $1,684.
"The data came out from the States and the initial reaction was buy. But disappointing follow-through and weakness in a couple of metals dragged down the whole complex," another LME trader said.
"There was a little bit of short covering just before the close - a few day traders sold it short and were booking profits," he added.
Nickel fell $75 to $12,850, while tin bucked the downtrend and closed up $150 at $8,800.