Trevali said it expected this quarter to reduce inventory build-up that curtailed Africa metal sales in the three months to the end of September. An inability to get paid for production was compounded in the last quarter by a decline in metal prices that saw the company book a "negative provisional pricing adjustment of $42.6 million" for the latest period.

Total payable September-quarter zinc output of 101.6 million pounds at a C1 cash cost of US72c/lb compared with 103.9Mlb production in the June quarter. Trevali said Perkoa 2018 zinc production guidance was raised to 172-180Mlb from 164-174Mlb previously. It maintained previous lower 2018 guidance for Caribou at 70-75Mlb (86-90Mlb).

The company carried net debt of $61.7 million at the end of September.

"Clearly Q3 was a challenging quarter from an African logistics and commodity price volatility perspective," Trevali president and CEO Mark Cruise said.

"Namibian shipments occurred immediately post quarter, we continue to focus on Perkoa concentrate haulage, commodity prices are currently stable and the macro zinc price environment remains constructive.

"Operationally, Caribou's guidance was adjusted downwards to allow the site to focus on increasing development to provide additional mine flexibility going forward.  This was largely offset by another stellar production quarter from Perkoa, with the net result that the company remains on track to achieve annual production guidance."

Trevali shares (TSX: TV) were flat Wednesday at C53c and are trading at one-third of their levels earlier this year.