Louisville, Kentucky — Zinc-focused Trevali Mining produced more payable zinc and silver in the first quarter, but lead was down and new President and CEO Ricus Grimbeek said Monday he was conducting a thorough review of the company's four-mine portfolio.

In the job for less than a month, Grimbeek, a mining engineer by background, replaced Mark Cruise.

Asked during the Vancouver-based company's Q1 results call whether he might be willing to sell one or more of the mines, Grimbeek said no, at least at this time.

"All four are cash-flow positive," he said about Rosh Pinoh in Namibia, Perkoa in Burkina Faso, Santander in Peru and Caribou in New Brunswick. "I think there are ways we can be better than what we are with our current assets."

Grimbeek plans to continue an indepth study of the mines over the next 90 days and then report back to analysts later this summer, he said.

Trevali produced 100.6 million lb of payable zinc in the first quarter, up 2% from a year ago. Perkoa led th way with 39 million lb, followed by Rosh Pinoh at 26.8 million lb

Payable zinc sales totaled 125.4 million lb in the January-March period, up 40% from the first quarter of 2018.

Payable silver output climbed 33% in Q1, while payable lead production fell 7%.

Grimbeek and other company officials talked at length about zinc concentrate treatment charges, which they said have risen significantly in 2019.

"They're up to $245/mt now, significantly from the $145 benchmark last year," he said. Despite the higher treatment charges, he said miners are still getting about 70% of the recovered zinc price, "which is above historic ratios."

Zinc concentrate smeting and refining charge benchmark terms are still in the process of being finalized for 2019, officials said, with market expectations remaining in the range of $245.

Trevali's consolidated production outlook for 2019 remains unchanged at between 361 million and 401 million lb of payable zinc, 44 million-49 million lb of payable lead and 1.3 million-1.5 million oz of payable silver.

-- Bob Matyi, newsdesk@spglobal.com

-- Edited by Richard Rubin, newsdesk@spglobal.com