VANCOUVER (miningweekly.com) – Zinc-focused miner Trevali Mining has reported first-quarter production that was generally in line with expectations as previous guidance had indicated a light quarter relative to the rest of the year, owing to the impact of seasonal winter conditions on Caribou’s zinc recoveries, in New Brunswick, and mill maintenance at Santander, in Peru.

During the period ended March 31, the Perkoa operation, in Burkina Faso, carried the company’s consolidated production, as Rosh Pinah, in Namibia, produced less zinc but much more lead than expected, and Caribou produced less zinc and more lead than expected, and Santander production was more negatively impacted by maintenance at one of the ball mills.

On a consolidated basis, first-quarter production came to 99-million payable pounds of zinc, compared with 31.9-million pounds in the corresponding period of 2017, 12-million pounds of payable lead, compared with 10-million pounds of lead a year earlier, and 336 927 oz of payable silver, which was slightly lower than the 345 661 oz produced in the year-earlier period.

Perkoa produced 45.9-million pounds of payable zinc, on slightly higher throughput and higher zinc grade and recovery than expected. At Rosh Pinah, slightly higher throughput and significantly higher lead grade and recovery were offset by lower zinc grade and recovery. As a result, zinc output was 22.8-million pounds payable and lead output came to 3.9-million pounds.

At Caribou, the first-quarter results continued to be affected by seasonal winter conditions, which contributed to zinc recoveries of only 75%. In general, mill throughput, grades and recoveries were all slightly slow, resulting in zinc output of 19.1-million pounds of payable metal, and lead output of 7.2-million payable pounds.

Mill maintenance on one of the ball mills at Santander had a greater negative impact on throughput than expected, which conspired with a lower lead grade and recovery to pressure production downwards. However, the negative impact of these features was somewhat offset by a higher zinc grade and recovery rate than expected, resulting in zinc output totalling 11-million pounds of payable metal and lead production of 1.2-million pounds.

Trevali provided per tonne unit costs for the first time and indicated that Perkoa costs were at the high end of the 2018 full-year guidance and above 2018 guidance at all three of the other mines.

The results sent the company’s TSX-listed equity down 4.8% for the day at C$1.18 a share.