VANCOUVER (miningweekly.com) – Canada’s largest diversified miner Teck Resources has added about 50 000 t of zinc output to the full-year guidance for its Red Dog mine, in Alaska.

Vancouver-headquartered Teck advised that improving recoveries in the last few months has prompted the company to lift guidance to a range of 525 000 t to 550 000 t of zinc, up from the most recent guidance range of 475 000 t to 500 000 t of zinc.

The company increased production because of changes in mine sequencing and improved metallurgical recoveries, enabling higher-grade mill feed with a greater percentage of ore from the Qanaiyaq pit in the second half of the year.

Meanwhile, Teck expects yearly zinc output at Red Dog over the next five years to range between 475 000 t and 550 000 t of zinc.

However, the guidance is dependent on Teck completing a mill upgrade project that is expected to increase average mill throughput by about 15% over the remaining mine life, helping to offset lower grades and harder ore in the Aqqaluk pit.

This project has robust economics and is expected to be complete by the fourth quarter of 2019, at a capital cost of $110-million. As the upgrade project will permit lower-grade material to be processed, the current mine life, based on existing developed deposits, will remain unchanged through to 2031.

Meanwhile, Teck's regional exploration efforts have focused on a significant high-grade zinc deposit, known as Aktigiruq, for several years. Situated on 100% Teck-owned state claims 12 km north-west of the Red Dog operations, Aktigiruq is located next to the Anarraaq deposit.

Despite the current drill hole spacing not being enough for a mineral resource estimate, Teck advised that the drill data suggests an exploration target for Aktigiruq in the range of 80-million tonnes to 150-million tonnes of mineralisation, grading between 16% combined zinc plus lead and 18% combined zinc plus lead.

If realised, this would make the Aktigiruq zinc deposit one of the top undeveloped zinc deposits in the world. Past production since 1989 to the end of 2016 for the Red Dog operations is 78.3-million tonnes at 19.6% zinc and 5.3% lead and Red Dog’s proven and probable reserves at December 31, 2016 were 50.9-million tonnes at 15% zinc and 4.2% lead.