North of 60 Mining News - The mining newspaper for Alaska and Canada's North

With the goal of establishing an underground mine at the Palmer volcanogenic massive sulfide project in Southeast Alaska, Constantine Metal Resources Ltd. and its joint venture partner Dowa Metals & Mining Alaska Ltd. focused their 2021 field program on geotechnical and environmental drilling to support the development of an underground exploration ramp and feasibility-level studies for a mine at this zinc-copper-silver-gold-barite project.

According to the most recent calculation, the South Wall and RW zones at Palmer host 4.68 million metric tons of indicated resource averaging 5.23% (539 million pounds) zinc, 1.49% (154 million lb) copper, 30.8 grams per metric ton (4.6 million ounces) silver, 0.3 g/t (451,000 oz) gold, and 23.9% (1.12 million metric tons) barite.

South Wall, RW, and the nearby AG zone host an additional 9.59 million metric tons of inferred resource averaging 4.95% (1.05 billion lb) zinc, 0.59% (124 million lb) copper, 69.3 g/t (120.6 million oz) silver, 0.39 g/t (21.4 million oz) gold, and 27.7% (2.65 million metric tons) barite.

A 2019 preliminary economic assessment outlined plans for a 3,500-metric-ton-per-day mill at Palmer that would produce 1.07 billion lb of zinc, 196 million lb of copper, 18 million oz of silver, 91,000 oz of gold, and 2.89 million metric tons of barite over an initial 11-year mine life.

Funded by Dowa Metals & Mining Alaska Ltd., the US$8.8 million program budgeted for Palmer last year was originally expected to involve roughly 6,000 meters of exploration, resource upgrade, and geotechnical drilling.

Contractor staffing issues and low drill productivity, however, caused the Constantine Mining LLC joint venture to focus the drilling on the vital geotechnical and environmental aspects of the program.

As a result, eight diamond holes for a total of 2,917 meters were drilled.

This includes two infill and hydrological holes drilled into the lower reaches of South Wall, which hosts the bulk of the resources.

One hole, CMR21-143B, cut 36.9 meters averaging 0.16% copper, 2.16% zinc, 16.68 g/t silver, 0.09 g/t gold, and 17.5% barite; and 6.9 meters averaging 2.1% copper, 7.08% zinc, 40.57 g/t silver, and 0.42 g/t gold in the lower part of South Wall.

In addition to the infill drilling, another six geotechnical holes were completed in the Palmer deposit area to provide hydrological information, including water volume and water quality.

Besides drilling, Constantine reports that extensive geotechnical, engineering, and environmental studies were carried out during the 2021 field season.

Data from this and previous programs are being applied to an application for an amended waste permit that will allow Constantine Mining LLC JV to begin planned underground exploration during the summer of 2023.

Surface resource upgrade and exploration drilling at the South Wall and RW zones, as well as the nearby AG deposit, is being considered while the underground preparation and development work takes place. Geological, geotechnical, and hydrological data collected during this time will be used for permitting and feasibility level studies that determine future mine development at Palmer.

As a result of Dowa's funding of the 2021 program, Constantine's interest in the Constantine Mining LLC JV was diluted to 46.6% as of the end of September. Constantine remains the operator of the Palmer project, for which it receives a management fee.

In October, Constantine acquired Hornet Creek, a VMS copper-gold project with similarities to Palmer in an area of Idaho with excellent access and infrastructure.

Author Bio

Shane Lasley, Publisher

Over his more than 16 years of covering mining and mineral exploration, Shane has become renowned for his ability to report on the sector in a way that is technically sound enough to inform industry insiders while being easy to understand by a wider audience.

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