Osisko expands Pine Point zinc resource
Mining Explorers 2019 – Published Nov. 1, 2019
Last updated 8/14/2020 at 9:29am
With a vision to become a leading base metals mining company, Osisko Metals Inc. is rapidly adding to the stores of zinc at its Pine Point project about 42 kilometers (26 miles) east of Hay River, Northwest Territories.
Cominco (now Teck Resources) produced an estimated 14 billion pounds of zinc and 4 billion lb of lead from around 64 million metric tons of ore averaging about 10 percent zinc-lead from a mine operated at Pine Point from 1964 to 1988.
The near-surface ore was mined from 52 open pits along a 60-kilometer (37 miles) trend. In all, the Canadian miner identified more than 90 such deposits in this area of the property.
Osisko Metals has not wasted any time building resources in the material Cominco left behind. In 2018 and the first four months of 2019, the company had drilled 1,031 holes at Pine Point.
Based on the results from the first 317 of these holes, combined with historical drilling, 38.4 million metric tons of inferred resource averaging 4.58 percent (3.9 billion pounds) zinc and 1.85 percent (1.6 billion lb) lead were calculated for this project on the south shore of Great Slave Lake in Northwest Territories.
The open-pit inferred resource outlined so far by Osisko is found in 42 undeveloped pits and extensions of two previously mined pits across five geographic zones – East Mill, Central, North, West and N204 zones – stretching some 65 kilometers (40 miles) across the district-scale project.
The property's main core – East Mill, Central and North zones – hosts 23.4 metric tons of the inferred resource averaging 6.3 percent zinc-equivalent, or 2.3 billion lb of zinc and 900 million lb of lead.
The remaining 714 holes focused largely on upgrading the inferred resources to the higher confidence indicated category.
This summer, Osisko began exploring for new mineralization below and along strike of the known mineralized horizons.
To identify targets for this resource expansion drilling, the company had an innovative helicopter-borne gravity gradiometry geophysical survey flown over the mineralized trends at Pine Point designed to identify the denser sulfide mineralization where most of the zinc is found on the property.
Results from this geophysical survey, coupled with new site-wide digital compilation and re-interpretation of historical datasets were used to target a 5,000-meter drill program that got underway in late August.
"Following extensive compilation work and advanced geological modelling, our exploration team has a better understanding of the structural controls associated to the distribution of lead-zinc mineralization in the 60-kilometer-long system," said Osisko Metals President and CEO Jeff Hussey. "We have identified several high priority targets that were not explored by previous operators."
The team's compilation work covering the East Mill, Central and North Trend zones along a 25-kilometer (16 miles) section of the property identified 100 drill holes with significant mineralization outside the current resource areas, indicative of near-surface mineralizing systems that were not pursued by previous operators.
Highlights from these orphaned holes include: 13.72 meters averaging 16.75 percent zinc and 8 percent lead in hole YR77-23-01; 6.1 meters of 5.28 percent zinc and 0.48 percent lead in YR86-04-14; 3.05 meters of 14.8 percent zinc in 6351; 4.26 meters of 12.2 percent zinc and 2.76 percent lead in 1362; and 5.27 meters of 16.24 percent zinc and 5.03 percent lead in 1883.
Osisko said its compilation work and analysis has also identified the potential for zinc-lead mineralization in the deeper Pine Point Formation, a more than 50-meter-thick underlying zone that has seen less historical exploration. Cominco mined 17.5 million metric tons of ore averaging 6.2 percent zinc and 2 percent lead from the X-15 deposit in this formation; and 149,700 metric tons of ore averaging 12.9 percent zinc and 7 percent lead. Both zones are in the deeper Pine Point formation.
Osisko also plans to drill priority gravity anomalies along favorable structural trends that could lead to the discovery of additional near-surface higher-grade deposits with prismatic sphalerite (zinc) and galena (lead) crystals.
A high-resolution Lidar (Light Detection and Ranging) topographic survey flown in 2018 was able to highlight structural controls and subtle circular collapse breccia structures that are indicative of the high-grade prismatic zinc-lead deposits the company is seeking.