Completion Of Surface Mining Of High Grade Jumbo Vein

COEUR D'ALENE, ID - Idaho Strategic Resources reported on the completion of surface mining of the high-grade Jumbo Vein and plans for exploration of the Jumbo Vein by drifting along the vein from the pit bottom. Surface mining of the Jumbo Vein resulted in 4,000 tonnes of ore at a grade of 17.3 grams per tonne (gpt) gold.

Vice President, Grant Brackebusch, said, "Following completion of surface mining, we plan to advance an underground drift to the south along the vein towards a high-grade drill intercept from 2011 (GC 11-41T: 0.9 meters (m) true thickness at 137 gpt gold) which is at about the same elevation as the bottom bench - 1069 m. As previously mentioned, it is worth noting that the sample from the Jumbo Vein where it enters the pit wall was 0.6 meters (m) wide (true thickness) and assayed 152 gpt gold."

The Jumbo Vein consists of a banded quartz vein that typically occurs 10 to 20 m in the hanging wall of the Idaho Fault. It is known to occur in the central part of the Golden Chest mine property and had minor production in the late 1890's to early 1900's.

The recent surface mining consisted of a small pit on a near-surface section of the vein, following it down from the 1115 m elevation to the 1069 m elevation. On each mined bench, the Jumbo Vein was typically exposed for 22-26 m along strike with a width of 0.3 to 1.0 m. The average vein strike was N18oE and average dip was 53o NW. The vein was well-oxidized with abundant iron-oxides and minor amounts of pyrite, arsenopyrite, and chalcopyrite. Visible gold was often seen in hand samples.

As the Jumbo Pit was mined, blast hole drill cuttings were sampled and assayed to direct ore control. An average weighted grade for the ore polygons, based on the blast hole samples, was 13 gpt gold. However, more selective mining occurred along the vein in practice and composite samples of mined truckloads showed a higher weighted average of 17.3 gpt gold. Three vein chip samples were taken across the vein exposed in the southeast pit wall as mining progressed down in the Jumbo Pit.

"The horizontal distance between the portal site and the GC 11-41T drill intercept is approximately 90 m and the purpose of the drifting will be to establish the continuity of the vein and gold grade between these two points. We will sample each round (about 50 tonnes) during the mining cycle which will be stockpiled on the surface near the portal pending assay results. Rounds above cutoff will be routed to the mill for processing which should help offset the cost of the drifting allowing for a low-cost method of exploration of this very high-grade vein. If this drifting is successful, the next step would be to portal in at a lower elevation and drift on the vein to establish the vertical continuity of the Jumbo Vein. The drifting project is anticipated to start in the second quarter of 2023,” said Brackebusch.