Black Bear assay re-analysis delivers higher Shafter silver grades

The work is part of the company’s push to validate Shafter’s 17.57Moz foreign mineral resource, prepared under Canadian NI 43-101 standards, and assess its conversion into a JORC-compliant resource.

Black Bear Minerals (ASX:BKB) says the preliminary program indicates silver upside across several intercepts, while also identifying gold, lead and zinc not captured in the silver-only foreign resource.

The standout result came from hole SW5, where re-analysis returned 6.7m at 408g/t Ag from 9.1m, including 1.2m at 1222g/t.

This compares with the historical intercept of 6.7m at 266g/t Ag and represents a 54% increase in contained silver.

A re-assay from hole 201200306 returned 23.8m at 147g/t Ag from 5.5m, including 10.4m at 231g/t.

The historical comparison was 23.8m at 134g/t Ag from 4.9m, including 10.4m at 208g/t.

The re-assays add weight to the company’s broader plan to advance Shafter towards a maiden JORC resource and Rapid Mine Restart Study.

CEO Dennis Lindgren said the results strengthened confidence in the quality, continuity and growth potential of the Shafter mineralised system.

“These are outstanding results, with re-analysis of historic core returning 6.7m at 408g/t silver, a 54% increase in contained silver across the broader interval, and confirming peak grades up to 1,222g/t silver,” he said.

“Together with the encouraging twin-hole results, this continues to strengthen our confidence in the quality, continuity and growth potential of the Shafter mineralised system, while providing a clear basis to expand the historic core re-analysis program in supporting key catalysts including; advancing JORC conversion, continuing exploration and progressing the Shafter restart studies.”

Silver country: Shafter sits near Marfa in Texas, on a carbonate belt extending into Mexico’s prolific Eastern Sierra Madre silver district. Pic: BKB

Black Bear said the comparison remained preliminary because the historical and new assays were taken from different portions of the core and analysed using different methods.

Across 108 comparable assays from five holes, however, the re-assays generally trended equivalent or higher. The company is cataloguing historical pulps for further checks that would remove potential sampling bias from comparing different core portions.

Some intercepts also increased in width after wall rock assays returned grades above the 137g/t silver cut-off used in the foreign estimate, or after sampling was extended around previously untested mineralised zones.

The program also added gold and multi-element analysis to historical core, much of which had previously been assayed only for silver.

Hole 201200602 returned 3.1m at 181g/t Ag, 0.7g/t Au, 1.1% Pb and 3.4% Zn from surface, including 1.2m at 167g/t Ag, 1.5g/t Au, 1.6% Pb and 4.0% Zn from 1.8m.

The same broader interval was historically reported as 3.1m at 134g/t Ag from surface but was not been tested for gold, lead or zinc.

Black Bear says the foreign resource includes only silver, leaving potential by-product upside not reflected in the estimate.

Shafter has a long production history, with the historic Presidio Mine producing 35.2Moz of silver at an average grade of 521g/t between 1883 and 1942.

Black Bear will broaden check analysis across additional historical drill programs where suitable core is available.

The company plans to extend re-analysis across the full foreign resource footprint and sample beyond intervals selected by earlier operators.

That work is expected to feed into a future JORC mineral resource estimate, ongoing exploration and restart studies at Shafter.

Black Bear is also planning limited infill drilling to validate the foreign resource and support a maiden JORC resource and Rapid Mine Restart Study.

Additional work will include systematic sampling of historical mine workings at Presidio, where material left in drift and stope walls remains outside the resource across about 1km of strike.