Black Bear Minerals (ASX:BKB) has announced it will broaden historic core re-analysis across its Shafter Silver Project in Texas, the US, after further assays returned higher silver grades than the original results.
The company plans to extend the review to all available legacy drilling programs and across the footprint of Shafter’s foreign mineral resource estimate (MRE).
Underground drill hole 201200603 returned 3.7m @ 47 grams per tonne silver (Ag) from 0m, compared with the historical result of 3.7m @ 19g/t Ag. This represents a 147% increase in contained silver across the interval.
A separate 0.6m interval returned 169g/t Ag from 11m, against the original result of 117g/t Ag.
Drill hole 201200604 returned 8.5m @ 525g/t Ag from 0m, including 0.7m @ 1,360g/t Ag. The broader interval contained 6% more silver than the historical result of 8.5m @ 493g/t Ag.
The program has now produced 174 comparable assay pairs from seven drill holes. Preliminary analysis indicates the new results tend to contain more silver than the historical dataset.
Black Bear says the four-acid digestion used for the new assays may provide more complete digestion than the earlier two-acid method. However, it cautions that differences between laboratories and natural variability within the remaining core may also have contributed to the results.
Multi-element analysis of the historic core also returned 11.6m @ 1.4% zinc (Zn) and 1.3% lead (Pb) from 0m in 20120604, including 7.3m @ 0.2g/t gold (Au).
CEO Dennis Lindgren says the results support expanding the review while the company works towards a JORC Code 2012-compliant estimate.
“We will continue to extend the historic core review across the broader resource footprint as we progress towards JORC conversion, MRE upgrade, and rapid mine restart study,” Lindgren says.
Shafter hosts a foreign MRE of 17.57 million ounces of silver prepared under Canadian National Instrument 43-101 standards. It is not currently reportable under the JORC Code 2012.
Black Bear says it also plans limited infill drilling, further sampling of previously untested core, and systematic sampling of the historic Presidio Mine workings.
Write to France Pinzon at Mining.com.au
Images: Black Bear Minerals
