Infill drilling confirms Alamo Dorado

Results from reverse-circulation drilling at the Alamo Dorado silver project in Sonora state, Mexico, have confirmed the continuity of the mineralization along strike and downdip, and indicated potential new zones of mineralization at depth.

Property-holder Corner Bay Minerals (BAY-T) mounted the program to establish grades and widths along a 600-metre strike length previously tested by reverse-circulation drilling, and to explore for more mineralization downdip and across the strike of the known zones. The program included extending the length of earlier drill holes, testing downdip from known mineralized intersections, and infill drilling to bring the grid interval down to 50 metres from 100 metres.

Extensions to previously drilled holes encountered a series of new mineralized zones beyond those found when the holes were originally drilled. On line 200 South, two extended holes, 9 and 14, both cut new mineralization at depth with higher silver grades than had been found in earlier drilling.

On line 100 South, essentially through the middle of the known deposit, extensions of holes 1 and 2 intersected additional mineralization at depth with lower grades than the original holes had encountered nearer surface.

Corner Bay also drilled 13 infill holes, on lines midway between the 100-metre grid of drill sections. These largely confirmed the grades and widths encountered in the original drill program. The best intersection was in No. 29, an infill hole on line 250 South, where a 117-metre interval graded 222 grams silver and 0.41 gram gold per tonne.

Four holes drilled on previously drilled sections intersected mineralized zones downdip from the known mineralization. Hole 39, on 100 North, cut an 81-metre interval grading an average of 51 grams silver and 0.4 gram gold. Near the southern end of the deposit, on line 300 South, hole 40 cut 12 metres grading 47 grams silver and 0.01 gram gold.

Two holes drilled on 100 South, Nos. 30 and 31, intersected silver and gold mineralization downdip from previously drilled holes, in generally narrower and lower-grade zones. Hole 30 cut 52 metres grading 42 grams silver and 0.08 gram gold, while hole 31 cut 105 metres grading 20 grams silver and 0.18 gram gold. Earlier holes updip from No. 30 and 31 had encountered 130-140 metres of silver and gold mineralization.

The deposit is still open to the northwest and downdip; the company has now drilled four holes along the northwestern extension of the structure, about 400 metres west of the previously drilled zone of mineralization on sections 150 North and 250 North.

Hole 22, on 250 North, intersected 18 metres grading 19 grams silver and 0.04 grams gold. Hole 23, on 150 North, cut a 117-metre interval with 18 grams silver and 0.04 gram gold. Despite the lower silver grades, Corner Bay continues to see the northwestern extension as an area where more drilling is needed, noting that the geology there is still poorly known.

Corner Bay has commissioned a resource calculation to incorporate the new drill results. Consulting firm Mintec will also be doing a preliminary pit design and calculating a reserve estimate. An earlier calculation put the resource at 48 million tonnes grading 42 grams silver and 0.15 gram gold.

Diamond drilling, to provide P-size (85-mm) core for metallurgical testing, is under way and Corner Bay expects the program to conclude by the end of November. The company’s metallurgical consultant, Metcon Research, will make a composite sample and test the leachability of the mineralized material. Metcon is scheduled to report the results early in the new year. Preliminary column and bottle-roll tests made on drill cuttings indicated gold and silver recoveries of about 90% after 24 hours in a dilute cyanide solution.