McEwen Copper Inc., a subsidiary of McEwen Mining Inc. [MUX-TSX, NYSE], released the latest assay results from its 100%-owned Los Azules project, Argentina, which continues to deliver long intercepts of good grades.
The drill program has three important objectives: improve confidence in the resource by converting Inferred mineral resources to the Indicated category; accelerate project advancement with metallurgical, hydrological and geotechnical drilling and test the limits of the depth extension of the higher-grade mineralization.
Results from this drilling program will be used to update the 2017 Los Azules Preliminary Economic Assessment. The updated version will be released in Q1, 2023.
The 2017 PEA was calculated using prices of US$3/lb copper, US$1,300/oz gold and US$17/oz silver price. It projected robust economics, driven by large operating margins, large annual production, a short payback period and long mine life. Drilling is halted for winter and will resume in October when spring arrives in Argentina.
Earlier this year, Mining Intelligence ranked Los Azules as one of the world’s top five largest undeveloped porphyry copper deposits that is not already owned by a major mining company.
The opportunity to expand the deposit at depth remains open for further testing. While the median depth of drill holes within the Los Azules resource database is 175 meters (m), it is not uncommon for porphyry copper mineralization to extend well beyond a kilometer or more of depth. Numerous drill holes have encountered strong copper grades below the 2017 PEA pit bottom. Only three holes have been drilled to a depth of a kilometer and all encountered mineralization.
The highest-grade mineral domains at Los Azules are clearly the hydrothermal and magmatic breccias and late-stage quartz veins which can extend kilometres to depth. There are numerous examples of such deposits in Argentina and Chile. The most recent is Filo Mining’s spectacular assay results of earlier this year. The Filo deposit is 300 kilometres north of Los Azules, also in the San Juan province, Argentina.
The deepest occurrence of a breccia at Los Azules is at a hole depth of some 810 m in drill hole AZ1299 and deepest occurrence of late-stage quartz veins is found at 990 m down the same hole.
A dedicated exploration program associated with higher grade domains at Los Azules has not yet been conducted. Most holes drilled to date are vertical and intersect the breccias at very low angles. Improving our understanding of the nature and distribution of the highest-grade mineral zones at Los Azules is a priority for the upcoming drilling seasons.
Hole AZ22158 returned an attractive intercept of 222.0 metres grading 0.95% copper, including 44.0 metres grading 1.38% copper. Partial results were reported in the Los Azules Progress Report #3 published on June 23, 2022. Hole AZ22166 was stopped at the arrival of winter and will be completed in spring.
Section 36-36′ received eight new drill holes during the recent campaign. The final intercept reported was hole AZ22162, which targeted the gap between hole AZ22138 (522.1 metres grading 0.42% copper) and AZ22139.
Hole AZ22162 returned 348.0 metres grading 0.28% copper, while also ending in enriched mineralization. It appears to correlate well with historic hole AZ0838 (188.3 metres grading 0.27% copper).
Hole AZ22163 returned 194.0 metres grading 0.56% copper. AZ22163 includes 8.0 metres of high-grade 1.04% copper and supports 146.0 metres of high-grade 1.10% copper reported in historic hole AZ0620. Hole AZ22167 (80.4 metres grading 0.21% copper) results are as expected and similar to the historic hole LA0402.
Hole AZ22149 (296.4 metres returned 0.55% copper, including 54 metres of 1.38% copper), drilled just west of the center of the section, was released in a June 23 exploration update. Hole AZ22161, drilled east of the centre of the section, with 238.0 metres grading 0.58% copper and including 10 metres of 1.10% copper, supports historic intercepts in adjacent holes AZ1060A (221.0 metres grading 0.53% copper) and AZ18136 (194.0 metres grading 0.43% copper), all below the 30-year pit shell, indicating significant potential for mineralization at depth.
Holes AZ22147 and AZ22165 were drilled off the west and east flanks to delimit margins of the deposit and did not encounter significant mineralization.