A re-launched exploration program at the Alacrán project in northern Mexico has returned very high grades of silver, gold, copper, lead and zinc for owner Azure Minerals (ASX: AZS).
Approximately 21 samples collected from mine dumps at five separate groups of historical mine workings to the southeast of the property returned high grades of precious and base metals, with 10 returning values greater than 1,000 grams per tonne silver, 17 returning values greater than 1.0g/t gold and 12 returning values greater than 10% lead.
Sampling was deliberatively selective to determine grades of historically-mined ore, and five new targets were identified with maximum assays of 3,675g/t silver, 24.1g/t gold, 2.3% copper, 33.5% lead and 21% zinc.
Azure said the precious and base metals content and strongly-elevated levels of other pathfinder metals indicate the vein-hosted, quartz-sulphide mineralisation may be of the Intermediate Sulfidation (sub-epithermal) type and likely related to the nearby Cerro Alacrán porphyry-hosted copper-gold-molybdenum body.
The company said first-pass sampling has been “very encouraging” and has planned further systematic sampling and detailed mapping of veins to determine targets for follow-up trenching and drilling.
The old mines targeted by Azure are located between 1.5-2km south and southeast of Cerro Alacrán and were identified by geological mapping undertaken by Canadian diversified resource company and Azure’s former partner in the Alacrán project, Teck Resources.
Azure’s work is the first modern sampling to have been completed at these locations.
Previous operations at the old mines focused on exploiting precious and base metal-rich veins hosted in volcanic and porphyry rocks.
Mapping shows that such veins occur extensively throughout the southeast of the property with some individual veins mapped over strike lengths of more than 500m.
Azure said the mine dumps comprise material mined from quartz-sulphide veins with abundant dump material showing obvious copper, lead and zinc sulphide mineralisation and silver sulfosalts.
“At the surface, the veins within the old mine workings exhibit cocks comb and banded quartz textures with sulphide-rich pods and layers comprising galena, sphalerite, pyrite, and sparse chalcopyrite, with copper mostly occurring as malachite, turquoise, and lazurite,” it reported.
Previous resource drilling at Alacrán was suspended in December 2016 when Teck exercised its right to earn back a 51% interest in the project by sole-funding US$10 million of exploration expenditure between 2017 to 2020.
Disappointed by the potential of porphyry-hosted copper mineralisation discoveries confirmed at Cerro Alacrán, Teck agreed in May to sell its rights and interests in Alacrán. By August, Azure had regained 100% ownership of the project.
Under the terms of the acquisition, Teck has retained a 19.9% stake in Azure.
Azure now plans to expand Alacrán’s initial mineral resource estimate of 150,000 ounces gold and 4.8 million ounces silver in 5.4Mt at 0.9g/t gold and 28g/t silver.
The company’s previous greenfields exploration at the project discovered the near-surface, high-grade Mesa de Plata silver deposit and the adjacent Loma Bonita gold-silver deposit.
Last week, Azure announced it had raised $4 million (before costs) through a placement to institutional investors to relaunch an aggressive exploration push at Alacrán.
The proceeds will go towards advanced-stage activities at the project, with priority on increasing the silver and gold resource base at Mesa de Plata and Loma Bonita.
Azure managing director Tony Rovira said strong investor support will enable the company to move forward with its exploration and development plans.
“This fundraising places [the company] in a strong position moving forward, as we seek to increase the existing resource estimates and conduct additional greenfields exploration to discover and develop more precious metals deposits on this project,” he said.
“It is great to have all of this project back in our portfolio and we are very pleased to return to Alacrán after a three-year hiatus.”
At midday, shares in Azure Minerals were up 5.56% to $0.190.