Almaden Minerals has reported positive results from an updated NI 43-101-compliant preliminary economic assessment (PEA) of its 100% owned Ixtaca gold-silver project in Puebla state, Mexico, 150 km east of Mexico City. The updated PEA considers a 30,000-mt/d base-case scenario that significantly reduces initial capital requirements for project development, in comparison with the initial PEA, and also considers a ramp-up case that would start with a 7,000-mt/d mill and ramp up to 30,000 mt/d by year six.

Initial capital cost for base-case development is estimated at $399 million; initial capital cost for the ramp-up scenario is estimated at $244 million.

Under the base-case scenario, the Ixtaca project would produce an average of 130,000 oz/y of gold and 7.788 million oz/y of silver over a mine life of about 12 years. Life-of-mine mill feed would total 125.3 million mt at an average grade of 0.43 g/mt gold and 25.71 g/mt silver.

The project is planned as an open-pit mining operation, using contractor mining. Major mining equipment would include 177-mt-capacity haul trucks with 27-m3 shovels. The life-of-mine strip ratio would be 1.7:1.

The Ixtaca base-case scenario includes a 30,000-mt/d processing plant to produce gold and silver doré on site. The plant would include conventional crushing, grinding, gravity, flotation, concentrate leaching, and Merrill-Crowecircuits. Average process recoveries for gold and silver are expected to be 90%, based on test work carried out at the Blue Coast Research laboratory in British Columbia, Canada.

Almaden has initiated work toward a prefeasibility study of the Ixtaca project, including further metallurgical studies, geo-mechanical and geotechnical drilling, static geochemical test work to characterize rock chemistry, and long lead-time environmental and water monitoring. Other work under way includes environmental baseline monitoring such as flora and fauna studies, climate monitoring, water-quality sampling, and surface-water hydrology monitoring.

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