Sierra Madre Announces Test Mining Throughput in Excess of 425 Tonnes per Day at La Guitarra

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Vancouver, British Columbia--(Newsfile Corp. - October 23, 2024) - Sierra Madre Gold and Silver Ltd. (TSXV: SM) (OTCQX: SMDRF) ("Sierra Madre" or the "Company") is pleased to provide an operational update on activities at the La Guitarra silver-gold mine complex in Estado de Mexico, Mexico.

Test mining and processing has been ongoing since June 25th, 2024. Beginning in October, the company began testing the operation of all three ball mills simultaneously and in various combinations. Daily throughput in the grinding and flotation circuits has been as high as 504 wet metric tonnes per day (WMT/d). From October 1st to October 18th, throughput has averaged 428 WMT/d. This average includes scheduled downtime to reline one mill and normal rainy season power outages. The Company expects commercial production to begin before the end of the year.

The flotation plant has been in continuous operation since the beginning of testing. Silver recoveries to date have averaged 78%. Based on recommendations from the Company's metallurgical consultants, a new reagent combination will be tested to enhance silver recovery of oxidized material. Gold recoveries have steadily increased from 74% in June to the current October average of 87%.

Since the commencement of test operations, a total of 39,272 tonnes of economically interesting mineralized material has been put through the processing circuit. A total of 690.44 dry metric tonnes of concentrate has been shipped to MRI Trading. Average provisional concentrate payment grades have been 2,903 g/t sliver and 34.74 g/t gold.

Test mining continues to provide sufficient tonnages to sustain the milling operations. A new development plan has been put into place to accelerate the mining of insitu mineralized material, reducing the reliance on oxidized retaques, which are backfill from 1990's stopes (see Company press release from September 5, 2024 for more information on retaques).

A new vein outside the 2023 NI 43-101 resource estimation, D-2, has been delineated and test production operations initiated (see Company press release from November 1, 2023 and the Company's SEDAR+ issuer profile for more details on the 2023 resource estimation). Test stope development in the San Rafael II area, the deepest portion of the Guitarra mine, has begun on an identified large block of mineralized material in the Doncellas vein.

Qualified Person

Mr. Gregory Smith, P. Geo, Director of Sierra Madre, is a Qualified Person as defined by NI 43-101, and has reviewed and approved the technical data and information contained in this news release. Mr. Smith has verified the technical and scientific data disclosed herein.