Velardeña: Issue date August 2023. “Velardeña Project, Technical Report Summary” prepared by Tetra Tech. Initial Assessment for the property as defined under U.S. SEC Regulation S-K 1300. Two economic models were prepared for the Project: one includes Inferred Mineral Resources (MII Plan) in the analysis, and the second excludes the Inferred material (MI Plan). The economic model results are based on Mineral Resources that, by definition, are not Mineral Reserves, and do not have demonstrated economic viability. The TRS assumes prices of $1,826/oz gold, $22.71/oz silver, $1.02/lb. lead (“Pb”) and $1.31/lb. zinc (“Zn”). Mineral resources were calculated having an effective date of June 1, 2023, are reported as diluted tonnes and grade to 0.7 meter fixed width and are reported at a $195 NSR cutoff.
The 43-101 Technical Report was completed as a Preliminary Economic Assessment (“PEA”) by Tetra Tech with an issue date of August 18, 2023. Resources were calculated with an effective date of June 1, 2023, using the same prices and terms shown above.
Rodeo: Dec. 31, 2022. “Rodeo Project Technical Report Summary” prepared by Tetra Tech. Updated Assessment for the property as defined under U.S. SEC Regulation S-K 1300. Rounded to the nearest 100, columns might not total due to rounding.
Mineral resources were validated by the external firm of Tetra Tech through the effective date of December 31, 2022. After adjusting for mineral extraction at Rodeo for 2022, the estimate of mineral resources at the Rodeo Property at December 31, 2022, was prepared. Aaron Amoroso, an employee of the Company and “qualified person” pursuant to S-K 1300, prepared the estimate. The resources are reported at a cutoff of 1.0 g/t Au for stockpiling and 1.45 g/t Au for processing. Numbers reported as mineral resource are constrained to a mine design of 1 g/t Au.
El Quevar: February 2018. Resources prepared in accordance with Canadian National Instrument 43-101 - Standards of Disclosure of Mineral Projects (“NI 43-101”). Amec Foster Wheeler E&C Services, Inc., a Wood Group PLC company. "NI 43-101 Technical Report on Updated Mineral Resource Estimate", February 26, 2018. Cutoff grade 250 g/t.
Santa Maria: September 2018. Resources prepared in accordance with Canadian National Instrument 43-101 - Standards of Disclosure of Mineral Projects (“NI 43-101”). Tetra Tech. "Technical Report & Updated Preliminary Economic Assessment", September 14, 2018. Silver equivalents calculated at 74:1. Cutoff grade 180 g/t. Prices assumed: Au $1,238/oz and Ag $16.63/oz.
Yoquivo: The Mineral Resource estimate is reported in accordance with the Canadian Institute of Mining, Metallurgy and Petroleum (“CIM”) Definition Standards for Mineral Resources and Mineral Reserves using the 2019 edition of the CIM Estimation of Mineral Resources and Mineral Reserves Best Practice Guidelines. The estimate was prepared by the independent engineering firm Mine Technical Services (“MTS”), with an effective date of February 24, 2023.
Mineral Resource table notes:
Yoquivo diamond drilling was conducted by Eco Drilling México S. de R.L. de C.V with a Coretech CSD 1300G rig. Drill holes were drilled to depths ranging from 150m to 351m and were drilled at azimuths of 107° to 347o and a dip ranging from -45o to -76°. No water was encountered during drilling. Holes were positioned with a hand-held GPS (accuracy +/- 5 meters) and later surveyed with a Differential GPS once the drilling campaign was completed.
Samples of the core were obtained using a diamond saw to cut the core in half, retaining one half for a permanent core record, and the other sent for analysis.
Drill-core samples were shipped to ALS Chemex sample preparation facility in Chihuahua, Chihuahua, Mexico for sample preparation and for analysis at the ALS laboratory in North Vancouver, British Columbia, Canada. The ALS Chihuahua and North Vancouver facilities are ISO 9001 and ISO/IEC 17025 certified. ALS Global in North Vancouver is a facility certified as ISO 9001:2008 and accredited to ISO/IEC 17025:2005 from the Standards Council of Canada.
Samples were crushed to 70% passing 2mm (PREP-31) with a split of up to 250 grams pulverized to 85% passing 75 micrometers (-200 mesh). The sample pulps and crushed splits were transferred internally to ALS Global’s North Vancouver analytical facility for gold and multi-element analysis. Pulps (30 gram split) are submitted for Au analysis by fire assay with atomic absorption finish (Au-AA23) and silver samples were analyzed by atomic absorption (Ag-AA45).
Over-limit Au (>10.0 g/t Au) and Ag (>1500 g/t Ag) samples are analyzed by fire assay with gravimetric finish (Au-GRA22 and Ag-GRA21). Over-limit base metal samples (>10,000 ppm or 1%) are re-analyzed inductively coupled plasma atomic emission spectrometry using protocols for higher grade results (ICP-AES) for Cu, Pb and Zn (Cu-OG62, Pb-OG62, Zn-OG62).
In-house quality control samples (blanks, standards, duplicates, preparation duplicates) were inserted into the sample set by Golden Minerals. ALS Global conducts its own internal QA/QC program of blanks, standards and duplicates, and the results were provided with the Company sample certificates. The results of the ALS control samples were reviewed by Golden Minerals and the Company’s QP and evaluated for acceptable tolerances.
All sample and pulp rejects are stored at the Company’s secure warehouse in Velardeña, Durango pending full review of the analytical data, and future selection of pulps for independent third-party check analyses, if required.