This report presents the December 31, 2023, effective date technical disclosure for the San Ignacio Property in Guanajuato, Mexico, covering historical production, mineral processing methods, and proposed design considerations as reported for Guanajuato Silver Company Ltd.
Report context
The Technical Report on the San Ignacio Property, Guanajuato, Mexico, was prepared with an effective date of December 31, 2023, and a signing date of March 7, 2024, for Guanajuato Silver Company Ltd. The report documents the property's geology, mineralization, exploration history, production history, mineral resource estimate, and processing-related information. This article summarizes the processing-related content contained within the report, distinguishing between historical operating data, metallurgical testwork, and proposed design parameters. The report relies on information from historical operators, including Great Panther, and from work completed by Guanajuato Silver Company Ltd. (GSilver).
Processing route
Processing summary
The processing section of the technical report provides an overview of the recovery methods that have been applied to San Ignacio material, drawing on historical operating data and metallurgical testwork. The report does not present a single definitive flowsheet; instead, it describes the processing approaches used historically at the property's milling facilities and the results of metallurgical testing completed between 2011 and 2015, as well as recoveries reported by GSilver.
The report states that the San Ignacio property includes processing infrastructure. Historical production from 2013 to 2021 was processed through a conventional flotation and leaching circuit, and the report describes the plant throughput and recovery metrics associated with those operations.
Historical metallurgical test work (2011 to 2015)
Historical metallurgical test work was completed between 2011 and 2015, and the report provides a summary of this work. The testwork was undertaken to assess the recoverability of gold and silver from San Ignacio mineralization. The report does not provide the specific results of the testwork in the processing sections, but it notes that the testing was designed to establish recovery parameters for the design of processing facilities.
The reported metallurgical testwork was performed on representative samples of the mineralization types present at San Ignacio, including the Melladito, Intermediate, Nombre de Dios, and Purisima veins. The report notes that the testwork included both cyanidation and flotation testing, showing the processing routes that were subsequently used in the historical plant.
GSilver mineral processing and metallurgical recoveries
For the GSilver period, the report provides processing and metallurgical recovery information, presumably showing the operation of the existing plant on San Ignacio material. The report notes that GSilver has reported recovery data, but the details of the processing route and the specific recovery values are not presented in the processing sections of the report.
The report does not present a full process design basis for a new or modified processing facility. Instead, it appears that the processing information is primarily focused on describing the existing infrastructure and its historical and current performance.
Plant throughput summary
The report includes a plant throughput summary, indicating the capacity and utilization of the processing plant. The throughput summary provides information about the tonnage of material processed over time, showing the operational history of the facility.
Key reported parameters
The following table summarizes key processing-related parameters reported in the technical report. The basis for each parameter is identified as design (proposed or planned), actual (historical or operating data), or testwork (metallurgical testing).
| Parameter | Value | Units | Basis |
|---|---|---|---|
| Effective Date | December 31, 2023 | date | Report date |
| Historical Production Period | 2013 to 2021 | years | Actual |
| Metallurgical Test Work Period | 2011 to 2015 | years | Testwork |
| Plant Throughput | Not specified in processing sections | , | Not reported |
| Gold Recovery | Not specified in processing sections | % | Not reported |
| Silver Recovery | Not specified in processing sections | % | Not reported |
| Processing Methods | Flotation and leaching | , | Actual (historical operations) |
Project website: https://www.gsilver.com/mines/san-ignacio-mine
Project website: https://www.gsilver.com/news/2022c/794-ilverlosescquisitionofreatanthersexicanin20220804
Technical qualifications
The technical report contains specific limitations and qualifications regarding the processing and metallurgical information presented.
The report notes that the historical metallurgical test work (2011 to 2015) was completed during the Great Panther period and that the results were used to support the historical operations. The report does not state whether this testwork has been verified by GSilver or whether it would be sufficient for a current feasibility study.
The processing sections of the report do not include a detailed mass balance, a process design basis, or a flowsheet diagram. The report does not present a full list of process equipment, and it does not provide details on the plant's current condition or remaining life.
The report notes that the mineral resource estimate considers reasonable prospects for eventual economic extraction, and the processing assumptions used in that assessment are based on the historical operating data and the metallurgical testwork. However, the report does not provide a detailed breakdown of the processing cost assumptions or the recovery factors applied in the resource estimate.
The technical report is based on data that have been reviewed and verified by the qualified persons, but the report notes limitations on the verification of historical data, including metallurgical testwork data, which may not have been independently verified by GSilver or the authors.
Source: Technical Report on the San Ignacio Property, Guanajuato, Mexico, effective December 31, 2023, sections 13 (Mineral Processing and Metallurgical Testing) and 17 (Recovery Methods).
