This NI 43-101 technical report presents a preliminary economic assessment for the San Antonio Project, including proposed processing methods, historical testwork, and design criteria.
Report context
The San Antonio Project is located in Baja California Sur, Mexico. This NI 43-101 Technical Report on Preliminary Economic Assessment was prepared for Heliostar Metals Ltd. with an effective date of 30 November 2024. The report was prepared by Mine Technical Services Ltd., Hard Rock Consulting LLC, Kappes, Cassiday & Associates, and Stantec Consulting Services Inc. The report documents proposed recovery methods and plant design for a heap leach operation, supported by historical metallurgical testwork programs conducted between 1997 and 2012.
Processing route
Proposed Process Design
The preliminary economic assessment proposes a conventional crushing and heap leaching recovery method. The process flow sheet includes primary crushing, secondary crushing, and tertiary crushing stages. After crushing, material is fed to heap stacking with lime addition. The proposed heap leach operation is followed by an adsorption circuit using carbon. Carbon treatment completes the proposed processing route.
Primary Crushing
The process plant design includes a primary crushing circuit as the first stage of size reduction for run-of-mine material.
Secondary Crushing
Secondary crushing is specified in the plant design to further reduce material particle size prior to tertiary crushing.
Tertiary Crushing
The design includes a tertiary crushing stage to achieve the target crush size for heap leaching.
Heap Stacking and Lime Addition
After tertiary crushing, the proposed design conveys material to a heap stacking system. Lime addition is incorporated at this stage for pH control and cyanide protection during leaching.
Heap Leaching
The proposed heap leach facility design provides for solution application to the stacked ore. The report notes heap leach facilities as a separate design element.
Adsorption
The proposed design includes an adsorption circuit for gold recovery from pregnant solution using carbon.
Carbon Treatment
Carbon treatment is specified in the process design for gold recovery from loaded carbon.
Historical Metallurgical Testwork
The report documents multiple historical metallurgical testwork programs conducted prior to this preliminary economic assessment. Testwork programs were completed in 1997, 2008 (by SGS Durango and by Metcon), 2010 (Metcon), 2010 (Metcon environmental testwork), and 2012 (Metcon). These programs provided the basis for recovery estimates used in the preliminary economic assessment.
Recovery Estimates
Recovery estimates are reported in Section 13.3 of the technical report. The recovery estimates are based on the historical metallurgical testwork programs.
Metallurgical Variability
Section 13.4 of the technical report documents metallurgical variability considerations for the San Antonio Project deposits.
Deleterious Elements
Section 13.5 of the technical report addresses deleterious elements identified during metallurgical testwork.
Key reported parameters
| Parameter | Value | Unit | Basis |
|---|---|---|---|
| Primary crushing | Design | N/A | Proposed design |
| Secondary crushing | Design | N/A | Proposed design |
| Tertiary crushing | Design | N/A | Proposed design |
| Heap stacking with lime addition | Design | N/A | Proposed design |
| Heap leaching | Design | N/A | Proposed design |
| Adsorption | Design | N/A | Proposed design |
| Carbon treatment | Design | N/A | Proposed design |
| Metallurgical testwork programs | 1997, 2008, 2010, 2012 | N/A | Historical testwork |
| Recovery estimates | Section 13.3 | percent | Testwork basis |
| Metallurgical variability | Section 13.4 | N/A | Testwork basis |
| Deleterious elements | Section 13.5 | N/A | Testwork basis |
Project website: https://www.heliostarmetals.com/projects/development/san-antonio/
Technical qualifications
This report was prepared as a National Instrument 43-101 Technical Report for Heliostar Metals Ltd. The quality of information, conclusions, and estimates contained herein is consistent with the level of effort involved in the report authors’ services, based on information available at the time of preparation, data supplied by outside sources, and the assumptions, conditions, and qualifications set forth in this report. This report is intended for use by Heliostar, subject to terms and conditions of its contracts with each of the report authors. Except for the purposes legislated under Canadian provincial and territorial securities law, any other uses of this report by any third party is at that party’s sole risk. The report is a preliminary economic assessment and includes forward-looking information. The metallurgical testwork is historical in nature and was completed prior to the effective date of this technical report.
Source: San Antonio Project, Baja California Sur, Mexico, NI 43-101 Technical Report on Preliminary Economic Assessment, effective date 30 November 2024, Sections 1.0, 13.0, 17.0, and Important Notice.
