This technical report describes the mineral processing design, historical testwork, and proposed recovery methods for the Salares Norte gold and silver mine in Chile.
Report context
This technical report is dated 31 December 2021 (effective date) and was prepared for the Salares Norte gold and silver project located in Chile, South America. The report covers mineral processing and metallurgical testing results, recovery methods, and proposed plant design under National Instrument 43-101 standards.
Processing route
Metallurgical testing background
Metallurgical testwork was conducted across multiple programs. McClelland Laboratories Inc completed testing in 2013, with additional programs in 2017–18. Plenge conducted testing in 2015 on two ore types: Agua Amarga and Brecha Principal. ALS completed a testing program in 2016. The testwork investigated sample head assays, mineralogy, and recovery estimates.
Mineralogy
The mineralogical studies identified the gold and silver mineralisation characteristics relevant to processing. The mineralogical assessment informed the proposed processing approach and recovery expectations.
Recovery estimates
Recovery estimates were developed from the metallurgical testing programs. These estimates form the basis for the process plant design and expected metallurgical performance.
Ore hardness
Ore hardness characteristics were evaluated through the testwork programs. Hardness parameters are reported as processing factors that influence comminution circuit design and energy requirements.
Deleterious elements
Deleterious elements present in the ore were identified through the testwork programs. These elements are considered processing factors that may affect recovery methods, reagent consumption, or concentrate quality.
Flow sheet and design
The report presents a proposed process flow sheet and plant design. The flow sheet is based on the metallurgical testwork results and ore characterisation data. Design parameters were established from the testwork programs.
Process plant performance
Process plant performance is discussed in the context of the proposed design. Actual operating data from historical performance is not presented in this section; the discussion relates to expected performance based on testwork and design criteria.
Processing risks
Processing risks identified in the report include factors related to ore hardness variability, deleterious element content, and metallurgical response. These risks are documented as part of the processing method description.
Process plant requirements
Process plant requirements are specified based on the proposed design and testwork results. These include equipment specifications, throughput capacity, and infrastructure needs.
Key reported parameters
| Parameter | Value | Basis |
|---|---|---|
| Metallurgical testwork | Multiple programs (McClelland 2013, 2017–18; Plenge 2015; ALS 2016) | Testwork |
| Ore types tested | Agua Amarga, Brecha Principal | Testwork |
| Recovery estimates | Reported | Testwork |
| Ore hardness | Reported | Testwork |
| Deleterious elements | Identified | Testwork |
| Flow sheet | Proposed design | Design |
| Plant performance | Discussed | Design |
| Processing risks | Identified | Design and testwork |
Project website: https://www.goldfields.com/reports/annual_report_2016/minerals/assessment-and-reporting-criteria.php
Technical qualifications
The report specifies that processing factors, including ore hardness and deleterious elements, are documented. Recovery estimates are based on metallurgical testing programs. The flow sheet and plant design are proposed, with plant performance discussed in the context of design parameters. Actual operating data is not presented for the process plant; the information is derived from testwork and proposed design criteria.
Source: Technical Report – National Instrument 43-101 – Salares Norte Gold and Silver Mine, Chile, South America. Effective Date: 31 December 2021. Sections 13 (Mineral processing and metallurgical testing) and 17 (Recovery methods).
