Ikkari and Pahtavaara PEA Report

This report presents the preliminary economic assessment results for the Ikkari and Pahtavaara gold projects in Finland, based on historical operating data, metallurgical testwork, and proposed process design.

Report context

The Preliminary Economic Assessment (PEA) for Rupert Resources Ltd., covering the Ikkari and Pahtavaara projects in Finland, carries an effective date of 10th January 2023. The report was prepared by Tetra Tech Ltd. and presents mineral processing and metallurgical testing results, mineral resource estimates, mining methods, and recovery methods for both deposits.

Processing route

Pahtavaara Metallurgical Testwork

The Pahtavaara metallurgical testwork comprised comminution, gravity recovery, flotation, leaching, solid-liquid separation, and environmental testing. Head grade was established as part of the testwork program. Comminution testing was conducted to determine ore breakage characteristics. Gravity recovery testwork evaluated the potential for gravity gold recovery. Flotation testwork was performed to assess concentrate production. Leaching testwork examined gold extraction from flotation concentrate. Solid-liquid separation testwork investigated dewatering characteristics. Environmental testing assessed tailings and waste characteristics.

Ikkari Metallurgical Testwork

Ikkari metallurgical testwork included comminution, gravity recovery, flotation, leaching, cyanide destruction, solid-liquid separation, and environmental tests. Head grade was determined as part of the program. Comminution testing assessed ore hardness and grinding requirements. Gravity recovery testwork evaluated free gold recovery potential. Flotation testwork examined concentrate grade and recovery. Leaching testwork investigated gold dissolution from flotation concentrate. Cyanide destruction testwork assessed treatment of leach residues. Solid-liquid separation testwork evaluated thickening and filtration characteristics. Environmental tests assessed geochemical and geotechnical properties.

Proposed Process Design

The proposed recovery methods, described in Section 17.0 of the report, were developed following a trade-off evaluation that considered GSL testwork and process options across multiple operational scenarios. The Ikkari process description includes a basis of design section, while the Pahtavaara process description also presents a basis of design. The proposed comminution circuit includes gravity gold recovery. Flotation is included as a concentration step. The leaching circuit includes flotation concentrate solid-liquid separation, Pahtavaara concentrate re-pulping, and leaching. The adsorption/desorption/recovery circuit includes carbon-in-pulp adsorption, desorption, and carbon regeneration. A gold room is included for final gold recovery. Cyanide destruction is incorporated for treatment of leach tailings. Tailings storage is separated into flotation tailings and cyanide destruction tailings. Water management includes mill process water and water treatment.

Historical Mining Methods

The Pahtavaara mining method includes open pit mining with resource modelling, modifying factors, mine optimisation, geotechnical analysis, cut-off grade determination, pit optimisation results, optimisation sensitivity analysis, open pit design, mine schedule, and equipment selection. The Pahtavaara underground mining method is also described, including consideration of open pit to underground transition. The Ikkari mining methods similarly include open pit mining with resource modelling, modifying factors, mine optimisation, geotechnical analysis, cut-off grade determination, pit optimisation results, optimisation sensitivity analysis, open pit design, mine schedule, and equipment selection. Ikkari underground mining methods are also described, including open pit to underground selection. A combined schedule is presented for the 3.5 Mt/a SLC case.

Mineral Resource Estimates

Mineral resource estimates are presented for Pahtavaara, Ikkari, and Heinä Central. The Pahtavaara resource estimate includes database validation, interpretation and modelling, data flagging and compositing, statistical analysis, variography, block modelling, bulk density data, grade estimation, depletion for mining activity, resource classification, and resource reporting. Ikkari resource estimation similarly includes database validation, interpretation and modelling, data flagging and compositing, statistical analysis, variography, block modelling, bulk density data, grade estimation, depletion for mining activity, resource classification, and resource reporting. Heinä Central resource estimation includes introduction, database validation, interpretation and modelling, statistical analysis, variography, block modelling, bulk density data, grade estimation, resource classification, and resource reporting. No mineral reserve estimates are presented in the report.

Key reported parameters

Technical qualifications

The report includes the following specific limitations: This document is for the confidential use of the addressee only. Any distribution to parties other than the addressee is prohibited without the prior written authorisation of Tetra Tech Ltd. Tetra Tech Ltd. shall not be liable for any claims, losses or damages that arise directly, or indirectly, from the use of this document for any other purpose than for the Project mentioned herein or from modification of this document by other than Tetra Tech Ltd., or a party specifically authorised in writing by Tetra Tech Ltd., subsequent to its issue as a printed paper original to which signature(s) or Professional Engineering Stamps have been affixed. No mineral reserve estimates are presented in Section 15.0 of the report. The mineral resource estimates are subject to depletion for mining activity where applicable. The metallurgical testwork results are derived from specific test programs and may not be representative of all material types.

Source: Preliminary Economic Assessment: Ikkari and Pahtavaara – Finland, Document No: 03627A-0000-REP-002A, Effective Date: 10th January 2023.