Technical report updates Mineral Resource and Mineral Reserve estimates for the Chelopech underground copper-gold mine in Bulgaria, effective 31 May 2025.
Report context
This technical report, prepared for DPM Metals Inc. (DPM) by Environmental Resources Management Ltd (ERM), provides an update to the Mineral Resource and Mineral Reserve estimates for the Chelopech Mine, located adjacent to the village of Chelopech in the Sofia District of Bulgaria, approximately 75 km east of Sofia. The report is dated 5 March 2026, with an effective date of 5 January 2026, and the Mineral Resource estimate (MRE) and Mineral Reserve estimate are current as of 31 May 2025. The Mined volumes used to deplete the Mineral Resource are also as of 31 May 2025. The report is prepared in accordance with NI 43-101 and CIM Definition Standards (May 2014).
Processing route
Overview
The Chelopech Mine processes ore to produce copper-gold and pyrite concentrates. The report presents historical plant production performance data, metallurgical testwork results, and predicted future production performance. No new flowsheet design is proposed in this update.
Historical Plant Production Performance
Data are reported for operations up to 31 October 2025. Ore processed, head grades, and metal recovery to copper concentrate are tabulated for this period. Copper concentrate and contained metal produced are also reported, alongside pyrite concentrate and contained metal produced, covering the same period.
Metallurgical Testwork
Several testwork programs are referenced. A pre-expansion summary was completed (Minproc Engineers, 2006). A geometallurgical testwork program was undertaken in 2017. A further testwork program was completed in 2021. Recovery models were updated in 2025. Gravity gold recovery and pyrite recovery summary data are included in the report, based on the pre-expansion summary.
Predicted Future Production
The report includes predicted metal distributions to copper-gold and pyrite concentrates for the life of mine (LOM) from 2026 to 2036. Scheduled metal production and distributions to gold and pyrite concentrates for the same period are also presented. These predictions are based on the designed mine schedule and the recovery models.
Process Flow and Infrastructure
The report includes a process flow diagram (Figure 17-1). The process plant infrastructure is described, including the initial upgrade (pre-2012), comminution, flotation, and concentrate handling. A paste backfill system and a tailings management facility (TMF) for flotation tailings are part of the site infrastructure. The underground jaw crusher station beneath the run-of-mine (ROM) bin at the 165 level is also described.
Key reported parameters
| Parameter | Unit | Design / Actual / Testwork Basis |
|---|---|---|
| Ore processed (historical, to Oct 31, 2025) | tonnes | Actual (reported by period) |
| Head grades (historical) | % Cu, g/t Au, g/t Ag | Actual (reported by period) |
| Metal recovery to copper concentrate (historical) | % Cu, % Au, % Ag | Actual (reported by period) |
| Copper concentrate produced (historical) | dry metric tonnes | Actual (reported by period) |
| Pyrite concentrate produced (historical) | dry metric tonnes | Actual (reported by period) |
| Predicted metal distributions to concentrates (2026-2036) | % | Testwork / Recovery model |
| Scheduled metal production (2026-2036) | tonnes Cu, oz Au, oz Ag | Designed / Recovery model |
| Copper concentrate terms (model) | % Cu grade (10% Cu assumed in trials) | Testwork / Recovery model |
| Metallurgical recovery algorithm (copper concentrate) | formula | Testwork (Table 15-2) |
| Metallurgical recovery limits (copper concentrates) | limits | Testwork (Table 15-3) |
| Variable operating cost adjusted to haulage distances | US$/t per block | Design / Cost model (Table 15-4) |
| Historical data for main consumables (to Oct 31, 2025) | various | Actual |
| Future requirements for energy, water, process materials | various | Projected |
Project website: https://dpmmetals.com/assets/producing/chelopech-mine/
Project website: https://dpmmetals.com/news-media/news-releases/dpm-metals-extends-chelopech-mine-life-to-ten-year-13379/
Project website: https://dpmmetals.com/
Technical qualifications
The report contains forward-looking information, including estimates, projections, and conclusions that involve significant risks and uncertainty. The qualified persons have attempted to identify factors that could cause actual results to differ materially, but there may be other factors not identified. Readers should not place undue reliance on forward-looking information, which is made as of the effective date of the report. The quality of information, conclusions, and estimates is consistent with the level of effort involved in ERM services, based on information available at the time of preparation, data supplied by outside sources, and the assumptions, conditions, and qualifications set forth in the report.
The concession agreement expires on 26 July 2029. Approximately 55% of the Mineral Reserve tonnage is planned to be mined and processed after July 2029. The report notes that an extension of the concession agreement is expected but cannot be guaranteed, and the expiry represents a risk, although unlikely.
Source: Mineral Resource and Mineral Reserve Update – Chelopech Mine, Bulgaria, Technical Report in accordance with NI 43-101. Effective Date: 5th January 2026, Report Date: 5th March 2026. Relevant sections include 1.11, 13, 15.2, 17, 18, and 25.
