Overview
The R-35 project, a cornerstone of the technical advancement at the Haib Copper deposit in southern Namibia, represents one of the most ambitious mineral processing initiatives in the modern copper sector. Managed by Koryx Copper Inc. (formerly known as Deep-South Resources Inc.), the project has evolved through rigorous value chain optimization studies to reach a steady-state production target of 35 million tonnes per annum (Mtpa). This designation, frequently associated with the “R-35” throughput model, marks a strategic transition from earlier, smaller-scale conceptual designs to a massive, high-throughput circuit designed to unlock the economic potential of one of the largest porphyry copper-molybdenum deposits in Africa.
Located in the arid Karas region near the Orange River, the R-35 project faces unique geographical and metallurgical challenges. The mineralization at Haib is characterized as a large-tonnage, low-grade porphyry system, necessitating a processing solution that prioritizes volume and efficiency to ensure commercial viability. The 2025 Preliminary Economic Assessment (PEA), conducted by specialized mining consultancies such as Qubeka, confirmed that the existing mineral resource is capable of supporting a 35 Mtpa total processing schedule for a Life-of-Mine (LoM) exceeding 23 years. The significance of the R-35 project extends beyond its scale; it serves as a technical benchmark for the integration of hybrid processing technologies, combining a 28 Mtpa concentrator with a 7.0 Mtpa hydrometallurgical plant to treat varied ore types, including oxides and lower-grade sulphides. This dual-track approach ensures maximum metal recovery while optimizing the capital intensity of the operation.
Key Process Stages
The R-35 mineral processing circuit is designed with a multi-stage approach to handle the complex mineralogy of the Haib deposit. The flow sheet selection was finalized after extensive trade-off studies evaluating grind sizes, energy consumption, and recovery rates. Key stages include:
- Primary Crushing: Run-of-Mine (ROM) ore is processed through a heavy-duty primary gyratory crusher to reduce the material to a manageable size for the comminution circuit.
- Comminution Circuit (SABC): The design incorporates a Semi-Autogenous Grinding (SAG) mill, followed by ball milling and pebble crushing (SABC). This configuration was selected over other options (such as three-stage crushing or HPGR) to provide the necessary flexibility for varying ore hardness and to achieve the target grind size of 120 µm to 212 µm.
- Pre-Concentration via Coarse Particle Flotation (CPF): A critical innovation in the R-35 circuit is the implementation of CPF technology. This stage enables the rejection of approximately 4 Mtpa of barren tailings (particles larger than 150 µm) before the material enters the energy-intensive conventional froth flotation cells.
- Conventional Froth Flotation: The 28 Mtpa concentrator utilizes a series of rougher and cleaner flotation cells to produce a high-grade copper-molybdenum concentrate. The circuit is optimized for the recovery of chalcopyrite, the primary copper mineral at Haib.
- Hydrometallurgical Processing: A dedicated 7.0 Mtpa hydrometallurgical plant treats oxide ores and lower-grade sulphide material. This plant utilizes leaching technologies to extract copper from material that would otherwise be sub-economic for flotation.
- Concentrate Dewatering and Handling: The final concentrate is thickened and filtered to produce a dry product suitable for transport to international smelters, while water is recovered for internal recycling.
Critical Data
The following table summarizes the primary technical parameters of the R-35 mineral processing circuit as defined in the latest optimization reports.
| Parameter | Value | Unit |
|---|---|---|
| Total Design Throughput | 35,000,000 | tpa (dry) |
| Concentrator Throughput | 28,000,000 | tpa |
| Hydrometallurgical Plant Capacity | 7,000,000 | tpa |
| Estimated Life of Mine (LoM) | 23 | Years |
| Target Grind Size (P80) | 120 – 212 | µm |
| CPF Tailings Rejection Rate | 4,000,000 | tpa |
| Primary Comminution Method | SABC | Circuit Type |
| Water Recovery Target | >85 | % |
Technical Details and Sustainability
The technical depth of the R-35 project is best exemplified by its commitment to “Value Chain Optimization.” By moving to a 35 Mtpa throughput, the project leverages massive economies of scale to offset the lower head grades typical of porphyry copper deposits. A standout feature of the technical design is the primary grind size trade-off. Metallurgical test work evaluated sizes of 120 µm, 150 µm, and 212 µm to determine the optimal balance between power consumption and copper recovery. The inclusion of Coarse Particle Flotation (CPF) represents a paradigm shift in the circuit’s efficiency; by rejecting barren gangue material at a coarser size, the plant significantly reduces the “circulating load,” which in turn decreases the wear on downstream equipment and lowers the specific energy consumption per tonne of copper recovered.
Sustainability is not a secondary consideration for the R-35 project but is integrated into its core engineering. Namibia is an arid country where water management is a critical operational risk. The R-35 circuit addresses this through advanced thickening and filtration technologies that aim to recover the vast majority of process water. The proximity of the project to the Orange River provides a reliable source, but the design focuses on minimizing net consumption through closed-loop recycling. Furthermore, the massive scale of the 35 Mtpa operation presents an opportunity for the integration of renewable energy. Namibia’s high solar irradiance makes the site ideal for a dedicated solar farm, which could provide a substantial portion of the power required for the SABC circuit, thereby reducing the project’s carbon footprint and long-term operating costs.
From an environmental perspective, the use of CPF and hydrometallurgical pathways allows for a more targeted treatment of different ore types, minimizing the chemical footprint of the flotation circuit. The rejection of barren tailings at an early stage also results in a more stable tailings storage facility (TSF) profile, as the coarser material improves the structural integrity of the tailings mass. As the global demand for copper intensifies due to the electrification of transport and the expansion of renewable energy grids, the R-35 project’s high-capacity, technology-forward approach serves as a model for how large-tonnage, low-grade resources can be developed responsibly and profitably in the 21st century.
Future outlooks for the R-35 project include potential expansions or further optimizations of the molybdenum recovery circuit, which could provide additional credit revenue. The project remains a focal point for investors interested in large-scale copper exposure within a stable African mining jurisdiction. With its 23-year mine life and sophisticated processing flow sheet, R-35 is poised to become a significant contributor to the global copper supply chain.
Source: R-35 | Koryx Copper Technical Reports
Source: NI 43-101 Technical Report
This article provides an overview of mineral processing developments based on publicly available technical reports and industry analysis.
