Koryx Copper's 2025 preliminary economic assessment for the Haib porphyry copper project in southern Namibia treats 35 Mtpa in total. Higher-grade sulphide goes to two flotation modules, and oxide and low-grade sulphide go to a heap leach, SX and EW plant.
The Preliminary Economic Assessment of the Haib Copper Project, Namibia, NI 43-101 Technical Report, was prepared for Koryx Copper Inc. (formerly Deep-South Resources), with an effective date of 4 September 2025 and an issue date of 8 October 2025. It builds on the 1997 feasibility study, the 2021 PEA (amended in 2024) that considered a 20 Mtpa heap leach, and 2025 testwork. The concentrator treats 28 Mtpa of primary sulphide with at least 0.225% Cu. The hydrometallurgical plant treats 7.0 Mtpa of oxide and sulphide grading 0.150% to 0.225% Cu. The value chain optimization found that the resource could support a 35 Mtpa schedule for about 23 years.
Critical Data
| Parameter | Value | Unit | Notes |
|---|---|---|---|
| Report effective date | 4 September 2025 | Not applicable | PEA for Koryx Copper Inc. |
| Concentrator throughput | 28 | Mtpa | Two 14 Mtpa modules |
| Heap leach throughput | 7.0 | Mtpa | Grade A cathode, 99.995% Cu |
| Concentrator feed grade | 0.225–0.380, average 0.331 | % Cu | Molybdenum average 50 ppm |
| Crushing per module | 60-110 gyratory, three HP 900 cones, two 2.8 x 2.0 m HPGRs | Not applicable | Product 100% passing 16 mm, about 80% passing 6.5 mm |
| Ball mills | Four 22 ft x 32.75 ft EGL, 10 MW each | Not applicable | Two per module, 878 t/h per mill |
| Grind size | P80 150 (range 120 to 180) | µm | Flotation feed at 32 to 35% solids |
| Coarse particle flotation | HydroFloat on up to 50% of cyclone underflow | Not applicable | +150/-425 µm; rejects up to 20% of mill feed |
| Copper concentrate | Above 21% Cu, mass pull 1.0 to 1.8% | Not applicable | Moisture below 10% |
| Molybdenum concentrate | Above 45% Mo | Not applicable | Batch circuit; mass pull below 0.1% |
| Tailings | Two 62 m high-rate thickeners, 55 to 60% solids | Not applicable | Thickened wet tailings to the TSF |
| Heap leach | 75% Cu recovery, 400-day cycle, 45 to 50°C | Not applicable | Crush F80 5.8 mm |
| Design hardness | CWi 23 kWh/t, BBWi 21 kWh/t | Not applicable | 85th percentile values for equipment sizing |
Overview
The concentrator has two identical modules. Each runs primary and secondary crushing, a tertiary HPGR circuit and ball milling, with coarse particle flotation (CPF) on part of the cyclone underflow for coarse gangue rejection (CGR). Copper rougher flotation, regrind, cleaner and cleaner scavenger flotation follow. A molybdenum circuit runs in batch mode when feed grade and prices justify it. The copper and molybdenum concentrates are thickened, filtered, trucked to Lüderitz and shipped. The heap leach plant crushes material in a circuit identical to a concentrator crushing module and stacks it on a leach pad. Copper is recovered by solvent extraction (SX) and electrowinning (EW).
Key Process Stages
Flowsheet trade-offs. SABC, three-stage crushing and ball milling, and HPGR-ball circuits were compared at grinds of 120, 150 and 212 µm. HPGR-ball scored highest. Its capital cost is marginally higher than SABC, but it is expected to have the lowest operating cost. CPF on cyclone underflow scored highest among the CPF options and could cut operating cost by about 5% without a material loss of copper recovery. Wet thickened tailings were chosen over filtered or hybrid tailings on operating cost and power. Four on-site hydrometallurgical routes for the copper concentrate were assessed (Albion, BIOX MesoTHERM, pressure oxidation, and roast-leach-EW), and all would erode project value.
Crushing. Each module treats 2,317 t/h of run-of-mine with a 1,000 mm top size. A 60-110 gyratory crusher feeds three HP 900 secondary cone crushers in closed circuit with screens. Secondary product is stockpiled and fed to two 2.8 m x 2.0 m HPGRs in closed circuit with screens.
Milling and CPF. Each module has two 10 MW ball mills in parallel, each closed with a cyclone cluster, at 878 t/h per mill. Lime is added at the mill feed for a pH of 9.0 to 9.5, and the mills run at 72 to 75% solids. The CPF circuit screens and cyclones up to half of the cyclone underflow to a +150/-425 µm feed for HydroFloat cells. CPF concentrate returns to the mill, and coarse gangue goes directly to tailings. Testwork showed 94% stage recovery at 15% mass pull.
Copper flotation. Two circuits of 11.2 Mtpa each at 32% solids (or 11.9 Mtpa at 35% solids with 15% rejection) run rougher flotation, rougher concentrate regrind and cleaner flotation, with the cleaner tails going to cleaner scavengers. The mass pull is about 1.35% at the 0.33% Cu average feed grade. Reagents include lime, SEX collector, Senkol 700 promoter and MIBC frother.
Molybdenum recovery. When the copper-molybdenum concentrate carries enough molybdenum, it is dewatered, washed and conditioned. It then goes through rougher flotation and four cleaner stages, with NaHS depressing copper and fuel oil as collector. The final molybdenum concentrate is leached with NaCN and ferric chloride to remove residual copper. The report puts molybdenum recovery at about 35 to 40% when the circuit runs. It is justified only at high prices, above USD 60/kg.
Tailings and concentrate handling. Tailings from each module go to a 62 m high-rate thickener. The underflow is pumped through a booster station to the TSF at 55 to 60% solids. Copper concentrate goes through a 28 m thickener at 60 to 65% solids and filter presses with at least 312 m² of combined area, to below 10% moisture. The molybdenum concentrate uses a 5 m thickener and about 10 m² of pressure filtration.
Heap leach, SX and EW. The heap leach design follows the Mintek bacterial process tested in 2020 and the 2021 PEA. It runs at about 45 to 50°C, with heat retained by balancing irrigation and aeration, a 400-day leach cycle and 75% average copper recovery. Copper SX uses mixer-settlers in a two-extract, two-strip configuration, and EW uses stainless steel blank cathodes. Koryx is also running further Mintek column tests and chloride leach and Ceibo tests in parallel.
Additional Interesting Data and Summary
Concentrator water use is estimated at 0.44 to 0.54 m³/t milled, with tailings dam return water assumed at 30% of the water in the thickener underflow. Filtered tailings would cut water use to about 0.13 to 0.15 m³/t, at about USD 1.1/t more in operating cost. Trade-off studies planned for the PFS include bulk or particle sorting ahead of milling, Jameson cells, rail conveyors to the heap leach, and shipping concentrate through Walvis Bay. A screening option for the +150 µm CGR tailings, which could then be used in the TSF retaining wall, is also to be considered.
In summary, the 2025 Haib PEA moves from the 2021 heap-leach-only concept to a combined 35 Mtpa operation. A 28 Mtpa HPGR-ball concentrator with HydroFloat coarse gangue rejection makes copper and optional molybdenum concentrates, and a 7 Mtpa bacterial heap leach with SX-EW makes copper cathode.
Key Processes
- Gyratory and cone crushing with tertiary HPGR
- Ball milling to P80 150 µm
- HydroFloat coarse particle flotation for coarse gangue rejection
- Copper rougher, regrind, cleaner and cleaner scavenger flotation
- Batch molybdenum flotation and concentrate leaching
- Concentrate thickening and pressure filtration
- Thickened wet tailings disposal
- Bacterial heap leaching, solvent extraction and electrowinning
Source: Preliminary Economic Assessment of the Haib Copper Project, Namibia, National Instrument 43-101 Technical Report, prepared for Koryx Copper Inc., effective date 4 September 2025.
Earlier report summaries
Earlier versions of this profile, based on older technical reports, are retained below for source traceability. Dates and figures reflect each report’s own effective date and are superseded by the current information above.
Haib Project — PEA Update
This PEA update evaluates whole ore heap leaching with bacterial assistance as the sole recovery method for the low-grade, hard chalcopyrite orebody at Haib, supported by metallurgical testwork indicating copper recoveries exceeding 90%.
Haib is a large, low-grade copper deposit hosted largely in chalcopyrite, where conventional crushing, grinding, and flotation to produce a copper concentrate was determined not economically feasible due to low grade and ore hardness. The updated preliminary economic assessment (PEA) therefore considered only whole ore heap leaching for copper recovery. Current testwork has confirmed that bacterial assisted heap leaching can achieve copper recoveries over 90%. Ore is agglomerated, stacked on lined pads, and leached with sulfuric acid, with the pregnant leach solution processed through solvent extraction and electrowinning to produce copper cathodes or, optionally, copper sulfate pentahydrate. The project site is in the Karas Region of southern Namibia, with infrastructure planning addressing power supply, water, and transport, including potential rail and road connections.
Critical Data
| Parameter | Value | Unit | Notes |
|---|---|---|---|
| Resource basis for flowsheet | 456.9 | Mt | Measured and indicated resource used for flowsheet development |
| Copper feed grade | 0.31 | % Cu | Not explicitly restated in source, but consistent with stated low-grade feed |
| Copper recovery | >90 | % | Bacterial assisted heap leaching testwork result |
| Copper sulfate production cap | 50,000 | tpa | Copper sulfate pentahydrate |
| Anhydrous copper sulfate equivalent | 32,000 | tpa | Production cap |
| Global copper sulfate market | >400,000 | tpa | Projected by IMARC by 2022 |
| Potential market share | ~8 | % | Based on cap of 32,000 tpa anhydrous equivalent |
| Power demand options | 6 | options | Options 1–6 assessed |
| Water demand | 160–370 | m³/h | Depending on throughput and final products |
| Process water source | Orange River | , | Key source, plus recycled water from dry stacking |
| Access road upgrade | 12 | km | Existing road requires upgrade |
| Distance to Keetmanshoop Airport | 300 | km | Largest airport in Karas region |
| Solar plant reference | 5.78 | MW | Trekkopje solar plant in Erongo region |
Overview
The Haib deposit is a porphyry copper-molybdenum system that has been historically explored. The current PEA considered only whole ore heap leaching, due to ore hardness and low grade making flotation uneconomic. The process design uses high pressure grinding rolls (HPGR), agglomeration, heap leaching with forced aeration to support bacterial activity, and a solvent extraction–electrowinning plant. The project is designed to produce copper cathode, with an optional copper sulfate pentahydrate by-product stream limited by market considerations.
Key Process Stages
The process flowsheet includes primary crushing using a gyratory crusher, followed by secondary and tertiary crushing through cone crushers, then HPGR for fine grinding. Crushed ore is conveyed to an agglomeration drum, where sulfuric acid and bacteria are added prior to stacking on lined heap leach pads. The heap is irrigated via drip irrigation, and a forced aeration system supplies oxygen for bacterial activity. The pregnant leach solution is pumped to the SX plant where copper is extracted using an organic reagent, stripped with strong acid, and sent to electrowinning where copper plates onto cathodes. An iron precipitation step using limestone and lime removes iron and aluminium from a bleed stream. Copper sulfate pentahydrate production is possible through evaporation and crystallisation, with the product sold as a blue powder. The process plant includes a metallurgical laboratory, assay laboratory, open area storage, maintenance and warehouse, and control room.
Additional Interesting Data and Summary
Namibia remains dependent on imported refined petroleum products and has a critical electricity supply situation, with nearly half the population lacking access. The national grid is supplied largely by imports and domestic generation including the Ruacana hydropower plant and a solar plant near Trekkopje. A 600 MW transmission line extension to Zambia and Zimbabwe is under construction. Water availability is a critical factor: the Orange River is the key source, with additional water required mainly for dust suppression. The site is on state land used only for emergency stock grazing, so mining will not conflict with formal farming. The rail authority has confirmed that a rail link from the project area to Grunau could be laid relatively easily across the largely flat terrain. Copper is primarily used in electrical wiring, while copper sulfate has applications as a herbicide, fungicide, and in analytical reagents.
Key Processes
- Whole ore heap leaching with bacterial assistance (only recovery method considered)
- Crushing and HPGR for size reduction
- Agglomeration with sulfuric acid and bacteria
- Drip irrigation leaching on lined pads with forced aeration
- Solvent extraction and electrowinning to produce copper cathode
- Optional copper sulfate pentahydrate production, capped at 50,000 tpa (32,000 tpa anhydrous equivalent)
- Iron and aluminium removal via limestone and lime addition in a bleed treatment circuit
Source: Haib Project , PEA Update, 2020.
Project website: Haib Project, PEA Update
