Technical report and preliminary economic assessment update for the SMSZ Project in Mali, describing a proposed modular gravity-CIL processing plant with a nominal throughput of 1200 tonnes per day.
Report context
This NI 43-101 Technical Report and PEA Update on the SMSZ Project in Mali, prepared for Desert Gold Ventures Inc., is dated December 2025. The report describes a proposed upgraded modular processing plant designed as a conventional gravity-Carbon-in-Leach (CIL) circuit with a nominal throughput of 1200 tonnes per day (tpd), representing a doubling of the original design plant capacity from 600 tpd. The plant will process oxide ore from Barani East, Gourbassi West, and Gourbassi West North, and oxide and transitional ore from the Gourbassi East deposit.
Processing route
Process overview
The upgraded modular processing plant is designed as a conventional gravity-CIL circuit at 1200 tpd nominal throughput, equivalent to approximately 36 kilo tonnes per month (ktpm) or 432,000 tonnes per annum (tpa) at steady state, assuming 92% availability. Metallurgical testwork indicates strong amenability to gravity recovery, particularly for Barani East, and CIL leaching optimal for Gourbassi ores.
The flowsheet incorporates crushing, screening, grinding, classification, thickening, CIL leaching, desorption, electrolysis and smelting, with tailings disposal via wet discharge. Gravity concentration is integrated as a pre-leaching step to remove gravity recoverable gold, based on testwork recommendations. Loaded carbon is eluted in a 1 tonne per batch Zadra pressure elution column, followed by electrowinning and smelting to produce Doré gold bars on site. CIL tailings are detoxified and pumped to HDPE-lined tailings storage facilities.
The fully skid-mounted design is intended to permit relocation within three months with minimal production loss, confirming both technical and economic feasibility for the life-of-mine across all four ore sources.
Crushing circuit
The crushing circuit reduces Run-of-Mine ore to a particle size of P80 = 13 mm through a three-stage arrangement consisting of a primary coarse jaw crusher followed by a secondary fine jaw crusher and a tertiary cone crusher operating in closed circuit with a linear vibrating screen. Design criteria specify a maximum feed particle size F100 of 480 mm for the primary crusher and a product size P80 of 112 mm. The secondary crusher product size P80 is 62 mm, while the tertiary crusher product size P80 is 14 mm. All crushers, screens, and associated conveyors are individually skid-mounted with hydraulic support legs.
Grinding and classification
Crushed ore is reclaimed to a two-stage ball milling circuit. The primary mill (3.2 m diameter x 4.5 m length, 630 kW power loading) grinds crushed ore to an intermediate P80 of approximately 212 microns, with a spiral classifier in closed circuit. Steel ball loading for the primary mill is expected to be approximately 76 tonnes.
The secondary regrind ball mill (2.4 m diameter x 4.5 m length, 400 kW installed motor power) grinds final Knelson tailings to a P90 of 75 µm to achieve optimised gold liberation for CIL leaching. It operates in closed circuit with cyclones for classification. Steel ball loading for the secondary mill is expected to be approximately 44 tonnes.
Gravity concentration
Primary mill discharge reports to two continuous-feed Centrifugal Concentrators (STL-100 type). A two-stage configuration uses a primary batch Knelson concentrator followed by a secondary Knelson CVD (continuous variable discharge) unit processing the primary Knelson tailings. Combined concentrate from the two centrifugal concentrators is upgraded on two 6-S shaking tables to produce final gravity concentrate, collected in secure bins for subsequent smelting or future intensive cyanidation. Shaking table middlings are recycled to the primary mill, while table tailings are returned to the process stream ahead of secondary milling.
Design criteria indicate a concentrate mass pull of 0.08% of feed for all ore types. Concentrate grades from testwork for the gravity circuit are reported as: Barani East 20.11 g/t, Gourbassi West/West-North 2.57 g/t.
Leaching and adsorption
Gravity tailings are thickened to 40% solids and conditioned in two tanks of 510 m³ each, providing approximately 10 hours of conditioning residence time. Leaching then takes place in seven subsequent CIL tanks of 510 m³ nominal volume each, providing 41 hours of total residence time at design tonnage. The design leach residence time specified is 24 hours, which testwork indicates is exceeded for all ore types. Cyanide concentration is maintained at 300–400 ppm, pH at 10.5–11 using lime and caustic soda, with oxygen sparging to enhance leach kinetics. Carbon concentration in slurry is 20 g/L, using coconut shell carbon. Tailings gold grades from the CIL circuit based on testwork data are reported as: Barani East 0.17 g/t, Gourbassi West/West-North 0.06 g/t, Gourbassi East 0.20 g/t.
Elution and electrowinning
Loaded carbon from the second CIL tank is acid-washed and stripped in a 1-tonne-per-batch pressure Zadra elution column equipped with electric heaters. Elution stripping temperature is 150°C. Stripped carbon passes through a regeneration kiln before being returned to the circuit. Pregnant eluate is processed in electrowinning cells using steel wool cathodes to produce gold sludge, which is subsequently filtered, dried, and smelted with gravity concentrate in a conventional tilt-pour induction furnace to produce Doré gold bars containing greater than 90% gold and silver.
Tailings management
CIL tailings first pass over safety screens to capture residual carbon before entering an agitated detoxification tank. Cyanide is destroyed using SO₂ (or process air or sodium metabisulphite) in the presence of a copper catalyst and lime, with a target weak-acid-dissociable cyanide concentration of below 50 ppm prior to discharge. Detoxified tailings are pumped to HDPE-lined tailings storage facilities, with one facility at Barani East and one central facility serving the Gourbassi cluster after plant relocation. The Barani East TSF is designed with a total volume of 190,195 m³ and total height of 10 m. The Gourbassi West/West-North TSF has a total volume of 1,286,968 m³ and total height of 20 m. The Gourbassi East TSF has a total volume of 183,614 m³ and total height of 10 m.
Key reported parameters
| Parameter | Value | Basis |
|---|---|---|
| Nominal throughput | 1,200 tpd (432,000 tpa) | Design |
| Plant availability (milling/CIL) | 97.3% | Design |
| Crushing circuit availability | 78.1% | Design |
| Feed rate to milling/CIL | 54 tph | Design |
| Final grind size (primary mill P80) | 212 µm | Design |
| Final grind size (secondary mill P90) | 75 µm | Design |
| CIL residence time (total) | 44 hours | Design |
| CIL residence time (design leach) | 24 hours | Design |
| Conditioning tanks | 2 x 510 m³ | Design |
| Leach tanks | 7 x 510 m³ | Design |
| Cyanide consumption | 2 kg/t ore | Design |
| Caustic consumption (Barani East) | 15.57 kg/t ore | Design |
| Caustic consumption (Gourbassi W/WN) | 2.29 kg/t ore | Design |
| Elution capacity | 1 tonne per batch | Design |
| Gold recovery in gravity circuit (Barani East) | 69.49% | Testwork |
| Gold recovery in CIL circuit (Barani East) | 71.94% | Testwork |
| Gold recovery in CIL circuit (Gourbassi W/WN) | 90.34% | Testwork |
| Tailings grade (Gourbassi W/WN CIL) | 0.06 g/t | Testwork |
| Bond Ball Work Index | 10.0 kWh/t | Testwork/Design |
| Total installed power | approx. 3,058 kW | Design |
Project website: https://desertgold.ca/
Technical qualifications
The report states that no testwork was performed for KE and Keniegouloo ore types, and therefore no gravity or leaching recovery data is included for these sources. Mass balances for the gravity concentration circuit were calculated using testwork data, focusing on batch and continuous gravity separation for gold recovery. The leaching circuit mass balance was calculated using testwork data from the report's metallurgical testwork chapter. Crushing circuit mass balance was determined using simulation systems from Metso (My Plant Planner) and Sandvik Group (PlantDesigner). The installed power total of 3,058 kW excludes auxiliaries like lighting and controls, and power for minor components such as instrumentation, screens, and electrics is not explicitly listed in the quotation.
Source: Desert Gold Ventures Inc. NI 43-101 Mineral Resource Technical Report and PEA Update on the SMSZ Project – Mali, December 2025, Sections 17.1–17.3.
Consolidated report summaries
The following former standalone pages about this operation were consolidated here on October 25, 2026. They are retained for source traceability; dates and figures reflect each report’s own effective date and may be superseded by the current information above.
Desert Gold Ventures Inc. — SMSZ Project Technical Report
This technical report describes the proposed processing plant configuration for oxide and transitional ores from the Barani East, Gourbassi West, and Gourbassi West North deposits.
Report context
The report, dated August 2025, presents a preliminary economic assessment for the SMSZ Project in Mali. The processing section details a proposed single modular circuit design for 18.0 ktpm throughput, processing oxide and transitional ores in two phases: initially at Barani East (Years 1–3) and subsequently relocated to Gourbassi West and West North (Years 4–17).
Processing route
Proposed plant design
The final processing plant will be a single modular circuit designed for 18.0 ktpm (approximately 25 tph at 92% availability). The unified circuit accommodates metallurgical differences between ore types with tailored recovery efficiencies and includes scrubbing of run-of-mine ore to remove clay and fines, producing a coarse fraction and fines below 2 mm; two-stage crushing and screening of scrubbed ore to produce material with 80% passing 10 mm; primary milling of the minus 10 mm feed down to 212 µm; secondary milling of coarse slurry down to 75 µm; classification via cyclones in closed circuit; thickening of classified slurry to 40% solids; conditioning with cyanide and lime for carbon-in-leach (CIL) processing; conventional CIL processing with loaded carbon sent to elution; elution and electrowinning; smelting of electrowinning sludge combined with gravity concentrates to produce doré bars; and detoxification of CIL tailings for deposition in a lined tailings storage facility with water recycling.
Proposed phase operations
The single circuit is applied in two phases. The first phase at Barani East (Years 1–3) is designed to process 530 kt of ore at 1.67 g/t Au, yielding approximately 31.2 koz of gold at approximately 74% recovery. The report notes that CIL addresses moderate preg-robbing yielding approximately 72% recovery from testwork despite higher sulphide content. The second phase relocates the plant to Gourbassi West and West North (Years 4–17) to process 3,117 kt of ore at 0.83 g/t Au, yielding approximately 91.3 koz of gold at approximately 91% recovery, where CIL consistently achieves over 90% recovery due to the free-milling nature of the ore.
Upside potential for gravity recovery
An upside potential for recovery, specifically for Barani East, would be to include a gravity recovery step. The report states that Barani East will benefit from up to 69.5% of the available gold being recovered as a preliminary step, with CIL handling the remaining. The circuit would consist of primary gravity recovery via a batch Knelson and secondary gravity recovery with a Continuous Variable Discharge Knelson unit. Both concentrates will be upgraded with a Gemini Shaking Table before smelting. This would increase the overall gold recovery for the first 3 years to 92% as supported by testwork, if the grade can be controlled accordingly. Gourbassi West and West-North has a low overall gravity amenability for the ore at around 20% average which gives minimal benefit from the gravity circuit, with an estimated 1% increase in overall gold recovery and low smelting potential.
Historical operating data
No historical operating data is presented in the report. The processing description is based on proposed design criteria and testwork results.
Testwork basis
The report references metallurgical testwork supporting recovery estimates. For Barani East, CIL yields approximately 72% recovery from testwork, while gravity recovery testwork supports potential overall recovery of 92%. For Gourbassi West and West North, testwork shows CIL consistently achieves over 90% recovery. Mass pull values for the CIL mass balance were derived from recent testwork.
Key reported parameters
| Parameter | Units | Value | Basis |
|---|---|---|---|
| Plant throughput | ktpm | 18.0 | Design |
| Plant throughput (operating) | tph | 25 at 92% availability | Design |
| Annual RoM treatment rate | tpa | 216,000 | Design |
| Crushing circuit availability | % | 78.08 | Design |
| Milling and CIL circuit availability | % | 94.52 | Design |
| RoM feed size F80 | mm | 315 | Design |
| Primary mill product P80 | µm | 212 | Design |
| Secondary mill product P80 | µm | 75 | Design |
| Primary ball mill installed power | kW | 630 (725 installed) | Design |
| Secondary ball mill installed power | kW | 26 (30 installed) | Design |
| CIL conditioning residence time | h | 1.45 (Barani East), 1.48 (Gourbassi West) | Design |
| CIL leach residence time | h | 6.22 (noted as too short) | Design |
| Barani East: ore processed (Years 1–3) | kt | 530 | Proposed |
| Barani East: head grade | g/t Au | 1.67 | Proposed |
| Barani East: gold recovery (CIL only) | % | ~72 (testwork), ~74 (design) | Testwork/Design |
| Barani East: gold recovery (with gravity) | % | 92 | Testwork |
| Barani East: gold production | koz | ~31.2 | Proposed |
| Gourbassi West/West North: ore processed (Years 4–17) | kt | 3,117 | Proposed |
| Gourbassi West/West North: head grade | g/t Au | 0.83 | Proposed |
| Gourbassi West/West North: gold recovery | % | ~91 | Testwork |
| Gourbassi West/West North: gold production | koz | ~91.3 | Proposed |
| CIL tank volume (each) | m³ | 80 | Design |
| Number of CIL leach tanks | No. | 5 | Design |
| Carbon concentration in slurry | g/L | 20 | Design |
| Elution column capacity | kg | 600 (540 actual loading) | Design |
| Cyanide dosage | kg/t ore | 2 | Design |
| Doré bar gold purity | % | >90 | Design |
| Total installed power (big-ticket items) | kW | ~1,025.5 | Design |
Project website: https://desertgold.ca/
Technical qualifications
The report notes that the CIL leach residence time of 6.22 hours is too short for sufficient leaching, with an estimated 10% to 30% loss in recovery. It is advised to increase residence time by adding tanks or choosing bigger CIL tanks from the beginning.
The report states that the crushing circuit mass balance was determined utilising Metso My Plant Planner simulation software, with confirmation from Sandvik PlantDesigner. The thickener design was verified against testwork settling rates for water recovery estimates.
The process description is based on a preliminary economic assessment and does not constitute a feasibility study. The proposed gravity circuit for Barani East is identified as an upside potential subject to grade control.
*Source: Desert Gold Ventures Inc. NI 43-101 Mineral Resource Technical Report and PEA on the SMSZ Project – Mali, August 2025, Sections 17 Recovery Methods.*
Desert Gold SMSZ: 1200 tpd Gravity-CIL Gold Recovery Plant
Desert Gold SMSZ: 1200 tpd Gravity-CIL Gold Recovery Plant
Source: Desert Gold Ventures Inc (2026)
Website: https://desertgold.ca/desert-gold-advances-barani-gravity-plant-installation-and-confirms-july-19th-2026-commissioning-target-at-smsz-project-western-mali-2/
Critical Data
| Parameter | Value | Unit | Notes |
|---|---|---|---|
| Throughput | 1200 | tpd | Nominal plant capacity; 432,000 tpa at steady state |
| Mill Power | 630 (primary) / 400 (secondary) | kW | Primary mill installed power 725 kW; secondary installed 460 kW |
| Target Grind Size | 75 | µm | P90 for secondary mill product; primary mill P80 = 212 µm |
| Head Grade | 0.61 – 1.50 | g/t | Leach feed grade varies: Barani East 0.61, Gourbassi West 0.62, Gourbassi East 1.50 |
| Recovery % | 72 – 90 | % | Gold dissolution in CIL: Barani East 72%, Gourbassi West 90%, Gourbassi East 87% |
| Processing Capacity | 54 | tph | Milling, concentrator, and CIL circuit feed rate (21.9 h/day) |
| Energy Consumption | 10 | kWh/t | Bond Ball Work Index for both primary and secondary milling |
| Water Consumption | m³/t | Not explicitly provided; tailings thickener overflow recycled | |
| Operating Hours | 21.9 | hours/day | Milling and CIL circuit; crushing operates 17.6 h/day |
Overview
Desert Gold Ventures Inc. is developing the SMSZ Project (Barani Project) in Mali, featuring an upgraded modular processing plant designed as a conventional gravity-Carbon-in-Leach (CIL) circuit. The plant has a nominal throughput of 1,200 tonnes per day (tpd), equivalent to 432,000 tonnes per annum at 92% availability. The facility processes oxide and transitional ore from multiple deposits: Barani East, Gourbassi West, Gourbassi West North, and Gourbassi East, with a phased mining approach that optimizes resource utilization. Operations commence at Barani East for the first ~16 months, after which the modular plant is relocated to a central site near Gourbassi West for ~92 months, with Gourbassi East adding another ~18 months to the life-of-mine. The process design integrates crushing, grinding, gravity concentration, CIL leaching, desorption, electrowinning, and smelting to produce Doré gold bars on site. Gravity concentration is included as a pre-leaching step to recover coarse gold, especially from Barani East ore. The plant’s fully skid-mounted modular configuration enables rapid dismantling and relocation within three months, minimizing production downtime. Metallurgical testwork confirms strong amenability to gravity recovery and CIL leaching, with leach residence times of 44 hours at design tonnage. This technical report underpins a Preliminary Economic Assessment (PEA) update, demonstrating both technical and economic feasibility for the life-of-mine across all four ore sources.
Key Process Stages
- Stage 1: Three-Stage Crushing – Run-of-mine ore is reduced to P80 = 13 mm using a primary coarse jaw crusher, a secondary fine jaw crusher, and a tertiary cone crusher in closed circuit with a linear vibrating screen. All crushers and screens are skid-mounted with hydraulic support legs for easy relocation. Feed rate is 67.3 tph over 17.6 hours per day, with dust suppression water sprays.
- Stage 2: Primary Milling and Gravity Concentration – Crushed ore is ground in a primary ball mill (3.2 m x 4.5 m, 630 kW) to P80 = 212 µm in closed circuit with a spiral classifier. Mill discharge feeds two STL-100 centrifugal concentrators (Knelson) that recover coarse gold. Concentrate is upgraded on 6-S shaking tables to produce a high-grade gravity concentrate for direct smelting. Gravity tailings proceed to secondary milling.
- Stage 3: Secondary Regrind Milling – Gravity tailings are further ground in a secondary ball mill (2.4 m x 4.5 m, 400 kW) to a final grind size of P90 = 75 µm, ensuring optimal gold liberation for CIL. The mill operates in closed circuit with cyclones, with a circulating load of 300%. Slurry density is maintained at 50% solids, and the circuit handles 54 tph at 97.3% availability.
- Stage 4: Carbon-in-Leach (CIL) Circuit – Slurry from the thickener (40% solids) is conditioned with cyanide and lime in two 510 m³ tanks, then leached in seven 510 m³ CIL tanks providing 41–44 hours total residence time. Cyanide concentration is 300–400 ppm, pH 10.5–11, with oxygen sparging. Activated carbon (coconut shell, 20 g/L) adsorbs gold counter-currently. Loaded carbon is screened and sent to elution.
- Stage 5: Elution, Electrowinning, and Smelting – Loaded carbon is acid-washed and stripped in a 1-tonne/batch pressure Zadra elution column. Pregnant eluate undergoes electrowinning to produce gold sludge, which is filtered and dried. Gravity concentrate and electrowinning sludge are smelted together in a tilt-pour induction furnace to produce Doré gold bars (>90% Au+Ag) in 50 kg batches. The circuit processes 15 elution batches per month.
Additional Interesting Data and Summary
The gravity-CIL plant is designed with a fully modular skid-mounted configuration, enabling relocation within three months with minimal production loss—a key economic advantage for the phased mining plan. The crushing circuit operates at 67.3 tph over 285 days per year (78.1% availability), while the milling and CIL circuit runs 355 days per year at 97.3% availability. The CIL circuit comprises two conditioning tanks and seven leach tanks, each 510 m³, providing 44 hours total residence time at design tonnage. Cyanide dosing is maintained at 2 kg/t total (0.4 kg/t conditioning, 1.6 kg/t leach) with caustic soda and lime for pH control. Oxygen sparging enhances leach kinetics. Tailings undergo SO₂/air detoxification to reduce weak-acid-dissociable cyanide below 50 ppm before discharge to HDPE-lined tailings storage facilities—one at Barani East and a central facility for the Gourbassi cluster. Gold production estimates from testwork concentrate grades indicate smeltable gold of 67.8 kg/month from Barani East, 16.98 kg/month from Gourbassi West, 35.59 kg/month from Gourbassi West-North, and 63.90 kg/month from Gourbassi East, totaling 184.27 kg/month across all ore sources. The elution circuit processes 15 batches per month (1 tonne per batch) yielding approximately 4 Dore bars per month. Reagent systems are fully bunded with PLC/SCADA control for precise dosing. The plant design incorporates a 5,000-tonne live-capacity crushed ore stockpile with reclaim feeders. Economic impact is underscored by the PEA update, which extends the life-of-mine by ~18 months with Gourbassi East. Sustainability initiatives include water recycling from the thickener overflow and detoxification of cyanide prior to tailings storage. The modular design reduces environmental footprint at each site and allows rapid restoration post-mining. Future outlook includes potential expansion of the gravity circuit based on ore amenability, with the two-stage centrifugal concentrator configuration already providing flexibility for different ore types. The technical feasibility is confirmed through metallurgical testwork and regional operating benchmarks, ensuring robust gold recovery across all proposed feed sources.
Key Processes: Flotation, CIP/CIL, Cyanidation, Gravity Separation, Ball Mill, Crushing
Target Commodities: Gold
