Source: Heliostar Metals Ltd (2026)
Website: https://www.heliostarmetals.com/projects/development/cerro-del-gallo/
Critical Data
| Parameter | Value | Unit | Notes |
|---|---|---|---|
| Throughput | 16,667 | tpd | Nominal crushing capacity; design capacity 22,200 tpd |
| Mill Power | N/A | kW | Not specified in Section 17 |
| Target Grind Size | 4-6 | mm | 80% passing (P80) from HPGR tertiary crushing |
| Head Grade | 0.09 | % | Average copper grade in mine plan |
| Recovery % | N/A | % | Not provided in Section 17 |
| Processing Capacity | 16,667 | tpd | Nominal stacking rate on heap leach pad |
| Energy Consumption | N/A | kWh/t | Not provided in Section 17 |
| Water Consumption | N/A | m³/t | Not provided in Section 17 |
| Operating Hours | 18 | hours/day | Crushing section operates 75% of 24 hours; 360 days/year |
Overview
Heliostar Metals Ltd. is advancing the Cerro del Gallo Project (CdG) in Guanajuato, Mexico, a gold-silver-copper deposit amenable to heap leaching. The Pre-Feasibility Study (PFS) effective December 11, 2025, outlines a robust recovery flowsheet integrating state-of-the-art crushing, agglomeration, heap leaching, a SART plant, and a carbon adsorption-desorption-recovery (ADR) circuit. The ore is mined by conventional open-pit methods and processed at a nominal rate of 16,667 tonnes per day. A three-stage crushing system incorporating a primary jaw crusher, secondary cone crushers, and a high-pressure grinding roll (HPGR) achieves a final product size of 80% passing 4–6 mm. The crushed ore is agglomerated with cement and conveyor-stacked in 8-meter lifts on a 92-million-tonne capacity lined heap leach pad. The heap is irrigated with dilute sodium cyanide solution in two phases: 40 days at 12 L/h/m² and 80 days at 6 L/h/m², for a total leach cycle of 120 days. Pregnant solution containing gold, silver, and copper is treated in a SART plant, where copper and silver are precipitated as sulfides for sale as a filter cake, and the regenerated cyanide is recycled. Gold is recovered from the SART barren solution via carbon adsorption, desorption, electrowinning, and smelting to produce doré bars. This integrated approach maximizes metal recovery, reduces cyanide consumption, and generates additional revenue from the copper-silver precipitate, making Cerro del Gallo a technically and economically significant project.
Key Process Stages
- Stage 1: Three-Stage Crushing – Run-of-mine ore is dumped into a 200-tonne feed bin, passes a vibrating grizzly, and is crushed by a primary jaw crusher (open circuit, 80% passing 145 mm). The product is stockpiled, then reclaimed and conveyed to secondary crushing using two double-deck vibrating screens and two cone crushers in closed circuit (80% passing 36 mm). Tertiary crushing employs an HPGR in closed circuit with triple-deck vibrating screens to produce a final product of 80% passing 4–6 mm. Design capacities: nominal 16,667 t/d (696 t/h), design 22,200 t/d (925 t/h).
- Stage 2: Agglomeration and Stacking – Fine ore is reclaimed and conveyed to two parallel agglomeration drums, where cement (added from silos controlled by weightometers) and barren process solution are blended. The agglomerated ore discharges onto a stacking system comprising an overland conveyor, up to 23 mobile grasshopper conveyors, and a radial stacker. Material is placed in 8-meter lifts on the leach pad. The pad is constructed in four phases with a composite liner (clay/GCL and textured HDPE geomembrane) covering 139.8 hectares with a maximum heap height of 80 meters.
- Stage 3: Heap Leaching – Irrigation uses drip tubes with dilute sodium cyanide solution (approx. 1500 ppm CN). Leaching occurs in two stages: Phase 1 (first 40 days) at 12 L/h/m², Phase 2 (next 80 days) at 6 L/h/m². Barren solution is pumped at a nominal 1,280 m³/h (design 1,400 m³/h) from a barren tank via two horizontal centrifugal pumps. Antiscale agent is added. Pregnant solution is collected in the pregnant solution pond via a network of perforated drainage pipes and pumped to the SART circuit. Total leach cycle: 120 days.
- Stage 4: SART Plant – Pregnant solution is acidified with sulfuric acid, then sodium hydrosulfide is added to precipitate copper and silver as sulfides. The precipitate is thickened and filtered to produce a copper-silver filter cake sold to a smelter. The SART process releases cyanide from copper-cyanide complexes, allowing it to be recycled as free cyanide back to the leach circuit, reducing overall cyanide consumption. Gypsum slurry by-product is managed in a lined Gypsum Pond (2-year capacity).
- Stage 5: ADR Plant and Gold Recovery – Barren solution from SART is processed in a carbon adsorption-desorption-recovery (ADR) circuit. Gold is adsorbed onto activated carbon, periodically stripped using a desorption process, then electrowon onto stainless steel cathodes. The gold deposit is washed, filtered, dried, and smelted to produce doré bars. The ADR plant is designed to handle the full 1,400 m³/h flow from the SART circuit, ensuring efficient gold recovery with minimal losses.
Additional Interesting Data and Summary
The Cerro del Gallo heap leach facility is designed to process approximately 92 million tonnes of ore over its life, with a maximum heap height of 80 meters across 139.8 hectares. The pad is constructed in four phases with a composite liner system meeting Nevada Administrative Code 445A.434 and Mexican Standard NOM-155-SEMARNAT-2007. The liner consists of a 1.5-mm textured HDPE geomembrane over a 300-mm compacted soil liner (or GCL) and a 700-mm drainage layer overliner with minimum permeability of 1×10⁻¹ cm/sec. Solution collection uses perforated pipes (100–450 mm diameter CPE) maintaining a maximum hydraulic head of 0.7 m on the liner. The SART plant produces a copper-silver sulfide filter cake for sale, adding revenue while reducing cyanide consumption. Gypsum slurry from SART is stored in a double-lined pond (2-year capacity). A detailed pre-feasibility water balance accounts for average as-mined moisture, 1,280 m³/h nominal leach application, and evaporation; the barren tank has negligible storage. The Waste Rock Dump stores 30.3 Mt (of 33.3 Mt total) with dry density 1.9 t/m³. Stormwater diversion channels are sized for a 1-in-100-year, 24-hour event. Environmentally, the double-lined pregnant and event ponds provide secondary containment and leak detection, while underdrain systems capture spring water and seepage. The project operates 360 days per year, with crushing at 75% utilization (18 h/day). Future outlook includes phased leach pad expansion (Phases 2–4) without additional equipment, progressive reclamation of the WRD, and monitoring of gypsum for alternative disposal. The integrated heap leach–SART–ADR circuit positions Cerro del Gallo as a model for sustainable precious and base metal recovery in Mexico, with potential to reduce environmental footprint through cyanide recycling and co-product sales.
Key Processes: Heap Leaching, Cyanidation, Gravity Separation, Crushing
Target Commodities: Gold, Silver, Copper
Technical report and processing history
The following archived source profiles have been consolidated here to preserve the project’s processing history and study context.
Cerro del Gallo Project — 2026 Technical Report
Cerro del Gallo Project — 2026 Technical Report
| Company | Heliostar |
| Date | 2026 |
| Region | Mexico |
| Commodities | Gold, Silver, Copper |
| Mine Type | Open Pit |
| Throughput | 16,667 t/d |
| Status | Development |
Executive Summary
The Cerro del Gallo Project is a development-stage open-pit mine designed for the recovery of gold, silver, and copper via heap leaching. The ore, estimated to contain an average of 0.09% copper, is amenable to cyanide leaching. The project utilizes a three-stage crushing circuit incorporating jaw, cone, and high-pressure grinding roll (HPGR) crushers to reduce ore to 5mm before agglomeration with cement and stacking on a heap leach pad.
The processing circuit features a 120-day leach cycle with a composite liner system designed to meet North American and Mexican environmental standards. Pregnant solution from the heap is treated in a SART plant to precipitate copper and silver as sulfides, which are filtered and shipped to a smelter. The barren solution is then processed in a Carbon Adsorption-Desorption-Recovery (ADR) plant to recover gold, which is electrowon onto cathodes and smelted into doré bars.
The Heap Leach Facility (HLF) has a capacity of approximately 92 million tonnes and is designed in four phases. The facility includes Pregnant, Event, and Satellite ponds for solution storage and management, ensuring a zero-discharge operation during average climate conditions. Engineering and design cover complete crushing, leaching, and recovery systems with a nominal crushing capacity of 16,667 t/d.
Reports
Entities
Concepts
Website: https://www.heliostarmetals.com/projects/development/cerro-del-gallo/
Report Date: 2026
Region: Mexico
Project Status: Development
Commodity: Gold, Silver, Copper
Throughput: 16,667 t/d
Mine Life:
Mine Type: Open Pit
Ore type:
Cerro de Gallo — Technical Report
Cerro de Gallo — Technical Report
| Company | Cerro Resources |
| Mine | Cerro de Gallo |
| Date | 2024 |
| Region | Mexico |
| Commodities | Gold, Silver, Copper |
| Throughput | 4.5 Mt/a |
| Status | Development |
Executive Summary
The Cerro de Gallo project features a proposed processing plant designed to treat fully and partially oxidised ores with a throughput of 4.5 Mt/a. The plant utilizes a conventional cyanide heap leach circuit combined with a SART (Sulphidisation, Acidification, Recycle and Thickening) stage to recover copper and silver prior to gold recovery. Gold and silver are recovered via Carbon in Column (CIC) adsorption, followed by elution, electrowinning, and smelting to produce doré.
The facility is designed to produce approximately 62,246 oz of Au and 17,185 oz of Ag annually in doré, along with 884 tonnes of copper sulphide precipitate. The crushing circuit includes a primary jaw crusher, secondary cone crusher, and tertiary HPGR to achieve a target product size of P100 8mm. The heap leaching operation employs a valley fill method with four heaps in operation at any one time.
Website: https://www.heliostarmetals.com/projects/development/cerro-del-gallo/
Report Date: 2024
Region: Mexico
Project Status: Development
Commodity: Gold, Silver, Copper
Throughput: 4.5 Mt/a
Mine Life:
Mine Type:
Ore type:
Cerro del Gallo Heap Leach Project — 2020 Technical Report
This technical report describes the proposed processing facilities for gold, silver, and copper recovery from the Cerro del Gallo deposit using heap leaching and SART technology, supported by testwork results.
Report context
This technical report for the Cerro del Gallo Heap Leach Project, dated January 31, 2020, presents engineering and design criteria developed for a proposed processing plant incorporating crushing, heap leaching, SART, carbon adsorption-desorption-recovery (ADR), and gold refining. The processing route is based on testwork that indicated the ore is amenable to heap leaching for recovery of gold, silver, and copper.
Processing route
Crushing and agglomeration
The proposed design comprises a three-stage crushing system with an open primary circuit and closed secondary and tertiary circuits, operating seven days per week, 24 hours per day. Run-of-mine (ROM) material is delivered by haul truck into a 200-tonne ROM feed bin. A permanent rock breaker handles oversized material. ROM material is fed by a vibrating grizzly feeder; oversize is crushed by a primary jaw crusher operated in open circuit to produce 80% passing 145 mm. The primary product is stockpiled by a coarse ore stockpile feed stacker conveyor.
Material reclaimed from the primary crushed stockpile is conveyed to the secondary crushing circuit, which includes two double deck vibrating screens and two cone crushers operated in closed circuit with a product size of 80% passing 36 mm. Secondary screen undersize is conveyed to a secondary product storage bin, then transferred to the tertiary crushing circuit, which consists of an HPGR crusher operated in closed circuit with a fine screening plant. The final crushed product is designed for 80% passing 4 to 6 mm.
Tertiary screen undersize is stockpiled by a fine ore stacking conveyor. Material from the fine ore stockpile is conveyed to a splitting chute feeding two parallel agglomeration drums. Cement is added from two 150-tonne silos, with the addition rate controlled by weightometers. Cement consumption is estimated in the range of 84 to 334 tonnes per day depending on material type, with a life-of-mine average of 166 tonnes per day. Barren process solution is added in the agglomeration drums, and agglomerated material is conveyed to the stacking system.
Heap conveying and stacking
The heap leach is designed to be constructed in eight-meter lifts using a mobile conveyor stacking system. The Phase 1 system consists of an overland conveyor, 23 mobile grasshopper conveyors, an index feed conveyor, a horizontal index conveyor, and a radial stacker. Phases 2 through 4 will increase the leach area without additional equipment. After a lift has finished leaching and is sufficiently drained, a new lift is stacked over the old lift. The old lift is cross-ripped with a dozer prior to stacking to break up compacted ore. Stacked lifts progress in a stair-step manner.
Heap leaching
The proposed design specifies a single-stage leach system with no intermediate solution use. Irrigation uses a drip-tube system. Antiscale agent is added to the suction of barren and pregnant solution pumps.
The total leach cycle is designed for 120 days, based on metallurgical testwork. The first stage of 40 days applies solution at a nominal rate of 12 L/h/m², and the second stage of 80 days applies solution at 6 L/h/m². Leach solutions have an approximate cyanide concentration of 1500 ppm when applied to the heap. Two horizontal centrifugal pumps operating in parallel at the barren tank provide barren solution application. High-strength sodium cyanide solution and antiscale agent are added to the suction side of barren leach pumps. The combined nominal flow to the heap is 1,280 m³/h.
Heap leach facility design
The heap leach facility (HLF) was designed by Golder for an ore capacity of approximately 92 million tonnes using a dry ore density of 1.6 t/m³. The 139.8-hectare HLF has a maximum heap height of 80 meters. Ore is designed to be stacked at 16,667 tpd. The leach pad is divided into four construction phases providing approximately 1.2 million square meters of lined surface.
The foundation includes an underdrain system within natural drainages. Fill material for perimeter roads, process ponds, and leach pad foundations is intended to be sourced from waste rock mined from the pit.
The composite liner system consists of, from top to bottom: a 700-mm thick drainage layer overliner with solution collection pipes; a 1.5-mm thick, single-sided textured HDPE geomembrane; a 300-mm thick compacted soil liner bedding with permeability no greater than 1 x 10⁻⁵ cm/sec or a geosynthetic clay liner (GCL) with permeability no greater than 5 x 10⁻⁹ cm/sec; and prepared subgrade.
The Pregnant and Event Ponds use a composite liner with an additional secondary 1.5 mm HDPE geomembrane and geonet layers for dual-containment and leak detection. The Satellite Pond, not expected to receive fluids during average climate conditions, is designed with a single geomembrane liner system.
Solution collection cells use geomembrane-lined cell separation berms. Perforated collection pipes of 100 to 450 mm diameter N-12 corrugated polyethylene (CPE) are within the drainage layer. Cell outlet pipes are 600 mm diameter HDPE solid wall. The collection system is sized to maintain a maximum 700 mm hydraulic head on the liner system.
Storm water diversion channels are sized for the 1 in 100-year, 24-hour storm event. A Gypsum Pond, with double liner system, is designed to contain 2 years of gypsum produced from SART operations.
SART plant
Pregnant solution is treated in a SART plant for removal of copper and silver prior to the ADR plant for gold recovery.
Copper precipitation: Concentrated sulfuric acid (98 wt%) is diluted to 30 wt% and combined with pregnant solution in an in-line mixer to acidify to pH 4.0-4.5. The current design is for 1,400 m³/hr of pregnant solution (nominal 1,280 m³/hr). Thickener underflow recycle slurry at 15-43 m³/hr and 10-25 wt% solids is combined with fresh sodium hydrosulfide solution (25 wt%) in the Copper Recycle Mix Tank. Acidified pregnant solution, combined with recycled copper precipitate, passes through three agitated precipitation tanks with a total residence time of 15 minutes. Copper sulfide thickener overflow gravity flows to the Neutralization Reactor; underflow is recycled or advanced to filtration.
Thickener underflow at 2.0-5.6 m³/hr and 10-25 wt% solids is neutralized with caustic solution (20 wt%) to pH 7-8 in the Filter Feed Tank. Two filter presses operate with batch cycles every 4-8 hours. Filter cake is produced at 0.728 tph as 40 wt% cake (0.296 tph dry cake) based on 90% copper and 95% silver precipitation. Cake is conveyed to drying pads, sized to 100% minus 5 mm, and loaded into 20-ton containers or 1-tonne bulk bags.
Caustic scrubber systems: Tanks and sumps in the copper area are ventilated to a caustic scrubbing system with two packed towers. The normal operating case treats 6,800 Nm³/hr with 100 ppmv HCN and H₂S, discharging at 0.2 ppmv. An emergency scrubber treats a burst of 17,100 Nm³/hr at 76,800 ppmv H₂S and 61,300 ppmv HCN for 5 minutes.
Solution neutralization: Acidified thickener overflow is neutralized with slaked lime and recycled gypsum thickener underflow using a high-density sludge process. Neutralization occurs in a tank of approximately 5 minutes residence time. Gypsum thickener overflow gravity flows to the ADR plant. Underflow is recycled or advanced to storage.
Metal recovery (ADR)
The proposed ADR plant uses a single train of five cascade-type, open-top up-flow carbon adsorption columns, each with capacity for 10 tonnes of activated carbon. Loading is continuous; approximately 5 tonnes of carbon per day are expected to be treated, with stripping occurring about 7 times per week, each lasting 12 to 16 hours.
Carbon acid wash involves circulating dilute acid solution at pH 1.0-2.0 for 4 to 6 hours per 10-tonne batch.
Desorption uses a Zadra pressure elution circuit with hot caustic solution at 135°C and approximately 340 kPa (50 psig). Each cycle processes a 10-tonne batch in approximately 18 hours.
The electrowinning circuit operates in series with elution using stainless steel cathodes at a current density of approximately 50 amperes per square meter of anode surface. Loaded cathodes are removed about once or twice per week. Sludge is filtered, dried, and smelted in an electric furnace with fluxes to produce doré bullion.
Thermal carbon regeneration is performed after every elution cycle at approximately 750°C for ten minutes.
Key reported parameters
| Parameter | Design value | Basis |
|---|---|---|
| Nominal crushing capacity | 16,667 t/d (696 t/h) | Design |
| Design crushing capacity | 22,200 t/d (925 t/h) | Design |
| Design conveying capacity | 26,700 t/d (1,110 t/h) | Design |
| Crushing product size | 5 mm (80% passing) | Design |
| Operating days per year | 360 | Design |
| Operating time (crushing, conveying, agglomeration, stacking) | 75% | Design |
| Ore copper grade (average) | 0.09% | Mine plan estimate |
| Leach cycle (total) | 120 days | Design based on testwork |
| Phase 1 leach duration | 40 days | Design |
| Phase 1 application rate | 12 L/h/m² | Design |
| Phase 2 leach duration | 80 days | Design |
| Phase 2 application rate | 6 L/h/m² | Design |
| Barren solution flow (average) | 1,280 m³/hr | Design |
| Barren solution flow (design) | 1,400 m³/hr | Design |
| Cyanide concentration in leach solution | ~1500 ppm | Design |
| SART & ADR feed flow (design) | 1,400 m³/hr | Design |
| HLF ore capacity | ~92 Mt | Golder design |
| HLF lined area | ~1.2 million m² | Golder design |
| HLF maximum heap height | 80 m | Golder design |
| Heap lift height | 8 m | Design |
| Copper precipitation efficiency | 90% | Testwork basis |
| Silver precipitation efficiency | 95% | Testwork basis |
| Copper filter cake production | 0.728 tph (wet), 0.296 tph (dry) | Design calculation |
| Filter cake copper grade (maximum) | 61.6 wt% | Design assay estimate |
| Filter cake silver grade (maximum) | 1.174% | Design assay estimate |
| Cement consumption (LOM average) | 166 t/d | Design estimate |
| Cement consumption range | 84–334 t/d | Design estimate |
| Make-up water (average climate, Phase 1) | 84.9 m³/hr average | Water balance |
| Make-up water (average climate, Phase 4) | 53.7 m³/hr average | Water balance |
| Make-up water (1 in 100 dry year, all phases) | 127.3 m³/hr average | Water balance |
| Rinsing water treatment capacity (average year) | 127,000 m³/year | Design for reclamation |
| Rinsing water treatment capacity (1 in 100 wet year) | 620,000 m³/year | Design for reclamation |
Technical qualifications
The report specifies this is a pre-feasibility level evaluation. Several criteria are identified as assumptions rather than measured data. The water balance includes assumed values for as-mined moisture content and specific moisture retention of ore and waste rock. The report notes that material suitable for use as soil liner bedding appears to be sparse within the limits and immediate proximity of the HLF and WRD, and may need to be imported from local off-site sources. The process pond storage criteria include a 0.6 meter freeboard requirement across all ponds. The emergency scrubber gas burst calculations are noted as being based on review of plant operating data from a metal sulfide leach process with concentrated sulfuric acid.
Source: Cerro del Gallo Heap Leach Project, NI 43-101 Technical Report, January 31, 2020, Sections 17 Recovery Methods.
