Source: Minera Alamos Inc (2026)
Website: https://mineraalamos.com/our-assets/pan/
Critical Data
| Parameter | Value | Unit | Notes |
|---|---|---|---|
| Throughput | 14,000 | stpd | Total ore (crushed + ROM) stacked on leach pad |
| Crush Size | 6 | inches | Target product size from primary jaw crusher |
| Head Grade | 0.011 | oz/st | Average Au grade for past two years |
| Recovery % | 69–75 | % | Overall gold extraction on blended hard/soft ore, crushed to 6 inches |
| Processing Capacity | 4.7 | Mstpa | Peak annual crushed ore throughput (2021) |
| Leach Cycle | 90 | days | Typical duration of primary leach cycle per cell |
| Solution Application Rate | 0.0012–0.0026 | gpm/ft² | Gradual increase over leach cycle |
| Pregnant Solution Flow | 3,400 | gpm | Flow rate to carbon columns |
| Carbon Inventory | 4 | tons | Activated carbon in carbon columns |
Overview
Minera Alamos Inc. operates the Pan Gold Mine, employing a heap leach recovery method to extract gold from blended hard and soft ores. The operation has been refined since 2019 with the installation of a primary crushing system, significantly improving gold recoveries. Ore is mined from several pits, crushed to -6 inches, and blended with lime at 3.5 lbs/ton to regulate pH. The material is stacked in nominal 15-foot lifts on a leach pad, where cyanide solution is applied at rates ranging from 0.0012 to 0.0026 gpm/ft² over a 90-day leach cycle. Pregnant solution is collected at approximately 3,400 gpm and processed through carbon columns using a countercurrent adsorption system. Gold is stripped from the carbon via a pressure Zadra process, electrowon onto cathodes, and refined into doré bars for sale. The mine processes about 14,000 short tons per day, with crushed ore volumes peaking at 4.7 million short tons per year. The heap leach operation achieves gold extractions of 69–75% on blended material, with hard rock recovering 62% when crushed and soft rock recovering 85% when crushed. This comprehensive recovery method ensures efficient gold extraction while maintaining environmental compliance through robust solution management systems.
Key Process Stages
- Stage 1: Ore Preparation – Ore is mined from multiple pits at a 60:40 hard-to-soft ratio and hauled to the crushing facility. Lime is added directly to trucks at 3.5 lbs/ton for pH control. Ore is crushed to -6 inches using a 36×50″ Lippman jaw crusher, stockpiled, and then loaded into trucks for transport to the leach pad. Barren solution is added at drop points to initiate wetting and leaching early.
- Stage 2: Leach Pad Stacking and Management – Crushed or ROM ore is dumped in nominal 15-foot lifts on the leach pad. Prior to each lift, the existing pad surface is ripped in two directions with a D10 dozer using 6- to 8-foot shanks to ensure permeability. Drip tubes are buried to prevent ponding and channeling. Solution application starts at 0.0012 gpm/ft² and gradually increases to 0.0026 gpm/ft² over the 90-day leach cycle, targeting a 1:1 solution-to-ore ratio. Cells are ripped again before being buried by the next lift.
- Stage 3: Solution Collection and Pond Management – Pregnant solution percolates through the heap and is collected by drain pipes beneath the pad. It flows to the pregnant solution pond, which is designed to handle meteoric water from a 25-year, 24-hour storm event. Solution is pumped from the pond to the carbon columns at a rate of about 3,400 gallons per minute. Regular samples are taken from each phase to monitor pH, alkalinity, NaCN, and gold content for process optimization.
- Stage 4: Carbon Adsorption and Gold Stripping – Pregnant solution passes through carbon columns containing 4 tons of activated carbon, which adsorbs the gold in a countercurrent flow. Loaded carbon is transferred to an acid strip vessel, where a pressure Zadra process strips the gold from the carbon. The gold is plated onto stainless steel cathodes in electrowinning cells. Stripped carbon is regenerated in a rotary kiln for reuse.
- Stage 5: Refining and Doré Production – Gold- and silver-laden sludge is washed from the cathodes periodically, filtered, and loaded into a retort furnace to remove moisture and mercury. The retorted sludge is blended with fluxing agents and melted in a furnace. The molten gold is poured into button molds, where lighter slags are separated. The resulting doré bars are shipped to a commercial refiner for final processing.
Additional Interesting Data and Summary
The Pan Mine heap leach operation integrates robust environmental controls with efficient gold recovery. The solution management system includes pregnant and barren ponds sized for a 25-year, 24-hour storm event, ensuring all process solutions and meteoric waters are contained. Regular monitoring of pH, alkalinity, NaCN, and gold content across multiple leach pad phases allows operators to optimize irrigation rates and chemical additions, maintaining permeability and preventing clay blinding. The on-site laboratory supports rapid decision-making with two atomic adsorption (AA) machines—one for fire assays and one for cyanide shake tests—plus column and bottle roll testing capabilities. Metallurgical testwork indicates that crushing improves gold recovery by 10% over run-of-mine material. Current extractions are modeled using historical data, showing that approximately 75.5% of ultimate recovery occurs in Year 1, followed by 13.1% in Year 2, 6.5% in Year 3, 3.0% in Year 4, and 1.5% in Year 5. The leach pad recoverable gold inventory was estimated at 33,000 ounces as of the report effective date, calculated using a rolling monthly model that accounts for new gold placed and ounces produced. This model has been validated against actual production and shows consistent performance. The Pan Mine’s success in blending hard and soft ores, combined with disciplined stacking and solution application practices, makes it a benchmark for heap leach operations treating variable ore types. Future outlook includes continued optimization of the blend ratio and leach cycle parameters to further improve extractions. The operation’s economic impact is significant, generating steady doré production and maintaining a stable workforce. Sustainability initiatives include water recycling through the closed-loop solution system and minimizing energy consumption by using a single stage of crushing. The facility’s ability to adapt historical operational issues—such as permeability problems from clay segregation—into a controlled, high-recovery process demonstrates Minera Alamos’ technical expertise and commitment to responsible mining.
Key Processes: Heap Leaching, Cyanidation, Crushing
Target Commodities: Gold
Technical report and processing history
The following archived source profiles have been consolidated here to preserve the project’s processing history and study context.
Pan Gold Mine — 2025 Technical Report
Pan Gold Mine — 2025 Technical Report
| Company | Minera Alamos Inc. |
| Date | 2025 |
| Region | Unknown |
| Commodities | Gold, Silver |
Executive Summary
This NI 43-101 Technical Report details the recovery methods employed at the Pan Gold Mine, operated by Minera Alamos Inc. The facility utilizes a heap leach process to recover gold from ore mined from several open pits. Since 2019, the operation has incorporated a crushing system to improve permeability and recovery rates, blending hard and soft ore before stacking on the leach pad.
Ore preparation involves primary crushing to -6 inches, with lime added to regulate pH. The crushed material is stacked in 15 ft lifts on the leach pad, where cyanide solution is applied to percolate through the ore. Solution management includes drip tubes to prevent ponding and channelling, with pregnant solution collected and pumped to the processing plant. Recent operating results indicate consistent throughput of approximately 14,000 stpd with gold extractions improving since the crusher installation.
Gold recovery is achieved using carbon columns where activated carbon adsorbs gold from the pregnant solution. The loaded carbon undergoes a pressure Zadra process to strip the gold, which is then plated onto cathodes via electrowinning. The final product is refined into doré bars for sale. Laboratory facilities support ongoing optimization through column and bottle roll tests to monitor extraction efficiency.
Processing Profile
- Crushing: 36×50” Lippman Jaw Crusher
- Milling: N/A
- Flotation: N/A
- Leaching: Heap Leach (Cyanide)
- Recovery: Carbon Columns, Zadra Strip, Electrowinning
Website: https://mineraalamos.com/our-assets/pan/
Report Date: 2025
Region: Unknown
Project Status:
Commodity: Gold, Silver
Throughput:
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Pan Mine — 2023 Technical Report
Pan Mine — 2023 Technical Report
| Company | Calibre Mining |
| Date | 2023 |
| Region | Not Specified |
| Commodities | Gold |
Executive Summary
Calibre Mining operates the Pan Mine, utilizing a heap leach facility to recover gold from ore mined from the North and South Pan pits. The operation processes approximately 14,000 short tons per day (stpd) of ore, maintaining a specific blend of 60% hard to 40% soft material to ensure permeability and optimal leaching performance. Since 2019, the feed preparation involves primary crushing to -6 inches and the addition of lime to regulate pH prior to stacking on the leach pad.
The recovery process employs cyanide solution distributed via drip emitters to percolate through the ore heap. Pregnant solution is collected and treated in an existing Adsorption, Desorption, and Refinement (ADR) plant to produce doré for sale. Recent operating results indicate gold extractions ranging from 69% to 75% on the target blend, with ore grades averaging 0.012 opt Au over the past two years. The mine plan extends through 2030, with projected recoverable ounces totaling 209,000 ounces from crushed ore placed on the pad.
Operational challenges regarding ore permeability were addressed by modifying stacking methodologies and installing a crushing circuit in 2019. Current practices involve ripping the pad surface to maintain permeability and using dozers to blend material. Reagent costs have increased to $1.03/ton in 2022, primarily driven by cyanide and lime consumption. The operation continues to monitor gold extractions and pad inventory to ensure alignment with forecast models.
Processing Profile
- Crushing: 36×50” Lippman Jaw Crusher
- Milling: N/A
- Flotation: N/A
- Leaching: Heap Leach (Cyanide)
- Recovery: ADR Plant
Website: https://mineraalamos.com/our-assets/pan/
Report Date: 2023
Region: Not Specified
Project Status:
Commodity: Gold
Throughput:
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Pan Gold Project — 2021 Technical Report
Pan Gold Project — 2021 Technical Report
| Company | Fiore |
| Mine | Pan Mine |
| Date | 2021 |
| Region | Nevada, USA |
| Commodities | Gold |
| Throughput | 14,000 tpd |
| Status | Operating |
Executive Summary
This section details the recovery methods and operational results for the Pan Gold Project. The operation utilizes an open-pit mining method to extract hard and soft ore from the North and South Pan pits. The ore is processed using a heap leach circuit with a primary crushing stage and cement agglomeration to improve permeability and gold recovery. Significant improvements in gold extraction were achieved following Fiore’s acquisition, primarily through operational procedure changes and the installation of a crushing and stacking system.
Operational results indicate a steady increase in gold recovery rates from 33.2% in 2017 to 57.3% in 2019, with 54.1% recorded in the first half of 2020. The process involves crushing ore to a nominal 4 inches, mixing with cement and barren solution, and stacking on a leach pad. Pregnant solution is collected and treated in an existing conventional ADR plant. The mine employs 44 personnel and utilizes production water wells for process water requirements.
Processing Methods
- Crushing: Primary Jaw Crusher (Lippman 36 x 50)
- Leaching: Heap Leach with Drip Emitters
- Recovery: Adsorption, Desorption, Refining (ADR)
- Reagents: Cyanide, Caustic, Cement, Lime
Website: https://www.juniorminingnetwork.com/junior-miner-news/press-releases/523-tsx/cxb/109041-calibre-announces-acquisition-of-fiore-in-nevada-creating-a-diversified-americas-focused-growing-mid-tier-gold-producer.html
Report Date: 2021
Region: Nevada, USA
Project Status: Operating
Commodity: Gold
Throughput: 14,000 tpd
Mine Life:
Mine Type:
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Pan Gold Project — 2015 Technical Report
Pan Gold Project — 2015 Technical Report
| Company | Midway |
| Date | 2015 |
| Commodities | Gold |
| Throughput | 19,700 tpd |
| Annual Production | 76,000 oz Au |
Executive Summary
The Pan Gold Project utilizes heap leaching for gold recovery from Carlin-type ores located in the South Pan and North Pan pits. The initial operation focuses on run-of-mine material from the South Pan, though permeability issues due to clayey material have prompted the evaluation of a primary crusher and agglomeration system. This system is intended to re-handle existing ore on the leach pad and process fresh ore from the South Pan area pits in the future. The North Pan ore, which has higher permeability, will be processed concurrently with overliner material construction for the Phase 2 leach pad expansion.
The plant is designed for a throughput of 19,700 tons of ore per day, equating to 7.0 million tons of ore per year. The Adsorption-Desorption-Recovery (ADR) plant is designed for a solution flow rate of 5,000 gpm and is expected to produce approximately 76,000 ounces of gold per year. Reagent consumption is relatively low for Carlin-type ores, with estimated sodium cyanide usage at 0.35 pounds per ore ton and lime consumption between 2 and 3 pounds per ore ton. Cement is added during agglomeration to further reduce lime consumption.
Processing involves a primary jaw crusher for South Pan ores to facilitate material handling on conveyor belts. North Pan ores will undergo three-stage crushing to a P80 minus ½ inch prior to agglomeration. Once the permanent crushing and agglomeration facilities are commissioned, all production will be sourced from the South Pan series of pits. The system includes pregnant and barren solution ponds, drip tube irrigation for the leach pads, and a conventional ADR plant for gold recovery, including carbon regeneration and electrowinning cells.
Processing Methods
Website: https://www.ledcor.com/our-projects/project-gallery/project-gallery-mining/coals-mineral-metals/pan-project
Report Date: 2015
Region:
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Commodity: Gold
Throughput: 19,700 tpd
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