Liberty Gold Corp. (TSX:LGD; OTCQX:LGDTF) (“Liberty Gold” or the “Company”) is pleased to announce the results of a Preliminary Feasibility Study (“PFS” or the “Study”) prepared in accordance with National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”) at its flagship Black Pine Oxide Gold Project (“Black Pine” or the “Project”) in southern Idaho, USA. The Study supports a technically straight-forward, low capital intensity, open-pit, run-of-mine (“ROM”) (no ore crushing, screening or agglomeration) heap-leach operation processing oxide gold ore, with attractive economic returns.
The Study assumes a base-case gold price of $2,000/ounce (“oz”) and all figures in this news release are stated in United States dollars (“$” or “US$”) unless otherwise noted. Table 1 below presents a summary of the key metrics for the Black Pine PFS.
Cal Everett, CEO and Director of Liberty Gold commented: “This PFS highlights the strong economic potential at Black Pine, representing our vision for a low-risk, sustainable and long-lived gold mining operation in Idaho. It demonstrates the Project’s ability to exploit higher grades early in the mine life, allowing for solid cash flows over the first five years, with a production profile that reduces the payback period and maximizes the initial return for our investors. The PFS mine plan produces more than 2 million ounces of gold over a projected mine life of 17 years, creating a solid pathway towards mine permitting, project advancement and a future construction decision.”
“We believe there is significant upside for project optimization and resource growth going into a full feasibility study. Growth will be driven by new resource discovery from multiple target areas, upgrade of inferred mineral resources into the measured and inferred mineral resource categories and assessment of gold production potential from the reclaimed heap leach pad. Work in many of these areas is already beginning to yield encouraging results. We look forward to keeping the market apprised of our progress.”
PFS Overview
The PFS incorporates geological, assay, hydrological, metallurgical, geotechnical, environmental and cultural information collected by Liberty Gold and its consultants and contractors, as well as extensive historic information captured from the previous mining operation on site.
Project Description
Black Pine hosts a large, Carlin-style, sedimentary-hosted oxide gold system, located in southeastern Cassia County, southern Idaho, USA, a 2-hour drive north from Salt Lake City, Utah. The currently identified surface footprint of the gold mineralization extends over an approximate 18 square kilometre (“km2”) target area contained within Liberty Gold’s 69.3 km2 project area of which 40.6 km2 are permitted for exploration activities including drilling. (see press releases dated June 11, 2024 and September 25, 2024).
Black Pine is a past-producing open-pit, ROM heap leach mine, active from 1991 to 1997 when Pegasus Gold produced 435,000 oz of gold and 189,000 oz of silver from five open pits. Road access to the site is well established with the I-84 highway running directly adjacent to the project area and existing power at the mine gate. The location is sparsely populated, semi-arid, with no surface water exposed in the project area and no threatened or endangered species.
The production from the Project is subject to a 0.5% net smelter royalty (with a 50% buyback right to the Company, which has been assumed to be exercised in the economic analysis).
Mining
The PFS utilizes open pit mining with mine planning based on economic pit shells generated by mine planning software. Ore feed to the leach pad is planned at 50,000 tonnes per day or 18.3 million tonnes per year for the estimated 17-year life of mine. There will be a 9-month pre-production period to provide access to higher grade ore horizons for early years processing. There are significant opportunities to improve mid-life production through resource growth and conversion ahead of the feasibility study. Lower-grade ores are stockpiled throughout the mine life and re-handled on to the heap to optimize gold production.
Total material movement averages 47 million tonnes per year over life of mine, with a peak at 55 million tonnes per year. Ore is sourced from two large multi-phase open pits, together with six smaller ‘satellite’ open pits. The strip ratio is favourably low at 1.3:1 (waste:ore), resulting from the extensive envelope of lower-grade oxide gold mineralization surrounding the higher-grade horizons and permeating through the mass of carbonate host rock units.
The open pit mining at Black Pine is designed as a conventional, owner-operated surface mining operation, where the owner is responsible for planning and executing direct mining and all mine fleet maintenance, equipment mobilization, supervision, labor, geology and grade control. Blasting would be performed as a contract service. The PFS mine plan proposes a blended mine fleet of 400 tonne-class hydraulic excavators, 100 tonne-class hydraulic excavators, 11.5 cubic metre bucket front end loaders, 136 tonne off-highway haul trucks and 64 tonne off-highway haul trucks.
Metallurgy
Six phases of metallurgical testing have been completed on Black Pine oxide ores, using bulk samples and predominantly, large diameter PQ core. A total of six bulk samples and 174 variability composites have been tested at Kappes, Cassiday & Associates in Reno, Nevada and included extensive geo-metallurgical characterization, comminution testing, bottle roll and column leach testing and environmental characterization of head samples and column residues. The oxide ores respond very well to cyanide leaching with typically >80% of the leachable gold extracted in the first 10 days of laboratory column leaching. Modeling of column test data support ROM leaching as the preferred processing method, with a primary leach cycle of 90 days.
Commercial scale ROM gold and silver grade-recovery models have been developed for the geo-metallurgical oxide ore types, defined by gold cyanide solubility, location and lithology. The limited amount of mineralized carbonaceous material present at Black Pine has been extensively modelled and has been treated as waste rock.
Processing
Gold will be recovered using run-of-mine (no crushing, screening or agglomeration) heap leaching with material placed by mine haul truck stacking onto a single heap leach pad sited at the eastern extent of the Project. The pad is designed in four phases to contain up to 315 million dry tonnes of leachable material, with operational segregation of the oxide ore types in isolated cells on the leach pad to prevent comingling.
ROM-sized ore will be stacked in 10 metre (“m”) vertical lifts to a maximum heap height of 100 m. Lime will be added prior to truck dumping on the pad, ore will be ripped and subsequently leached with dilute cyanide solution using conventional irrigation. Leach solution will flow by gravity through the heap and be conveyed to the process solution tank. No surface ponds other than an emergency event pond are included in the PFS design.
Leached gold will be recovered from solution using a 3-train, activated carbon adsorption circuit. The gold (and any silver) will then be stripped from carbon using a desorption process followed by electrowinning to produce a precipitate sludge, which is refined on site in a furnace to produce final doré bars.
Process water is drawn from five existing, active water wells, located within 5 kilometres from the processing facility. Power is grid supply over an existing 25 kV line to the mine gate.
Cost Estimates
Capital and operating costs were estimated by M3 Engineering for the processing and general and administration components of the PFS costs estimate; all mining costs were estimated by AGP Mining.
The capital costs estimate presented in Table 4, is considered to have overall accuracy of -20% / +25%.
Sustainability
At Liberty Gold, sustainability is integral to our operations and decision-making, ensuring long-term value for stakeholders. Since 2021, we have published annual sustainability reports, reinforcing our commitment to transparency and accountability. At Black Pine, we engage regularly with stakeholders through updates, tours, and local events. We are deeply committed to preserving biodiversity, supporting sage grouse habitat restoration and funding a four-year mule deer migration study with Idaho Fish and Game. Sustainability initiatives included in the Black Pine PFS include renewable energy supply through local utility, no net increase in water draw, habitat mitigation, and waste rock backfill. We propose to explore mine fleet electrification and other key sustainable initiatives during feasibility to minimize our carbon and project footprint.
Further Opportunities
Optimization of the Black Pine Project will be evaluated ahead of and during feasibility. This includes:
- Potential to significantly increase the size and confidence of the resource at Black Pine. Approximately 60% of the project area has not yet been drill-tested:
- The infill drilling and step-out drilling at Rangefront, M-Zone and Discovery, if successful, could expand the mineral resource and convert inferred mineral resource into the measured and indicated mineral resource categories.
- Evaluation of the historic heap to determine the nature and extent of residual gold in the heap and its amenability to further processing.
- New discovery from a currently on-going drill exploration program on seven high-priority targets across the project area.
- The resulting feasibility mine plan would likely change based on continued exploration success and resource expansion.
- Mine planning and design focusing on cut-off grade optimization, stockpiling strategy, bulk-material movement options (e.g. conveyors) for ore to the heap, haul road layout optimization and the potential to expand leaching capacity to 24 million tonnes per year.
- Use of electric and potentially autonomous mining equipment in the open pits (shovels, drills & haul trucks).
- Further define the options for renewable energy, such as solar, to supply site requirements, particularly important for future electrification options.
Next Steps
- A Mine Plan of Operations is currently being drafted and is planned for submission to US federal and cooperating agencies in the fourth quarter of 2024 to commence formal mine permitting under the National Environmental Policy Act (“NEPA”).
- Advance all baseline studies required to support the mine permit applications.
- Technical work to further advance and de-risk the project towards feasibility level will continue into 2025 and the Company intends to conduct a feasibility study to provide the basis for a construction decision. Key areas of work include:
- Resource upgrade and growth,
- Evaluate historic heap potential as a future ore supply,
- Refine geo-metallurgical models and complete metallurgical testing required,
- Completion of additional studies on groundwater sources & quality, geotechnical data collection and design for the heap, pit slopes and rock waste facilities, and
- Feasibility level rock geochemical characterisation for environmental studies.
- An NI 43-101 compliant technical report on the Black Pine PFS will be available on SEDAR within 45 days of this release (the “Technical Report”), including all qualifications, assumptions and exclusions that relate to this PFS. The Technical Report is intended to be read as a whole and sections should not be read or relied upon out of context.
Black Pine Mineral Reserve Estimate
Mineral Reserves have been estimated for a conventional, multiple pit, open pit mining operation utilizing surface waste rock storage facilities, pits backfill, extensive ore stockpiling and direct haul to a single ROM heap leach facility. Pit slope angles were defined by geotechnical evaluation supported by hydrological analysis.
