Liberty Gold Validates Predicted Operating Gold Leach Recoveries Through Bulk Column Tests at Run-of-Mine Sizing
Black Pine bulk column tests support a low-cost ROM heap leach flowsheet by matching modeled gold recoveries and reagent consumption assumptions.
Rhea-AI Summary
Liberty Gold (LGDTF) reported Phase 6 metallurgical bulk column test results validating operating gold leach recoveries for run-of-mine (ROM) material at the Black Pine oxide gold project in Idaho.
Seven ROM-sized bulk samples (2–8 inch P80, ~10–15 tonnes each) were leached in 4 ft by 20 ft columns to simulate commercial ROM heap performance. Average weighted gold extraction from the bulk columns was 72.4%, in line with recoveries modeled in the recent Feasibility Study, with all samples falling within modeled ranges except Rangefront, which exceeded predictions. Reducing particle size from 10 inches to 1 inch increased extraction by less than 3%, supporting a no-crush ROM heap leach strategy.
On average, 90% of total gold extraction occurred within 36 days, and cyanide and lime consumption matched Feasibility Study assumptions. Six of seven ROM samples showed adequate permeability under simulated compaction to 150 m. Weighted average silver recovery was 21%, with peak extractions up to 39%.
Positive
- Bulk ROM gold extraction averaged 72.4%, consistent with Feasibility Study modeled recoveries.
- Reducing particle size from 10" to 1" improved extraction by less than 3%, supporting a no-crush ROM strategy.
- Rangefront Ppos bulk sample achieved 95% gold extraction at 0.43 g/t, overperforming modeled recovery by more than 13%.
- On average, 90% of total gold extraction was achieved within 36 days, indicating rapid leach kinetics.
- Bulk column cyanide and lime consumption aligned with Feasibility Study estimates, de-risking process operating cost assumptions.
- Bulk silver extraction reached up to 39%, with a weighted average recovery of 21%, above previous variability averages.
Negative
- One ROM-sized sample showed underperforming permeability due to high clay content, requiring identification and blending on the heap.
News Explained
The pre-production metallurgical program remains active: Phase 8B column testing has started, with results from Phases 8B and 10 expected in
AI-generated analysis. How Rhea-AI works. Not financial advice.
VANCOUVER, British Columbia, Sept. 17, 2026 (GLOBE NEWSWIRE) -- Liberty Gold Corp. (TSX: LGD; OTCQX: LGDTF) (“Liberty Gold” or the “Company”) is pleased to report results from its Phase 6 metallurgical test program on the Black Pine Oxide Gold Project (“Black Pine”) in southeast Idaho. This pre-production validation test work was conducted at the Reno laboratory of Kappes, Cassiday & Associates (“KCA”), using bulk column leaching (column dimensions 4 feet (“ft”) diameter by 20 ft high) on seven run-of-mine (“ROM”) sized samples (with particle sizes ranging from 2” to 8” P80), weighing approximately 10 to 15 tonnes each.
These columns are intended to simulate gold leach performance within a commercial ROM heap. The term “ROM” herein refers to blasted ore taken directly from the open pit and placed onto the heap leach pad without crushing, agglomeration or mechanical stacking, using a simple haul truck dump and dozer push/rip approach.
Gold extractions from the bulk column leaching program confirm the previously modeled gold leach recoveries for ROM-sized material at Black Pine. These findings validate key gold recovery assumptions incorporated into the Preliminary Feasibility Study (“PFS”) and updated in the recently released Feasibility Study (“FS”) results for Black Pine (see press releases dated October 10, 2024, and September 8, 2026).
Further, all metallurgical test work to date measuring gold extraction through leaching across a wide range of particle sizes (P80 ranging from fine (75 microns) to coarse (8 inches or ~200 millimeters)), consistently supports the economic viability of processing Black Pine ores through a ROM heap leach operation.
Jon Gilligan, President and CEO, Liberty Gold, commented, “At Black Pine, we’re conducting the detailed metallurgical work that many heap leach projects overlook. This is part of our disciplined, technical approach to the study phase and it will materially de-risk delivery as we move towards a construction decision. By validating gold leach extractions across the full range of particle sizes, we are optimizing the balance between mining costs and ultimate gold recoveries. These results confirm that our gold recovery models for ROM material are reliable and consistent. They provide additional confidence that predicted gold recoveries can be achieved through a simple, low-cost ROM processing strategy.”
Highlights
- Gold Extraction Insensitive to Particle Size: The modest improvement in gold extraction from coarse to fine particle size does not justify the cost of crushing. On average, for the material types tested, reducing the rock particle size from 10” to 1” increases gold extraction less than
3% . This relationship is characteristic for some Carlin-style oxide ores and this test work adds further validation to the weight of evidence from the extensive metallurgical test programs carried out by the Company over the last 8 years, which strongly indicate minimal value uplift from crushing or blasting to a finer particle size. - Modeled Recoveries Corroborated at Coarse Particle Sizes: The bulk column results confirm recoveries modeled at ROM particle sizes and provide additional confidence in the gold recovery predictions using FS metallurgical models going into detailed engineering design. Of particular note are the results from a) the Discovery upper Pola sample, which is indicative of early leach feed ore under the FS mine plan and performed within
0.5% of modeled gold recovery, and b) the gold extraction results from the Rangefront Ppos sample, which outperformed modeled gold recoveries by over13% . - Rapid Leach Kinetics Validated: Black Pine is emerging as a classic example of oxide ores where ROM gold extractions are rapid and relatively insensitive to particle size. On average,
90% of total gold extraction was achieved within 36 days of leaching, with several columns reaching the same milestone in 22 days or less. The commercial implication of this feature of the Black Pine ores is low cost ounce production with significant operational flexibility on the leach pad. - Demonstrated Reagent Consumption: Cyanide reagent consumption measured in crushed-rock laboratory column tests is typically higher than commercial-scale ROM heap leach operations and therefore requires scaling assumptions for financial modeling. Both cyanide and lime consumption values from bulk column testing demonstrate expected commercial-scale performance and have underpinned FS reagent consumption estimates. This information de-risks an important operating cost that is traditionally poorly predicted, creating increased technical confidence in process operating cost estimates.
- Favorable Permeability Results: Compacted permeability results for six of the seven ROM-sized samples tested show adequate solution percolation up to 150 meters (“m”) of simulated compaction. This contributes to a large data set at Black Pine showing that managed blending of select ores will maintain permeability within the heap leach pad. This is beneficial not only for ultimate gold recovery, but also for geotechnical stability of the heap leach facility. One sample underperformed as predicted due to high clay content. This material would be identified as clay with the current modeling methodology and blended as required on the heap.
Richard Zaggle, Senior Director, Mining and Metallurgy, Liberty Gold, commented, “Rangefront contains oxide ore with favorable leach characteristics, while also offering low processing costs. The bulk column program significantly strengthens an already extensive metallurgical column leach data set for Black Pine ores, with multiple variability columns delivering more than
Phase 6 Metallurgical Test Summary
The Phase 6 program was designed to validate modeled gold leach recoveries at coarse particle sizes to support a ROM heap leach processing route for Black Pine ores.
The Phase 6 program tested seven Black Pine ores, collected with an excavator (~20 tonnes per sample), six taken from historic pits and one taken off the surface (see Figure 1). Metallurgical composites were made up from bulk samples and leached at particle sizes ranging from a P80 of 75 microns up to ROM-size (8”). Larger particle size material was leached in bulk columns (dimensions 4’ diameter by 20’ high). These columns are much larger than a typical column test (see Figure 2) and are intended to simulate gold leach performance in commercial scale ROM leach pads.
Figure 1 – Summary Map of Black Pine Metallurgical Program Sample Locations
Figure 2 – Bulk columns (ROM Sizing) vs. normal columns and general difference in top size for particles
Seven samples were tested under standard test conditions for Black Pine oxide gold material, with results summarized below in Table 2. The average weighted gold extraction for the bulk columns was
Two results are of particular note:
- The Rangefront Ppos sample had the highest extraction tested at
95% for a 0.43 g/t gold head grade. This recovery is high for material at this gold grade and is considerably in excess of modeled recovery for the Ppos unit in Rangefront, even at finer crush sizes. The result may have significant implications for increasing the value of Rangefront as the Ppos unit is currently viewed as low value stripping material in the recently published FS. - The I-pit Pold sample extraction at
51.9% was an expected result as this rock unit is known to have lower gold extraction and the results are aligned with modeled recoveries.
It should be noted that columns which met or over-performed versus the modeled predictions are representative of a greater portion of the recoverable ounces within the resource, notably the larger mining phases at Black Pine, Discovery and Rangefront.
Table 1 shows results from the Phase 6 test work program with extraction results for all samples. Results include fine bottle rolls, coarse bottle rolls, small columns, and the bulk columns.
Table 1 – Phase 6 Gold Extraction Results
¹ Small columns are approximately 9 feet tall and 1 foot in diameter
2 Bulk columns are 20 feet tall and 4 feet in diameter
Black Pine ROM Modeling Methodology
The metallurgical database at Black Pine comprises more than 200 column leach tests on composite material sampled from large diameter (PQ) drill core and nine (9) bulk samples (3 by Noranda and 6 by Liberty Gold in 12’’ diameter columns at a P80 between 2 and 3 inches). In typical metallurgical test programs for new oxide gold deposits, gold extractions are tested at a variety of particle sizes ranging from very fine (P80 of 75 microns) to relatively coarse (P80 of 1”). Particle sizes significantly larger than 1” are generally not tested as sampling and testing is cumbersome and expensive. Liberty Gold has adopted and implemented an industry-proven approach using laboratory bottle roll and column leach protocols to accurately project commercial gold and silver recoveries at any particle size from laboratory data. An example of this methodology can be seen in Figure 3 and Table 2.
Figure 3 and Table 2 – An example of the methodology used across Black Pine to predict recovery at larger particle sizes than tested in laboratory conditions. This plot is for the B-pit sample (ROM Pilot #4).
The Company took the view that laboratory bulk column testing was an important de-risking step for new production planning, despite having commercial information from the historic operations at Black Pine, where ~30 million tonnes of ROM-sized ore was heap leached in the 1990’s.
Detailed Results
Extraction versus time graphs illustrate both the leach kinetics (rapid leaching rate in first 10 to 30 days) and relative extraction performance over the leach cycle for the seven bulk samples (see Figure 4).
Figure 4 – Extraction vs time for bulk columns
Figure 5 shows the recovery results for each sample tested, at variable size fractions, against ranges for recovery previously modeled by ore type. Ranges for extraction shown (shaded areas) are the P10-P90 ranges for previous variability sample results used to model extraction percentage as a function of particle size.
Figure 5 – Extraction vs particle size for material tested shown against previously modeled ranges by material type
Silver
Bulk column leach tests recorded silver (“Ag”) extractions up to
Ongoing Metallurgical Programs
Liberty Gold has an ongoing pre-production metallurgical program for Black Pine:
- Phase 8: Composites from 24 sonic drill holes (~1,400 meters) in the legacy heap leach pad are being tested for economic potential. Vat leach tests have been completed and a second round of column leach testing, Phase 8B, has started at KCA in Reno. Results are expected in H1 2027.
- Phase 9: Phase 9 involves a re-assay campaign of ~2,000 samples for LECO and Preg Rob focused on better understanding dilution risk with MET4 and Poc materials. Management considers current dilution assumptions to be conservative. These assays are pending and will be used to guide mining decisions in detailed engineering and future mine planning.
- Phase 10: 26 composites from additional core holes in Rangefront are being tested at KCA with a focus on all grade ranges across the primary gold hosting units in Rangefront. Results are expected in H1 2027. This program is focusing on increasing variability sample coverage in Rangefront.
- Phase 11: This program is focused on low grade samples (<0.1 g/t) across the deposit in order to improve the low-end gold extraction model. Results are expected in Q1 2027.
- Phase 12: Phase 12 will be focused on understanding potential extractions of waste dump material. This program will begin following completion of RC drilling currently happening on site.
These additional phases of work will continue to validate the feasibility level gold and silver recovery models. Further test work will be completed as needed to ensure model accuracy through detailed design and into production.
Quality Assurance - Quality Control
All metallurgical work at Black Pine was conducted at KCA Labs in Reno and is supervised by Gary Simmons, MMSA, formerly Director of Metallurgy and Technology for Newmont Mining Corp. Mr. Simmons has managed metallurgical programs on multiple Carlin-style oxide deposits in the Great Basin and has been the Metallurgical consultant for Black Pine since project inception.
The scientific and technical information contained in this news release has been reviewed and approved by Richard Zaggle, RM-SME, Senior Director, Mining and Metallurgy of Liberty Gold Corp., a Qualified Person as defined by NI 43-101.
ABOUT LIBERTY GOLD
Liberty Gold is a U.S.-focused gold company advancing Black Pine, its
For more information, visit libertygold.ca or contact:
Susie Bell, Vice President, Investor Relations and Corporate Communications
Phone: 604-632-4677 or Toll Free 1-877-632-4677
info@libertygold.ca
Richard Zaggle, RM-SME, Senior Director Mining and Metallurgy, Liberty Gold, is the Company's designated Qualified Person for this news release within the meaning of National Instrument 43-101 Standards of Disclosure for Mineral Projects ("NI 43-101") and has reviewed and validated that the information contained in the release is accurate.
This news release contains “forward-looking information” and “forward-looking statements” within the meaning of applicable securities laws, including statements or information concerning, future financial or operating performance of Liberty Gold and its business, operations, properties and condition; planned de-risking activities at Liberty Gold’s mineral properties; future updates to the mineral resource, the potential quantity, recoverability and/or grade of minerals; the potential size of a mineralized zone or potential expansion of mineralization; proposed exploration and development of Liberty Gold’s exploration property interests; the results of mineral resource estimates or mineral reserve estimates and preliminary feasibility studies; and the Company’s anticipated expenditures.
Forward-looking information is often, but not always, identified by the use of words such as "seek", "anticipate", "plan", "continue", "planned", "expect", "project", "predict", "potential", "targeting", "intends", "believe", "potential", and similar expressions, or describes a "goal", or variation of such words and phrases or state that certain actions, events or results "may", "should", "could", "would", "might" or "will" be taken, occur or be achieved. Forward-looking information is not a guarantee of future performance and is based upon a number of estimates and assumptions of management at the date the statements are made including, among others, assumptions about future prices of gold, and other metal prices, currency exchange rates and interest rates, favourable operating conditions, political stability, timely receipt of governmental or regulatory approvals, including any stock exchange approvals; receipt of a financing on time, obtaining renewals for existing licenses and permits and obtaining required licenses and permits, labour stability, stability in market conditions, availability of equipment, results or timing of any mineral resources, resource conversion, pre-feasibility study, mineral reserves, or feasibility study; the availability of drill rigs, successful resolution of disputes and anticipated costs and expenditures. Many assumptions are based on factors and events that are not within the control of Liberty Gold and there is no assurance they will prove to be correct.
Such forward-looking information, involves known and unknown risks, which may cause the actual results to be materially different from any future results expressed or implied by such forward-looking information, including, risks related to the interpretation of results and/or the reliance on technical information provided by third parties as related to the Company’s mineral property interests; changes in project parameters as plans continue to be refined; current economic conditions; future prices of commodities; possible variations in grade or extraction rates; the costs and timing of the development of new deposits; failure of equipment or processes to operate as anticipated; the failure of contracted parties to perform; the timing and success of exploration activities generally; the timing or results of the publication of any mineral resources, mineral reserves or feasibility studies; delays in permitting; possible claims against the Company; labour disputes and other risks of the mining industry; delays in obtaining governmental approvals, financing, timing of the completion of exploration as well as those factors discussed in the Annual Information Form of the Company dated March 25, 2026, in the section entitled "Risk Factors", under Liberty Gold’s SEDAR+ profile at www.sedarplus.ca.
Although Liberty Gold has attempted to identify important factors that could cause actual actions, events or results to differ materially from those described in forward-looking information, there may be other factors that cause actions, events or results not to be as anticipated, estimated or intended. There can be no assurance that such information will prove to be accurate as actual results, and future events could differ materially from those anticipated in such statements. Liberty Gold disclaims any intention or obligation to update or revise any forward-looking information, whether as a result of new information, future events or otherwise, except for material differences between actual results and previously disclosed material forward-looking information, or as otherwise required by law.
Except for statements of historical fact, information contained herein or incorporated by reference herein constitutes forward-looking statements and forward-looking information. Readers should not place undue reliance on forward-looking information. All forward-looking statements and forward-looking information attributable to us is expressly qualified by these cautionary statements.
Note to United States Investors Concerning Estimates of Measured, Indicated and Inferred Resources
The information, including any information incorporated by reference, and disclosure documents of Liberty Gold that are filed with Canadian securities regulatory authorities concerning mineral properties have been prepared in accordance with the requirements of securities laws in effect in Canada, which differ from the requirements of United States securities laws.
Without limiting the foregoing, these documents use the terms “measured resources”, “indicated resources”, “inferred resources” and “mineral reserves”. These terms are Canadian mining terms as defined in, and required to be disclosed in accordance with, NI 43-101, which references the guidelines set out in the Canadian Institute of Mining, Metallurgy and Petroleum (the “CIM”) – CIM Definition Standards, adopted by the CIM Council, as amended. However, these standards differ significantly from the mineral property disclosure requirements of the United States Securities and Exchange Commission (the “SEC”) in Regulation S-K Subpart 1300 (the “SEC Modernization Rules”) under the United States Securities Act of 1934, as amended. The Company does not file reports with the SEC and is not required to provide disclosure on its mineral properties under the SEC Modernization Rules and will continue to provide disclosure under NI 43-101 and the CIM Definition Standards.
Photos accompanying this announcement are available at:
https://www.globenewswire.com/NewsRoom/AttachmentNg/69f40f7d-7559-49d8-b158-9e9e5a6e35e2
https://www.globenewswire.com/NewsRoom/AttachmentNg/91630b0e-a182-4c48-97c7-808579514a8f
https://www.globenewswire.com/NewsRoom/AttachmentNg/1f615906-9679-4e25-8809-941a08214857
https://www.globenewswire.com/NewsRoom/AttachmentNg/aef4400b-9e4e-4b25-938a-65315bbf13b7
https://www.globenewswire.com/NewsRoom/AttachmentNg/7a051688-1ac1-4b60-b970-8435eba8cda6
https://www.globenewswire.com/NewsRoom/AttachmentNg/4159978c-bb86-45b7-9343-8e9811b8511b
FAQ
AI-generated questions and answers. How Rhea-AI works. Not financial advice.
What does Liberty Gold mean by run-of-mine (ROM) heap leach processing at Black Pine?
ROM at Black Pine refers to blasted ore taken directly from the open pit and placed onto the heap leach pad without crushing, agglomeration, or mechanical stacking. Ore would be deposited using haul trucks and managed with dozer push and ripping, supporting a simple, low-cost heap leach operation.
What ongoing metallurgical test phases are planned for Black Pine and when are results expected?
Liberty Gold outlines several additional phases:
- Phase 8/8B: Testing legacy heap leach pad material with vat and column leach; results expected in H1 2027.
- Phase 9: Re-assay of ~2,000 samples for LECO and Preg Rob to refine dilution risk; assays pending and will guide detailed engineering and mine planning.
- Phase 10: Twenty-six Rangefront composites under test across grade ranges; results expected in H1 2027.
- Phase 11: Low-grade (<0.1 g/t) samples to improve low-end extraction models; results expected in Q1 2027.
- Phase 12: Future program on waste dump material extractions, to start after current RC drilling.