Up to 82% Gold and 58% Silver Extraction; Finer Crush Improves Recovery; Agglomeration Not Required
HERMOSILLO, MX / ACCESS Newswire / September 25, 2026 / Tocvan Ventures Corp. (the "Company" or "Tocvan") (CSE:TOC)(OTCQB:TCVNF)(WKN:TV3/A2PE64) announces final results from an independent closed-circuit column leach metallurgical program on a bulk composite from the Gran Pilar Gold-Silver Project, Sonora, Mexico.
The work was completed by Laboratorio Tecnológico de Metalurgia S.A. de C.V. (LTM ISO/IEC 17025:2017 and ISO 9001:2015) on approximately 1,037 kilograms of bulk material crushed to two sizes (P80 3/4" and P80 3/8"), tested both agglomerated (Portland cement) and non-agglomerated. Four 6-inch-diameter columns, each loaded with ~146 kg of ore to ~5 metres height, were operated for 84 days (3-day cure, 77-day leach, 4-day wash, 3-day drain) at a target irrigation rate of 12 L/h/m² and 1 g/L NaCN. The tests were completed to optimize recovery strategy for the pilot facility as it nears completion.
Key Highlights
- Head grade of the composite: ~2.19-2.21 g/t Au and ~14.9-15.4 g/t Ag
- Bottle-roll tests (100% minus 10 mesh, 72 hours): Recovery of 89-91% Au and ~73% Ag.
- Closed-circuit columns after 77 days of leaching:
- P80 3/8": 81.6-82.3% Au and 54.8-58.0% Ag
- P80 3/4": 75.4-76.4% Au and 49.1-52.4% Ag
- Finer crush improved gold extraction by about 6 percentage points.
- Agglomeration did not materially improve gold or silver extraction and increased cyanide consumption.
- Non-agglomerated columns used less NaCN (1.08-1.29 kg/t vs 1.55-1.74 kg/t). Lime consumption was similar (~3.65-3.84 kg/t CaO).
- Copper dissolution was low (3.3-5.4%).
- Ag: Au ratio of ~4.7-5.0.
- Results are a clear improvement on the 2023 bulk-sample heap test (62% Au over 46 days on coarser material) and support heap-leach processing for the 50,000-tonne pilot facility targeting first production in Q4 2026.
Column Leach Summary
Column | Crush (P80) | Agglomerated | Au ext. (%) | Ag ext. (%) | Cu ext. (%) | NaCN (kg/t) | CaO (kg/t) |
CL-01 | 3/4" | Yes | 76.41 | 52.44 | 4.20 | 1.55 | 3.84 |
CL-02 | 3/4" | No | 75.36 | 49.12 | 5.13 | 1.08 | 3.67 |
CL-03 | 3/8" | Yes | 81.63 | 54.84 | 3.26 | 1.74 | 3.83 |
CL-04 | 3/8" | No | 82.25 | 57.99 | 5.36 | 1.29 | 3.65 |
Cycle includes 77 leach days + 4 wash + 3 drain. Calculated heads correlated well with assay heads.
"These closed-circuit column results give us a much clearer picture of how Gran Pilar material will perform under heap-leach conditions as we finish the 50,000-tonne pilot," said Christopher Gordon, CEO of Tocvan. "Gold extraction of 75 to 82 percent at commercial crush sizes, without agglomeration, is a clear improvement on the 2023 bulk test and supports first production later this year.
At the request of several major buyers evaluating our material, we have started additional metallurgical and product-characterization work. That program is designed to meet their due-diligence requirements and position us to sell gold-silver product on commercial terms as the pilot comes online."
Supporting Tests
- Static leach (6 days, 33% solids): 56-64% Au and 39-45% Ag; a useful lower-bound indicator for column performance.
- Screened head assays show gold and silver distributed across size fractions, with a larger share in the minus-10-mesh fines. Coarse-fraction gold on +140 mesh was ~8.4-8.6% of total gold; below the 25% threshold LTM uses to classify material as containing free gold.
- Multi-element ICP: Cu ~0.05%, Zn ~1.05-1.09%, S ~0.08%, As ~30-37 ppm. Low cyanide-soluble copper is consistent with the modest Cu extraction in columns.
Operating Observations
All four columns ponded at the design irrigation rate of 12 L/h/m². Average actual rates were reduced to 5.4-7.8 L/h/m². Agglomerated columns ran at slightly higher average rates than non-agglomerated columns. LTM concludes the material is moderately amenable to cyanide heap leaching at both crush sizes, with the 3/8" crush delivering the best gold and silver extractions. Agglomeration is not required for extraction and increases reagent use.
Relevance to the Gran Pilar Pilot
These closed-circuit columns were run closer to industrial conditions than bottle rolls or the earlier short-cycle bulk test. Gold extraction of 75-82% at heap-leach crush sizes, modest cyanide consumption on non-agglomerated ore, and low copper interference support the Company's 50,000-tonne permitted heap-leach pilot (target ~70% Au in earlier guidance) and the path to first gold-silver doré.
A finer crush (P80 3/8") is the main lever for higher recovery. Whether that extra recovery offsets crushing cost should be evaluated in the pilot and in subsequent engineering. Carbon vs Merrill-Crowe can be compared once pregnant-solution tenor and Ag:Au from the pilot are known.
About Tocvan Ventures Corp.
Tocvan Ventures Corp. is a dynamic exploration and near-term producer advancing high-potential gold and silver projects in the mine-friendly jurisdiction of Sonora, Mexico. At its flagship Gran Pilar Gold-Silver Project, Tocvan holds a 100% interest in over 22 km² of prospective ground, bolstered by the pivotal 2023 land acquisition that provides ample space for scalable mine infrastructure, including a planned 50,000-tonne pilot production facility. Recent exploration successes, including near surface 3.1 m at 19.4 g/t Au, underscore Gran Pilar's potential as a premier gold-silver asset. Additionally, Tocvan's 100% owned Picacho Gold-Silver Project, located in the prolific Caborca Trend-home to some of Mexico's largest gold deposits-positions the Company for further growth. With robust metallurgical results (up to 99% gold and 97% silver recovery) and a strategic capital to bolster growth, Tocvan is poised to deliver significant shareholder value in a market buoyed by record-high gold prices. With approximately 78.8 million shares outstanding, Tocvan is committed to unlocking the full potential of its assets through innovative exploration, strategic development, and investor-focused initiatives.
Brodie A. Sutherland, Executive Chair for Tocvan Ventures Corp. and a qualified person ("QP") as defined by Canadian National Instrument 43-101, has reviewed and approved the technical information contained in this release.
Quality Assurance / Quality Control
Sample preparation, fire assay, ICP-OES, and metallurgical tests were performed by LTM in Hermosillo. Calculated heads agreed closely with assay heads for Au, Ag, and Cu. Reagent consumptions are reported on a 97% NaCN / 43% CaO purity basis as used in the lab.
Cautionary Statement Regarding Forward Looking Statements
This news release contains "forward-looking information" which may include, but is not limited to, statements with respect to the activities, events or developments that the Company expects or anticipates will or may occur in the future. Forward-looking information in this news release includes statements regarding the Transaction and anticipated next steps. Such forward-looking information is often, but not always, identified by the use of words and phrases such as "plans", "expects", "is expected", "budget", "scheduled", "estimates", "forecasts", "intends", "anticipates", or "believes" or variations (including negative variations) of such words and phrases, or state that certain actions, events or results "may", "could", "would", "might" or "will" be taken, occur or be achieved.
These forward-looking statements, and any assumptions upon which they are based, are made in good faith and reflect our current judgment regarding the direction of our business. Management believes that these assumptions are reasonable. Forward-looking information involves known and unknown risks, uncertainties and other factors which may cause the actual results, performance or achievements of the Company to be materially different from any future results, performance or achievements expressed or implied by the forward-looking information. Such factors include, among others, risks related to the speculative nature of the Company's business, the Company's formative stage of development and the Company's financial position. Forward-looking statements contained herein are made as of the date of this news release and the Company disclaims any obligation to update any forward-looking statements, whether as a result of new information, future events or results, except as may be required by applicable securities laws.
There can be no assurance that forward-looking information will prove to be accurate, as actual results and future events could differ materially from those anticipated in such statements. Accordingly, readers should not place undue reliance on forward-looking information.
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For more information, please contact:
TOCVAN VENTURES CORP.
Christopher Gordon, CEO
1150, 707 - 7 Ave SW
Calgary, Alberta T2P 3H6
Email: chris@tocvan.ca
Tyler Muir, Corporate Communications
Telephone: 1 306 690 8886
Email: ir@tocvan.ca
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SOURCE: Tocvan Ventures Corp.
View the original press release on ACCESS Newswire:
https://www.accessnewswire.com/newsroom/en/metals-and-mining/tocvan-reports-positive-closed-circuit-column-leach-results-at-gran-pilar-1226934
