Pinnacle Receives Positive Results from Preliminary Metallurgical Tests at El Potrero with Average of 95.09% Gold Recovery
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Pinnacle Receives Positive Results from Preliminary Metallurgical Tests at
El Potrero with Average of 95.09% Gold Recovery
VANCOUVER, BRITISH COLUMBIA, October 28, 2025 (TSXV: PINN, OTC: PSGCF, Frankfurt: P9J)
– Pinnacle Silver and Gold Corp. ("Pinnacle" or the “ Company") is pleased to announce positive
results from the preliminary scoping metallurgical tests for the high-grade El Potrero gold-silver project
in Durango, Mexico including excellent gold recoveries up to 96.79% and averaging 95.09%.
Highlights:
• Three samples from the mineralized zone within the Pinos Cuates underground mine were sent
to the SGS Lab in Durango, Mexico for grinding, bottle roll cyanide leach and gravity tests.
• Initial grind calibration tests in a ball milling application achi eved a target grind of 80% passing
270 mesh (53 micron) particle size.
• Bottle roll cyanide leach tests resulted in consistently high gold recoveries of 92.81%, 95.68%
and 96.79%, averaging 95.09%. Silver recoveries were lower and more variable, at 41.41%,
73.53% and 49.11%, with an average of 54.68%, indicating the presence of a more complex
mineralogy and a need for further test work such as extended leach times.
• Average unoptimized reagent consumption was 0.71 kg/t NaCN and 1.62 kg/t CaO , both within
expected ranges for a preliminary test.
• Initial gravity tests utilising a Knelson concentrator and Mozley table resulted in variable
recoveries ranging from 29.1% to 76.38% for gold and 3.98% to 15.91% for silver.
“We are very pleased with the results from this preliminary round of metallurgical tests , especially for
gold recoveries, and considering that there were only three samples from one of the three historic
mines,” stated Robert Archer, Pinnacle’s President & CEO. “These tests were run using simple
baseline parameters and without any optimization. The results indicate that we need to conduct
mineralogical tests on the mineralization to determine the nature of the gold and silver occurrences.
While it is likely that gold occurs either as free particles or in electrum, silver can occur in electrum,
silver sulphides or silver sulphosalts. Once this has been established, further testing will be able to fine
tune the metallurgical processes in order to increase recoveries, particularly for silver. Metallurgical
testing is an iterative process, and it is expected that sampling of the other mines on the property will
result in further variations. However, this is the whole point of the testing as we aim to maximize
recoveries and streamline the flow sheet prior to rebuilding the plant.”
The Pinos Cuates mine is the central mine of the three historic workings on the Dos de Mayo low
sulphidation epithermal vein system at El Potrero. The three metallurgical samples were taken from the
raise and upper level of the mine , based upon the results of previous channel sampl ing. Each sample
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weighed approximately 25 kg. Samples were fire assayed with AAS finish for gold and silver, in
duplicate, and analysed for 32 elements by 4-acid digestion and ICP finish. The latter confirmed that
there are negligible amounts of copper, lead, zinc, arsenic, mercury or any other deleterious elements
present. Some variation between gold analyses of the channel samples versus the metallurgical
samples suggests the presence of a nugget effect, likely due to fine free gold, as silver analyses were
comparable. A comparison of the two sets of analyses can be seen in the table below:
Channel sample MET sample Au g/t Ag g/t
EPUG25097 2.91 108
EPMET25001 6.20 99
EPUG25136 13.00 56
EPMET25002 5.10 52
EPUG25421 34.60 228
EPMET25003 17.30 210
Prior to the bottle leaching tests, a grinding calibration was carried out for each sample using a ball mill
in order to achieve the target particle size for the leaching and gravity concentration tests, which was
80% passing 270 mesh (53 microns). This information will be used in future tests on hardness and
work index.
A bottle roll test was carried out for each sample, separately from the gravity test, in order to evaluate
the gold and silver extraction response for each method . The bottle roll test was performed in a 2-
gallon Nalgene bottle, using 1, 000 g of sample, with a retention time of 72 hours. Monitoring was
conducted at intervals of 12, 24, 48, and 72 hours to collect solution samples and evaluate the gold and
silver extraction kinetics. Additionally, sodium cyanide and lime consumptions were determined.
Dissolution kinetics showed rapid recoveries of 79 -92% for gold after only 24 hours, increasing
gradually to their ultimate levels of 92.81%, 95.68% and 96.79%, averaging 95.09%, after 72 hours.
Silver recoveries increased more gradually towards 41.41%, 73.53% and 49.11%, with an average of
54.68%, after 72 hours. It is considered that a longer leach time could improve the silver recoveries.
Sodium cyanide (NaCN) consumption ranged from 0.49 to 0.94 kg/t, while lime (CaO) consumption
ranged from 0.93 to 2.03 kg/t, both within expected ranges for unoptimized tests.
According to the SGS report, “ Gravity concentration using the Knelson concentrator is based on the
separation of mineral particles according to their density differences, applying centrifugal force. This
equipment concentrates the heavy minerals (such as free gold or high- density sulfides) into a small
volume of concentrate, while the lighter material is discharged as tailings.
The concentrate obtained from the Knelson is subsequently subjected to cleaning on a Mozley table,
which allows for a finer and more selective separation. This stage improves the purity of the final
concentrate by removing gangue minerals and obtaining a fraction richer in valuable minerals.
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For metallurgical balance purposes, the sum of the Knelson concentrate and the Mozley ‘ middlings’ is
necessary, since both products belong to the same gravity concentration stream and contain a
significant portion of the recovered metallic values. Combining these products provides a more
accurate representation of the total recovery attributable to the gravity circuit, preventing
underestimation of the metallic content in the overall balance.”
Approximately 20 kg of each sample with a particle size of 53 microns was used for the gravity tests.
Gold recoveries were somewhat variable, yielding 29.10% , 33.02% and 76.38%, whereas silver was a
little more consistent, albeit lower, with recoveries of 3.98% , 7.77% and 15.31%. As gold is heavier
than silver, it is normal for gold to yield higher recoveries in a gravity circuit. The particularly high gold
recoveries of 76.38% in one sample is likely due to the presence of a higher percentage of free gold. It
is worth noting that this sample also had the highest head assay of 17.2 g/t Au and the highest recovery
from leaching of 96.79%.
In subsequent metallurgical work, gravity and leaching tests will likely be conducted in series, with the
high-grade gravity concentrate being removed and the tails being leached. While it is normal for higher
grade material to yield higher recoveries, it is also considered that a finer grind and extended leach
times may improve recoveries at the lower end. These along with other optimized process details will
be addressed in the next testing stage.
Qualified Person
Mr. David Salari, P.Eng., a Director of Pinnacle and a Qualified Person as defined by National
Instrument 43-101, has reviewed and approved this news release.
Mr. Jorge Ortega, P. Geo, a Qualified Person as defined by National Instrument 43 -101, and the
author of the NI 43-101 Technical Report for the Potrero Project, has also reviewed and approved this
news release.
About the Potrero Property
El Potrero is located in the prolific Sierra Madre Occidental of western Mexico and lies within 35
kilometres of four operating mines, including the 4,000 tonnes per day (tpd) Ciénega Mine (Fresnillo),
the 1,000 tpd Tahuehueto Mine (Luca Mining) and the 250 tpd Topia Mine (Guanajuato Silver).
High-grade gold-silver mineralization occurs in a low sulphidation epithermal breccia vein system
hosted within andesites of the Lower Volcanic Series and has three historic mines along a 500 metre
strike length. T he property has been in private hands for almost 40 years and has never been
systematically explored by modern methods, leaving significant exploration potential.
A previously operational 100 tpd plant on site can be refurbished / rebuilt and historic underground
mine workings rehabilitated at relatively low cost in order to achieve near -term production once
permits are in place. The property is road accessible with a power line within three kilometres.
Surface rights covering the plant and mine area are privately owned (no community issues).
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Pinnacle will earn an initial 50% interest immediately upon commencing production. The goal would
then be to generate sufficient cash flow with which to further develop the project and increase the
Company’s ownership to 100% subject to a 2% NSR. If successful, this approach would be less
dilutive for shareholders than relying on the equity markets to finance the growth of the Company.
About Pinnacle Silver and Gold Corp.
Pinnacle is focused on the development of precious metals projects in the Americas. The high- grade
Potrero gold- silver project in Mexico’s Sierra Madre Belt hosts an underexplored low -sulphidation
epithermal vein system and provides the potential for near -term production. In the prolific Red Lake
District of northwestern Ontario, the Company owns a 100% interest in the past -producing, high-
grade Argosy Gold Mine and the adjacent North Birch Project with an eight -kilometre-long target
horizon. With a seasoned, highly successful management team and quality projects, Pinnacle Silver
and Gold is committed to building long-term, sustainable value for shareholders.
Signed: “Robert A. Archer”
President & CEO
FOR FURTHER INFORMATION CONTACT:
Email: [email protected]
Tel.: +1 (877) 271-5886 ext. 110
Website: www.pinnaclesilverandgold.com
Neither the TSX Venture Exchange nor the Investment Industry Regulatory Organization of Canada
accepts responsibility for the adequacy or accuracy of this release.