Pinnacle Receives More Positive Results from Second Round of Scoping Metallurgical Tests at El Potrero with Average Gold Recovery of 97.8% for the Main Dos de Mayo Vein
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Pinnacle Receives More Positive Results from Second Round of Scoping
Metallurgical Tests at El Potrero with Average Gold Recovery of 97.8% for
the Main Dos de Mayo Vein
VANCOUVER, BRITISH COLUMBIA, June 2, 2026 (TSXV: PINN, OTCQB: PSGCF, Frankfurt: P9J)
– Pinnacle Silver and Gold Corp. ("Pinnacle" or the “Company") is pleased to provide more positive
results from the second round of scoping metallurgical tests for the high -grade El Potrero gold- silver
project in Durango, Mexico. This second round of tests was broader in scope, including seven samples
compared to three in the first round, and encompassed all three historic mines on the Dos de Mayo
vein rather than just the Pinos Cuates mine, as well as the Estrella and Capulin veins.
Of particular note, bottle roll leach t ests for the Dos de Mayo vein continued to return consistently high
gold recoveries, averaging 97.8%, while gold recoveries of 97.6% and 97.4% were obtained for the
Estrella and Capulin veins , respectively. Silver continues to be more variable due to a more complex
mineralogy; however, recoveries increased to an average of 70. 02% for Dos de Mayo, 64.7% for La
Estrella and 80.5% for El Capulin.
Highlights:
• Seven mineralized samples were sent to the SGS Lab in Durango, Mexico for a second round
of metallurgical testing, including five samples from the three historic mines on the Dos de Mayo
vein, one from the Estrella vein and one from the Capulin vein.
• Head assays from the seven samples averaged 7.7 grams per tonne gold (g/t Au) and 116 g/t
silver (Ag), implying a robust grade for future mill feed.
• Seven corresponding sub-samples were sent to the SGS lab in Santiago, Chile for TIMA -X
mineralogical analyses. Gold in the form of electrum , a natural Au-Ag alloy, was detected in all
seven samples. In addition to the electrum, s ilver was also detected in all seven samples as
corresponding to the common silver sulphides argentite/acanthite (Ag 2S) and a less common
silver selenium sulphide aguilarite (Ag4SeS).
• All gold grains in the sub- samples were consistently under 50 microns in size and silver was
under 80 microns, giving a guideline as to the grind size necessary for processing. Due to the
consistent grain size, variability in grades appears to show a better correlation with the number
of grains detected in any given sample rather than the coarseness or type of mineral present.
• The five samples from the Dos de Mayo vein were composited for grinding tests, gravity
separation, and bottle roll leaching. However, the gravity tests did not improve the overall
recoveries of gold and silver.
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• Initial grind calibration tests in a ball milling application achi eved a target grind of 80% passing
270 mesh ( 61-63 micron particle size for the 3 samples) . The Bond Work Index (BWi) of 18.1
kWh/t is considered average for the three samples.
• The five-sample composite from the bottle roll cyanide leach tests (without prior gravity
separation), ground to 53 microns, resulted in a gold recovery of 97.83%, and a silver recovery
of 70.02%. The same composite, ground to only 75 microns, resulted in gold and silver
recoveries of 96.79% and 66.38%, respectively. Recoveries from La Estrella and El Capulin
returned 97.6% and 97.4% for gold , respectively, while silver recoveries were more variable, at
64.7% and 80.5%, respectively, reflecting the more complex silver mineralogy.
• Average unoptimized reagent consumption was 1.46 kg/t NaCN and 0 .70 kg/t CaO for the Dos
de Mayo composite, 0.79 kg/t NaCN and 0.60 kg/t CaO for La Estrella, and 1.09 kg/t NaCN and
0.60 kg/t CaO for El Capulin, all within expected ranges for a preliminary test.
“We are extremely pleased with the metallurgical results from this second round of tests , showing
robust head grades, improved recoveries for both gold and silver, and consistently high gold recoveries
across all three veins,” stated Robert Archer, Pinnacle’s President & CEO. “Although broader in scope
than the Phase I round, t hese tests were still run using simple baseline parameters with very little
optimization, leaving room for even further improvement. The mineralogical tests have identified the
dominant minerals present and demonstrate consistent grain sizes for both gold and silver . With that
information, we were able to conduct tests using a finer grind and achieve a slight increase in both gold
and silver recoveries. While the gold recoveries were consistent ly high between the three veins
sampled, silver was more variable and additional testing will determine whether the veins will be
blended at the plant or batch processed to maximize the silver recovery. Furthermore, the lack of
improvement in recoveries through the addition of a gravity circuit means that we will not have to incur
the cost of adding this to the plant. Overall, t hese results are providing valuable information as we
streamline the flow sheet prior to rebuilding the plant.”
Two samples were taken from each of t he Dos de Mayo and Pinos Cuates mines, and one from La
Dura mine, the three historic workings on the Dos de Mayo low sulphidation epithermal vein system at
El Potrero. After completing individual head assays and taking sub-samples for mineralogical analyses,
the five samples from the three Dos de Mayo mines were combined into a single composite that was
then assayed and used for subsequent test work . All initial samples 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. As in the Phase I metallurgical testing and all of the
channel samples assayed to date, t he ICP analyses confirmed that there are negligible amounts of
copper, lead, zinc, arsenic, mercury or any other deleterious elements present. A summary of head
assays can be seen in the table below.
The TIMA -X mineralogical analyses utilised a state-of-the-art scanning electron microscope and
demonstrated that all of the gold grains in the samples are consistently less than 50 microns in size and
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all of the silver particles are less than 80 microns , providing a guideline as to the grind size necessary
for the liberation of gold and silver. Consequently, gold and silver grades appear to be a function of the
number of particles containing gold and silver (Table 1) , rather than larger coarse ‘nuggets’ as is
common in vein-type deposits, although it is still not a one-to-one correlation. Individual sample grades
displayed a range of 1.4 to 23.3 g/t Au and 22 to 303 g/t Ag. The TIMA-X analyses also showed that all
of the gold detected in the sub- samples is present in the form of electrum, a natural gold- silver alloy,
although visible free gold has been observed in the field. In the TIMA-X samples, silver was also found
to occur in the form of the silver sulphides argentite/acanthite (Ag 2S) and the silver selenium sulphide
aguilarite (Ag4SeS). Interestingly, aguilarite was first discovered in Guanajuato, Mexico in the late 19 th
century.
Table 1: Head grades and grain counts for the seven samples tested
Sample No. Vein Mine Au
(g/t)
Ag
(g/t)
No. of Particles
with Gold Grains
No. of Particles
with Silver Grains
EPMET26001 Dos de Mayo Dos de Mayo 9.50 58 3 48
EPMET26002 Dos de Mayo Dos de Mayo 23.30 303 42 432
EPMET26003 Dos de Mayo Pinos Cuates 2.80 22 1 27
EPMET26004 Dos de Mayo Pinos Cuates 5.10 83 3 113
EPMET26005 Dos de Mayo La Dura 1.40 102 1 46
Composite of
EPMET26001-5 Dos de Mayo 7.70 116
EPMET26006 La Estrella 6.60 169 2 177
EPMET26007 El Capulin 4.90 91 2 106
Prior to the bottle roll leaching tests, a grinding calibration was carried out for each of the three samples
(the 5 -sample composite, La Estrella and El Capulin) 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. The
initial particle size ranged from 61- 63 microns, but finer grinding, to 53 microns, resulted in slightly
better gold and silver recoveries.
A bottle roll test was carried out for each sample, separate from the gravity test, 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 the retention time increased to 96 hours (from the
previous 72 hours in the Phase I tests). Monitoring was conducted at intervals of 12, 24, 48, 72 and 96
hours to collect solution samples and evaluate the gold and silver extraction kinetics. Additionally,
sodium cyanide and lime consumptions were determined.
Dissolution kinetics for the thr ee samples, at a 75 micron grind size, showed rapid recoveries of 90 -
92% for gold after only 24 hours, increasing gradually to their ultimate levels of 96 .6%, 9 7.6% and
97.4% after 96 hours. At a 53 micron grind size, the gold recovery from the composite sample initially
increased at a slightly lower rate but ultimately reached 97.8% after 96 hours.
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Silver recoveries for the three samples, at a 75 micron grind size, increased more gradually towards
65.7%, 64.7% and 80 .5% after 96 hours , while, at 53 microns, silver recover y from the composite
sample reached 71.7% after 96 hours. Although a longer leach time (from 72 to 96 hours) improved
the silver recoveries in two of the three samples , there is very little improvement in gold recovery after
48 hours. As such, a cost -benefit analysis will be conducted to determine if the extra silver recovered
justifies the cost of the additional leach time.
Sodium cyanide (NaCN) consumption for the three samples ranged from 0. 79 to 1.46 kg/t, averaging
1.11 kg/t, at a 75 micron grind size. Lime (CaO) consumption ranged from 0. 60 to 0.70 kg/t, and
averaged 0.63 kg/t . At a 53 micron grind size, the composite sample had a slightly lower NaCN
consumption of 1.24 kg/t but CaO was slightly higher at 0.80 kg/t. All figures are within expected
ranges.
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.
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 the composite sample with particle sizes of 53 and 75 microns was used for the
gravity tests and results compared to straight leaching of a one kilogram sample of each grind size.
The SGS report concludes that the “results indicate that both grind sizes presented high gold
recoveries through direct leaching, achieving recoveries of 97.83% Au and 70.02% Ag at 53 microns,
and 96.79% Au and 66.38% Ag at 75 microns. This suggests that the ore exhibits an excellent
response to cyanidation, particularly for gold.
On the other hand, the incorporation of a gravity concentration stage prior to leaching resulted in a
slight decrease in overall gold recovery and a more significant decrease in silver recovery for both grind
sizes. At 53 microns, the gravity-leaching circuit achieved overall recoveries of 96.34% Au and 57.37%
Ag, while at 75 microns overall recoveries of 95.53% Au and 58.49% Ag were obtained.
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The results show that the gravity stage did not provide a significant improvement in overall gold
recovery compared to direct leaching, while a penalty in silver recovery was observed. Overall, direct
leaching showed the best global metallurgical performance, especially for silver recovery.”
Test work is continuing, with the current focus on solid- liquid separation to guide the filtration process
for the impoundment of dry -stack tailings into a lined containment facility, whereby any excess water
will be recovered and recycled into the plant. Results will be released in due course.
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).
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
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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.