VANCOUVER, BC, Aug. 23,
2023 /CNW/ - Outcrop Silver & Gold
Corporation (TSXV: OCG) (OTCQX: OCGSF) (DE: MRG1) ("Outcrop
Silver") is pleased to report outstanding metallurgical
follow-up results from the high-grade Santa Ana silver project.
This phase of metallurgical testing was completed to characterize
the produced tailings and their environmental impact, simulate
real-life processing along a locked cycle, and characterize the
final products. The metallurgical test work confirms for the Santa
Ana project a premier level recovery based solely on flotation,
high quality and clean precious metal concentrate and a
flotation-only non acid-generating tailing.
Highlights
- The locked cycle flotation tests confirmed an outstanding
gold recovery of 97 % and a silver recovery of 93 %.
- The resulting gold and silver flotation concentrate yielded
9,488 grams per tonne of silver and 128 grams per tonne of
gold.
- Lower deleterious elements levels for favourable commercial
sale terms.
- Both ABA and NAG tests indicate no potential for acid
drainage generation from flotation tailings from Santa
Ana.
"The results from our more rigorous locked cycle tests, which
simulate a more realistic operating environment, have confirmed an
outstanding gold recovery of 97% and a silver recovery of 93%,"
commented Guillermo Hernandez, Vice
President Exploration. "These results, combined with positive
findings on acid generation and the very low content of deleterious
elements, are pivotal from both a technical and environmental
standpoint. These insights are crucial as we continue to refine our
understanding and derisking of Santa Ana, one of the premier grade
silver deposits in the world."
"The latest metallurgical results signify a promising future for
the Santa Ana project. Achieving such high recoveries through
flotation alone, combined with the production of a marketable clean
high-grade concentrate, underscores the project's immense
potential," commented Ian Harris,
Chief Executive Officer. "Furthermore, the environmentally
conscious test work indicates clean tailings, which aligns
perfectly with our commitment to responsible mining. This is not
just good news—it's a testament to the project's viability and our
dedication to advancing it in the most sustainable and efficient
manner."
Metallurgical Test
Work
Outcrop Silver prepared four core sample composites using coarse
laboratory rejects (see news release dated February 23, 2022). Two samples for each vein as
follow: samples POR-01 and POR-02 for the La Porfia vein and
samples PAR-01 and PAR-02 for Paraiso vein. Each composite weighted
approximately 50 kilograms, and the samples represented two
metallurgical domains: high-grade and low-grade. The high-grade
composites represent the average grade in the ore-shoot, while the
low-grade represents Outcrop Silver's "significant result"
threshold. SGS Metallurgical Services Chile has conducted all
preparation and testing to date.
The latest metallurgical work consists of kinetic flotation
locked circuit tests on the PAR-2 sample from the Megapozo shoot of
the Paraiso vein (see news release dated November 03, 2022) and Acid-Drainege Generation
potential assessment. Table 1 shows the metallurgical balance,
final recovery of 97.14% for gold and 92.85% for silver, producing
a concentrate grading of 128.74 grams per tonne of gold and 9,488
grams per tonne of silver.
|
|
Grades
|
Recoveries
%
|
Product
|
Mass
%
|
Ag
g/t
|
Au
g/t
|
Fe %
|
S %
|
Ag
|
Au
|
Fe
|
S
|
Final
Concentrate
|
5.17
|
9,488
|
128.74
|
35.36
|
46.75
|
92.85
|
97.14
|
31.89
|
74.83
|
Tails
|
94.83
|
40
|
0.21
|
4.12
|
0.86
|
7.15
|
2.86
|
68.11
|
25.17
|
Calculated
Head
|
100.00
|
512
|
6.30
|
6.02
|
3.54
|
100.00
|
100.00
|
100.00
|
100.00
|
Assayed Head
|
539
|
6.14
|
7.27
|
3.81
|
|
|
|
|
Table 1. Summary Metallurgical Balance
Mineral Concentrate
Characterization
The resulting concentrate was also chemically characterized with
ICP at SGS Chile under the analytical method ICP040B for a complete
43-element screening to determine concentrations of potential
deleterious elements. The arsenic content is 0.43%, and the
antimony is 0.09% showing acceptable levels for commercial terms of
sale. Such characterizations are vital, offering insights into the
concentrate's quality and ensuring it aligns with industry
standards for marketability.
As %
|
Co
ppm
|
Cu %
|
Fe %
|
Mn
ppm
|
Pb %
|
Sb %
|
Zn %
|
0.43
|
118
|
0.35
|
36.96
|
49
|
5.93
|
0.09
|
6.02
|
Table 2. Summary of potential deleterious elements
Particle Mineral Analysis (PMA) and Trace Mineral Search (TMS)
for mineralogical characterization of the gold and silver
concentrate through QEMSCAM performed at SGS Chile allowed to
determine the majority of gold is present as electrum with the
silver proportion ranging from 57 to 86%. The electrum is closely
related to silver sulfides, pyrite, sphalerite, and galena. TMS
also determined the lack of free gold grains in the concentrate. On
the other hand, forty percent of silver minerals are free and as
sulfides, like Argentite, and are associated with pyrite, galena,
sphalerite, and electrum.
Net Acid Generation (NAG) and
Acid-Base Accounting (ABA) Test
The NAG test is a static test used to predict the generation of
acid rock drainage during and after a mining operation. It is
considered a stand-alone prediction tool, and it is based on the
chemical reaction to accelerate the oxidation of sulfide minerals
in a sample.
The ABA test is the most commonly used static method for
characterizing mining waste. It is a screening method for
determining the mine waste's acid generation and neutralization
potential. The ABA test includes determining the waste's
sulfur/sulfide content.
The tails from the locked cycle flotation tests were analyzed
with NAG and ABA tests. The NAG and ABA static tests highly
indicate the ability to produce non-acid generating tails, offering
significant environmental benefits. Such outcomes align with
Outcrop Silver's dedication to minimizing environmental impact. As
the project progresses, future testing will include dynamic test
work to further confirm these positive results.
Next Steps
Outcrop Silver plans to conduct additional metallurgical studies
on different vein composites and an overall representative
composite of the Santa Ana project, following the recommendations
from the recent test work report. Furthermore, we will explore
additional recovery methods and refine the flow sheet to further
optimize the project, ensuring the best balance between efficiency
and sustainability.
About Santa Ana
The 100% owned Santa Ana project comprises 27,000 hectares, 190
kilometres from Bogota, Colombia.
Santa Ana consists of regional-scale parallel vein systems covering
a majority of the Mariquita District. The Mariquita District is
Colombia's highest-grade primary
silver district, where mining records date to at least 1585, with
historic silver grades reported being among the highest in
Latin America from dozens of
mines.
Santa Ana maiden resource estimate contains an estimated
indicated resource of 24.2 million ounces silver equivalent at a
grade of 614 grams per tonne silver equivalent and an inferred
mineral resource of 13.5 million ounces silver equivalent at a
grade of 435 grams per tonne silver equivalent, based on the NI
43-101 Technical Report titled "Santa Ana Property Mineral Resource
Estimate," dated June 8, 2023, and
prepared by AMC Mining Consultants. The resource is comprised of
the seven vein systems (commonly containing multiple parallel veins
and multiple ore shoots) discovered to date – Santa Ana
(San Antonio, Roberto Tovar, San
Juan shoots); La Porfia (La Ivana); El Dorado (El Dorado, La
Abeja shoots); Paraiso (Megapozo); Las Maras; Los Naranjos and La
Isabela.
Veins with similar high grade and thickness exist along strike
toward the south, forming a high-grade silver enriched trend that
extends for 30 kilometres. Outcrop Silver's exploration team has
identified numerous additional veins based on high-grade samples
from outcrop and historical workings that have yet to be drill
tested. Outcrop Silver remains focused on identifying new vein
targets with high-grade potential, and adding substantially
derisked mineralized silver-bearing veins that will increase the
published maiden resource.
About Outcrop
Silver
Outcrop Silver is advancing the Santa Ana high-grade silver
deposit with exploration activities aiming to expand the current
mineral resource. Santa Ana is being advanced by a highly
disciplined and seasoned professional team with decades of
experience in Colombia.
Qualified Person
Edwin Naranjo Sierra is the
designated Qualified Person for this news release within the
meaning of the National Instrument 43-101 (NI 43-101) and has
reviewed and verified the technical information in this news
release. Mr. Naranjo has an MSc degree in Earth Science and is a
Fellow of the Australasian Institute of Mining and Metallurgy
(FAusIMM) and of the Society of Econimic Geology.
ON BEHALF OF THE BOARD OF DIRECTORS
Ian Harris
Chief Executive Officer
+1 604 294 9039
harris@outcropsilverandgold.com
www.outcropsilverandgold.com
Kathy Li
Vice President Investor Relations
+1 778 783 2818
li@outcropsilverandgold.com
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Forward-looking statements are based on the opinions and estimates
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that may cause the actual results, level of activity, performance
or achievements of Outcrop to be materially different from those
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attempted to identify important factors that could cause actual
results to differ materially from those contained in
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may be other factors that cause results not to be as anticipated,
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events could differ materially from those anticipated in such
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forward-looking statements and forward-looking information. Outcrop
will not update any forward-looking statements or forward-looking
information that are incorporated by reference herein, except as
required by applicable securities laws.
SOURCE Outcrop Silver & Gold Corporation