Meridian Reports Initial Metallurgical Testwork Results from Cabaçal High-grade 29% copper concentrate produced with excellent recoveries of 94% for copper and 87% for gold achieved
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Meridian Reports Initial Metallurgical Testwork Results from Cabaçal
High-grade 29% copper concentrate produced with excellent recoveries of 94% for
copper and 87% for gold achieved
LONDON, United Kingdom, July 20, 2022, Meridian Mining UK S (TSX: MNO), (Frankfurt/Tradegate: 2MM,
OTCQB: MRRDF), (“Meridian” or the “Company”) is pleased to announce preliminary metallurgical results
of Cabaçal’s copper-gold VMS mineralization by SGS Lakefield in Canada. Meridian has completed its initial
round of crushing, grinding , gravity -separation and flotation testing with the results highlighting the
simple flowsheet needed to mill Cabaçal’s copper-gold mineralization. These preliminary results are from
representative samples1 drilled across the deposit (“Figure 1”) and indicate significantly higher recoveries
of copper and gold than those used in the historical resource calculation 2 but are in -line with those
recorded from the Cabaçal Mine's four-year production history. The metallurgical program is ongoing and
more results are pending.
HIGHLIGHTS REPORTED TODAY
Meridian achieves high-grade 29% copper concentrate from Cabaçal met program;
Meridian reports preliminary high recoveries of 94% for copper and 87% for gold at Cabaçal;
Significantly higher metallurgical recoveries achieved to those used in the 2009 historical
resource;
Excellent metallurgy combined with robust grades of shallow copper-gold mineralization
highlights open-pit potential at Cabaçal
Cabaçal’s copper-gold mineralization is liberated via a coarse grind of ~200 microns;
Eco-friendly and simple floatation of Chalcopyrite via a frother and collection by Xanthate;
Cleaner concentrates from partial regrind with lime addition to remove the gangue and depress
pyrite;
Representative concentrate samples to be made available for smelter performance analysis; and
A Bond Work Index of 11.2 indicates medium soft rock as does the Abrasion Index of 0.28.
Dr Adrian McArthur, CEO and President comments : “These initial metallurgical results from Cabaçal’s
layers of copper-gold VMS mineralization are very consistent with the mine’s historic ore production
records and confirm that Cabaçal’s mineralization responds very well to simple processing methods
yielding clean concentrates with high grades of copper and gold via strong recoveries. This initial test work
has been on the bulk mineralization and is ongoing while the testwork on the high -grade gold veins will
commence shortly where we expect to replicate again the mine’s high recoveries. These preliminary results
exceed the recovery assumptions by up to 9% for copper and 22% for gold, compared to the assumptions
used in the historical resource of 85% and 6 5% respectively. Our drill results to date from Cabaçal have
also delineated a much larger footprint of copper-gold mineralization than that of the historical resource,
and combined with the expected final metallurgical results , bodes well for our first Cabaçal resource
statement in late September. Controlling the Cabaçal copper-gold belt with the potential to produce future
1 Meridian news releases: December 13, 2021, January 31, February 7, March 22 and April 26, 2022
2 Meridian news release August 26, 2020
volumes of high quality, clean copper concentrates with significant values of gold and silver, free of 3 rd
party royalties or off -take agreements sets Meridian apart f rom most of the evolving copper -gold
development companies”
CABAÇAL’S METALLURGY YIELDS PROMISING OUTCOMES FOR SIMPLE AND EFFECTIVE PROCESSING OF ITS COPPER-GOLD
VMS MINERALIZATION TO CONCENTRATE AND POTENTIALLY FOR DORÉ BARS
Meridian took representative mineralized rock samples from a selection of drill holes representing typical
mineralized zones from across the Southern, Central and Eastern Copper Zones in the Cabaçal mine
setting, and from the unmined trends the Cabaçal Northwest Extension. These were sent to SGS Lakefield
in Canada for the crushing, grinding, flotation and gravity separation test work. The best test result to
date was from a batch test using optimum conditions produced a copper concentrate that contained 29%
Cu, 15 g/t gold with total recoveries of copper and gold of 94% and 87% respectively. The Company is very
encouraged by these excellent recoveries for both copper and gold. The variability test range (“Figure 2”)
is typical of Cabaçal’s 2,000m of copper-gold mineralization, but far below the historic feed grades of the
Cabaçal Mine that was processing selectively mined high-grade gold & copper ores (“Table 1”). These
results validate Meridian’s concept that excellent recoveries would be achievable from the expected feed
grades of a potential open pit operation at Cabaçal.
SGS created a master composite grading 0.6% Cu and 0.6g/t Au by combining representative samples and
then used this composite for the various tests conducted. The crushed rock was then ground in a rod mill
to a range of sizes between 86 and 298 µm to examine the impact of particle size on the effectiveness of
flotation. The grind size selected was based on the Cabaçal mine’s former processing parameters with
input f rom the previous Mill Superintendent . The flotation test results showed good recoveries of
sulphides across the range of particle sizes tested , indicating that grind size had little affect on
performance and that a coarser grind would be satisfactory.
Twelve flotation tests to date, have been conducted on the master composite using a range of variables
including grind size, residence time , chemical additions, and gravity recovery . In all cases , the time
required to float the sulphide minerals was typical for sulphide ores with the copper floating first followed
by the other minor sulphides present. Gravity recovery has consistently been ~ 30% for Au , the balance
recovered by flotation.
Xanthate and frother were used in all the rougher flotation tests yielding resulting of typically 97% for
copper in the floated product and very little in the tails. Most of the other sulphide minerals present also
ended up in the rougher float concentrate. Examination of the floated material by microscope indicated
that a significant portion of the middling particles floated were a combination of chalcopyrite and gangue
material.
The cleaner tests were run using both a regrind or none as well as using fresh water or lime addition. The
regrind to 45µm was very effective in separating the gangue material from the copper sulphides and the
lime addition to pH 10 was very effective in depressing the pyrite and pyrrhotite present into the cleaner
tails.
The standard Bond Work Index (“BWI”) test was con ducted on the Cabaçal rock which produced an
average bond work index of 11. A BWI of between 12 -15 is considered to be medium -soft hardness so
Cabaçal’s mineralization is relatively soft meaning it requires much less electricity to crush and grind one
tonne of mineralization. The Project will potentially further benefit from being adjacent to the
neighbouring low-cost hydro-electric generation plants supplying a clean, stable energy grid.
ABOUT CABAÇAL
In November 2020, Meridian signed a Purchase Agreement to acquire 100% ownership certain tenements
covering the historical Cabaçal and Santa Helena lines and the along strike tenements from two, private,
Brazilian companies (“Vendors”). Subsequently, Meridian expanded its land tenure to t oday’s 55km of
strike length. Cabaçal had two historical, shallow, high-grade selectively mined underground mines that
cumulatively produced ~ 34 million pounds of copper, ~170,108 ounces of gold, ~1,033,532 ounces of
silver and ~103 million pounds of zinc via conventional flotation and gravity metallurgical processes.
Meridian has defined an open 2,000m trend of shallow copper-gold mineralization centred on the Cabaçal
Mine. This mineralization trends northwest-southeast, sub-crops along its northeast limits and dips to the
southwest at 26° and is up 90m thick; presenting excellent open -pit geometry and mineral endowment.
Meridian is currently focused on infilling this 2,000m zone.
Cabaçal’s base and precious metal-rich mineralization is hosted by v olcanogenic type, massive, semi -
massive, stringer, and disseminated sulphides within units of deformed metavolcanic-sedimentary rocks
(“VMS”). A later stage sub -vertical gold overprint event has emplaced high -grade gold mineralization
truncating the dipping VMS layers. It was explored and developed by BP Minerals/Rio-Tinto from 1983 to
1991 and then by the Vendors in the mid 2000’s. This historical exploration database includes over 83,000
metres of drilling, extensive regional mapping, soil surveys, metallurgy from production reports and both
surface and airborne geophysics. The majority of Cabaçal’s prosects remain to be tested.
Cabaçal has excellent infrastructure with access by all-weather road, industrial electricity provided by the
adjacent hydroelectric power station supplying this clean energy grid, and local communities provide a
large population to draw employees from. Cabaçal consists of 1 mining license, 1 mining lease application
and 4 exploration claims which total 28,324 hectares. A further three licences totalling 15,941 Ha are
awaiting formal transfer from the ANM following the licence auction system.
ABOUT MERIDIAN
Meridian Mining UK S is focused on the acquisition, exploration, and development activities in Brazil. The
Company is curre ntly focused on resource development of the Cabaçal VMS copper -gold project,
exploration in the Jaurú & Araputanga Greenstone belts located in the state of Mato Grosso; exploring
the Espigão polymetallic project and the Mirante da Serra manganese project i n the State of Rondônia
Brazil.
On behalf of the Board of Directors of Meridian Mining UK S
Dr. Adrian McArthur
CEO, President, and Director
Executive Chairman
Meridian Mining UK S
Email: [email protected]
Ph: +1 (778) 715-6410 (PST)
Note
This metallurgical testwork has been undertaken at SGS Canada Minerals Lakefield which conforms to
the requirements of ISO/IEC 17025 and is accredited by the Standards Council of Canada. Samples of
half core were delivered and stage-crushed to -10 mesh (1.7 mm), blended, and rotary split into test
charges. Head samples will be split from each of the sub-samples for assay and mineralogy. A master
composite was generated by combining portions of the individual samples. Each of the variability
samples and the master composite have been analysed by Cu by XRF, Au by fire assay, S by Leco, multi-
elements by ICP scan, and specific gravity by pycnometer. Mineralogical review is conducted by
QEMSCAN.
Qualified Person
Dr Adrian McArthur, B.Sc. Hons, PhD. FAusIMM., CEO and President of Meridian as well as a Qualified
Person as defined by National Instrument 43 -101, has supervised the preparation of the technical
information in this news release.
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FORWARD-LOOKING STATEMENTS
Some statements in this news release contain forward-looking information or forward-looking statements
for the purposes of applicable securities laws. These statements address future events and conditions and
so involve inherent risks and uncertainties, as disclosed under the heading "Risk Factors" in under the
heading "Risk Factors" in Meridian's most recent Annual Information Form filed on www.sedar.com.
While these factors and assumptions are considered reaso nable by Meridian, in light of management’s
experience and perception of current conditions and expected developments, Meridian can give no
assurance that such expectations will prove to be correct. Any forward-looking statement speaks only as
of the date on which it is made and, except as may be required by applicable securities laws, Meridian
disclaims any intent or obligation to update any forward -looking statement, whether as a result of new
information, future events, or results or otherwise.
Figure 1 Collar locations of core used in metallurgical program.
Figure 2 Rougher Grade-Recovery curves from Variability testing on Cabaçal’s copper and gold
mineralization reported today.
Table 1: Cabaçal Mine’s Historical 1990 production results.