Eloro Resources Ltd. (TSX-V: ELO; OTCQX: ELRRF; FSE:
P2QM) (“Eloro”, or the “Company”) is pleased to provide an
update on its preliminary metallurgical testwork program for the
Iska Iska silver-tin polymetallic project in the Potosi Department,
southern Bolivia. The work program including testwork for
development of a preliminary metallurgical flowsheet and
preliminary mineralogical characterization, is being carried out by
Blue Coast Research Ltd. (“Blue Coast”) based in Parksville, BC.
The objective is to develop the preliminary flotation flowsheet to
maximize lead, zinc and precious metals into saleable concentrates
in the Santa Barbara polymetallic deposit and to develop a
preliminary flowsheet for tin in both the Santa Barbara and the
deeper tin-dominant mineralization.
Blue Coast has world-class metallurgical
testing, analytical services, flowsheet development, consulting,
and operational support. Their excellent team has been augmented
with the addition of Mr. Mike Hallewell, C.Eng., a senior
independent mineral processing consultant based in Cornwall,
England, who has extensive specialist knowledge in the recovery of
tin at mining operations and exploration projects worldwide.
The metallurgical testing is being directed by
Richard Gowans, P.Eng., Principal Metallurgist for Micon
International Limited, who is an independent Qualified Person as
defined under NI 43-101.
Tom Larsen, CEO of Eloro, commented: “The
metallurgical testing program at Blue Coast is progressing well.
The initial focus of their work was on the Santa Barbara
polymetallic mineralization for Ag, Zn and Pb recovery based on
samples from discovery hole DHK15 and hole DHK-18. The tin-rich
zone in hole DSB-06 was also selected for testing but at that time
it was uncertain how this mineralization was connected to the Santa
Barbara polymetallic deposit. However, with further drilling and
solid work by our geological and geophysical team, we now know that
there is extensive tin mineralization at depth beneath the
polymetallic mineralization. Once testing is completed on DSB-06,
we will be adding additional samples from tin-rich holes to enable
further development of an appropriate flow sheet for tin. While
arsenic and other potentially deleterious elements are being
tracked during the testwork program, these are not anticipated to
be a material issue at the levels in current tests.”
Metallurgical Samples
The samples used for the preliminary program
completed to date comprise three representative metallurgical
samples from existing drill core. The initial three composites
are:
- Composite drill
hole DHK-15, from 131 m to 198 m, mineralized breccia.
- Composite drill
hole DHK-18, from 76 m to 140 m, mineralized dacitic envelope.
- Composite drill
hole DSB-06, from 413 m to 477 m, tin-rich mineralized zone.
Approximately 60 m of quarter-core from each
drill hole was selected for these three metallurgical composite
samples. The head analyses for these three composites are presented
in Table 1. It is noted that the arsenic (As) grade is relatively
low, being less than = 0.03% for all the three composite samples.
Although not anticipated to be a material issue at these levels,
the As and other potentially deleterious elements will be tracked
during the testwork program.
Table 1: - Metallurgical Sample Head Analyses
Sample ID |
Au |
Ag |
Bi |
Cd |
Cu |
In |
Pb |
Zn |
Sn |
As |
Fe |
S |
S- |
ppm |
ppm |
ppm |
ppm |
ppm |
ppm |
% |
% |
% |
ppm |
% |
% |
% |
DHK-15 |
0.02 |
29.6 |
34 |
120 |
114 |
30 |
1.21 |
2.48 |
0.12 |
289 |
2.37 |
3.51 |
3.07 |
DHK-18 |
0.02 |
32.1 |
14 |
185 |
370 |
24 |
1.01 |
2.89 |
0.12 |
178 |
3.03 |
4.49 |
4.37 |
DSB-06 |
0.03 |
5.80 |
25 |
0.6 |
103 |
<20 |
0.01 |
0.01 |
0.49 |
169 |
4.89 |
4.10 |
4.23 |
Note: ppm = grams per tonne (g/t)
The initial testwork completed by Blue Coast at
the end of May 2022 included preliminary mineralogical
characterization studies, open circuit sulphide flotation scoping
tests and locked cycle flotation tests using composites DHK-15 and
18. The work conducted on DHK-15 and 18 factored into consideration
the preliminary test work conducted by the Universidad Técnica de
Oruro on different samples.
The DSB-06 sample is extracted from deeper
higher-grade tin mineralization that is seen to replace the
polymetallic lead-zinc-silver-tin mineralization type at depth and
this sample has become the subsequent focus of the ongoing tin
studies at Blue Coast. Additional tin-rich samples will be added
for further testing after the initial test program is
completed.
Mineralogical Characterization of
Metallurgical Composites
The Iska Iska composites DHK-15, DHK-18 and
DSB-06 were analyzed using the TESCAN Integrated Mineral Analyzer
(TIMA), a fully automated analytical scanning electron microscope,
to measure bulk mineralogy, sulphide grain size and liberation to
support the metallurgical test program. In addition, a suite of
electron microprobe analyses was completed on various sulphide and
oxide species to better understand overall mineral chemistry and
tin deportment.
Sulphide minerals in base metal composites
DHK-15 and DHK-18 consisted of mainly sphalerite, galena and
pyrite. Sulphide mineral liberation was very good at the test grind
of 80% passing (P80) 70 microns and flotation testwork, described
below, was able to achieve good lead-zinc separation. Non-sulphide
gangue minerals in all composites consisted of quartz, various
phyllosilicate minerals including micas, chlorite and kaolinite,
and minor Fe oxides.
Cassiterite (a tin oxide mineral) was the
dominant tin mineral identified in tin composite DSB-06.
Cassiterite was moderately liberated (69% of grains had liberation
of 80% or better at the test grind of P80 70 microns). Cassiterite
formed middling particles with pyrite, rutile, quartz and iron
oxides. Pyrite in DBS-06 was well liberated. Initial flotation
testwork, described below, focused on separating pyrite from the
cassiterite.
Microprobe analyses were completed on a group of
pyrite, sphalerite, galena and cassiterite grains in the
metallurgical composites. Tin was identified in trace amounts
within the structure of galena and sphalerite in the base metal
composites, suggesting that the sulphide concentrates will contain
a small amount of tin.
Geometallurgical
Characterization
Separate to the testing of the metallurgical
composites, a program of integrated mineralogical analysis is
underway on a series of core slabs from Hole DSBU-03. This hole
(see press release dated March 1, 2022) intersects both base metal
and tin mineralization and is being used to develop a strong
mineral reference library for the resource. The slabs have received
hyperspectral (SWIR/VNIR), XRF and RGB scanning by GeologicAI and
are now being prepared for petrographic analysis using TIMA and
microXRF mapping. The combined data set will be used as a reference
library to support the on-site automated core scanning program.
Lead-Zinc-Silver Flotation
Following a series of batch rougher and cleaner
tests where the preliminary flotation circuit was developed, locked
cycle tests (LCT) were completed using DHK-15 and DHK-18. A locked
cycle flotation test is a series of identical batch flotation tests
where recycled material from the previous cycle is added to the
appropriate location in the flowsheet in the current cycle. The LCT
is a standard method used to simulate continuous operating
conditions.
The lead-zinc sequential flowsheet used for the
LCTs included primary grinding followed by lead rougher flotation,
lead rougher concentrate regrinding and 3 stages of lead cleaner.
The lead rougher tailings and lead first cleaner tailings fed the
zinc rougher stage, and similar to the lead circuit, the flowsheet
included regrinding of zinc rougher concentrate followed by three
zinc cleaner stages. The final residue streams were the zinc
rougher tailings and zinc first cleaner tailings.
Each LCT comprised 6 cycles where the final
cycles were deemed to be relatively stable and the circuit appeared
to reach equilibrium. Summaries of the average results from the
last 3 cycles for both tests are presented in Tables 2 and 3.
Table 2: Summary of Locked Cycle Test
Average Results for Sample DHK-15
Product |
Wt. % |
Assays |
% Distribution |
Ag(g/t) |
Pb(%) |
Zn(%) |
Fe(%) |
S(%) |
Ag |
Pb |
Zn |
Fe |
S |
Pb Cl.3 Conc. |
2.0 |
1047 |
56.7 |
7.37 |
8.84 |
22.6 |
68.1 |
86.9 |
5.9 |
6.1 |
13.1 |
Zn Cl.3 Conc. |
4.3 |
186 |
1.58 |
49.6 |
10.9 |
34.3 |
26.5 |
5.3 |
87.1 |
16.6 |
43.4 |
Zn Cl.1 Tail |
5.2 |
23 |
0.58 |
1.16 |
19.8 |
21.7 |
4.0 |
2.3 |
2.4 |
36.3 |
33.0 |
Zn Ro. Tail |
88.6 |
0 |
0.08 |
0.13 |
1.30 |
0.40 |
1.4 |
5.5 |
4.5 |
40.9 |
10.5 |
Calc. Head |
100.0 |
30 |
1.28 |
2.45 |
2.83 |
3.39 |
100.0 |
100.0 |
100.0 |
100.0 |
100.0 |
The LCT DHK-15 lead recovery into the final lead
concentrate grading 56.7% Pb was 86.9% while the silver grade was
1,047 g/t. The zinc recovery into a final zinc concentrate
containing 49.6% Zn was 87.1%. The total silver recovery was 94.6%,
including 68.1% and 26.5% into the lead and zinc concentrates,
respectively.
Table 3: Summary of Locked Cycle Test
Average Results for Sample DHK-18
Product |
Wt. % |
Assays |
% Distribution |
Ag(g/t) |
Pb(%) |
Zn(%) |
Fe(%) |
S(%) |
Ag |
Pb |
Zn |
Fe |
S |
Pb Cl.3 Conc. |
1.4 |
1057 |
56.2 |
7.10 |
5.40 |
18.9 |
43.5 |
72.2 |
3.4 |
2.2 |
5.9 |
Zn Cl.3 Conc. |
5.0 |
258 |
1.40 |
51.4 |
8.27 |
32.0 |
37.6 |
6.4 |
86.9 |
12.0 |
35.2 |
Zn Cl.1 Tail |
9.6 |
39 |
1.00 |
1.36 |
11.7 |
11.9 |
10.9 |
8.7 |
4.4 |
32.4 |
25.1 |
Zn Ro. Tail |
84.0 |
3 |
0.17 |
0.19 |
2.21 |
1.84 |
8.1 |
12.6 |
5.2 |
53.4 |
33.8 |
Calc. Head |
100.0 |
34 |
1.10 |
2.96 |
3.47 |
4.56 |
100.0 |
100.0 |
100.0 |
100.0 |
100.0 |
The lead recovery for LCT DHK-18 into the final
lead concentrate grading 56.2% Pb was 72.2% while the silver grade
was 1,057 g/t. The zinc recovery into a final zinc concentrate
containing 51.4% zinc was 86.9%. The silver recovery totalled
81.0%, including 43.5% and 37.6% into the lead and zinc
concentrates, respectively.
Samples of final concentrate products from each
LCT have been submitted for multi-element analyses to assess the
distribution of other potential valuable or deleterious
components.
The preliminary flotation test results are very
encouraging. The results received so far for drill hole sample
DHK-15 are considered very good with high lead, zinc and silver
recoveries, and although sample DHK-18 results were not quite as
good for lead, zinc recovery was high and overall silver
distribution into the final products was good.
Acceptable separate lead and zinc concentrates
containing significant payable silver that adds considerable value
to these products have been produced from both samples. Work will
continue at Blue Coast and other metallurgical laboratories to fine
tune the flotation conditions to maximize metal recoveries and
quality of concentrates produced.
Tin Metallurgy
DSB-06 tin-rich sample contains low levels of
lead, zinc and silver-bearing sulphides, the main sulphide mineral
present in this sample being pyrite. No stannite (a tin sulphide
mineral) is present in this sample; the tin mineralisation consists
entirely of cassiterite.
The pyrite to cassiterite ratio in DSB-06 is
circa 5:1. The Blue Coast approach has been initially focused on
removing the pyrite prior to traditional beneficiation methods of
cassiterite that are employed, using gravity followed by tin
flotation. The pyrite is well liberated across all size fractions
tested and therefore, the preliminary bulk sulphide flotation
sulphur recoveries were good.
A preliminary study has identified that grinding
the sample generates predominantly fine cassiterite grains that are
more amenable to tin flotation technology. Staged comminution
options will be considered to minimise fine cassiterite production
in conjunction with staged gravity recovery of whatever coarse
grained cassiterite is present and recoverable at, as early a stage
in the process as possible.
Gravity release analysis by size testwork on
bulk sulphide flotation tailings is in progress to identify the
amenability of the mineralization to gravity concentration.
One bulk sulphide rougher flotation test
followed immediately by a rougher tin flotation test has been
conducted using unoptimized conditions. The rougher tin flotation
cassiterite stage recovery was encouraging suggesting that the
mineralization will be amenable to tin flotation technology.
Further mineralogical work is in progress on the tin flotation
rougher concentrates produced to ascertain if this rougher
concentrate contains predominantly free liberated cassiterite that
would therefore be expected to be upgraded by cleaning. Tin
flotation is a universally practised technology and used by all the
major hard rock tin mines globally as a method of recovering
cassiterite that is too fine grained for conventional gravity
concentration.
The tin mineralogy and physical competence will
be linked to geological attributes. This will become a key feature
in contextualising any variances in these parameters across the
deposit. The GeologicalAI scanner, which is now on site and will be
operational shortly, and the geometallurgical work noted above,
will be very important in characterizing the geological
attributes.
The test work is too premature to quote tin
recovery numbers, but the initial mineralogy shows that the tin
minerals are all in the form of cassiterite with insignificant
amounts of stannite. Furthermore, the preliminary testing indicates
that tin flotation will be a key recovery route and the preliminary
tin flotation test work results are encouraging.
Qualified Person
The metallurgical testing is being directed by
Richard Gowans, P.Eng., Principal Metallurgist for Micon
International Limited, who is an independent Qualified Person as
defined under NI 43-101. Mr. Gowans. has reviewed and approved the
technical content of this news release.
Dr. Osvaldo Arce, P. Geo., General Manager of
Eloro’s Bolivian subsidiary, Minera Tupiza, and a Qualified Person
in the context of NI 43-101, supervised all exploration work at
Iska Iska. Dr. Bill Pearson, P.Geo., Executive Vice President
Exploration for Eloro, and who has more than 45 years of worldwide
mining exploration experience including extensive work in South
America, manages the overall technical program, working closely
with Dr. Osvaldo Arce, P.Geo. Dr. Quinton Hennigh, P.Geo., Senior
Technical Advisor to Eloro and Independent Technical Advisor, Mr.
Charley Murahwi P. Geo., FAusIMM of Micon International Limited are
regularly consulted on technical aspects of the project.
Eloro is utilizing both ALS and AHK for drill
core analysis, both of whom are major international accredited
laboratories. Drill samples sent to ALS are prepared in both
ALS Bolivia Ltda’s preparation facility in Oruro, Bolivia and
the preparation facility operated by AHK in Tupiza with pulps sent
to the main ALS Global laboratory in Lima for analysis. More
recently Eloro has had ALS send pulps to their laboratory at Galway
in Ireland. Eloro employs an industry standard QA/QC program with
standards, blanks and duplicates inserted into each batch of
samples analyzed with selected check samples sent to a separate
accredited laboratory.
Drill core samples sent to AHK Laboratories are
prepared in a preparation facility installed and managed by AHK in
Tupiza with pulps sent to the AHK laboratory in Lima, Peru. Au and
Sn analysis on these samples is done by ALS Bolivia Ltda in Lima.
Check samples between ALS and AHK are regularly done as a QA/QC
check. AHK is following the same analytical protocols used as with
ALS and with the same QA/QC protocols. Turnaround time continues to
improve, as laboratories return to more normal staffing levels.
Eloro Resources at the PDAC
Eloro will be participating at the PDAC 2022
convention in Toronto and invites you to visit us at Booth IE3326
(Investors Exchange) in the South Building, Metro Toronto
Convention Centre from June 13-15, 2022.
About Iska Iska
Iska Iska silver-tin polymetallic project is a
road accessible, royalty-free property, wholly controlled by the
Title Holder, Empresa Minera Villegas S.R.L. and is located 48 km
north of Tupiza city, in the Sud Chichas Province of the Department
of Potosi in southern Bolivia. Eloro has an option to earn a 99%
interest in Iska Iska.
Iska Iska is a major silver-tin polymetallic
porphyry-epithermal complex associated with a Miocene possibly
collapsed/resurgent caldera, emplaced on Ordovician age rocks with
major breccia pipes, dacitic domes and hydrothermal breccias. The
caldera is 1.6km by 1.8km in dimension with a vertical extent of at
least 1km. Mineralization age is similar to Cerro Rico de Potosí
and other major deposits such as San Vicente, Chorolque, Tasna and
Tatasi located in the same geological trend.
Eloro began underground diamond drilling from
the Huayra Kasa underground workings at Iska Iska on September 13,
2020. On November 18, 2020, Eloro announced the discovery of a
significant breccia pipe with extensive silver polymetallic
mineralization just east of the Huayra Kasa underground workings
and a high-grade gold-bismuth zone in the underground workings. On
November 24, 2020, Eloro announced the discovery of the SBBP
approximately 150m southwest of the Huayra Kasa underground
workings.
Subsequently, on January 26, 2021, Eloro
announced significant results from the first drilling at the SBBP
including the discovery hole DHK-15 which returned 129.60 g Ag eq/t
over 257.5m (29.53g Ag/t, 0.078g Au/t, 1.45%Zn, 0.59%Pb, 0.080%Cu,
0.056%Sn, 0.0022%In and 0.0064% Bi from 0.0m to 257.5m. Subsequent
drilling has confirmed significant values of Ag-Sn polymetallic
mineralization in the SBBP and the adjacent CBP. A substantive
mineralized envelope which is open along strike and down-dip
extends around both major breccia pipes. Continuous channel
sampling of the Santa Barbara Adit located to the east of SBBP
returned 442 g Ag eq/t (164.96 g Ag/t, 0.46%Sn, 3.46% Pb and 0.14%
Cu) over 166m including 1,092 g Ag eq/t (446 g Ag/t, 9.03% Pb and
1.16% Sn) over 56.19m. The west end of the adit intersects the end
of the SBBP.
Since the initial discovery hole, Eloro has
released a number of significant drill results in the SBBP and the
surrounding mineralized envelope which along with geophysical data
has defined a target zone 1400m along strike, 500m wide and that
extends to a depth of 600m. This zone is open along strike to the
northwest and southeast as well as to the southwest. The Company’s
nearer term objective is to outline a maiden NI 43-101 compliant
mineral resource within this large target area. This work is
advancing well with the mineral resource targeted to be completed
in Q3 2022. Exploration drilling is also planned on other major
targets in the Iska Iska Caldera Complex, including the Porco and
Mina 2 areas.
About Eloro Resources Ltd.
Eloro is an exploration and mine development
company with a portfolio of gold and base-metal properties in
Bolivia, Peru and Quebec. Eloro has an option to acquire a 99%
interest in the highly prospective Iska Iska Property, which can be
classified as a polymetallic epithermal-porphyry complex, a
significant mineral deposit type in the Potosi Department, in
southern Bolivia. Eloro commissioned a NI 43-101 Technical Report
on Iska Iska, which was completed by Micon International Limited
and is available on Eloro’s website and under its filings on SEDAR.
Iska Iska is a road-accessible, royalty-free property. Eloro also
owns an 82% interest in the La Victoria Gold/Silver Project,
located in the North-Central Mineral Belt of Peru some 50 km south
of Barrick’s Lagunas Norte Gold Mine and Pan American Silver’s La
Arena Gold Mine. La Victoria consists of eight mining concessions
and eight mining claims encompassing approximately 89 square
kilometres. La Victoria has good infrastructure with access to
road, water and electricity and is located at an altitude that
ranges from 3,150 m to 4,400 m above sea level.
For further information please contact
either Thomas G. Larsen, Chairman and CEO or Jorge Estepa,
Vice-President at (416) 868-9168.
Information in this news release may contain
forward-looking information. Statements containing forward looking
information express, as at the date of this news release, the
Company’s plans, estimates, forecasts, projections, expectations,
or beliefs as to future events or results and are believed to be
reasonable based on information currently available to the Company.
There can be no assurance that forward-looking statements will
prove to be accurate. Actual results and future events could differ
materially from those anticipated in such statements. Readers
should not place undue reliance on forward-looking information.
Neither the TSXV nor its Regulation Services
Provider (as that term is defined in the policies of the TSXV)
accepts responsibility for the adequacy or accuracy of this
release.
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