Bulk Tonnage Metallurgical Tests Return Significantly Higher Silver Head Grade of 91 g Ag/t Compared with the 31 g Ag/t Average Grade from the Original Twinned Holes in the Polymetallic Domain at Iska Iska, Potosi Department, Southwestern Bolivia
Bulk Tonnage Metallurgical Tests Return Significantly Higher Silver Head Grade of 91 g Ag/t
Compared with the 31 g Ag/t Average Grade from the Original Twinned Holes in the
Polymetallic Domain at Iska Iska, Potosi Department, Southwestern Bolivia
Metallurgical tests from a 6.3 tonne PQ drill core bulk sample representative of the
higher grade Polymetallic (Ag-Zn-Pb) Domain returned a significantly higher average
silver value of 91 g Ag/t compared to the weighted average grade of the original
twinned holes at 31 g Ag/t strongly suggesting that the average silver grade is likely
significantly underreported in the original twinned holes due to the much smaller
sample size
The metallurgical tests confirm the viability of “O re-Sorting” and Dense Media
Separation at Iska Iska Project.
Excellent pre-concentration results from the higher grade Polymetallic (Ag-Zn-Pb)
Domain are now proven in a bulk sample. The 91.9% r ecovery of silver and lead with
76.0% recovery of zinc into a high grade (176g/t Ag, 1.88%Pb, 2.86%Zn = 299.15 g Ag
eq/t) potential mill feed stream that contains only 46.6% of the Run of Mine Tonnage.
The introduction of the pre-concentration stage allows Eloro to have more operational
flexibility based upon conducting economic trade of f scenarios between reducing
downstream capital-operating costs and optimizing overall metal recoveries.
XRT Ore Sorting is proposed for the coarser size fractions and Dense Media Separation
(“DMS”) for treatment of the finer fractions so as to pull on the strengths of both
technologies. The size split between the two techno logies is unoptimized and the
current results support the ability to potentially “ore sort” slightly coarser rocks than
tested which would further increase the overall benefits of pre-concentration.
Tin (Sn), although not included in the 132 million tonnes higher-grade starter pit area
(MRE), is expected to potentially contribute to the enhanced values in the initial
Preliminary Economic Assessment (“PEA”) with additi onal metallurgical testing and
infill drilling.
Toronto, Canada, January 23, 2024 – Eloro Resources Ltd. (TSX: ELO; OTCQX: ELRRF; FSE:
P2QM) (“Eloro”, or the “Company”) is pleased to announce the final results of its bulk metallurgical
test program on the Iska Iska silver-tin polymetallic project in the Potosi Department of southwestern
Bolivia.
Tom Larsen, CEO of Eloro commented: “The substantiv e difference in average silver grade in the
bulk sample compared to the twinned holes strongly suggests that the silver grade in the two original
twinned holes is likely significantly underreported due to the much smaller sample size. The recently
released results from the definition drill program in the same general area within the initial MRE (see
Eloro press releases dated December 18, 2023 and Ja nuary 11, 2024) which yielded a number of
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higher-grade Ag intersections, also reflected in th e improved silver grade equivalent values, further
supports this underreported silver grade conclusion . These results highlight the fact that tighter
spaced drilling is required to have a more representative sampling of high-grade areas in the Iska
Iska deposit to obtain a more accurate estimate of the likely true overall grade.”
Mr. Larsen continued: “While the initial test progr am focussed on the higher-grade part of the
Polymetallic Domain as this is where the bulk of th e current mineral resource is, further testwork is
planned on the Tin Domain which is very under-drill ed. The recent definition drilling reported
significant Sn results and it is expected that additional definition drilling will expand and upgrade the
tin resource so that it can potentially be included in the preliminary economic assessment (“PEA”) in
progress.”
Mike Hallewell, newly appointed as Eloro’s Senior V P Engineering Projects/Metallurgy said: “The
results indicate that 91.9% of the Silver and Lead, and 76.0% of the zinc can be pre-concentrated
into a relatively high-grade mill feed product cons tituting only 46.6% of the original tonnage. The
upgraded product results in higher flotation plant feed grades that will assist flotation stage
recoveries. Both XRT “Ore Sorting” and DMS are well known, low risk separation technologies that
provide Eloro with a great opportunity to significantly reduce operating and capital costs, reduce the
mine cut-off grade and enhance flotation stage reco veries. The small differences in the -60mm+25
mm and -25mm+9.5 mm size fractions suggests that the top size could be increased above 60 mm.
This would increase the percentage of Run-of-Mine (“ROM”) secondary crushed material that would
report for pre-concentration, which would enhance the overall benefit of pre-concentration. The much
higher Ag grades of 91 g Ag/t in the bulk metallurg ical sample as compared to the twinned holes
grade of 31g Ag/t is very encouraging. This along with the very high test recoveries for Ag, will have
a major positive effect on potential project economics.”
METALLURGICAL TEST PROGRAM
As previously reported (see Eloro press release dat ed November 1, 2023), three metallurgical drill
holes totalling 940 m were completed at the Iska Is ka project. Two holes targeted the higher-grade
Polymetallic (Ag-Pb-Zn) Domain while the third hole sampled the higher-grade Tin Polymetallic (Sn-
Ag-Pb) Domain. These metallurgical holes were dril led using PQ core (~85mm Ø) and were
designed to twin previous HQ core drill holes which contained representative mineralization with
values for the predominant higher grade Polymetalli c (Ag-Zn-Pb) outlined in Table 1. As shown in
Figure 1, these metallurgical holes were targeted i n the potential higher-grade starter pit area at
Santa Barbara which contains an estimated mineral r esource at a cutoff of NSR US$25/t of 132
million tonnes at 24.3 g Ag/t, 1.11% Zn and 0.50% P b (72.06 g Ag eq/t) (see Eloro press release
dated October 17, 2023). The drill core selected for testing from these holes, which totaled 7.9 tonnes
from 519 m of drill core, was shipped to Wardell Armstrong International (“WAI”) in Cornwall, England,
for crushing to 60mm and sizing into five different size fractions. The -60 mm+9.5 mm crushed and
sized product was sent to TOMRA GmbH based in Wedel , Germany, for separate cascade “ore-
sorting” tests on -60 mm+25 mm and -25mm+9.5 mm.
The testing program reported in this release focuss ed on the two PQ drill holes in the Polymetallic
Domain which contain the majority of the tonnage and metal, namely MET-DSBU-10 and MET-DSB-
30. The sample size tested was 6.3 tonnes from 418m of the overall drill core sent to WAI. Further
PQ diamond drilling is planned to obtain a bulk met allurgical sample from the sulphide Tin Domain,
in addition to testing MET-DSB-32 which is in the o xide zone of the Tin Domain. The Tin Domain,
although it contains an inferred mineral resource of 110 million tonnes grading 0.12% Sn, 14.2 g Ag/t
and 0.14% Pb (38.02 g Ag eq/t) (see Eloro press release of October 17, 2023), is very under-drilled
especially to the west. The recent definition drilling reported significant Sn results and it is expected
that additional definition drilling will expand and upgrade the Sn resource so that it can potentially be
included in the PEA in progress.
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The -9.5 mm+0.85 mm size fractions were subject to heavy liquid analysis performed on two separate
size fractions (-9.5mm+5mm and -5mm+0.85 mm) to identify the amenability of the finer size fractions
to Dense Media Separation (“DMS”). The -0.85 mm material and the pre-concentrated products from
the “ore sorting” and heavy liquid tests will provi de testwork material for further PEA level grinding
and flotation metallurgical testwork at WAI. This work builds on previous metallurgical test work using
representative Iska Iska samples, as summarized in the Company’s National Instrument 43-101 (“NI
43-101”) Technical Report filed on Sedar+ (see Eloro press release dated October 17, 2023).
These metallurgical drill holes also provided an im portant comparative bulk sample test of
mineralization grade relative to the weighted average grade of the twinned holes.
Figure 1: Cross Section of MRE Block Model showing Locations of Metallurgical PQ Holes and
Original Holes Twinned
Notes: OP = Open Pit defining mineral resource esti mate (MRE), NSR – Net Smelter Revenue, HG = Higher
Grade, LG= Lower Grade. Block model from Micon Int ernational Limited MRE (see Eloro press release
dated October 17, 2023)
SUMMARY HIGHLIGHTS
1. Overall Summary Tests
The main focus of this testwork phase has been on t he predominant Ag-Pb-Zn Sulphide Domain
which accounts for the majority of the mineral reso urce tonnage and metal values. Table 1 below
shows the compelling results from this preliminary study on the full bulk PQ sample representative of
the higher grade Polymetallic (Ag-Zn-Pb) Sulphide d omain. The results indicate that 91.9% of the
silver and lead, and 76.0% of the zinc can be pre-c oncentrated into a relatively high-grade mill feed
product constituting only 46.6% of the original ton nage. The upgraded product results in higher
flotation plant feed grades that will assist flotation stage recoveries. While 91.1% of the bulk sample
(-60mm+0.85mm) reports to pre-concentration the rem aining 8.9% of the material by-passes pre-
concentration and can be blended directly with the pre-concentrated feed ahead of grinding.
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Table 1: Overall Pre-concentration Results
Table 2 below compares the individual back calculat ed head assays coming from the PEA
preconcentration test work program with the assays from the 1/2 HQ twinned exploration holes. The
overall weighted average Ag assay was significantly higher in the bulk PQ metallurgical hole sample
at 91 g/t Ag as compared with the two original HQ geological tw inned holes at 31 g/t Ag. This
substantive difference in average Ag grade strongly suggests that the silver grade in the two original
twinned holes is likely to be significantly underre ported due to the much smaller sample size. The
recently released results from the definition drill program in the same general area (see Eloro press
releases dated December 18, 2023, and January 11, 2024) which yielded a number of higher-grade
Ag intersections, further supports this conclusion. These results highlight the fact that tighter spaced
drilling is required to have a more representative sampling of high-grade areas in the Iska Iska
deposit to obtain a more accurate estimate of the likely true overall grade.
Table 2: Back Calculated Head Assay
2. Ag-Zn-Pb Sulphide Domain -60 mm+25 mm XRT Ore So rter Result
In test 4.4, metal recoveries of 77.8%, 89.2% and 91.0% of zinc, lead and silver, respectively, were
achieved into a pre-concentrate that comprised 38.1 % of the feed weight. The pre-concentrate
assayed 2.91% Zn, 2.05% Pb and 180g/t Ag (308.37 g Ag eq/t). These “ore” sorter results are
presented in Table 3 and Figure 2 below.
Size Fraction Pre-conc Technique Unoptimised Setting W t% g/t Ag %Pb %Zn Ag eq Ag Rec % Pb Rec % Zn Rec %
-60mm+25mm XRT "Ore" Sorting Eject Medium Low Grade 12 .9 180.0 2.05 2.91 308.37 25.3 27.6 23.7
-25mm+9.5mm XRT "Ore" Sorting Eject Medium Low Grade 1 7.7 183.0 1.72 2.96 305.13 37.5 31.8 24.9
-9.5mm+5.0mm DM S 2.65 SG Sinks 2.0 156.0 2.38 3.47 314.61 3 .5 5.0 4.4
-5.0mm+0.85mm DM S 2.65 SG Sinks 5.1 196.0 2.37 3.68 356.98 11.0 12.7 11.9
-0.85mm None N/A 8.9 149.0 1.58 1.96 236.74 14.6 14.7 11.0
46.6 176.0 1.88 2.86 299.15 91.9 91.9 76.0
Notes:
Abbreviations are as follows: mm = millimetres, Pre -conc= Pre-concentration, XRT=X-Ray Transmission. S G = Specific Gravity, Wt% = Weight percent,
XRT=X-Ray Transmission, DMS = Dense Media Separati on, SG = Specific Gravity, Wt% = Weight percent, g/t = grams per tonne, Ag=Silver, Pb=Lead,
Zn = Zinc, Ag eq = Silver equivalent, Rec = Recovery. Silver equivalent (Ag eq) grades are calculated using 3-year average metal prices of Ag = US$22.52/oz,
Zn = US$1.33/lb and Pb = 0.95/lb and preliminary metallurgical recoveries of Ag = 88%, Zn = 87%, Pb= 80%.
Mill Feed
Mill Feed
Test Parameters
Size Fraction Wt kg Wt% %Pb %Zn g/t Ag Ag eq
-60mm+25mm 2137 33.8 0.87 1.42 75 136.16
-25mm+9.5mm 2689 42.5 0.80 1.50 89 149.68
-9.5 mm 45m m 278 4.4 1.18 1.87 78 161.83
-5mm+0.85mm 653 10.3 1.23 1.99 105 190.98
-0.85mm 563 8.9 1.58 1.96 149 236.74
PQ Drill Core 6320 100.0 0.95 1.58 91 157.73
1/2 HQ Twinned Holes 898 1.10 1.92 31 120.38
See Notes on Table 1. kg = kilograms
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Table 3: -60mm+25mm XRT “Ore” Sorter Cascade Results
Figure 2: -60mm+25mm Weight Yield Vs Metal Recovery to product
3. Ag-Pb-Zn Sulphide Domain -25 mm+9.5 mm XRT “Ore” Sorter Result
In test 1.4, metal recoveries of 81.9%, 89.5% and 89.6% for zinc, lead and silver, respectively,
were achieved into a pre-concentrate that comprised 41.6% of the sample feed weight. The
pre-concentrate assayed 2.96%Zn, 1.72%Pb and 183g/t Ag (305.13 g Ag eq/t). These “ore
sorter” results are presented in Table 4 and Figure 3 below.
Table 4: -25mm+9.5mm XRT Ore Sorter Cascade Results
Test 4.1 Eject High Grade 86.5 4.19 4.19 6.85 8.06 832 116 0.02 20.1 38.5 46.2
Test 4.2 Eject High Medium Grade 105.5 5.11 9.30 5.51 5.22 534 784.85 35.9 55.4 65.8
Test 4.3 Eject Medium Grade 269.0 13.04 22.34 3.82 3.03 2 83 453.75 59.9 77.1 83.5
Test 4.4 Eject Medium Low Grade 325.5 15.77 38.11 2.91 2.05 180 308.37 77.8 89.2 91.0
Test 4.5 Eject Low Grade 505.5 24.50 62.61 2.08 1.35 106 1 97.80 91.4 96.2 95.3
Test 4.5 Non-Eject Waste 771.5 37.39 100.00 1.35 0.87 74 1 32.82 100.0 100.0 100.0
2063.3 100.00
Test 4.5 Non-Eject Waste -20mm 73.7 3.45
TOTAL 2137.2
See NotesTable 1. Σ = Sum
Σ Pb
Product
Σ Ag
Product
Sample ID
Assay
Σ Mass %
to
Σ% Zn
Product
Σ% Pb
Product
Σg/t Ag
Product
Σ Ag eq
Product
Σ Zn
Product
Mass Metal Distribution, %
kg %
Test 1.1 Eject High Grade 170.5 6.46 6.46 7.83 6.76 845 11 75.91 33.7 54.7 64.3
Test 1.2 Eject High Medium Grade 225.0 8.52 14.98 5.41 3.74 435 659.96 54.0 70.2 76.7
Test 1.3 Eject Medium Grade 350.5 13.28 28.26 3.84 2.35 2 57 415.84 72.3 83.0 85.4
Test 1.4 Eject Medium Low Grade 352.5 13.35 41.62 2.96 1.72 183 305.13 81.9 89.5 89.6
Test 1.5 Eject Low Grade 566.5 21.46 63.08 2.18 1.20 123 2 12.82 91.6 94.9 95.5
Test 1.5 Non-Eject Waste 974.5 36.92 100.00 1.40 0.77 87 1 43.70 100.0 100.0 100.0
2639.5 100.00
Test 1.5 Non-Eject Waste -8mm 49.3 1.83
TOTAL 2688.8
See NotesTable 1. Σ = Sum
Sample ID
Mass Metal Distribution, %
kg % Σ Mass%
to
Σ% Zn
Product
Σ% Pb
Product
Σg/t Ag
Product
Σ Zn
Product
Σ Pb
Product
Σ Ag
Product
Assay, %
Σ Ag-eq
Product
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Figure 3 -25mm+9.5mm Weight Yield Vs Metal Recovery to product
4. Ag-Zn-Pb Sulphide Domain -9.5 mm+5.0 mm DMS Heav y Liquid Results
In 2.65 Specific Gravity (“SG”) sinks, metal recoveries of 85.3%, 92.7% and 92.3% of zinc, lead and
silver, respectively, were achieved into a pre-concentrate that consisted of 45.9% of the feed weight.
The 2.65 SG Sink product assayed 3.47% Zn, 2.38% P b and 156 g/t Ag (314.61 g Ag eq/t). These
heavy liquid test results are presented in Table 5 and Figure 4 below.
Table 5: -9.5mm+5.0mm DMS Heavy Liquid Results
Weight
2.65 SG 45.94 2.38 3.47 156 314.61 92.66 85.25 92.27
2.70 SG 29.54 3.52 4.86 263 484.13 88.20 76.83 89.45
2.75 SG 22.90 4.38 5.82 339 604.73 85.22 71.25 86.78
2.80 SG 16.75 5.72 7.18 463 792.78 81.25 64.34 84.53
2.85 SG 10.90 8.06 9.31 711 1140.22 74.60 54.33 78.49
2.90 SG 9.25 9.16 10.33 838 1313.37 71.91 51.12 75.36
See NotesTable 1. Σ = Sum, SG-Specific Gravity
Assay, % (ppm)
Σ Ag eq
Product
Product Σ Mass% to
Product
Distribution, %
Σ %Pb to
Product
Σ %Zn to
Product
Σg/t Ag to
Product
Σ Pb
Product
Σ Zn
Product
Σ Ag
Product
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Figure 4: -9.5mm+5.0mm Weight Yield Vs Metal Recovery to product
5. Ag-Zn-Pb Sulphide Domain -5.0 mm+0.85 mm DMS Hea vy Liquid Results
In the 2.65 SG sinks, metal recoveries of 91.4%, 95 .5% and 92.1% of zinc, lead and silver,
respectively, were achieved into a pre-concentrate that comprised 49.5% of the feed weight. The
2.65 SG Sink product assayed 3.68%Zn, 2.37%Pb and 1 96g/t Ag (356.98 g Ag eq/t). These heavy
liquid test results are presented in Table 6 and Figure 5 below.
Table 6: -5.0mm+0.85mm DMS Heavy Liquid Results
Weight
2.65 SG 49.50 2.37 3.68 196 356.98 95.48 91.39 92.12
2.70 SG 29.11 3.86 5.63 361 605.37 91.33 82.28 88.73
2.75 SG 26.26 4.23 6.11 400 665.16 90.43 80.52 87.97
2.80 SG 18.28 5.83 7.93 575 920.31 86.66 72.72 85.14
2.85 SG 13.65 7.49 9.72 770 1193.39 83.15 66.54 81.92
2.90 SG 12.30 8.15 10.39 854 1306.19 81.55 64.11 80.50
See NotesTable 1. Σ = Sum, SG-Specific Gravity
Σ Zn
Product
Σ Ag
Product
Distribution, % Assay, % (ppm)
Σ Ag-eq
Product
Σ Pb
Product
Σ Mass% to
Product
Product Σ %Pb to
Product
Σ %Zn to
Product
Σg/t Ag to
Product
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Figure 5: -5.0mm+0.85mm Weight Yield Vs Metal Recovery to product
Qualified Person (“QP”)
The metallurgical test program was directed by Mike Hallewell, B.Sc., F.I.M.M.M., F.S,A.I.M.M.,
F.M.E.S., C.Eng, Senior VP Engineering Projects/Metallurgy, and a Qualified Person (QP) as defined
by NI 43-101 in consultation with Richard Gowans, P.Eng., an independent QP as defining by NI 43-
101. Previous metallurgical work completed on Iska Iska is summarized in the NI 43-101 Technical
Report (see Eloro press release dated October 17, 2 023) prepared by Micon International Limited.
Independent QPs for the Technical Report are Charle y Murahwi, P.Geo., FAusIMM, Richard
Gowans, P.Eng., Ing. Alan J. San Martin, MAusIMM (CP) and Abdul Aziz, Drame, P.Eng., all of whom
are independent QP’s as defined by NI 43-101. Mr. Murahwi completed site visits in January 2020
and November 2022.
Wardell Armstrong International, based in Cornwall, UK, an internationally respected minerals
processing laboratory, carried out the crushing of the bulk sample for shipment to TOMRA and
completed metallurgical tests and assays on resulting products.
As part of the Tomra Group, TOMRA Mining, headquartered in Wedel, Germany, is a leading provider
of ore sorting technologies, particularly specializing in X-ray Transmission (XRT) sorting. Among the
latest advancements to enhance and improve finer pa rticle separation, Tomra introduced a cutting-
edge ejection module. This innovative module is spe cifically designed to increase separation
accuracy and significantly reduce air consumption, thereby positively impacting operational
expenditures (OPEX). Tomra’s extensive global reach has a proven track record in handling large-
scale projects.
Dr. Bill Pearson, P.Geo., Vice President Exploratio n, Eloro and a QP as defined by NI 43-101 has
reviewed and approved the technical content of this news release. Dr. Pearson who has more than
49 years of worldwide mining exploration, developme nt and production experience, including
extensive work in South America, manages the overal l technical program, working closely with Dr.
Osvaldo Arce, P.Geo. General Manager of Eloro’s Bol ivian subsidiary, Minera Tupiza S.R.L., and a
Qualified Person in the context of NI 43-101, who h as supervised all field work carried out at Iska
Iska. Dr. Arce supervised the on-site drilling and collection of the PQ core. Shipping to Wardell