Eloro Resources Ltd. (TSX-V: ELO) (OTCQX: ELRRF) (FSE: P2QM) is pleased to announce that Minera Tupiza S.R.L., Eloro’s Bolivian subsidiary has completed 13 diamond drill holes totalling 2,898 metres of both underground and surface drilling at its optioned Iska Iska property in the Potosí Department of southern Bolivia. This is the first drilling ever carried out on the property. Figure 1 is a plan map showing locations of drill holes along with geology and alteration. Results from Hole DHK-01 to DHK-05 are reported in this press release; results for the other holes are pending. Due to the polymetallic nature of the deposit, silver equivalent and where applicable gold equivalent values have been included for comparative purposes.
The Iska Iska altered-mineralized zone as currently defined is approximately 550m wide and has been initially drill tested over a strike length of 600m as shown in Figure 1. The zone is wide open along strike as well as downdip. Figure 2 is a west-east geological cross section highlighting the major breccia pipe discovery. Significant assay results are given in Table 1. Table 2 gives collar coordinates and azimuths/orientations for all drill holes completed to date. Results are also reported for additional channel sampling in the Huayra Kasa underground workings with complete results including previously released results (see press release October 8, 2019) in Table 3.
Discovery of Major Breccia Pipe with Extensive Silver Polymetallic Mineralization
Underground holes DHK-03 and -04 drilled at 00E and -500E, respectively, intersected a major mineralized breccia pipe located just east of the underground workings as shown in Figures 1 and 2. Significant results from these holes justifying further detailed work include:
The highlighted significant zones also have anomalous copper values of between 0.01% and 0.07% Cu against background values of much less than 0.01% Cu which may be a significant indicator of the potential for more copper at depth.
Tom Larsen, Chairman and CEO of Eloro, commented: “This is a very exciting discovery confirming that Iska Iska has excellent potential to host a significant silver polymetallic mineral deposit that is potentially bulk mineable. We will be continuing our drilling program as well as expanding our exploration efforts along strike including carrying out gravity and magnetic surveys to outline additional potential pipes. 3-D modelling is also in progress to better understand the geometry of the pipe as well as the distribution of mineralization within it to facilitate further drilling. Concurrently with these activities, preliminary metallurgical test-work will be conducted to support future mineral resource estimation.”
Dr. Quinton Hennigh, P.Geo., Senior Technical Advisor to Eloro commented: “These first holes provide our first indication that Eloro has discovered a significant new silver polymetallic system akin to other such systems in the prolific southern Bolivian Potosi mineral district. All holes drilled to date have encountered visible mineralized intercepts. Interestingly, a gold-bismuth-rich phase of mineralization is also present within this complex system. Mineralization occurs in and adjacent to a large effusive breccia pipe along the margin of a major volcanic caldera. Breccia pipes such as the one we have discovered are important hosts of bulk tonnage ore bodies in many producing mines in epithermal and porphyry deposits especially in the Andean Cordillera of Central and South America. These pipes tend to occur in clusters, and recent geologic work by our Bolivian geologic team led by Dr. Osvaldo Arce indicates the setting at Iska Iska is conducive for discovery of such a cluster. Our next seven holes, all with visible intervals of mineralization, explore more of this newly discovered breccia pipe. Notably, hole DHK-012, a surface hole, encountered 300m of mineralized breccia at depth. We eagerly await results from these holes.”
A surface drill was brought in to allow further drilling of the newly discovered breccia pipe which occurs along the contact between a Miocene dacitic dome which has intruded Ordovician sandstones. To date five (5) additional holes (DHK-08 to DHK-12) have been completed confirming that the pipe is oval-shaped with a west-east dimension of 150m and north-south dimension of 200m. As shown in Figure 2 the pipe appears to have a southeasterly plunge. The deepest hole thus far, DHK-12, intersected 300m of mineralized breccia before intersecting mineralized granodiorite.
Within the mineralized granodiorite, there is widespread propylitic alteration consisting of epidote, fluorite and pyrite which suggests that the bottom of the hole is on the margin of a polymetallic porphyry system. Further drilling will be required to confirm the actual base of the pipe as the granodiorite intersected in Hole DHK-12 may be an apophyse (offshoot) from a larger intrusion at depth which could potentially host a porphyry copper deposit. It is also evident that the high-grade vein/breccia zones previously mined in the adjacent Huayra Kasa workings are very likely distal mineralized structures related to the breccia pipe and the porphyry system. This view is further supported by the synchrotron study of the underground channel samples (see press release dated June 25, 2020) which concluded that the four mineralogical domains identified by mineral cluster analysis are related and represent a single, large mineralizing system.
High grade Gold-Bismuth Zone Identified in Underground Workings at Huayra Kasa
Additional channel sampling carried out in the underground workings at Huayra Kasa has identified a north-northwest trending high grade gold-bismuth zone along the west margin of the breccia pipe as shown in Figure 3. Channel sampling here returned 7.1 g Au/t, 0.2% Bi , 28.3 g Ag/t, 1.1% Zn and 0.6% Pb (8.29 Au eq/t) over an average width of 3.04m for a strike length of 47m. Drill hole DHK-05 collared in Drill Bay #1 intersected 6.51g Au/t, 0.07% Bi and 31.96 g Ag/t (7.68 g Au eq/t) over 11.85m grading including 29.56 g Au/t,0.26% Bi/t and 63.69 g Ag/t (31.94 g Au eq/t) over 2.31m on the strike extension of this zone.
A second subparallel zone also occurs approximately 40m to the west where channel sampling returned 3.2 g Au/t, 0.18% Bi, 40 g Ag/t, 1.3% Zn and 0.7% Pb (4.7 g Au eq/t) over an average width of 1.27m for a strike length of 22.5m. Drill hole DHK-01, drilled from Drill Bay #1 intersected 3.9 g Au/t and 0.52% Bi (5.34 g Au eq/t) over 1.85m including 10.2 g Au/t and 1.1% Bi (13.23 Au eq/t) over 1.25m. Drill hole DHK-03 in the central part of the breccia pipe returned 3.72 g Au/t and 0.50% Bi (4.28 g Au eq/t) over 1.08m indicating that this high-grade gold-bismuth mineralization is much more widespread.
The channel sampling also confirmed the distribution of significant silver polymetallic mineralization within the Huayra Kasa workings. Figure 4 shows the distribution of Ag, Zn and Pb. Zn has the widest distribution with Ag and Pb zones occurring within the broader Zn envelope. Significant results include:
Significant values of indium have also been identified in both the underground channel samples and selected sampling of the diamond drill holes (see Table 4 for partial results in underground samples). Indium is usually associated with zinc however complete analytical data is not yet available to fully report on overall indium contents but indium is certainly a potentially payable metal.
Iska Iska Compared to Polymetallic Mines and Deposits in Southwestern Bolivia
Geologically, Iska Iska is in the southwest part of the Eastern Cordillera of Bolivia which hosts a number of major polymetallic mines and mineral deposits as shown in Figure 5. Table 4 lists geological characteristics of these mines and mineral deposits.
Dr. Osvaldo Arce, P.Geo. Manager of Minera Tupiza S.R.L and an expert on Bolivian geology commented: “The Huayra Kasa adit occurs along the contact between Ordovician sandstone and a Miocene dacitic dome. The breccia pipe has been emplaced in or near the ring fault zone along the northern side of the Iska Iska caldera which is a collapse structure that subsided as a result of the eruption of large volumes of dacitic and andesitic lava flows during Miocene time. Sericitic, argillic and decarbonization alteration is widespread in a zone at least 550m wide that extends 600m along strike and is open to the west and east. The high-grade gold and bismuth mineralization appear to be an earlier stage and occur mostly along structures at or near the contact zone between sandstone and dacite. Silver, zinc and lead mineralization, in contrast, is more widely distributed in the whole mineralized system and overprints the earlier high-grade gold and bismuth zones. The final stage of mineralization appears to be a late overprint of zinc and indium.”
Dr. Arce continued, “The Southeastern Andes polymetallic province is characterized by the presence of collapse/resurgent calderas, which were subsequently mineralized by both high temperature minerals such as cassiterite and wolframite associated with dacitic to rhyolitic subvolcanic stocks, overprinted by a late epithermal high and intermediate sulphidation events. The silver polymetallic type of mineral deposit represents the most common type of mineralization in the country. These deposits are characterized by a polymetallic signature (Sn, Ag, Zn, Pb, Bi, W, Au, Sb), which is usually telescoped and spatially related to intrusions. San Vicente and Tasna are hosted in sedimentary rocks; Cerro Rico de Potosí, Tatasi and Chorolque are hosted mostly in igneous rocks; whereas San Cristobal, Pulacayo, and Iska Iska are hosted in both sedimentary and igneous rocks. It is very likely that the mineralized granodiorite intersected in Hole DHK-12 is on the margin of a major porphyry complex at Iska Iska.”
Dr. Osvaldo Arce, P. Geo., a Qualified Person in the context of National Instrument 43-101, has reviewed and approved the technical content of this news release. Dr. Bill Pearson, P.Geo., Chief Technical Advisor for Eloro, and who has more than 45 years of worldwide mining exploration experience including extensive work in South America, provides technical oversight to the program in consultation with Dr. Quinton Hennigh, P.Geo., Senior Technical Advisor to Eloro and Independent Technical Advisor, Mr. Charley Murahwi P. Geo., FAusIMM of Micon International Limited. Drill samples are prepared in SGS BOLIVIA SA’s preparation facility in Oruro, Bolivia with pulps sent to the main SGS laboratory in Lima, Peru for analysis by fire assay for gold and silver as well as 31 element ICP. Eloro employs an industry standard QA/QC program with standards, blanks and duplicates inserted into each batch of samples analyzed.
About Iska Iska
Iska Iska silver 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. The property can be classified as a silver polymetallic (Ag, Zn, Pb, Au, Cu, Bi, Sn, In) epithermal-porphyry complex. This is an important mineral deposit type in the prolific South Mineral Belt of Bolivia.
Silver polymetallic mineralization at Iska Iska occurs within a Miocene possibly collapsed/resurgent caldera that consists of granodioritic stocks and five (5) dacitic domes which are each about 500m in diameter. These rocks intrude/extrude an intensely deformed sequence of Ordovician shales, siltstones, and sandstones, which are partially covered by Miocene pyroclastic rocks. The silver polymetallic mineralization occurs mainly as veins, vein swarms, veinlets, stockworks, disseminations and in breccias associated with intense hydrothermal alteration. The Iska Iska dome complex has several major phases of igneous breccias, quartz porphyries, dikes and dacitic syn-kinematic flows.
Geological mapping on the property by Eloro has revealed the spatial and temporal zonation of alteration and vein minerals in an area of about 5 square kilometres. The silver polymetallic mineralization occurs mainly as veins, subsidiary vein swarms, veinlets, stockworks, and disseminations, forming a subvertical vein system in both the stock and the volcanic and sedimentary rocks. Preliminary evaluation work including 42 channel samples in underground and on surface workings at Iska Iska returned significant results as summarized below. All of the channel samples included altered wall rock with widths ranging between 1.20 to 5.55 m, averaging 2.90 m (see press release of October 8, 2019 for further details).
Silver-polymetallic mineralization within the Iska Iska system occurs over a potential strike length of more than 2.5km along major ring structures in the caldera complex. A synchrotron study of the underground channel samples (see press release dated June 25, 2020) concluded that the mineral cluster analysis identified four mineralogical domains that cover the entire sampling area suggesting they are related and represent a single, large mineralizing system. Furthermore, the mineralogy of the domains is consistent with minerals identified in hand specimen and are likely related to a telescoped porphyry/epithermal style of mineralization.
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 recently 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.
Table 1. Significant Mineralized Intercepts in Holes DHK-01 to DHK-05, Huayra Kasa.
All drill core is HQ size (63.5mm)
*At the present time no estimate of true width can be made but will be determined when additional drill results are available. Tr = trace
** Formula for Ag g eq/t = Ag g/t + (Zn %*33.1)+ (Pb %*23.6)+ (Au g/t*76.6)+ (Bi%*75.1)
*** Formula for Au g eq/t) = Ag eq/t/76.6
Table 2: Summary of Diamond Drilling at Huayra Kasa to November 9, 2020
Underground Holes – DHK-01 to -07, -013, -014; Surface Holes – DHK-08 to -12
Table 3: Assay Results for Underground Channel Sampling, Huayra Kasa (Refer to Figures 3 and 4 for sample locations).
Table 4: Geological Characteristics of Major Polymetallic Mineral Deposits, Southern Andes Potosi District, Bolivia
|ALTERATION TYPES||DEPOSIT TYPE|
|Iska Iska (Ag, Pb, Zn, Au, Bi, In)||Empresa Minera Villegas & Minera Tupiza-Eloro Resources||Exploration by Minera Tupiza subsidiary of ELORO RES.||Ordovician sandstone, Tertiary dacite dome & granodiorite stock||Breccia, stockwork & disseminations||Argillic, sericitic, propylitic in dacite & epidote, fluorite, magnetite in granodiorite||Bolivian type Porphyry-epithermal complex|
|Chorolque (Sn, W, Au)||COMIBOL
Production by Mining Cooperatives
|Resources ≥ 100 Mt @ 1.5% Sn, 1.5% WO3||Ordovician shale, siltsone, sandstone & Miocene subvolcanic dacite stock||Breccia, veins & veinlets||Quartz-tourmaline, sericite, chlorite||Polymetallic Bolivian type within an intrusion|
(Bi, Au, Cu, W, Sn)
Production by Mining Cooperatives
Resources > 30Mt ; Reserves 840,000 t @ 1.35% Bi, 1.35 g Au/t, 1.16% Cu, 0.21% WO3)
|Ordovician shale, siltsone, sandstone & Miocene Quartz-feldspathic porphyric dikes||Veins, veinlets & anticline hinges||Sericite, potassic, advanced argillic & tourmaline||Polymetallic Bolivian type associated to sedimentary rocks|
|San Vicente (Ag, Zn, Pb, Cu, Sn)||COMIBOL
Production by Pan American Silver
≥ 9 Mt @300 g/t Ag;
0.3 % Cu;
0.3 % Sn
|Oligocene fanglomerate, Ordovician shales & porphyritic dacite dikes||Massive, replacement veins filling pre-existent faults, shear zones & bonanza zones||Silicification in shear zones||Polymetallic Bolivian type associated to sedimentary rocks|
Production by Mining Cooperatives
≥ 40 Mt @ 80 g/t Ag, 2% Sn
|Ordovician shales & sandstone, Cretaceous limestones, lava flows, volcanic domes & dacitic dikes||“Rosary” veins, shear zones, bonanza zones, stockwork & dissemination||Silicification, sericite, argillic & propylitic||Bolivian type Porphyry-epithermal complex|
(Ag, Zn, Pb)
Production by Minera San Cristobal subsidiary of Sumitomo Corp.
≥ 100 Mt @ 63 g/t Ag, 1.5% Zn, 0.5% Pb
|Central depression of about 4 km in diameter filled by up to 300 m thickness of volcaniclastic lacustrine sediments.||Steep fractures & breccias, stratiform disseminations in volcaniclastic-lacustrine sediments, irregular open space fractures, narrow hydrothermal breccias||Illite with disseminated pyrite of an intermediate argillic assemblage||Volcanic hosted massive polymetallic (epithermal type)|
(Ag, An. Pb)
Exploration by Silver Elephant
≥ 30 Mt @ 435 g/t Ag, 3.5% Zn, 2.1% Pb
|Silurian sedimentary rocks & igneous Neogene aged rocks||Veta Tajo is part of a large structural system striking east-west & dipping 75° to 90° south.||Propylitic, sericitic, moderate-advanced argillic, & siliceous||Volcanic hosted massive polymetallic (epithermal type)|
Web sites of mentioned companies;
Book: Metalliferous Ore Deposits of Bolivia (Arce, 2009);
Book: Yacimientos Metalíferos de Bolivia (Arce, 2020).
Note: Resources and Reserves figures are provided for information purposes only and may not necessarily be compliant with National Instrument 43-101
Photos accompanying this announcement are available at
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