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Geology
[135 kb]
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Alteration Mapping
[93 kb]
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CuOx & Veinlet Density
[110 kb]
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Cu in Trenches
[87 kb]
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Mo in Trenches
[86 kb]
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Au in Trenches
[84 kb]
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Drill Hole Map & Geology
[731 kb]
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Drill Hole Locations
[135 kb]
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Picaron Exotic Drill Hole Map
[235 kb]
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Picaron Exotic Drill Hole Locations
[267 kb]
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Incahuasi-Lena Annotated
[235 kb]
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Porphyry Copper Targets
Picaron Porphyry Target
The Picaron hydrothermal alteration zone on the western margins of the Victoria JV property extends for approximately 2,000m N-S x 1,000m E-W, but appears to continue under post-mineral gravels and ignimbrites to the northeast, east and southeast. Principal host rocks are inter-bedded clastic red-beds and andesitic volcanics. Minor dacite porphyries outcrop and the area is cut by post-mineral andesite dykes and dacite porphyries. Supergene oxidation and leaching has been intense over most of the Picaron outcrops, largely exposed in historic trenches, with abundant supergene kaolin, jarosite, limonite and porcelainous alunite. Supergene turquoise is common in some areas and was the subject of historic exploitation in shallow pits. A well-developed quartz-vein stockwork occurs in the northern half of the sub-cropping alteration zone, over an area of approximately 600m x 300m.
Historic work includes trenching and relatively shallow RC drilling by Rayrock and RTZ/Rayrock in the 1990s (6 holes for 1,200m), and Teck in 2006 (5 holes for 1,140m). It should be noted that several of these holes were drilled through post-mineral cover materials to the east of the sub-cropping alteration zone.
The Picaron alteration zone is underlain by a well-developed, gradient array IP chargeability anomaly, which indicates sulphide mineralisation at depth beneath the leached outcrops.
Hochschild has completed 1,703 meters of diamond drilling in 4 angled holes at Picaron to date (VPI-DD-11-001, 002, 003 and 004), with a nominal spacing between the holes of 250m.
A fully developed diorite-hosted porphyry Cu+Mo±Au system was cut in the drilling, with multiple generations of early-, inter- and late-mineral porphyries, displaying variable potassic, sericitic and propylitic alteration assemblages, and multiple generations of quartz and sulphide veinlet stockworks. Alteration, mineralisation and veinlet vectors seem to indicate increasing copper and molybdenum values at depth. Further, initial interpretations of results from drilling and previous trenching suggest a possible differentiation between a Cu+Mo mineralising event and a separate Cu+Mo+Au mineralising event.
All 4 holes completed were highly anomalous in copper, due to the presence of chalcopyrite, with lesser molybdenum and local gold intercepts. Locally, individual sample intervals, generally 2m long, returned up to >1% Cu and up to >100ppm Mo. The best continuous intercepts include:
| • | | VPI-DD-11-001: | 39.0m @ | 575 ppm Cu + | 50.6 ppm Mo from 8.0m |
| | 109.9m @ | 745 ppm Cu + | 40.1 ppm Mo from 59.1m |
| | 17.9m @ | 1,030 ppm Cu + | 83.8 ppm Mo from 262.1m |
| • | | VPI-DD-11-002: | Minor copper intercepts |
| • | | VPI-DD-11-003: | 41.0m @ | 1,293 ppm Cu + | minor Au intercepts from 224.0m |
| | 34.6m @ | 869 ppm Cu + | 15.6 ppm Mo from 316.0m |
| | 11.0m @ | 2,102 ppm Cu + | 27.8 ppm Mo + 0.1 g/t Au from 357.0m |
| • | | VPI-DD-11-004: | 20.0m @ | 800 ppm Cu + | 61.9 ppm Mo from 172.0m |
All four drill holes passed through a sequence of volcaniclastic rocks, which host the porphyritic intrusions, and through a shallowly-dipping fault at depth into a sequence of calcareous sediments. These calcareous sediments have returned anomalous gold values immediately beneath the fault zone in three holes:
| • | | VPI-DD-11-002: | 12.7m @ | 0.17 ppm Au from 319.3m |
| • | | VPI-DD-11-003: | 2.0m @ | 0.19 ppm Au from 431.0m |
| • | | VPI-DD-11-004: | 5.4m @ | 0.27 ppm Au from 406.0m |
Picaron "Exotic" Target
Hochschild has completed 1,512m of reverse circulation drilling in 15 vertical holes (VPI-RC-11-005 to 019), centred on an area of post-mineral gravels located approximately 1.35km northeast of the Picaron porphyry copper target. This drilling was designed to follow-up a possible "exotic" copper intercept in a historic drill hole (VRC-20) completed by Rayrock in the 1990s that included 1m @ 0.137% Cu + 0.265% Mn in gravels from 59m depth.
The 15 new holes form a semi-regular grid, with nominal drill hole spacings of 100m (N-S) by 50m (E-W), and cover a total area of approximately 400m (N-S) by 100m (E-W). The drilling appears to have defined a palaeo-channel in the gravels containing Mn-rich copper oxides (most likely copper wad or neotocite). Results for the first 10 holes (VPI-DD-11-005 to 014) include the following intercepts:
| • | | VPI-RC-11-005: | 46m @ 0.13% Cu + | 0.28% Mn from 24m |
| o Includes: | 6m @ 0.39% Cu + | 0.63% Mn from 60m |
| • | | VPI-RC-11-006: | 8m @ 761 ppm Cu + | 0.15% Mn from 20m |
| • | | VPI-RC-11-006: | 26m @ 694 ppm Cu + | 0.17% Mn from 40m |
| • | | VPI-RC-11-007: | 8m @ 743 ppm Cu + | 0.21% Mn from 32m |
| • | | VPI-RC-11-008: | No significant intercepts |
| • | | VPI-RC-11-009: | No significant intercepts |
| • | | VPI-RC-11-010: | 14m @ 0.39% Cu + | 0.43% Mn from 18m |
| o Includes: | 6m @ 0.53% Cu + | 0.62% Mn from 24m |
| • | | VPI-RC-11-011: | 14m @ 553 ppm Cu + | 0.13% Mn from 30m |
| • | | VPI-RC-11-012: | 20m @ 866 ppm Cu + | 989 ppm Mn from 22m |
| • | | VPI-RC-11-013: | 18m @ 0.22% Cu + | 0.31% Mn from 14m |
| o Includes: | 4m @ 0.42% Cu + | 0.37% Mn from 24m |
| • | | VPI-RC-11-014: | No significant intercepts |
The highest copper value intercepted to date is 0.66% Cu over one 2m interval in hole VPI-RC-11-010 (from 24m).
Incahuasi Porphyry Target
The Incahuasi target consists of a large hydrothermal alteration zone approximately 3,500m NE-SW x 1,500m NW-SE, centred on andesitic volcanics and tuffs with minor rhyolites and sediments of Late Jurassic to Lower Cretaceous age. The alteration zone is located at the southern end of the Victoria Property, on the western side of the main Domeyko Fault structures that cut across the property, and is cut by the NW-SE trending Quebrada Incahuasi.
Previous exploration includes surface sampling and trenching by RTZ in the early 1990s. No historic drilling has been carried out.
The outcrops display an intensely supergene altered jarositic + limonitic leached capping, with supergene kaolinite and some supergene alunite. Widespread illite alteration has been determined from Terraspec. Sporadic quartz-vein stockworks are visible in trenches and some outcrops, particularly towards the north-east margins of the outcropping alteration zone. Some granular quartz veins with central suture lines likely represent "B" veins, suggesting the former presence of potassic alteration that has subsequently been overprinted by later alteration events (and supergene alteration). A narrow NE-SW trending zone of tourmaline breccias may be structurally controlled. Weak propylitic alteration occurs in outcrops to the south and east, indicating porphyry zonation. Hydrothermal alteration continues under post-mineral colluvium, gravels and volcanics to the north and south, suggesting the overall alteration system may yet be larger.
A series of small historic copper workings in post-mineral lithic tuffs to the immediate south of the Incahuasi alteration zone were exploiting exotic copper (chrysocolla and wad) almost certainly derived from the Incahuasi leached capping.
RTZ work focused on gold + arsenic + antimony anomalies in soils and rocks, although no drill testing of these anomalies was carried out. However, the poorly developed quartz-vein stockworks, including the likely presence of "B" veins, suggests a porphyry-related affinity. Additionally, surface geochemistry reveals anomalous molybdenum in soils and rocks in the northern part of the colour anomaly, coincident with some of the "B" veins identified in the field, as well as discontinuous zinc in soil anomalies surrounding the Incahuasi alteration zone, suggesting a partial zonation pattern.
A single IP geophysical test line running E-W across the Incahuasi alteration zone indicates a strong IP chargeability anomaly open at depth, indicating the presence of sulphides. Drill testing of this large hydrothermal system will probably require holes to +600m in order to ensure penetration of the lithocap and intersection of possible copper mineralisation at depth.
Cenizas Porphyry & Precious Metals Target
The Cenizas area consists of a large hydrothermal alteration zone approximately 2,000m E-W x 3,000m N-S, centred on clastic and volcaniclastic sequences of Late Jurassic age, located to the south of the Chaco Quebrada and bounded by the Cenizas Fault to the east. Small plugs of post-alteration andesite and rhyolite porphyry have also been identified.
The outcrops appear to represent a supergene altered jarosite + limonite leached capping, with supergene kaolinite and some supergene alunite. Silicification is variable across the outcrops, and minor quartz veining occurs. Hydrothermal muscovite and dickite have been identified from Terraspec, indicating that at least parts of the Cenizas alteration zone represents a high-level "lithocap" environment with vestiges of advanced argillic alteration. Immediately south of the colour anomaly, strong propylitic alteration (epidote disseminations and veinlets +/- calcite) in andesitic rocks occurs, together with small hydrothermal breccias.
The main targets identified by historic workers at Cenizas have been areas of massive jarosite + limonite cementing three discontinuous, N-S trending zones of fault brecciation (Western, Central and Eastern). These zones are exposed within the overall Cenizas colour anomaly over strike lengths up to 1,500m with widths varying from 50m to 200m. Small, tourmaline-cemented breccia bodies are associated with these zones, and minor secondary copper minerals have been identified on fractures.
The main geochemical anomalies of interest to explorers to date have been gold + arsenic + antimony in soils and rocks, with the best anomalies along the jarosite-rich breccia zones. However, copper, molybdenum, lead and rarely silver anomalies have also been identified. Previous exploration to date by RTZ (21 inclined RC drill holes for a total of 2,792m), El Dorado (2 inclined RC holes for a total of 411m), Teck (2 inclined RC holes for a total of 378m), and Iron Creek (6 inclined RC holes for a total of 1,130m) has all been directed towards relatively shallow gold mineralisation, mostly related to the jarositic fault breccia structures. The best intercept was from Iron Creek hole CE005 with 174m @ 0.44g/t Au associated with high arsenic. More recently Hochschild completed 712m of drilling in 2 RC holes.
The Cenizas hydrothermal alteration zone probably represents a supergene-altered lithocap setting above a possible porphyry target. The jarosite-rich breccia structures with anomalous gold + arsenic +/- antimony +/- copper +/- silver probably represent the remnants of a high-sulphidation overprint cutting across a sericitic alteration zone, which lies above the proposed porphyry copper target. Flanking propylitic alteration together with strong zinc in soil anomalies supports a zoned porphyry interpretation.
Additionally, the Cenizas alteration zone is underlain by a strong IP chargeability anomaly that is open at depth, supporting the continuation of sulphide mineralization at depth.
Chaco Porphyry Target
The Chaco covered porphyry target is located to the north of the Quebrada Chaco, and is underlain by the southern continuation of the Vaquillas Mine area gradient array IP chargeability anomaly. Historic drilling to date by Mena has intercepted minor copper mineralization (up to 280.6 ppm over 112m) hosted in a possible peripheral propylitic alteration halo to a porphyry centre. Several historic holes through the gravels indicate the presence of widespread propylitic alteration, with additional intercepts into feldspar porphyry with associated sericitic alteration further east. Space between existing historic drill holes is sufficient to hide a copper centre.
Vetas Negras Oeste Porphyry Target
The Vetas Negras Oeste covered porphyry target is associated with a small gradient array IP chargeability high located about 2km west of the Vetas Negras epithermal veins, and may be related to the Cenizas Fault. Drilling to the west of Vetas Negras has found leached dacite porphyry with sericitic alteration. This corresponds to a large magnetic low feature, within a larger magnetic high. Further dacite porphyry, andesitic volcanics and sediments with argillic and/or propylitic alteration have been found in other historic drill holes. Surface colluvial sampling shows weak copper and molybdenum geochemical anomalies open to the NW, but geophysics and geology suggest that potential may also lie to the SW.
Vaquillas Mine Porphyry Target
The Vaquillas Mine area is located on the eastern margins of a large (approximately 5,400m NNW-SSE x 1,500m E-W), gradient array IP chargeability anomaly that is open to the south. The anomaly is bounded by the Vaquillas Fault to the east and the Cenizas Fault to the west, and trends NNW as per the main known faults and breccia structures at Vaquillas. The Vaquillas Mine area is also located within an elongated resistivity high that parallels the Vaquillas Fault. The IP chargeability anomaly is much larger than the known mineralization in the Vaquillas Mine area and is open at depths beyond 500m from surface. The precious metals mineralization in the Vaquillas Mine area has the attributes and characteristics of an intermediate-sulphidation epithermal gold + silver system, likely located above and/or on the margins of a porphyry copper centre, and on the edges of a porphyry copper lithocap. Depending on the degree of telescoping of the overall porphyry copper system, the IP chargeability anomaly might represent the deeper portions of such a system including, at least in part, the porphyry copper +/- molybdenum +/- gold centre. Whilst much of the IP chargeability anomaly is likely related to disseminated and veinlet pyrite hosted within advanced argillic and/or sericitic alteration halos above and around the proposed copper centre, copper mineralization may accompany these alteration types. The main target, however, would be a high-hypogene grade, potassic-altered core hosting the bulk of copper mineralization, probably hidden within the overall geophysical anomaly due to the overlying sericite +/- pyrophyllite + pyrite alteration.
Leña Porphyry Target
Leña is a recently studied area of hydrothermal alteration some 3,000m NNE-SSW x 1,000m E-W in size, located approximately 2km east of, and trending sub-parallel to, Incahuasi. This large area of hydrothermal alteration comprises a feldspar porphyry intrusive complex that has been extensively silicified with hypogene alunite at surface. A volcanic unit lying on the western flanks of the altered porphyry has been completely replaced by vuggy silica. A small outcrop, possibly representing a small dyke, containing dark grey, wormy quartz veinlets occurs at the base of the main hill, on the flanks of a small quebrada.
Previous exploration work consisted of two lines of colluvial soil sampling carried out by RTZ in the 1990s.
The hydrothermal alteration system at Leña may represent the higher, lithocap levels of a porphyry system, and may have potential for gold at near surface levels, and possibly copper at depth (>750m). Limited historical soil sampling at Leña reveals a surface molybdenum geochemical anomaly that may represent a moly' "plume" within the lithocap environment. This could lie above a possible copper centre and may represent a vectoring guide.
Qualified Person
Demetrius Pohl, Certified Professional Geoscientist (CPG), is the Company's Qualified Person as defined by National Instrument 43-101, and is responsible for the accuracy of the technical information in this project summary. Dr. Pohl has verified that it is an accurate summary of the reports provided to Iron Creek by Hochschild, and contained within reports by historic workers. However, Iron Creek has not independently verified Hochschild's exploration results, or those of historic workers.
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