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Victoria Property Summary
The Victoria land package, located along the Domeyko Fault System in the L. Eocene-Oligocene magmatic arc of northern Chile, has potential for porphyry copper deposits (+/- Mo +/- Au) together with genetically related, zoned, high, intermediate, and low-sulphidation epithermal precious metals deposits.
The Victoria properties are subject to a binding letter of intent with Hochschild Mining Holdings Limited (Hochschild), where Hochschild is able to earn a 60% interest in the properties by sole-funding US$6 million in exploration expenditures in the properties prior to 31/12/2013.
The Vaquillas Mine area, where most work by Hochschild to date has been focused, consists of breccias and veins likely representing intermediate-sulphidation epithermal Au+Ag (+ Zn + Mn +/- Pb + quartz +/- barite +/- calcite + clay) mineralization located above and/or lateral to a porphyry copper centre. The Vetas Negras and Victoria vein systems likely represent distal epithermal Ag+Mn (+/- Au +/- Sb +/- As + quartz + barite +/- calcite) veins to one or more porphyry centres.
Porphyry targets occur at Cenizas, Incahuasi, and possibly at depth beneath the Vaquillas Mine area. Further potential for blind porphyry targets under post-mineral cover exists to the north, west and/or southwest of Vetas Negras (Vetas Negras Oeste), between the Quebrada Chaco and the Vaquillas Mine (Chaco), and in the large covered area between the Vaquillas Mine and Picaron (Azul Profundo).
The Nueve Vidas area appears to show characteristics of diorite-hosted, low-grade porphyry gold mineralization together with auriferous contact skarns.
Typical for northern Chile and the Atacama Desert, all areas have been strongly affected by supergene oxidation and leaching effects, particularly those areas that contained hypogene sulphide mineralization, giving rise to abundant supergene clays and oxide and sulphate minerals in the mineralization target areas, and obscuring to a greater or lesser degree the hypogene mineralogy of these areas at surface.
The presence of major faults related to the Domeyko Fault System cutting across the property, often concealed under Miocene cover rocks, such as the Cenizas and Vaquillas Faults, is likely to have modified the zonation patterns and relative locations of mineralization areas to proposed source porphyry intrusions, due to a combination of post-mineral strike-slip and vertical block faulting. The major fault strands of the Domeyko Fault System, particularly the Cenizas and Vaquillas Faults can be traced across most of the property even though largely under cover, as they are readily apparent on satellite imagery and the various geophysical data sets that cover the property.
Precious Metals Targets
Vaquillas Mine
The abandoned small open pit mine and related underground workings at the Vaquillas Mine area are located along the Vaquillas Fault, about half way between the Vetas Negras and Victoria vein systems, on a modest structural high that is surrounded by post-mineral Miocene gravels and ignimbrites. The main host to the hydrothermal alteration and mineralization at Vaquillas is a series of andesitic volcanic breccias and lithic tuffs of Late Jurassic to Early Cretaceous age, together with rhyolite/dacite domes that occur predominantly to the SW. Hydrothermal alteration that affects most of the rocks is dominated by illite and smectite. It is possible that sericitic alteration takes over at deeper levels.
Mineralization at Vaquillas, which has been the subject of historical, small-scale, open-pit mining, consists of N-S to NNW trending, steeply W dipping, hydrothermal breccia bodies together with multiple fine veinlets of quartz and/or sulphide between the main breccia bodies. Disseminated, breccia matrix-filling, and veinlet controlled pyrite, together with a series of silver sulphosalts, argentite and likely acanthite, occur. Sphalerite is abundant in the hydrothermal breccias, together with minor galena and trace copper minerals. Quartz, barite, manganese oxides and minor calcite are the main gangue minerals. Although being known as a silver mine, the most important economic metal at Vaquillas is gold.
An important suite of later NW to WNW trending quartz veins, with altered and bleached halos, cross-cut the main Vaquillas breccias structures, and in some cases may displace them slightly. These cross-cutting veins have higher gold and silver values than the Vaquillas breccias. The predominant veins are typically 0.5m to 2m wide, have strike lengths of the order of at least 600m before disappearing under post-mineral cover, have been the subject of historical shallow workings (probably within the oxide zone only), and occur in at least 4 main sets: to the SW, N, E and W of the Vaquillas pit. One example, to the SW of the Vaquillas open pit, includes a vein exposed in trench Z6 at surface and grading 5.33 g/t Au and 290 g/t Ag over 1.5m, which was intersected in historic drill hole VRC-11 drilled by Rayrock at about 75m vertical depth with grades of 6.18 g/t Au and 118 g/t Ag over 7m (not true width). Other high grade intercepts, notably in drill holes VVQRC-09-003 (1m @ 37.5 g/t Au and 68.4 g/t Ag), VVQRC-09-005 (1m @ 4.94 g/t Au and 60.9 g/t Ag) and VVQDD-10-033 (1.13 m @ 78.3 g/t Au and 802 g/t Ag) also likely represent cross-cutting veins. Significant further work remains to be done to evaluate the potential of these high-grade veins.
The whole area has been affected by supergene oxidation and leaching to variable depths, but typically in the order of 70m. Abundant iron oxides, sulphates and supergene kaolinite are products of the supergene processes in the oxide zone.
The bulk of Hochschild drilling to date has been oriented ENE-WSW to intersect the main Vaquillas breccia structures. Nevertheless, some cross-cutting veins have been sampled at surface and intersected in drill holes at depth as indicated above.
Hochschild's main focus is on the precious metals oxide resource along the main Vaquillas breccia structure trend. Most drilling to date by Hochschild has been RC (8,883m of RC drilling in 32 holes), with two diamond drill holes recently completed (715m of diamond drilling in 2 holes) and diamond hole 32 being a twin of RC hole 17. Best results include are summarized below:
DRILL HOLE |
From (m) |
To (m) |
Intercept (m) |
Au (g/t) |
Ag (g/t) |
VVQRC-09-002 |
195.00 |
216.00 |
21.00 |
1.10 |
128.50 |
Including |
204.00 |
208.00 |
4.00 |
3.30 |
580.50 |
VVQRC-09-004 |
132.00 |
151.00 |
19.00 |
1.00 |
5.90 |
VVQRC-09-013 |
0.00 |
273.00 |
273.00 |
1.00 |
16.10 |
Including |
56.00 |
106.00 |
50.00 |
1.20 |
30.90 |
And |
167.00 |
273.00 |
106 |
1.40 |
19.80 |
VVQRC-09-017 |
59.00 |
129.00 |
70 |
0.50 |
58.20 |
|
154.00 |
160.00 |
6.00 |
0.89 |
7.10 |
VVQRC-09-018 |
247.00 |
282.00 |
35.00 |
0.52 |
7.70 |
VVQRC-09-021 |
170.00 |
186.00 |
16.00 |
0.81 |
7.30 |
|
212.00 |
224.00 |
12.00 |
0.69 |
60.10 |
VVQRC-09-022 |
195.00 |
219.00 |
24.00 |
0.31 |
93.20 |
|
237.00 |
277.00 |
40.00 |
0.27 |
37.40 |
VVQRC-10-024 |
87.00 |
103.00 |
16.00 |
1.27 |
25.4 |
|
107.00 |
113.00 |
6.00 |
0.87 |
2.83 |
|
199.00 |
210.00 |
11.00 |
0.44 |
12.00 |
VVQRC-10-026 |
17.00 |
24.00 |
7.00 |
0.63 |
11.50 |
|
81.00 |
95.00 |
14.00 |
1.16 |
4.00 |
|
103.00 |
109.00 |
6.00 |
0.68 |
1.00 |
|
119.00 |
132.00 |
13.00 |
0.44 |
1.00 |
VVQRC-10-027 |
5.00 |
19.00 |
14.00 |
0.43 |
24.00 |
Including |
14.00 |
18.00 |
4.00 |
0.83 |
74.25 |
|
203.00 |
213.00 |
10.00 |
0.32 |
6.50 |
|
222.00 |
230.00 |
8.00 |
0.60 |
0.80 |
VVQRC-10-028 |
123.00 |
130.00 |
7.00 |
0.72 |
1.40 |
VVQRC-10-029A |
54.00 |
56.00 |
2.00 |
0.20 |
132.00 |
|
124.00 |
130.00 |
6.00 |
0.44 |
2.00 |
|
181.00 |
191.00 |
10.00 |
0.36 |
17.80 |
VVQDD-10-032 |
66.3 |
96.3 |
30.00 |
0.60 |
138.13 |
|
100.6 |
149.6 |
49.00 |
1.14 |
32.63 |
Including |
131.45 |
136.2 |
4.75 |
2.38 |
84.20 |
And |
138.95 |
145.5 |
6.55 |
2.28 |
85.24 |
|
156.90 |
169.00 |
12.10 |
1.34 |
5.05 |
VVQDD-10-033 |
68.00 |
95.85 |
27.85 |
0.62 |
62.70 |
Including |
74.95 |
81.00 |
6.05 |
1.45 |
202.81 |
|
98.00 |
113.18 |
15.18 |
0.58 |
34.31 |
|
120.50 |
124.60 |
4.10 |
0.65 |
113.49 |
|
125.86 |
131.50 |
5.64 |
0.43 |
75.61 |
|
134.50 |
145.00 |
10.50 |
8.90 |
116.31 |
Including |
141.42 |
142.55 |
1.13 |
78.3 |
802 |
|
145.65 |
158.90 |
13.25 |
0.45 |
16.95 |
The intercepts reported are the length of the drill core intersection as the true orientation of the mineralization remains to be fully established. Intercepts were averaged using a 0.2 g/t Au cut-off and/or a 12 g/t Ag cut-off. Less than 1% of internal intercepts were accepted below the cut off grades and no capping was used in the calculations.
Significantly, diamond drill hole VVQDD-10-32 drilled as a twin to reverse circulation hole VVQRC-09-017, located in the approximate center of the Vaquillas Mine trend and immediately to the west of the small, historic open pit, returned significantly better gold and silver values (see following table), suggesting losses of fine material in the presence of water in the original RC drilling. Further diamond drill hole twins are planned to check this conclusion.
DRILL HOLE |
From (m) |
To (m) |
Total Intercept (m) |
Au (g/t) |
Ag (g/t) |
VVQDD-10-032 |
67.13 |
169.00 |
101.87 |
0.91 |
56.87 |
VVQRC-09-017 |
63.00 |
165.00 |
102.00 |
0.44 |
37.35 |
Vetas Negras
The Vetas Negras silver veins located towards the northern end of the Vaquillas property are hosted within a rhyolitic dome that is in faulted contact with Late Jurassic calcareous sediments to the east. This fault is the northern continuation of the Vaquillas Fault. Veins exposed at surface and in old workings are composed of quartz, barite, manganese and iron oxides, likely manganese and iron carbonates, and minor calcite, and are anomalous in silver, antimony and zinc, with minor gold and arsenic. The veins often present banded epithermal textures. Silver is likely present as silver sulphosalts and typical grades from surface sampling of exposed veins range from around 50 g/t to +700 g/t.
Hochschild has completed 1,270m of RC drilling in 5 holes targeting the principal mapped veins at depth. Best results include 10m @ 0.14 g/t Au and 58.8 g/t Ag, including 1m @ 0.37 g/t Au and 196 g/t Ag (VMNRC-09-005); and 3m @ 0.14 g/t Au and 57.2 g/t Ag including 1m @ 0.35 g/t Au and 152 g/t Ag (VMNRC-09-005).
Victoria (I, II & III)
The Victoria silver veins are separated into three sub-areas -- Victoria I, II and III -- and are located to the south of the Chaco Quebrada and to the east of Cenizas and Nueve Vidas, along the southern continuation of the Vaquillas Fault structure. Most work has been concentrated on the Victoria II cluster of veins to date. As at Vetas Negras, veins exposed at surface and in old workings at Victoria are composed of manganese and iron oxides, manganese and iron carbonates, quartz, barite and minor calcite, often displaying banded epithermal textures. However, the host rocks at Victoria are porphyritic dacites, and clastic and volcanic sediments and tuffs of Upper Jurassic age, underlain by carbonate sequences at depth. Micro-diorite dykes cross-cut the area. Hydrothermal breccia-vein structures are also apparent. At surface the structures are highly anomalous in silver, antimony, mercury, lead and zinc, with minor gold and arsenic. Silver is likely present as silver sulphosalts and typical grades from surface sampling of exposed veins range from 10 g/t to +300 g/t.
Hochschild has completed 2,015m of RC drilling in 9 holes at Victoria II targeting the principal mapped veins at depth. No significant results were recorded.
Nueve Vidas
A medium-grained, porphyritic diorite hosting veinlet and disseminated magnetite and minor epidote is exposed in trenches and minor outcrops at Nueve Vidas, located immediately SW of the Cenizas colour anomaly. Drilling in and around Nueve Vidas has also identified tonalite, monzonite and granodiorite intrusive phases, which have been collectively referred to as the Nueve Vidas Intrusive Complex (NVIC). The magnetite-rich dioritic body coincides exactly with a strong, circular magnetic high feature approximately 1.5km in diameter. A smaller, less intense, circular magnetic feature is located about 3.5km to the NNW and may represent a similar magnetic diorite porphyry centre.
Fine grained clastic, volcaniclastic and calcareous sediments surrounding the diorite porphyry appear to have been affected by contact-skarn type alteration. Trenching indicates that the NVIC is cut by a series of narrow, red-clay filled fault/gouge zones. One of these clay-filled gouge zones is approximately 100m wide and has been mapped in a series of trenches in the NW corner of the porphyritic diorite outcrops, trending NW-SE over a strike length of about 400m.
Soil samples, surface trench samples, and drill samples indicate that the magnetite-rich diorite porphyry and some of the surrounding skarn-altered sediments are highly anomalous in gold, but only modestly anomalous in Ag, As and Sb, with minor sporadic Cu kicks. Au often occurs alone, without other accompanying anomalous metals. The clay-filled fault/gouge zones are typically anomalous in Au.
The best gold result in trenches is from historic RTZ trench TR27 cutting the NW-trending clay fault/gouge zone indicated above, with 4m @ 6.69 g/t Au (+ 22.6 g/t Ag + 0.11% Cu), whilst the best drill intersection comes from Hochschild's RC hole VCNRC10-004 drilled approximately 450m NW of TR27, where 12m @ 8.91 g/t Au and 21 g/t Ag, including 4m @ 22.18 g/t Au and 36.1 g/t Ag, was intersected. However, other drilling along the proposed NW-SE trending zone of interest has failed to reproduce these encouraging results, with only low-grade anomalies reported. Elsewhere within the NVIC, grades from trenches, RAB drilling and RC drilling give typical results in the 0.3 g/t Au to 0.6 g/t Au range over several meters to 10s of meters, with occasional kicks up to around 1 g/t Au to 1.2 g/t Au over a few meters. Hochschild has completed a total of 4,095m of RC drilling in 13 holes at Nueve Vidas to date.
Porphyry Copper Targets
Vaquillas Mine Porphyry Target
The Vaquillas Mine area is located on the eastern margins of a large (5,400m NNW-SSE x 1,500m E-W), strong IP chargeability anomaly that is open to the south. The area 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. 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 Au+Ag 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 Cu +/- Mo +/- Au 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 the proposed porphyry system, 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.
Cenizas Porphyry Target
The Cenizas area consists of a large colour anomaly approximately 2km E-W x 3Km 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 andesite and rhyolite porphyry have also been identified.
The outcrops appear to represent an intensely supergene altered jarosite +/- haematite + limonite leached capping, with abundant supergene kaolinite and some supergene alunite. Silicification is variable across the outcrops, and minor quartz veining occurs. Sericite has been identified in a number of areas, and supergene kaolinite together with the iron sulphates and oxides probably overprint what was originally a large sericite + pyrite +/- silica alteration zone. 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 +/- haematite +/- 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 Au + As + Sb in soils and rocks, with the best anomalies along the jarosite-rich breccia zones. However, Cu, Mo, Pb and rarely Ag anomalies have also been identified. Historic drilling to date by RTZ and Mena and more recently by Hochschild (712m in 2 RC holes) has intercepted minor Au mineralization (up to 1.34 g/t over 10m) associated with strong As anomalies. Some wider intersections (>100m) of approximately 0.5 g/t Au material with arsenic have also been intersected. The Cenizas colour anomaly is partially flanked by discontinuous zinc in soil halo, particularly to the NW and S -- the latter being coincident with widespread propylitic alteration.
The Cenizas colour anomaly probably represents a supergene-altered base of lithocap setting above a likely porphyry target. The jarosite-rich breccia structures with anomalous Au + As +/- Sb +/- Cu +/- Ag probably represent the remnants of a high-sulphidation overprint (lodes?) cutting across a sericitic alteration zone, lying above the proposed porphyry copper target. The intensity of supergene processes and the abundance of jarosite suggest that strong pyrite mineralization was present originally. 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 mineralization at depth. As at Vaquillas Mine, the main target 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.
Incahuasi Porphyry Target
The Incahuasi area consists of a large colour anomaly approximately 3,000m NE-SW x 1,500m NW-SE, centered on andesitic volcanics and tuffs with minor rhyolites and sediments of Late Jurassic to Lower Cretaceous age. The colour anomaly 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 itself cut by the NW-SE trending Quebrada Incahuasi.
Incahuasi shows a number of characteristics that are similar to Cenizas. The outcrops appear to represent an intensely supergene altered jarosite +/- haematite + limonite leached capping, with abundant supergene kaolinite and some supergene alunite. Sericite has been identified in a number of areas, and supergene kaolinite together with the iron sulphates and oxides probably overprint what was originally a large sericite + pyrite +/- silica alteration zone. Sporadic quartz-vein stockworks are visible in trenches and some outcrops. Some granular quartz veins with central suture lines and bleached halos likely represent "B" veins, suggesting the former presence of potassic alteration that has subsequently been overprinted by the sericitic alteration (and supergene alteration), indicating telescoping of the porphyry system. Other, crystalline quartz veins may be "D" veins. Minor tourmaline breccias occur in road cuts and trenches, and weak propylitic alteration (epidote) occurs in outcrops to the south, indicating porphyry zonation.
As at Cenizas, the interest at Incahuasi to date has been focused on Au + As + Sb anomalies in soils and rocks, although no drill testing of these anomalies has been carried out at Incahuasi to date. However, as at Cenizas, Incahuasi almost certainly represents the sericitic base of a lithocap to an underlying porphyry copper system. In the case of Incahuasi, the presence of "B" veins suggests that greater telescoping has occurred and that the porphyry target may be closer to surface. Additionally, surface geochemistry reveals a strong Mo anomaly in the northern part of the colour anomaly, coincident with some of the "B" veins identified in the field, and strong zinc in soil anomalies occur to the east and north of the Incahuasi colour anomaly, suggesting a partial zonation pattern.
Azul Profundo Porphyry Target
The covered Azul Profundo porphyry target is flanked by the Picaron alteration zone to the west. Picaron represents an intensely supergene leached capping, probably situated on the immediate periphery to a copper centre, located on the western margins of the Vaquillas Property, WSW of the Vaquillas Mine area and on the western margins of the large Vaquillas Pampa. The alteration zone is about 2,000m N-S x 1,000m E-W in outcrop, but disappears under post-mineral Miocene gravels to the N, E and SE.
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. The supergene leaching has been intense over most of the Picaron outcrops, largely exposed in trenches, with abundant supergene, porcelainous alunite, jarosite, some turquoise, and sporadic haematite and limonites. Minor quartz veining occurs and generally increases to the S and SE.
An analysis of historic drill holes around Picaron shows that propylitic alteration occurs to the N and NE with increasing intensity of propylitic alteration towards the south. Dacite porphyries and sericitic alteration are recorded to the S and W, beneath the Picaron outcrop area. "A" veins together with Cu-oxides and trace Cu + Mo sulphides are reported in holes close to the outcrop centre and crucially, potassic alteration (K-biotite) associated with trace pyrite and chalcopyrite is noted in the last 16m of a hole bordering the pampa to the east.
Overall zonation patterns from outcrop and drill holes suggests that the post-mineral covered area to the SE or E between the Picaron outcrops, the Vaquillas Mine, and the Quebrada Chaco is still open for a potential porphyry center.
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 IP chargeability anomaly. Historic drilling to date by Mena has intercepted minor continuous Cu 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 porphyry target is associated with a N-S trending IP chargeability high located about 2km west of the Vetas Negras epithermal veins, and may be related to the Cenizas Fault. The weakly developed Sandon porphyry outcrops some 4km to the north of Vetas Negras and consists of variable sericite-altered dacite porphyry with minor quartz veining. Hydrothermal breccias have been reported. Historic drilling to the west of Sandon, through post-mineral cover, has intersected weak alteration (argillic and/or propylitic) and pyrite mineralization in bedrock, associated with a large magnetic high feature. Drilling to the west of Vetas Negras has found leached dacite porphyry with sericitic alteration. This corresponds to a large magnetic low feature, within the overall magnetic high indicated above. 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 Cu and Mo geochemical anomalies open to the NW, but geophysics and geology suggest that potential may also lie to the SW.
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