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Regional Geology

The dominant geological feature of this region is the north-south trending Neogene (23 - 2.5 million years ago (Ma)) metallogenic belt that extends along the slopes of the Andean Cordillera in Chile and Argentina.  In central Chile, this metallogenic belt includes world class Cu-Mo porphyries, such as: Los Pelambres-El Pachón located 75km north of the Vizcachitas deposit, Río Blanco-Los Bronces located 80 km to south of Vizcachitas and El Teniente located 180 km to the south.

In central Chile, the Neogene metallogenic belt coincides with the position of Miocene volcanic centers and associated flat-lying volcanic rocks, sills, and dikes. The Miocene volcanic sequence, with an average thickness of 2,500 m, comprises andesite, basalt (lavas and sills), dacite, and intercalations of rhyolitic tuff, which constitute a north-south belt approximately 20 km wide (Farellones Formation; Thiele, 1980; Rivano et al., 1990). Eruption of these volcanic rocks occurred at a number of volcanic centers, possibly localized by intersections of regional structures. These volcanic rocks overlie folded Oligocene (34 – 23 Ma) to early Miocene andesitic volcanic and continental sedimentary rocks (Abanico and Coya-Machalí Formations in a non-conforming manner; Thiele, 1980; Charrier et al., 2002).

The Neogene porphyry Cu-Mo deposits occur within hydrothermal alteration zones related to multiphase porphyritic stocks with compositions ranging from quartz diorite to granodiorite. These intrusions and their country rocks host dense networks of sulphide-bearing veins and associated hydrothermal breccia complexes. The country rocks are: late Miocene basaltic and andesitic volcanic rocks, diabase sills, and gabbro at El Teniente; Miocene andesite and a middle Miocene granodioritic batholith at Río Blanco-Los Bronces (San Francisco batholith; Serrano et al., 1996); and folded Lower Cretaceous (145 - 100 Ma) volcanic and sedimentary rocks at Los Pelambres (Atkinson et al., 1996).

Dates obtained by General Minerals Corporation on biotite from four intrusive rocks yielded ages between 10.4 and 12 ± 0.3 Ma for the Vizcachitas project (Osterman, 1997).

Local and Property Geology

As part of the project review carried out in 2015, the Los Andes Copper geologist relogged all of the 146 diamond drill holes that have been drilled on the property since the 1990’s.

The relogging was carried out under the leadership of Gonzalo Saldias, a very experienced Chilean porphyry geologist. This logging identified the importance of the early diorite porphyry and the later hydrothermal breccias in controlling the higher grade mineralisation. The previous geological model had grouped together all the dioritic rocks and the various breccias. The new model has differentiated these units.

The host rocks at Vizcachitas are Oligocene-Miocene (33-5.3 Ma) andesite of the Abanico Formation. The earliest intrusive phase at Vizcachitas was a sequence of diorite units ranging from fine grained through to porphyritic phases. The early diorite porphyry is generally deeper and on the eastern side of the project. In some drill holes it was only intersected in the last tens of meters of the drill holes.

The extent of hydrothermal breccias had not been fully recognised in the previous logging. The current mapping shows that there are two areas: one to the south east and the other in the central core of the project. The central core hydrothermal breccia has been cut by a later diatreme breccia.

The relogging showed that these higher grade geological units extend over a distance of 1,400 metres north-south and 700 metres east-west. The mapping shows that these breccias have grades increasing with depth and demonstrates the potential for higher grades below the current drilling.

2015 / 2016 Drill Program

The 2015 / 2016 drill program was designed to test the new geological model and support assumption that the higher grades are associated with the early diorite porphyry and the later hydrothermal breccias.

Drill Hole V2015-01

This hole was drilled in the northern part of the central core. The purpose of this hole was to demonstrate whether the high grade mineralisation associated with the diorite porphyry extended 200 metres to the west from the historical drill holes.

The top of bedrock was located at 68.70 metres and the drill hole intersected the diorite porphyry with potassic alteration at a depth of 216 metres and continued within this unit to the end of the hole at 476 metres. The average grade with the diorite porphyry was 260.40 metres at 0.467 % Cu, 285 ppm Mo and 1.0 g/t Ag from a down hole depth of 216.0 metres, this included 0.601 % Cu, 258 ppm Mo and 1.2 g/t Ag over a length of 64.00 metres. The drill hole supports the continuity of the higher grade diorite porphyry to the west and demonstrated that the mineralisation is open at depth.

Drill Hole V2015-02

This hole was drilled on the western edge of central core. The aim of this hole was to drill to the west of the known mineralisation, seeking to intersect the lower grade granodiorite intrusive which defines the western limit of the project.

The drill hole did not intersect the granodiorite intrusive but drilled the andesite host rock with potassic alteration from a depth of 60.10 metres to a depth of 288.00 metres where it intersected a tonalite porphyry which continued to the end the hole at 459.80 metres.

Within the andesite, from a depth of 142.00 metres, the average grade was 0.60 % Cu, 170 ppm Mo and 1.84 g/t over 52.00 metres, associated with stronger alteration. The average grade for the whole drill hole was 0.35 % Cu, 107 ppm Mo and 1.0 g/t over a length of 399.65 metres.

While the drill hole did not reach the western limit of the project, it showed that the mineralised system extended further westward than the proposed model and demonstrated the core of the project has significant sections with grade of greater than 0.6 % Cu.

Drill Hole V2015-03

This hole was drilled in middle of central core, 140 metres to the east of V2015 02. The aim of the hole was to test the depth extension of the mineralisation identified in the shorter historical drill holes which finished in good mineralisation at a depth of approximately 200 metres.

The drill holes intersected andesitic bedrock with supergene mineralisation at a depth of 44.1 metres. The supergene mineralisation continued to approximately 80 metres and the grade over this sequence was 0.743 % Cu, 146 ppm Mo and 1.9 g/t Ag over 39.10 metres.

From a depth of 141.10 metres, the drill hole intersected a sequence of ingenious breccias, hydrothermal breccias and a diorite porphyry to a depth of 444.8 metres. The higher parts of the sequence are identified by the quartz sericite alteration and high pyrite to chalcopyrite ratio. With depth, the potassic alteration increases and the pyrite to chalcopyrite ratio decreases although never below 1:1. This would indicate the drill hole is still in the higher part of the porphyry system and there is potential for higher grades at depth. The grade over this sequence is 0.404 % Cu, 241 ppm Mo and 1.1 g/t Ag over a length of 303.7 metres.

At a depth of 444.80 metres the drill hole intersected an andesite with potassic alteration and is notable for the low copper grades and the higher molybdenum grade. The grades are 0.172 %Cu, 332 ppm Mo and 0.4 g/t Ag over a length of 90.20 metres. This andesitic sequence is interpreted as being the potassic central of the porphyry system.

Drill Hole V2015-04

This hole was drilled in the northern extent of the central core, 180 metres to the north-west of drill hole V2015-01, to test the northern extension of the mineralisation identified in the first drill hole.

The drill hole intersected the diorite intrusive bedrock at a depth of 64.90 metres and continued in the same type of rock to a depth of 656.00 metres, except for a short 15 metres sequence of tonalite porphyry. A leached cap extended from 64.9 metres to 186.0 metres.

From a depth of 186.0 metres to a depth of 656.0 metres, a length of 470.0 metres, the average grade was 0.350 % Cu and 152 ppm Mo with 0.8 g/t Ag. This included 44.0 metres with an average grade of 0.448 % Cu, 96 ppm Mo and 1.1 g/t Ag.

While this hole did not intersect the higher grade diorite porphyry identified in historical drill hole V-39, it has shown that moderate grade mineralisation extends further north than previously demonstrated in the 2014 block model.

Drill Hole V2015-05

This hole was drilled in the eastern part of the central core, 280 metres to the south-east of V2015-03. The purpose of this hole was to demonstrate the northern extension of the hydrothermal breccias identified in the relogging of the historical drill holes to the south.

The top of bedrock was located at 36 metres with the drill hole intersecting a sequence of andesitic host rock, cut by diorite porphyry and hydrothermal breccias. The leached zone extended to a depth of 72 metres before entering the supergene mineralisation. From 72.0 metres to a depth of 192.0 metres, a length of 120.0 metres, the average grade was 0.537% Cu, 169 ppm Mo and 1.4 g/t Ag.

The drill hole intersected a hydrothermal breccia from 492.2 metres to 544.3 metres, a total length of 52.1 metres, with an average grade of 0.812 % Cu, 190 ppm Mo and 2.0 g/t Ag. This supports the extension of the higher grade breccias from the south.

Drill Hole V2015-06b

The V2015-06a hole could not pass through the gravels.

The V2015-06b hole was drilled in the north east extent of the central core, 270 metres to the north-east of drill hole V2015-01, between two outcropping late stage diatremes. The new geological model indicates the potential for porphyry style mineralisation in this area. If proven this would open up a large area within the 2014 block model that is currently identified as waste rock.

The drill hole intersected a post mineral dacite dyke at a depth of 3.0 metres and was stopped at a depth of 67 metres. The drill hole has not been assayed.

Drill Hole V2015-07

This hole was drilled to 150 metres south of drill hole V2015-05 to test central core of the project area.

The drill hole could not pass through the gravels and was abandoned at a depth of 52.00 metres.

Drill Hole V2015-08

This hole was drilled in the eastern part of the central core, 270 metres to the north of V2015-05. The aim of the hole was to show the depth extension of the mineralisation beneath the historical drill holes drilled in this area.

From a depth of 3.0 metres to a depth of 61.5 metres the hole intersected a post mineralisation dacite dyke. The drill hole then entered the andesite host rock that has been intruded by small tourmaline and hydrothermal breccias. The leached zone extended to 130.0 metres. From a depth of 130.0 metres, the drill hole intersected 502.0 metres @ 0.631 % Cu, 209 ppm Mo and 1.3 g/t Ag.

The upper part of drill hole was andesite host rock with strong stockwork and minor intervals of breccia with a post mineral dacite dyke from 184.0 metres to 198.8 metres. The mineralisation in this section was 54.0 metres @ 1.023 % Cu, 128 ppm Mo and 1.4 g/t Ag from 130.0 metres downhole depth and 37.0 metres @ 0.92 % Cu, 132 ppm Mo and 2.0 g/t Ag from a downhole depth of 198.8 metres. This high grade mineralisation is near surface and would be mined in the early years of any mine project.

At a depth of 235.8 metres the drill hole intersected the early diorite porphyry and intersected a total of 396.3 metres @ 0.566 % Cu, 233 ppm Mo and 1.2 g/t Ag. This intersection shows the importance identifying the early diorite porphyry and shows the good primary mineralisation in the central core of the project. From a depth of 632.0 metres to the end of drill hole at 725.5 metres the drill hole intersected tonalite porphyry which from 706.0 metres was cut by a hydrothermal breccia. The average grade over this section was 93.5 metres @ 0.362 % Cu, 566 ppm Mo and 0.7 g/t Ag. The substantially higher molybdenum values had a significant effect on copper equivalent grade.

This drill hole demonstrates the near surface higher grades in the supergene enriched andesite and the good grades that are associated with the early diorite porphyry. The drill hole confirmed the new geological model in this area demonstrating that the grades seen in the shorter historical drill holes extended to at least 700 metres below the surface.

 
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