Antucoya West Geophysics Update
Chile’s star in copper-gold
ASX ANNOUNCEMENT
24 January 2014
ESTRELLA RESOURCES LIMITED
ACN 151 155 207
AUSTRALIAN REGISTERED OFFICE:
Level 7, 15 Castlereagh Street
Sydney NSW 2000 Australia
CONTACT DETAILS:
Telephone: +61 2 9993 4478
Facsimile: +61 2 9993 4433
Email: admin@estrellaresources.com.au
CHILE OFFICE:
Pedro de Valdivia 555 Piso 11 (Oficina
1101) Santiago, Chile
ASX CODE: ESR
For further information please contact:
Dr. Jason Berton MAusIMM
Managing Director
Tel:
Mob:
Fax:
Email:
+61 2 9993 4478
+61 402 199 166
+61 2 9993 4433
jb@estrellaresources.com.au
Antucoya West Geophysics Update
HIGHLIGHTS
Identifies a 7 km2 high chargeability zone at Antucoya West Prospect
within Project Altair being less than 2 km west of Antofagasta
Minerals’ Antucoya porphyry deposit.
Geophysical surveys define extensive anomalous chargeability
responses potentially associated with sulphide mineralisation.
Elevated chargeability responses observed at over 35% of the
observation points.
1.
Overview
Estrella Resources Limited (ASX:ESR) (Estrella or Company) is pleased to
report that the recent Induced Polarisation (IP), Resistivity (Res) and
Magnetotelluric (MT) surveys at the Antucoya West Prospect within Project
Altair conducted by Southern Rock Geophysics (SRG) has identified a 7 km2
high chargeability zone less than 2 km east of Antofagasta Minerals’
(Antofagasta) Antucoya porphyry deposit (Antucoya Deposit).
Figure 1. The VIP survey results show high chargeability responses in the
southeast of Antucoya West Prospect being less than 2 km to the west of
Antucoya Deposit.
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2.
Vector Induced Polarisation results
SRG performed a Vector Induced Polarisation (VIP) survey over the Antucoya West Prospect area (Figure 1),
totalling 80 observation stations. The objective of the survey was to characterize the distribution of the
chargeability and resistivity parameters to define potential response characteristic of disseminated porphyry
style sulphide mineralisation.
In SRG’s opinion, general responses over 25 msec are characteristic of sulphide mineralisation in volcanic
and intrusive geological environments similar to elsewhere in the district.
There are high chargeability responses over 25 msec evident in the southeast of the survey area of the
Antucoya West Prospect (Figure 1), trending towards the north and open in directions out of the current
survey coverage.
In Figure 2, the VIP responses have been overlaid on the airborne magnetics for the Antucoya West Prospect
to qualitatively assess correlations between the two datasets. The most noteworthy characteristic about the
now identified anomaly (Figure 2) is that it trends toward the west along the known magnetic anomaly that
trends west-northwest to northwest and extends over Antofagasta’s Antucoya Deposit, which is located less
than 2 km to the east.
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Figure 2. The VIP survey results for Antucoya West superimposed on the Analytic Signal of the first Vertical
derivative (ASVI) total magnetic image for Altair Project. The high chargeability zone in the southwest of
the VIP image displays a near 1:1 relationship with the west-northwest trending ASVI magnetic anomaly.
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3.
Magneto-Telluric and Resistivity inversion results
MT and resistivity data was also used by SRG to derive a 1D resistivity inversion model for each VIP station.
The 1D models are then interpolated into a 3D block model from which depth slice figures were produced to
analyse the results. Figure 3 shows the 3D depth slice for 300 metres beneath the surface and is provided as
a representative example of the conductivity responses at depth. SRG concluded that the south and
southeastern areas of Antucoya West results indicate deeper conductivity to a depth of at least 900 metres.
The conductivity zone identified by the MT-resistivity inversion model is compatible with the chargreable
zone found in the VIP survey (Figure 3).
Figure 3. Magneto-telluric and resistivity inversion model depth slice for 300 metres below the surface
displays conductive zones in the south and southeast of Antucoya West.
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4.
Next Steps for Antucoya West
Estrella is currently incorporating hyperspectral data image processing and ground reconnaissance of
identified geological alteration areas of interest to constrain the 7 km2 of prospective surface area. Infill
geophysics is also in planning to assist in further identifying fault structures and zones of high strain which
are more likely to host mineralisation. Once these activities have been completed, Estrella expects to test
the area for mineralisation with mechanical drilling.
5.
Antucoya porphyry deposit
The Antucoya porphyry project (owned by Antofagasta Minerals PLC) is currently being developed (CAPEX
US$ 1.9B), will have a 20 year mine life and is on schedule to produce its first copper cathode production in
April 2015. The Antucoya mine will be a conventional open pit with heap-leaching using sea water and
solvent-extraction electro-winning processing of the ore to produce 85,000 tpa of copper cathode for the
first 5 years.
Figure 4 Aerial view of the Antucoya porphyry project construction (source: Antofagasta Minerals PLC –
Antucoya Site Visit presentation http://www.antofagasta.co.uk/investors/reports-andpresentations/year-2013).
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6.
Commentary
Commenting on the exploration success at Colupo, Estrella's Managing Director, Dr. Jason Berton, said:
“The Vector IP results have neatly ‘fit’ into the anomalous magnetic trend that extends across
Antofagasta Minerals’ Antucoya porphyry deposit and confirms our opinion that the Antucoya porphyry
deposit is not an isolated occurrence and is likely to be part of a mineralised porphyry system that trends
into the Antucoya West area.
Estrella’s Antucoya West Project is a large prospective area and we are progressing quickly to define
exploration targets within the area that will be drill tested.”
Competent Person’s Statement
Exploration information in this announcement is based upon work undertaken by Dr. Jason Berton, the Managing Director and a fulltime employee of Estrella Resources Limited whom is a Member of the Australasian Institute of Metallurgy and Mining (AusIMM). Dr
Berton has sufficient experience that is relevant to the style of mineralisation and type of deposit under consideration and to the
activity which he is undertaking to qualify as a ‘Competent Person’ as defined in the 2012 Edition of the ‘Australasian Code for
Reporting of Exploration Results, Mineral Resources and Ore Reserves’ (JORC Code). Dr Berton consents to the inclusion in this
presentation of the statements based on his information and context in which they appear.
About Estrella Resources
Directors and Management
Estrella Resources Limited is an ASX listed, Chilean
focused copper-gold exploration company. Estrella
has a number of exploration projects in Chile. With
a highly experienced board, a strong operational
and management team and a sole focus on Chilean
copper and gold projects, the Company is well
positioned to develop its projects and add value for
shareholders.
Dr. Jason Berton
Managing Director
ESTRELLA RESOURCES LIMITED
ACN 151 155 207
ASX CODE: ESR
Gavin Solomon
Non-Executive Chairman
ORDINARY FULLY PAID SHARES:
96,601,000
Julian Bavin
Non-Executive Director
UNLISTED OPTIONS:
11,130,000
Simon Kidston
Non-Executive Director
Justin Clyne
Company Secretary
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