VANCOUVER, Jan. 7, 2019 /CNW/ - Mirasol Resources Ltd.
(TSX-V: MRZ,
OTCPK: MRZLF)
(the "Company"
or "Mirasol") is pleased to provide an
exploration update for the Company's Gorbea property package in
Chile, that is subject to a
recently announced non-binding Heads of Agreement for an Option to
Farm-in with Newcrest International Pty Limited, a wholly owned
subsidiary of Newcrest Mining Limited (ASX: NCM;
"NCM" – see news release December 10,
2018). Gorbea comprises a claims package totaling 26,684 ha
(266.84 sq. km) including the Atlas and Titan Au+Ag+Cu projects,
within the highly prospective Mio-Pliocene mineral belt of northern
Chile (Figure 1).
- Subject to completion of ongoing due diligence, NCM has
committed US$4 million in exploration
expenditures, including a minimum of 3,000
m of drilling over the first 18 months of the Option
Period.
- Mirasol and NCM are advancing the drill permitting process and
upgrading the exploration camp ahead of a planned Q1 2019 restart
of exploration program that will initially focus on Atlas,
including detailed remapping mapping, alteration vectoring studies
and 60 line-km of CSAMT geophysics, and diamond core drilling.
- At Atlas, significant progress in geological understanding has
been derived from Mirasol's initial interpretation US$8 million of exploration data generated under
a recently terminated Joint Venture on the Gorbea package (see news
release April 13, 2018).
- Outcomes include recognition of a large breccias complex at
Atlas that is host to the better gold mineralization, a development
of a new alteration vectoring model suggesting that a number of
previous drill holes with anomalous Au+Ag assays may have been
terminated early above the potentially better mineralized zone and
recognition of new target areas where gold mineralization may occur
closer to surface.
The scale of the Atlas Au+Ag system, combined with the
relatively modest amount of exploration drilling to date
(10,499 m in 26 holes) and the range
of priority targets identified, highlights the project as a large,
under-explored HSE system, requiring further drill testing for
potential large tonnage bulk minable Au+Ag mineralization.
Atlas Prospect Update
Atlas is centered on the Dos Hermanas andesite to dacite
composition, lava, pyroclastic and dome field that hosts the
large-area, argillic to advanced argillic alteration and Au+Ag
system which characterizes the prospect. A combination of
assays from detailed stream sediment, soil and rock chip sampling
outline a precious metal "footprint" for the Atlas system of
approximately 14 sq. km.
A 53 sq. km conventional PDP electrical geophysical survey over
the central part of the Atlas project outlined large resistivity
anomalies along the NE oriented Cerro
Chaco fault zone and a 4.5 km diameter resistivity feature,
interpreted to delimit a large zone of stronger alteration and
silicification (Figure 2). The circular resistivity feature
contains the more significant bodies of breccia identified to date,
that host the better intersections of Au+Ag mineralization
encountered in drilling at Atlas. Only a small part of the
circular resistivity feature has been drill tested at this
time.
Recent radiometric age-dating of alunite alteration associated
with Au+Ag mineralization at Atlas has returned a determination of
20.6 ma ±0.6 ma1. Previous reported age-dating of
alunite from Mirasol's adjacent Titan Au (Cu) project, returned an
age date of 17.08 ma ±0.8 ma2. These ages
correlate with Lower to Middle Miocene mineralization events
recognized in the Maricunga Au+Ag+Cu Belt, located 150 km to the
south, which has produced significant metallic deposits, including
Pan Pacific Copper's Caserones mine (4.6 Mt Cu3) and
Kinross Gold Corporation's La Coipa High Sulfidation Epithermal
(HSE) Au+Ag district (5.5 Moz Au and
295 Moz Ag4; Figure 1).
Exploration at Atlas has shown Au+Ag mineralization is hosted
by:
1)
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Vuggy silica –
alunite structures, such as the 900 m long Atlas Gold Zone (AGZ)
where limited shallow drilling on the NW end of the structure
returned an anomalous intersection of 24 m at 0.18 g/t Au and 13.1
g/t Ag (Table 1). The un-drilled areas of higher-grade rock chip
sampling at the center and SE end of the AGZ trend returned assays
of up to 8.86 g/t Au and 44.7 g/t Ag and 16.75 g/t Au and 43.9 g/t
Ag, representing a target area for future drilling.
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2)
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Multiphase
phreatomagmatic and hydrothermal breccia bodies, that are seen at
various prospects across the Atlas project. Where
mineralized, these breccias are altered to quartz-alunite ±
jarosite ± dark hematite assemblage with vuggy silica textures. The
Steam Heated Zone (SHZ) breccia body hosts the best drill
intersections to-date, which reported 114.1 m at 1.07 g/t Au and
1.8 g/t Ag, including 36 m at 2.49 g/t Au and 3.1 g/t (Table
1). Brecciation is a key feature in many large HSE precious
metal deposits, where the breccia bodies act as both a conduit for
mineralizing fluids and a host rock for economic concentrations of
mineralization. The presence of widespread strongly altered
brecciation is considered one of the positive features of the Atlas
project.
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The SHZ Au+Ag mineralized breccia body has not been fully
delineated by drilling. As currently defined by 0.1 Au g/t cutoff,
the body has dimensions of 950 by 500
m, up to 120 m thick and is
open to depth and laterally in all directions. The SHZ
mineralization is located beneath a +230
m "barren" alteration cap. The presence of a barren
alteration cap at Atlas is a characteristic in common with other
recent HSE Au+Ag discoveries in the Mio-Pliocene belt, including
the Salares Norte deposit (3.7 Moz
Au and 49.5 Moz
Ag5) located 65 km to the south of Atlas,
undergoing a feasibility study by Gold Fields Ltd6.
Relogging of Atlas core holes by Mirasol along a NW-SE oriented
cross section through the SHZ body (Figure 3 and Figure 4) has led
to the following understanding of the prospect:
1)
|
The SHZ
mineralization may be located at progressively shallower depths to
the NW, toward a 700 m long gap in drilling, located between the
SHZ breccia zone and the AGZ. Drilling to test for shallower
potential high-grade mineralization in this "gap" is a
priority;
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2)
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The development of a
more detailed alteration / mineralization model for the SHZ breccia
mineralization. The model suggests that the better
mineralized zone has a low-grade outer "jarosite alunite cap" that
is recognized as either a jarosite-alunite matrix vuggy breccia or
a cream-coloured, jarosite-bearing silica veinlets or breccia
matrix. Au+Ag grade improves beneath the low grade "jarosite-
alunite cap" and at depth into the mineralized body.
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3)
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Mineralization is
deeply oxidized beyond the base of drilling to +370 m below
surface. Au+Ag is associated with a multiphase breccia with vuggy
quartz textures and coarse alunite ± jarosite and dark hematite
interpreted to be after original sulfide.
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The recognition of a low-grade jarosite-alunite cap, immediately
overlying the SHZ mineralization may be used to vector to zones of
potentially better Au+Ag grade at the SHZ. This highlights that a
number of drill holes in the SHZ and other breccia bodies (holes
CLATDH0016, 21, 23 and 25) at Atlas appear to have been prematurely
terminated in the low-grade cap, potentially not intercepting nor
testing the underlying potentially better-grade
mineralization. The presence of deep oxidation associated with
hematite replacement of original sulfide mineralization has also
been noted at the giant Veladero HSE gold mine (17.3 Moz Au and 195.5 Moz
Ag7) operated by Barrick
Gold in the Mio-Pliocene belt of Argentina, where deep oxidization of the
mineralization is attributed to a combination of late-stage heated
ground water collapsing into the system at the later stages of the
mineralizing system, as well as post mineral supergene processes.
Oxidation of the mineralization can be an indication of positive
metallurgical characteristics for gold recovery in HSE precious
metal deposits.
Stephen Nano, President and CEO
of Mirasol, has approved the technical content of this news
release. Mr Nano is a Charter Professional geologist and Fellow of
the Australasian Institute of Mining and Metallurgy (CP and
FAusIMM) and is a Qualified Person under NI 43 -101.
Under the terms of the pervious Gorbea Joint Venture (terminated
in April 2018), all exploration was
managed by the then joint venture partner. Pre-joint venture
exploration on the projects was managed by Stephen C. Nano, who is the Qualified Person
under NI 43-101. Exploration data generated from the previous
Gorbea Joint Venture program was reviewed and validated by Mirasol
prior to release. The technical interpretations presented here are
those of Mirasol Resources Ltd.
Mirasol applies industry standard exploration sampling
methodologies and techniques. All geochemical rock and drill
samples are collected under the supervision of the company's
geologists in accordance with industry practice. Geochemical assays
are obtained and reported under a quality assurance and quality
control (QA/QC) program. Samples are dispatched to an ISO 9001:2008
accredited laboratory in Chile for
analysis. Assay results from surface rock, channel, trench, and
drill core samples may be higher, lower or similar to results
obtained from surface samples due to surficial oxidation and
enrichment processes or due to natural geological grade variations
in the primary mineralization.
Forward Looking Statements: The information in this news release
contains forward looking statements that are subject to a number of
known and unknown risks, uncertainties and other factors that may
cause actual results to differ materially from those anticipated in
our forward-looking statements. Factors that could cause such
differences include: changes in world commodity markets, equity
markets, costs and supply of materials relevant to the mining
industry, change in government and changes to regulations affecting
the mining industry. Forward-looking statements in this release
include statements regarding future exploration programs, operation
plans, geological interpretations, mineral tenure issues and
mineral recovery processes. Although we believe the expectations
reflected in our forward-looking statements are reasonable, results
may vary, and we cannot guarantee future results, levels of
activity, performance or achievements. Mirasol disclaims any
obligations to update or revise any forward-looking statements
whether as a result of new information, future events or otherwise,
except as may be required by applicable law.
Neither the TSX Venture Exchange nor its Regulation Services
Provider (as that term is defined in the policies of the TSX
Venture Exchange) accepts responsibility for the adequacy or
accuracy of this news release.
1
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Ar/Ar radiometric age
date determination commissioned by Yamana Gold, performed at
Sernageomin Geochronology Laboratories in Santiago,
Chile.
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2
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Ar/Ar radiometric age
date determination commissioned by Mirasol Resources, performed at
Australian National University Argon Facility in Canberra,
Australia
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3
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S&P Global Market
Intelligence
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4
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S&P Global Market
Intelligence
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5
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Gold Fields Mineral
Resource and Mineral Reserve Supplement to the Integrated Annual
Report,2017.
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6
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Gold Fields.
(2017). Integrated Annual Report 2017.
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7
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S&P Global Market
Intelligence
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Additional
Explanatory Notes:
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*
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AuEq60 is the sum of the value of
gold and silver in a given interval represented as a gold
equivalent g/t value calculated via the formula: Au assay in g/t +
(silver assay in g/t ÷ 60)
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SOURCE Mirasol Resources Ltd.