Golden Arrow's prospect generator activities are focused on identifying,
acquiring and advancing precious and base metal projects with the
potential for world class discovery. Golden Arrow seeks to leverage the
Company's exploration exposure by attracting partners to fund work on
its high quality mineral projects, such as Mogote. For details on joint
venture opportunities, please
contact our Project Marketing Coordinator.
Golden Arrow's Mogote copper-gold-silver porphyry/epithermal project is
centrally-located in the prolific Vicuna District of northern San Juan
Province which includes NGEx Resources Inc's Josemaria copper-gold
deposit in Argentina and Goldcorp Inc./New Gold's El Morro gold-copper
porphyry deposit in Chile. Mogote covers multiple large
porphyry/epithermal targets and hosts classic Andean-type porphyry
copper-gold mineralization and related alteration associated with a
Miocene diorite porphyry intrusive system.
Mogote is located 350 kilometres northwest of San Juan City, San Juan
province, Argentina and adjoins the international border between Chile
and Argentina. Access to the property is possible from either Chile or
Argentina, but because special arrangements need to be made to cross the
international border where there are no established crossing points,
practical access is currently from the Argentina side. The subject
property is located in moderate to steep mountainous terrain on the
upper eastern slopes of the Andean Cordillera, with elevations ranging
from 4,300 to 5,500 metres above sea level.
This Mogote project area is considered to be the southern extension of
the Maricunga Gold-Copper Belt as well as the geologic bridge to the El
Indio Gold Belt to the south. World-class porphyry and epithermal
deposits which occur within these mineral districts include: El
Indio--Tambo (10 million ounces gold production, reserves and resources;
Jannes et. al., 1999), Pascua--Lama--Veladero (27.9 Moz Proven and
Probable gold equivalent reserves- Barrick Gold Corporation website
04/13) and Marte/Lobo (6.1 million ounces of Proven and Probable gold
reserves; Kinross Gold Corporation website 04/13).
Mogote lies within a regional belt of hydrothermally altered rocks
referred to as the 'Faja de Potro'. Alteration is related to high-level
intrusions and subvolcanic hydrothermal activity, with potential for
porphyry copper-gold, as well as precious metal epithermal deposits.
The region is underlain by extensive volcanic units and related
intrusives of the Middle Miocene and older, making the area particularly
attractive for mineral exploration. Regional mapping indicates that
the Mogote Property is underlain by Oligocene -- Early to Middle Miocene
age volcanic rocks of the Penas Negras and Dona Ana Formations.
Property Geology and Mineralization
The property is underlain by basement rocks of the Permian age Choiyoi
Group, which are faulted against and overlain by Tertiary age volcanic
rocks. Alteration at Mogote is characterized by early porphyry style
alteration with a later epithermal alteration overprint. Age dating of
both the porphyry and epithermal style alteration would be required to
determine the possible genetic relationships between both styles of
alteration and mineralization. There are three distinct porphyry
centers at Mogote, related to a ~15Ma diorite porphyry system; Filo
Este, Filo Central, and Zona Colorida.
The dominant alteration associated with mineralization is a potassic
assemblage of biotite, magnetite, quartz, and potassium feldspar.
Mineralization is also found associated with propylitic alteration
consisting of chlorite, quartz, magnetite, and calcite. This alteration
is hosted in microdiorite, fine-grained diorite, and Tilito breccias,
and the grade of hypogene mineralization is largely a function of quartz
vein density. Quartz veins consist of 2-10 millimetre wide A-type
veins that are continuous over several meters of length and are
generally stockwork in nature. A-type quartz veins are 1-10 millimeter
veins of magmatic/hydrothermal quartz with disseminated magnetite,
biotite, chalcopyrite, pyrite, and bornite. They generally form
stockworks, but locally are sheeted and range in density from one per
metre to four per centimetre. Hypogene sulfide mineralization consists
largely of chalcopyrite, bornite, and pyrite with local hypogene
alteration of copper sulfides to digenite, chalcocite, and covellite.
Surface oxidation of chalcopyrite, bornite, and pyrite has resulted in
various sulfates, carbonates, and iron oxides that include antlerite,
brochantite, malachite, azurite, goethite, hematite, and jarosite.
Overprinting the potassic alteration at both Filo Este and Filo Central
and throughout the Mogote Property is weak to moderate
anhydrite-carbonate veins that are commonly oxidized to gypsum within
the zone of surface oxidation.
The Filo Este porphyry center is an exposed potassic and propylitic
altered core with moderate copper-gold-silver mineralization hosted in
15 Ma microdiorite and diorite and 23.1 Ma Tilito breccias. The area of
mineralization has been defined by talus and rock sampling, trenching,
ground magnetics, time domain IP, and 1,475 metres of core drilling.
Surface geochemistry defines a +500 ppm copper and +200 ppb gold anomaly
over 1700 metres of strike length in an east west direction and 700
metres width north to south and extends toward the Argentine border with
Chile. Samples were collected on roughly a 50 metre spacing.
The Filo Central anomaly has at least two exposed areas of potassic
alteration hosted in microdiorite, fine-grained diorite phases, and
Tilito Formation breccia. Alteration throughout the anomalous area
consists of mixed potassic and propylitic, and locally moderate to
strong sericite-pyrite. The sericite-pyrite alteration has strong
structural control and is at times epithermal in nature with weakly
developed vuggy silica and alunite. The +500 ppm copper-in-talus-fines
extends for over 3.5 kilometres in a northwest direction along Filo
Central ridge and is up to 900 metres wide. This anomalous zone also
contains high levels of gold (up to 4.5 ppm), molybdenum (up to 260
ppm), silver ( up to 26.7 ppm), and locally arsenic (up to 468 ppm).
Sampling coverage to date is roughly on 100 metre centres.
The Zona Colorida porphyry center is located south of the Macho Muerto
fault and exposes the upper advanced argillic and quartz-sericite-pyrite
levels of a possible diorite porphyry mineral system. Alteration is
hosted in Tilito formation and medium grained diorite porphyry. Limited
talus fines and rock chip sampling and limited geologic mapping have
defined the Zona Colorida as a porphyry center that has undergone strong
sericite-quartz-pyrite alteration. Sampling and to date has yet to
demonstrate near surface potential for either porphyry copper-gold or
epithermal gold-silver mineralization, however the zone has been
interpreted to represent the steam-heated cap to a buried epithermal
- Early 2000 - IMA Exploration Inc. (now Kobex Minerals Inc.)
carried out several surface exploration programs on the Mogote property.
- Late 2003 - After the property was optioned by Golden Arrow a
detailed program of surface mapping and sampling and geophysics, and
trenching was carried out. This work confirmed the presence of a major
mineralized porphyry beneath the Filo Este zone of potassic and
propylitic alteration. Ground magnetics suggest a shallow porphyry
system underlying Filo Este ridge with strong magnetite alteration that
covers an area of at least 1.5 kilometres by 800 meters. A 600 metre
trench was excavated over the Filo Este zone of potassic alteration and
encountered 510 meters of continuous mineralization that averaged 0.196%
copper and 0.331 ppm gold.
- March 2004 Drilling - Filo Este
In March 2004, the Company carried out a 1,475 metre, five hole diamond
drill program and conducted further geological mapping and talus fine
sampling on the northern part of the Mogote Property. The drilling
tested a portion of the Filo Este porphyry target to a depth of up to
495 metres over a strike length of 860 metres and a width of
approximately 250 metres. Hole MOG-04-1 had to be abandoned at 71.6
metres and hole MOG-04-1A was drilled from the same location to target
depth. Highlights of the drill results are provided in table form
In addition to the drill program, regional surface work was carried out
on Filo Central and other targets in March 2004 to advance them to the
drill-ready stage. This work comprised detailed mapping, additional
step-out talus sampling and road/trench construction. Talus fine
sampling on the Filo Central target, defined by a strong magnetic
signature coextensive with highly anomalous surface geochemistry, has
now extended the surface copper-gold geochemical anomaly of greater than
0.1 ppm Au and 500 ppm Cu to 4,000 x 800 metres. Within this anomaly is
a 600 x 400 metre area of greater than 0.5 ppm.
- January-February 2005 Drilling -- Filo Este and Filo Central
Between mid-January and early February 2005 the Company completed a
Phase II 2,577 metre 9-hole RC drill program on the Mogote Property. Of
the nine holes, four were found to contain significant gold-copper
mineralization hosted in porphyry or in metamorphosed volcanic sediments
at the margin of porphyry.
All the Phase II drill holes were sited to test strong areas of
potassic-altered intrusive porphyries within the Filo Este and Filo
Central anomalies, defined by strong magnetics, highly anomalous copper
and gold geochemistry and surface alteration. Five holes were completed
on Filo Este over an east-west strike extent of 1.4 kilometres spanning
a north-south distance of 720 metres. The remaining four holes were
spaced out over 1.6 kilometres of strike length along Filo Central. All
drill holes were located on the Argentina side of the international
The significant intercepts include:
The Phase I and II drill programs was carried out under the supervision
of project geologist Steven K. Jones, M.Sc., C.P.G., a Qualified Person
under NI-43-101 guidelines. Assays for the drilling program were
performed by Alex Stewart Labs, Mendoza, Argentina, an internationally
recognized assay service provider.
All significant intercepts were from holes on Filo Este. Drill holes
MOG-7, 8, and 12 are all located in the northwest corner of the property
and in the northwestern portion of the Filo Central anomaly. These
holes were all hosted in, or spatially related to, a newly mapped
occurrence of fine-grained intrusive porphyry that is interpreted as an
early porphyry phase that typically alters to potassic or intermediate
Copper and gold mineralization in the drill holes was related to
potassic quartz-biotite alteration and directly related to early vein
density and local silicification. Vein hosted and disseminated sulfides
include chalcopyrite, pyrite, and minor bornite.
On September 9, 2010 the Company announced that it had entered into an
option agreement with Vale Exploracion Argentina, S.A. ("VEASA"), a
wholly-owned subsidiary of Vale S.A. ("Vale"). On December 7, 2012, the
Agreement was amended to extend the option period by one year.
During the first year program Vale completed detailed lithological and
alteration mapping on the Zona Colorida and Stockwork Hill zones, rock
sampling, petrography and PIMA work as well as 40 lines of geophysics
including 32 km of IP, 180 km of ground magnetics, 51 km of radiometrics
and 170 km of digital GPS surveying. The geophysical surveys covered
the central and a portion of the southern Mogote property.
On June 18, 2012, the Company announced the results of Vale's 8 hole,
3,695 m drill program that was completed during Q1 and Q2, 2012. Vale's
drilling confirmed the existence of a copper porphyry system below the
large and prominent steam leached alteration zone at the Zona Colorida.
Five widely spaced drill holes were completed at Zona Colorida with an
average depth of 575 m. All holes encountered a multi-phase porphyry
system with long intervals of intense quartz-pyrite vein stockworks and
classic porphyry alteration, containing low grade copper mineralization.
The best drill intercept recorded was in hole MGT DH5, from 68 m to 118
m (50 m interval) that averaged 0.224% copper.
In January 2013, Vale commenced a 10-hole, 4,653 m drill program on the
Mogote project. The drill program targeted both porphyry copper-gold and
precious metal epithermal mineralized zones identified during Vale's
2011-12 field program. On July 24, 2013, the Company announced that
Vale provided notice of its decision to terminate the option agreement.