23 December 2009
AIM & PLUS:MARL
Inaugural Drilling at Buenaventura and Perro Chico, Northern Chile, Indicates
Potential for Iron Oxide Copper Gold Mineralisation.
Mariana Resources Ltd (‘Mariana’ or ‘the Company’), the AIM quoted exploration
and development company focussed in Argentina and Chile,announces positive
results from initial drilling programmes at its Buenaventura and Perro Chico
Iron-Oxide-Copper-Gold (‘IOCG’) projects in the prospective Atacama Region in
northern Chile. The drilling, which indicates potential for IOCG
mineralisation, comprised 2280m of reverse circulation (‘RC’) drilling and 969m
of diamond core drilling on three holes at the Buenaventura project and five
holes at the Perro Chico project.
Highlights
* Evidence of IOCG style alteration with varying intensity of mineralization
is present in all eight drill holes, and whilst well-mineralised centres
have yet to be located, the size of the two systems suggest concealed IOCG
mineralisation may be present.
Buenaventura Project:
* * Cerro Berta prospect – drilling indicates the 4x1km silica-albite
alteration cap is strongly anomalous in copper and may be overlying an
IOCG system.
* Cerro Brecha prospect – indications of IOCG mineralization were
intersected to a depth of 650m on the flank of magnetite-rich andesite
breccia body.
* Perro Chico Project – all holes which were designed to test gravity
anomalies intersected indications of IOCG mineralisation and associated
alteration.
* * Belleza prospect – Drill hole PC-DDH-01 intersected a 40m mineralised
zone averaging 0.56% Cu and an underlying 250m zone of intense pyritic
mineralisation to the end of hole at 296m – the mineralised zone is open
to the north and northwest.
* An international mining company based in the US has been granted a three
month exclusive period to negotiate a joint venture farm-in for follow-up
exploration at the Buenaventura and Perro Chico. Negotiations include a
possible alliance focussing on wider IOCG exploration potential in Chile.
Mariana Managing Director John Sutcliffe said, “These first drilling results
confirm the IOCG potential of the Buenaventura and Perro Chico Projects. The
current negotiations for a joint venture to follow up exploration at
Buenaventura and Perro Chico, together with a possible alliance focussing on
wider IOCG exploration potential in Chile, is a very positive development for
Mariana which could substantially accelerate its IOCG programme.”
Buenaventura Project (50km NNE Copiapo)
The 44 sq km Buenaventura Project, which islocated in the highly prospective
Atacama Fault Zone, is under a joint venture agreement with Sociedad Minera
Contractual Buenaventura. Under the agreement, Mariana can earn a 51% interest
by expenditure of US$3million over three years from April 2008, and up to 80% by
completing a bankable feasibility study within a further four years. Mariana’s
current programme covers two specific target areas, namely the Cerro Berta and
Cerro Brecha prospects.
AtCerro Berta, an area not previously drilled, a large silica-albite alteration
zone was targeted by two RC drill holes, located 1km apart, in the northern
portion of the area. Both holes intersected strong alteration typical of IOCG
systems, including magnetite, hematite and anomalous copper-gold. Hole BV-RC-01
was drilled to 500m and encountered anomalous copper and gold from near surface
to 440m, with the highest assays returning:
* 6m @ 0.32% Cu plus 0.44g/t Au from 374m.
The second hole (BV-RC-02) was terminated at 358m due to technical problems;
however anomalous copper was encountered throughout, with the bottom 90m
averaging 415 ppm Cu and 23 ppb Au.
AtCerro Brecha, a single deep hole tested the upper part of an anomaly
interpreted to be dense iron oxides (from 3D modelling of the 2008 gravity
survey) below known shallow IOCG type copper/gold mineralisation. BV-RD-01 was
drilled as a pre-collared diamond hole to 651m. It intersected strong hematite
and minor magnetite (10-20%) from 180-234m with anomalous copper (120-1500ppm)
from 210-272m. In the cored section, the rock is mainly an andesitic breccia
with IOCG style alteration. Anomalous copper mineralisation (chalcopyrite) was
intersected from 454-490m (120-1500 ppm Cu). Andesite breccia with associated
magnetite was intersected from about 490m to the bottom of hole and may be the
source of the gravity anomaly. While no economic intercepts were made,
preliminary interpretation is that a potentially large IOCG system could be
present in the vicinity.
Perro Chico Project (67km SSW Copiapo)
Three distinct zones, all related to gravity anomalies, were drilled at the
Belleza, El Sauce and Pancho prospects. Mariana can acquire 100% of the 549
hectare property by making option payments totalling US$205,000 with a buy-out
of US$600,000 at the end of the 39-month option period in December 2010. The
Company also has a surrounding 6,600 hectares under application.
AtBelleza, core hole PC-DDH-01 intersected a 40m zone of strong copper-gold
mineralisation and an underlying 250m long zone of intense pyritic
mineralisation, up to the end of the hole at 296m. Best results were:
* * 40m @ 0.56% Cu from 6m
Including
* * 22m @ 0.81% Cu + 0.15 g/t Au from 6m.
The hole was collared 100m north of PC-RC-01 to target down-dip of stratabound
copper mineralisation exposed in shallow artisanal mining workings.
Mineralisation, consisting of copper oxides and sulphides, is hosted by skarn,
sedimentary and andesitic lithologies. Alteration includes calcite, magnetite,
hematite, chlorite-epidote and intense pyritisation. Anomalous copper-gold and
high iron are present from the collar to 84m down-hole.
Also at Belleza, an RC hole PC-RC-01, 100m south of PC-DDH-01, tested a nearby
gravity anomaly and the southern extension of the known copper-gold
mineralisation. Andesites, with some high iron oxides and anomalous copper,
were intersected. The southern extension of the Belleza mineralisation was not
intersected and is inferred to have been faulted off to the south. The
mineralisation intersected in hole DDH-01 is, however, open to the north and
northwest of the Belleza workings.
AtPancho, 2km south-southwest of Belleza, hole PC-RC-02 tested the best gravity
anomaly under 66m of gravel cover. It intersected a sedimentary sequence with
weak to moderate IOCG style alteration with anomalous copper from 66m to end of
hole at 388m. The highest copper sections were:
* 6m @ 0.5% Cu from 106m (including 2m @ 1.1% Cu)
* 8m @ 0.1% Cu from 142m
* 8m @ 0.2% Cu from 354m.
AtEl Sauce, located 2.5km east of Pancho and 3km southeast of Belleza, two holes
were drilled to test a gravity anomaly. Hole PC-RC-03 intersected andesite
breccias with minor calcareous shales and IOCG style alteration. Magnetite with
some minor chalcopyrite and pyrite were present. Anomalous sections included:
* 44m @ 598 ppm Cu from 230m.
Hole PC-DDH-02 was similar with highest copper values as follows:
* 58m @ 406 ppm Cu from 54m.
Further Exploration
The Buenaventura and Perro Chico Projects represent very large and strong IOCG
systems and the results of this first drilling campaign encourage further
exploration. Ground magnetic and other geophysics will be considered at both
projects prior to the next stage of drilling.
Furthermore, an international mining company based in the US has been granted a
three month exclusive period to negotiate a joint venture farm-in for follow-up
exploration at Buenaventura and Perro Chico, and a possible regional programme.
A formatted PDF version of the release, including drill hole locations, is
available on Mariana’s website under Latest News:
www.marianaresources.com <
http://www.marianaresources.com/>
For further information:
John Horsburgh (Chairman) Mariana Resources Ltd +61 2 94374588
John Sutcliffe (MD) Mariana Resources Ltd +593 99 808080
Rob Adamson RFC Corporate Finance Limited +61 2 9250 0041
(Nomad)
Will Souter RFC Corporate Finance Limited +61 2 9250 0050
(Nomad)
Joe Lunn (Analyst) FinnCap (Broker) +44 20 7600 1658
Matthew Robinson FinnCap (Broker) +44 20 7600 1658
Felicity Edwards St Brides Media and Finance +44 20 7236 1177
Ltd (PR)
Hugo de Salis St Brides Media and Finance +44 20 7236 1177
Ltd (PR)
Additional Information
IOCG background
IOCGs are economically important complex copper deposits hosted within
hydrothermal systems with associated iron oxides and can be enriched in gold,
silver, uranium and rare earths. They display strong hydrothermal alteration,
brecciation, important regional and local structures and geophysical expressions
in the form of prominent magnetic or gravity anomalies. Alteration varies from
deposit to deposit but is usually a mix of sodic-calcic (albite-epidote) and
potassic (k-felspar). Deeper albite-magnetite alteration can be overlain by
silica-k-felspar-sericite in the upper zones of an IOCG system. The major IOCG
mines are in Australia (South Australia, Queensland), northeastern Brazil and
northern Chile. The Atacama Fault Complex of northern Chile is considered to be
one of the world’s most prolific IOCG belts, hosting Freeport’s giant Candelaria
copper deposit.
Qualified Person
The exploration programme is being directed by the Chile Exploration Manager, Mr
Walter Espinosa under supervision of Managing Director Mr John Sutcliffe.
Exploration information in this announcement has been compiled by John
Sutcliffe who is a Fellow of the Geological Society of London, a Chartered
Engineer and a Member of the Institute of Mining and Metallurgy. Mr Sutcliffe
has sufficient experience relevant to the style of mineralisation and types of
gold deposit under consideration and to the activity that he is undertaking to
qualify as a Competent Person as defined in the JORC Code.
Quality Assurance/Quality Control
All technical information for the Company’s Argentina projects is obtained and
reported under a quality assurance and quality control (QA/QC) programme. All
samples are collected under the supervision of the Company geologists and
dispatched via commercial transport to ALS Chemex laboratories in Santiago de
Chile. ALS Chemex's quality system complies with the requirements for the
International Standards ISO 9001:2000 and ISO 17025: 1999. Samples returning
greater than 10 g/t gold and/or greater than 100 g/t silver are assayed using
gravimetric analyses. Systematic assaying of sample duplicates and commercially
prepared standards and blanks is performed for analytical reliability.
[HUG#1366826]