The Mt Gibson Project (Mt Gibson) is located 290km
northeast of Perth, in the Murchison Province of Western Australia,
and 100 km south of the world-class Golden Grove volcanic-hosted
massive sulphide (zinc-copper) mine owned by Oxiana Limited. Both Mt
Gibson and Golden Grove lie within the same volcano-sedimentary
sequence: the Yalgoo-Singleton Greenstone Belt.
Click here
to view a district geology map.
On
8 May 2007, Legend announced a Farm-In and Joint Venture
Agreement with Oxiana Exploration Pty Ltd, a wholly-owned subsidiary
of Oxiana Limited. Under the terms of the agreement, Oxiana may earn
a 75% interest in the project by funding $10 million of exploration
within 7 years, with Legend 25% free-carried to completion of a
bankable feasibility study and a decision to mine. Oxiana must spend
$1.2 million within 18 months before having a right to withdraw.
Technical input from Oxiana geologists at the
Golden Grove mine site, whose experience in the region and with this
style of mineralisation, will be extremely valuable in assisting
exploration activities at Mt Gibson.
Legend originally acquired Mt Gibson from Oroya
Mining Limited in November 2005, principally to pursue the untested
volcanic-hosted massive sulphide potential (zinc-copper-gold)
beneath the existing oxide gold pits.
Mt Gibson comprises 215km2 of exploration and
mining tenements, and a gold mine with associated plant and
infrastructure that is currently on care and maintenance. The mine
infrastructure is connected to the State Electricity Grid and
includes a:-
- 1 million tonne per annum mill,
- modern camp equipped to accommodate 160
employees and contractors,
- serviceable airstrip,
- established bore field.
Mt Gibson started life as a gold mining operation
in 1986 following the discovery of gold in outcropping laterite
(ironstone). Mining was conducted until 1998, with 95% of ore coming
from 14 open pits. The operation produced 870,000 ounces of gold
from 16.5Mt of ore at an average grade of 1.68 grams per tonne
(g/t).
The current gold resource (indicated and inferred)
is 8,754,000 tonnes at an estimated grade of 1.98 g/t gold (559,000
ounces of gold). This resource is not economic at the current gold
price.
A coherent zinc anomaly with a strike-length of
over 5 km has been delineated by approximately 7,000 shallow holes
(depth less than 100m) drilled to evaluate the near-surface gold
resource. This zinc anomaly is broadly coincident with the main line
of open pits.
Click here to view an aerial photograph of the Mt Gibson open pits
and the footprint of the near-surface zinc anomaly.
Only 21 holes have ever been drilled deeper than
300 metres vertically beneath the near-surface zinc anomaly, and
these were designed to test gold targets. Not all deep holes were
assayed for zinc, although zinc sulphide was observed in many. Of
the holes that were assayed for zinc, hole BGRCD-009 returned the
best result of 4m at 13.4% Zn from 775m to 779m.
The limited historical drilling has defined a
zinc-rich position within the mafic-felsic volcanic sequence.
Exhalative, boron-rich seafloor sediments, mainly of volcanogenic
chemical sedimentary origin, are inferred to have formed at the same
time as the zinc mineralisation. The near-surface oxide gold
mineralisation is interpreted, in part, to reflect oxidised
volcanic-hosted massive sulphide, similar to the situation at Golden
Grove.
Between June and August 2006, Legend completed an
eight hole deep diamond drilling programme totalling 5,978.6m,
targeting volcanic-hosted massive sulphide zinc-copper
mineralisation over a 6km strike length. All drillholes intersected
sub-economic zinc sulphide mineralisation, associated with laminated
cherty metasediments intercalated with mafic and intermediate
volcanics. The
predictive geological model developed as a results of this
drilling has identified important trends to new opportunities within
this large base metal system.
Click here to view the
current Mt Gibson mineral resource summary.
LINKED DIAGRAMS
Mt Gibson
District Geology Map
Mt Gibson
Project Area Map
Mt Gibson Aerial photograph of open pits and footprint of
near-surface zinc anomaly
Mt Gibson
Predictive Geological Model.
