The Company’s Australasia segment
consists of Sunrise Dam and Tropicana located in Australia. The Sunrise
Dam Gold Mine is located in the northern goldfields of Western
Australia, northeast of Kalgoorlie and south of Laverton. In the Sunrise
Dam Gold Mine, mining is conducted by contractors and the ore is
treated in a conventional gravity and carbon-in-leach (CIL) processing
plant, which is managed by the Company.
The Tropicana Gold Mine is located
in Western Australia, east north-east of Kalgoorlie and east of Sunrise
Dam. The Tropicana mine is a fly in fly out operation with village
facilities at the mine. The Tropicana joint venture (JV) is a joint
venture between AngloGold Ashanti Australia and Independence Group.
Mining occurs from two pits, Tropicana and Havana with a contractor
mining fleet. The mine is a fly in fly out operation, with a mine site
village and aviation services operated from Perth and Kalgoorlie. The
Tropicana JV includes approximately 3,000 square kilometers of tenure in
the Tropicana belt, with exploration programs seeking both satellite
extensions to the Tropicana Gold Mine and discoveries with standalone
potential.
This is mining operations AngloGold Ashanti in Australia :
Sunrise Dam Mine
Sunrise dam gold mine is located
220km northeast of Kalgoorlie and 55km south of Laverton in Western
Australia. Mining of the Crown Pillar at the base of the 490m deep pit
was completed in early 2014. By year-end, underground mining, which is
conducted by a contract mining company, was the primary source of ore.
Ore is treated via conventional gravity and carbon-in-leach (CIL)
processing plant which is owner-managed.
Gold ore at Sunrise Dam is
structurally and lithologically controlled within gently dipping
high-strain shear zones (for example, Sunrise Shear) and steeply dipping
brittle-ductile low-strain shear zones (for example, Western Shear).
Host rocks include andesitic volcanic rocks, volcanogenic sediments and
magnetic shales. Total ore reserves as of the end of 2009 were 1.73Moz.
Total mineral resources were 3.62Mozoz Au.
The mine comprises a large open
pit, which is now in its 11th year of operation, and an underground
mine, which began production in 2003. All the mining is carried out by
contractors and ore is treated in a conventional gravity and
carbon-in-leach (CIL) processing plant which is owner-managed.
Production for 2009 decreased 7% to
401,000oz, compared to 433,000oz for 2008.”Production for 2007 rose by
an expected 29% to hit a record 600,000 oz, compared to 465,000 oz for
2006.”The GQ zone in the open pit provided the anticipated large volumes
of high-grade ore, which accounted for the increase in annual gold
production. Some 157,000oz oz of gold came from the underground mine.
Progress was made in developing access to the Cosmo, Dolly and Watu
lodes, and 2,000m of underground capital development and 6,100m of
operational development were completed. A total of 67,400m of diamond
drilling was also completed.
Processing plant through put in
2009 increased to 3.9Mt from 3.8Mt due to plant productivity improvement
initiatives. Total cash cost increased to $646/oz from $531/oz (up by
17.8%).Despite rising costs, the greater volume of ore mined, and the
high value of the Australian dollar, the increase in production, due
primarily to the higher grade of ore mined, resulted in the decrease in
cash costs, year-on-year.
Sunrise expects to produce
381,000oz to 398,000oz of gold from the mine in 2010, with over
157,000oz produced from the underground mine. The underground production
is expected to increase for the next few years, with a peak annual
capacity target of over 200,000oz a year targeted for 2013.
Tropicana Mine
Tropicana gold mine is located
200km east of Sunrise Dam and 330km east-northeast of Kalgoorlie.
Tropicana mine is a joint venture between AngloGold Ashanti (70% and
manager) and Independence Group NL (30%), First gold was poured ahead of
schedule and on budget in September 2013, following development
approval in November 2010. The open pit operation features a large
scale, modern processing plant which uses conventional carbon-in-leach
technology and includes high-pressure grinding rolls for
energy-efficient comminution.
The Tropicana gold project
discovered in 2005, the project includes over 13,000km² of tenements
extending over 300km of the historic contact zone between the Yilgarn
Craton and the Albany Fraser provinces.”The project is a joint venture
between AngloGold Ashanti Australia (70%) and the Independence Group
(30%).”The project is a joint venture between AngloGold Ashanti
Australia (70%) and the Independence Group (30%).It is expected to
produce 470,000 to 490,000oz of gold annually over the first three years
of production and the average production during its mine life is
expected to be 330,000 to 350,000 ounce per annum.
The Tropicana deposit is
geologically different from other Archaean-aged, greenstone-hosted gold
deposits found in the Yilgarn Craton. The Yilgarn Craton was formed
following a period of intense tectonic and magmatic activity. It is
dominated by granitic igneous, volcanic and gneiss metamorphic rocks,
significant faults and intrusive basic dykes. The area is regionally
characterised by the extreme weathering that resulted in the formation
of a 100m thick regolith. “Mineralisation is up to 63m thick and has
been drilled to a down-dip length of 600m. It remains open at depth.”
Towards the west, the deposit is
dominated by Archaean and Proterozoic aged granitic, volcanic and
metamorphic rocks of the Yilgarn Craton.Younger sedimentary deposits
that unconformably lie over the Archaean and Proterozoic rocks dominate
the geology of the deposit towards the east.A north-south trough hosts
the deposits that also include alluvial, lacustrine and Aeolian
deposits. These deposits, ranging in thickness between 600m and 4,300m,
have been formed due to rock erosion and weathering, and stages of
marine incursion.
The deposit is comparatively
featureless and extends over a strike length of 4km. The three main
physiographic units of the deposit include sediment dominant zones,
ferruginous and siliceous duricrusts, weathered bedrock and colluvial
materials.The sediment dominant zones are characterised by Aeolian sands
that form extensive areas of plains and longitudinal dunes that are on
an average 10m in height and between 1.5km and 5km in length.The width
of the east-west oriented dunes ranges between 100m and 200m. The
interdune areas are between 250m and 800m wide. Due to their symmetrical
shape and presence of well developed vegetation, the dunes and sand
plains are considered to be relatively stable and mature. Between 1961
and 1970, the dunes exhibited no significant movement or modifications,
confirming the maturity of the landscape.
The sediment dominant zones also
host fluvial silts, halite deposits, and marine silts and clays that
correspond to the existing and palaeo drainage systems.Regional zones of
rock exposure are observed across the project area, typically along the
ridge surface and low breakaway features. These zones of exposure have
developed due to physical and chemical weathering of the less strong
kaolinitic areas.
Mineralisation is found within
Archaean aged high grade quartzofeldspathic gneiss rocks that are
associated with late biotite and pyrite alteration. It occurs as one or
two laterally extensive planar lenses with a moderate dip.Mineralisation
is up to 63m thick and has been drilled to a down-dip length of 600m.
It remains open at depth.
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