australia's identified mineral resources 2004 - Geoscience Australia

AUSTRALIA’S IDENTIFIED MINERAL RESOURCES 2004
‘life of mine’ plan by 2006. Early studies have shown that Olympic Dam could produce up to 350 ktpa
copper by extending underground mining and in excess of 500 ktpa copper by developing an open
pit mine on the southern ore body additional to existing underground operations.
A major drilling campaign continued during 2003 to explore and delineate the southern orebody,
the results of which will be used to evaluate the various mining options as part of the study.
Mt Isa (Qld): Xstrata Plc reported that 2003 production was impacted by difficult mining
conditions during the first half of the year with annual mine production down by some 7% on
2002. A significant increase in underground development at both the X41 and Enterprise mines
(at Mount Isa) is aimed at countering anticipated falling grades by increased production in 2004.
Whim Creek (WA): Straits Resources announced that it would develop the deposit near Port
Hedland with first production from the open pit expected in late-2004. Straits will use the plant and
equipment from its former Girilambone mine in New South Wales. It is expected that over 50 kt of
copper will be produced over a four year operational life.
Tritton (NSW): Tritton Resources was floated by Straits Resources to develop the Tritton copper
project, near Girilambone, based on a total resource of 14 Mt at 2.7% Cu. The operation will initially
mine 660 ktpa of ore rising to 900 ktpa in the fifth and following years. Mining will be by
underground methods with some ore supplied from a small open pit. Development costs for the
project are expected to be about $38.5 million.
Mt Gordon (Qld): Aditya Birla Group, one of India’s largest business houses purchased Mt Gordon
from the Western Metals receiver in a deal that avoided shut down and preserved the bulk of the
workforce and supplier arrangements.
Nifty (WA): Aditya Birla Group is determining the viability of a 2.5 Mtpa underground development
that will increase production from 27.5 ktpa to 100 ktpa. Previous owner, Straits Resources sold the
project to Birla earlier in 2003 for $148.2 million.
Lady Annie (Qld): Buka Minerals completed a pre-feasibility study for a 13 ktpa heap leach solvent
extraction-electrowinning operation based on reserves of 4.4 million tonnes grading 1.8% Cu
containing 79 kt of copper and costing $30 million to develop.
Other developments included:
■
■
Ivanhoe Mines acquired all the mining and exploration leases held by Selwyn Mines, and
the copper smelter at Port Kembla (capacity of 120 ktpa copper) owned by a Japanese
consortium, closed during the year because of lower copper prices.
Diamond
Diamond is composed of carbon and is the hardest known natural substance, but a sharp blow can
shatter it. It also has the highest thermal conductivity of any known material at room temperature.
Diamonds are thought to form 150–200 km below the Earth’s surface at high temperatures
(1050–1200°C) and pressures (45–55 kilobars). They are carried to the surface within kimberlite and
lamproites that intrude through the crust. These intrusions form narrow cylindrical bodies, called
‘pipes’ and only a very small proportion have significant diamond content. When pipes are eroded,
liberated diamonds may accumulate in alluvial deposits. Diamonds may be found far from their
source as their hardness allows them to survive multiple episodes of erosion and deposition.
29
The quality of diamonds is subdivided into gem, near gem and industrial categories. In rare cases,
up to 90% of diamonds in a deposit are of gem quality but most economic deposits contain 20 to
40% gem quality diamonds. Current uses for diamond include jewellery, stone cutting and polishing,
computer chip manufacture, machinery manufacture, mining and exploration, construction and
transportation services. A large proportion of industrial diamond is manufactured and it is also
possible to produce synthetic diamonds of gem quality.