australia's identified mineral resources 2004 - Geoscience Australia

AUSTRALIA’S IDENTIFIED MINERAL RESOURCES 2004
the last coin in general use to contain silver (80% silver, 20% copper). Silver is mined and produced
mainly as a co-product of lead, zinc and, to a lesser extent, copper and gold. Today, photographic
paper and film, followed by the electronics and jewellery/tableware industries are the most important
users of silver. Demand for silver as an anti-bacterial agent is likely to double over the next few years
as its use increases in water treatment (as an ioniser with copper in domestic swimming pools) and
for biocide and bacteriostatic activity in plastic and textiles formulations. Silver based biocides are
also being tested as a replacement for arsenic-based preservatives in wood treatment.
Resources
ZINC
Australia’s EDR for zinc increased by 5% to 34.8 Mt in 2003. Queensland remained pre-eminent, its
EDR increasing from 17.81 Mt to 20.5 Mt and increased its share of the total EDR to 62%. The rise
in EDR was predominantly affected by the reclassification of resources at Century and Mt Isa while
other resources remained steady. The Northern Territory at 9.9 Mt had the second largest EDR and its
share of national EDR was 28.5% compared to 31.1% in 2002. New South Wales had the third largest
EDR with 2.8 Mt (3.0 Mt in 2002). This decrease was primarily due to depletion of resources through
production. Western Australia’s EDR fell again to 0.9 Mt, (1.5 Mt in 2002), mainly due to production
depleting Golden Grove resources, while Victoria remained unchanged at 0.4 Mt. Tasmania’s EDR
increased to 0.3 Mt (0.26 Mt in 2002), due to an increase at Rosebery.
Paramarginal demonstrated resources of zinc fell by 29% from 8.79 Mt to 6.26 Mt due to
reclassification of the Mt Isa and McArthur River resources. Submarginal demonstrated resources fell
from 16.3 Mt to 16.0 Mt over the year. These global variations are attributed to relatively small
changes in most states and the Northern Territory in both categories.
Total inferred zinc resources increased by 33% to 31.8 Mt in 2003 following the addition of 11 Mt to
the Mt Isa resource.
LEAD
Australia’s EDR of lead increased in 2003 by 11% to 19.3 Mt of contained lead. Queensland retained
the premier ranking with its EDR increase from 9.1 Mt in 2002 to 10.2 Mt in 2003, representing 53%
of total EDR. This was due to increased resource definition at Mt Isa and Century. The Northern
Territory decreased slightly from 5.75 Mt to 5.53 Mt EDR, or 39% of the national total. New South
Wales recorded another drop in EDR from 1.8 Mt in 2002 to 1.7 Mt in 2003, due to depletion of
resources through production at Broken Hill and Elura. EDR in Western Australia increased by 72%
to 1.8 Mt due to reclassification of resource at the Magellan deposit. Tasmania’s EDR rose by 0.01 Mt
(10%) to 0.09 Mt due to a minor increase in Rosebery resources.
Australia’s paramarginal demonstrated resources of lead are 1.9 Mt. Submarginal demonstrated
resources totalled 9.2 Mt. The aggregate sub-economic resources were 7% more than in 2002.
Total inferred lead resources rose by over 1.5% to 24.9 Mt in 2003 following an increase in resources
at the Mt Isa deposit.
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SILVER
Australia’s EDR of silver increased in 2003 by 7% to 42.9 kt of contained silver. Queensland remained
pre-eminent and its EDR rose from 29.1 kt to 32.2 kt, and its share of the total EDR rose from 73%
to 75% in 2003. The increase was mainly a result of reclassification of the Mt Isa and Cannington
resources, which offset decreases at Hilton. The Northern Territory at 4.8 kt again had the second
largest EDR and its share of national EDR was marginally down to 11.1% compared to 12.6% in
2002. South Australia had the third largest EDR with 2.4 kt (unchanged from 2002) and was followed
by New South Wales at 2.2 kt (unchanged from 2002), with minor increases at Broken Hill and
Elura offsetting decreases at Tritton deposit. Western Australia was next with 0.8 kt (0.4 kt in 2002),
followed by Tasmania with 0.31 kt (0.26 kt in 2002), due to minor increases at Rosebery, with
Victoria unchanged at 0.28 kt.