australia's identified mineral resources 2005 - Geoscience Australia
australia's identified mineral resources 2005 - Geoscience Australia
australia's identified mineral resources 2005 - Geoscience Australia
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AUSTRALIA’S IDENTIFIED MINERAL RESOURCES <strong>2005</strong><br />
Magnesite<br />
Magnesite (magnesium carbonate) is marketed in three main forms: (1) crude magnesite, primarily for<br />
use in chemicals and agriculture; (2) dead-burned magnesia, a durable refractory for use in cement,<br />
glass, steel and in metallurgical industries; and (3) caustic calcined magnesia, for use in making<br />
oxychloride and oxysulphate cements for flooring and wallboards, mouldings and acoustic tiles,<br />
and various environmental and chemical applications.<br />
Resources<br />
EDR of magnesite was virtually unchanged at 344 Mt in 2004, with only a slight reduction through<br />
production from the Kunwarara mine in Queensland. South <strong>Australia</strong> has the largest holding of EDR<br />
with a global resource of 579 Mt of magnesite of which 235 Mt is classified as EDR.<br />
Queensland has the second largest inventory of EDR. The bulk of this is at Kunwarara (70 km<br />
northwest of Rockhampton), where <strong>Australia</strong>n Magnesium Corporation Ltd has an inferred global<br />
resource of 1 200 Mt of magnesite-bearing material. Within this resource, which contains an inferred<br />
resource of 500 Mt of magnesite, the company has <strong>identified</strong> several high-grade magnesite zones,<br />
which are classified by <strong>Geoscience</strong> <strong>Australia</strong> as EDR. The Kunwarara deposit contains substantial<br />
accumulations of very high-density “bone-type” magnesite, which is characterised by nodular and<br />
cryptocrystalline structure and low iron-content.<br />
The Arthur River deposit in Tasmanian has indicated resource of 26 Mt of magnesite, which is<br />
classified as EDR. Magnesite in this deposit is typically around 42.8% MgO and is part of a much<br />
larger resource of 195 Mt in the Arthur-Lyons River area (about 53 km south of Burnie).<br />
Subeconomic demonstrated <strong>resources</strong> of 57 Mt of magnesite are unchanged from 2003. All of these<br />
<strong>resources</strong> occur in Queensland and Tasmania. Inferred <strong>resources</strong> are also the same at around 930 Mt,<br />
with Queensland accounting for 50% followed by South <strong>Australia</strong> (31%) and Tasmania (16%).<br />
Accessible EDR<br />
All magnesite EDR is accessible for mining.<br />
JORC Reserves<br />
Around 10% of AEDR comprise JORC Code reserves. The remaining represents <strong>resources</strong> assessed<br />
by <strong>Geoscience</strong> <strong>Australia</strong> from the measured and indicated categories of industry reported <strong>mineral</strong><br />
<strong>resources</strong>, as defined under the Code and other classification systems used by companies not listed<br />
on the <strong>Australia</strong>n Stock Exchange. At the rate of production in 2004, magnesite <strong>resources</strong> in the JORC<br />
Code reserves categories are adequate for 64 years.<br />
Exploration<br />
Data relating to exploration expenditure for magnesite are not published by ABS on either a state or<br />
national basis.<br />
Production<br />
In 2004, <strong>Australia</strong>n Magnesium Corporation Ltd mined 3.83 Mt (3.02 Mt 2003) of crude magnesite<br />
ore at Kunwarara, which was beneficiated to produce 543 306 t of magnesite (470 038 t in 2003).<br />
This produced 86 854 t of dead-burned magnesia (108 190 t in 2003), 62 299 t of calcined magnesia<br />
(56 143 t 2003) and 25 324 t of electrofused magnesia (25 064 t in 2003).<br />
45<br />
World Ranking<br />
According to <strong>Geoscience</strong> <strong>Australia</strong> and USGS data, <strong>Australia</strong> has about 5% of the world’s EDR of<br />
magnesite. Russia, North Korea and China, together, account for nearly 70% of the world’s EDR of<br />
magnesite. The Kunwarara deposit is the world’s largest known resource of cryptocrystalline, nodular<br />
magnesite, a high quality ore.