Magnesite

<div id="content_div_50782"> <p><strong>Roy Towner</strong> (<a href="mailto:roy.towner@ga.gov.au">roy.towner@ga.gov.au</a>)</p> <p>Magnesite (magnesium carbonate MgCO<sub>3</sub>) is marketed in three main forms:</p> <ul> <li>crude magnesite, primarily for use in chemicals and agriculture;</li> <li>dead-burned magnesia, a durable refractory used in the cement, glass, steel and metallurgical industries; and</li> <li>caustic calcined magnesia, for use in making oxychloride and oxysulphate cements for flooring and wallboards, mouldings and acoustic tiles as well as various environmental and chemical applications.</li> </ul> <h2>Resources</h2> <p>Economic Demonstrated Resources (EDR) of magnesite remained unchanged in 2011 at 330 million tonnes (Mt). South Australia (SA) continued to have Australia&#39;s largest holding of EDR with 235&nbsp;Mt, which is unchanged from 2006. The bulk of these resources occur as interbeds of sedimentary magnesite within the Skillogalee Dolomite at the Witchelina and Mount Hutton deposits, up to 30 kilometres (km) northwest of Leigh Creek. The average magnesite grade is 40% magnesium oxide (MgO).</p> <p>Queensland (Qld) has Australia&#39;s second largest inventory with 63&nbsp;Mt of magnesite EDR. The bulk of this resource occurs at Kunwarara, 70&nbsp;km northwest of Rockhampton, where Queensland Magnesia Pty Ltd has global resources of 1200&nbsp;Mt of magnesite-bearing material. Within this global resource, which has an Inferred Resource of 500&nbsp;Mt of magnesite, several high-grade magnesite zones have been classified as EDR. The Kunwarara deposit occurs as sheet-like lenses of magnesite with an average thickness of 7.6&nbsp;metres extending over about 63&nbsp;square kilometres. It contains four high-grade zones of very high-density bone-type, low iron ultrafine-grained cryptocrystalline to microcrystalline nodular magnesite.</p> <p>The third largest inventory of EDR is in Tasmania (Tas) where the Arthur River deposit has a measured resource of 13.2&nbsp;Mt with an average magnesite grade of 43.4% MgO. The resource is part of a much larger global resource of 195&nbsp;Mt in the Arthur-Lyons River area, about 53&nbsp;km south of Burnie.</p> <p>The remainder of Australia&#39;s EDR occurs in the Winchester deposit 70&nbsp;km south of Darwin in the Northern Territory (NT), at Thuddungra 80&nbsp;km northwest of Young in New South Wales (NSW), and at Bandalup 20&nbsp;km east of Ravensthorpe in Western Australia (WA).</p> <p>Subeconomic Demonstrated Resources of 57&nbsp;Mt of magnesite remained unchanged from 2006. All of these resources occur at Triple Four in central Qld and at Main Creek in northwest Tas.</p> <p>Inferred Resources of magnesite remained unchanged in 2011 at 836&nbsp;Mt with Qld accounting for 56%, followed by SA with 35% and Tas with 5%. The remaining resources are in NSW, the NT and WA.</p> <h2>Accessible EDR</h2> <p>All magnesite EDR is accessible for mining.</p> <h2>JORC Reserves</h2> <p>Joint Ore Reserves Committee (JORC) Code reserves comprise total magnesite in Proved and Probable Ore Reserves as defined in the JORC Code. In 2011, JORC Code reserves of 37.5&nbsp;Mt (unchanged from 2010) accounted for approximately 11% of Accessible Economic Demonstrated Resources (AEDR). At Australia&#39;s 2010-11 rate of production, magnesite resources in the JORC Code reserves categories are adequate for almost 58 years.</p> <h2>Exploration</h2> <p>Data associated with exploration expenditure for magnesite are not published by the Australian Bureau of Statistics.</p> <h2>Production</h2> <p>The bulk of Australia&#39;s magnesite production was by Queensland Magnesia Pty Ltd which supplied high-grade electrofused and dead-burned magnesia to the global refractory market, as well as calcined magnesia for a wide range of applications. In 2010-11, the company produced a total of 644&nbsp;325 tonnes of magnesite (275&nbsp;819 tonnes in 2009-10). About 1647 tonnes of magnesite was produced from the Myrtle Springs region in SA in 2011.</p> <h2>World Ranking</h2> <p>According to Geoscience Australia and United States Geological Survey (USGS) data, Australia has about 4% of the world&#39;s EDR of magnesite, which total 8750&nbsp;Mt. Russia, China and North Korea jointly account for almost 66% of the world&#39;s EDR. The Kunwarara deposit in Qld is the world&#39;s largest known resource of ultrafine-grained cryptocrystalline to microcrystalline nodular magnesite.</p> <p>According to USGS data, world production of magnesite totalled 20.65&nbsp;Mt. The world&#39;s largest producers of magnesite in 2011 were China (69%), Russia (6%), Turkey (5%), and Austria (3%).</p> <h2>Industry Developments</h2> <p>Korab Resources Limited recently engaged Tenova Group&#39;s Bateman Engineering to conduct an update of a feasibility study completed by the Bateman/Multiplex consortium in 2001 on its <strong>Winchester</strong> deposit in the NT. The company is continuing investigation into being a supplier of magnesium oxide (MgO) based building products. MgO is used extensively in Canada, Asia and the USA to produce low-cost, high-strength building materials which do not expand or shrink when submerged in water or heated and are potential substitutes for fibro-board, plaster-board, chipboard and ceramic tiles. MgO-based products are fire-resistant to 1200&nbsp; <span>0</span> C.</p> <p>Beacon Hill Resources Plc through its subsidiary Tasmania Magnesite NL, holds mineral tenure over two large, high-grade magnesite deposits at <strong>Arthur River</strong> and <strong>Lyons River</strong> in northwest Tas. The company announced the results of a preliminary scoping study into the Arthur River project in the June quarter 2012. The study demonstrated a pre-tax nett present value of $42 million based on a mine life of 17 years and a 292&nbsp;000 dry tonnes per annum (tpa) operation producing on average 100&nbsp;000&nbsp;tpa of calcined magnesia.</p> <p>The company is considering carrying out a full feasibility study, which would include the submission of a development proposal and environmental management plan to secure mining approval, the completion of the approved drilling program and the securing of a joint venture and/or off-take partners to fund the development of the project. The Arthur River deposit has a defined JORC compliant Measured Resource of 13&nbsp;Mt of magnesite and an Inferred Resource of 10&nbsp;Mt.</p> <p>In 2010, Archer Exploration Limited through its wholly-owned subsidiary, Leigh Creek Magnesite Pty Ltd, acquired most of the magnesite deposits formerly owned by SAMAG. The deposits contained a combined JORC resource of 413&nbsp;Mt with an average grade of 41.3% MgO. To develop its <strong>Leigh Creek</strong> magnesite deposits the company is seeking joint venture partners with technical and marketing expertise in magnesite, caustic-calcined magnesia and dead-burned magnesia.</p> </div> <div id="content_div_50633"> <div id="pageNav"><ul><li class="previous">PREVIOUS: <a href="http://www.ga.gov.au/data-pubs/data-and-publications-search/publications/aimr/lithium">Lithium</a></li><li class="break">|</li><li class="pageNavContents"><a href="http://www.ga.gov.au/data-pubs/data-and-publications-search/publications/aimr/contents">Contents</a></li><li class="break">|</li><li class="next">NEXT: <a href="http://www.ga.gov.au/data-pubs/data-and-publications-search/publications/aimr/manganese-ore">Manganese Ore</a></li></ul></div> </div>