Resumen de Thessally Resources view prospects in Australia's magnesite market

Andrew Scogings, Matthew Robert Barnett

• Magnesite is the mineral name for MgCO[subscript]3 with a theoretical MgO content of 47.8% MgO and 52.2% CO[subscript]2. Deposits of magnesite are of two main types; (i) macrocrystalline or sparry rocks (Wilson, 2013) where Mg solutions have altered dolomite to magnesite, and (ii) cryptocrystalline magnesite replacing ultramafic rocks within the weathered profile. Other types of magnesite, such as sedimentary beds, crystalline magnesite replacement in ultramafic rocks and saline brines, do occur but are of secondary significance from an economic point of view. Also a pure form of magnesia (MgO) is produced from sea water.

  In 2012 USGS data shows world production capacity of CCM as 2.72m tonnes MgO and DBM as 7.64m tonnes MgO (Bray, 2012). Australia's share of this production capacity in 2012 was 8% CCM and 1.4% DBM. China dominates the supply of CCM with 53% of production capacity. Russia (3.4%), Spain (5.5%), and Brazil and Canada (3.5%) are other significant CCM producers, according to the USGS.

  As the main products from magnesite mines are in the calcined MgO form, this is how the product specifications are quoted. For CCM produced from natural magnesite the range of MgO is 85-95%, with 85-90% MgO being the typical range for animal feeds and fertilisers and 90-95% MgO for bulk industrial applications such as construction and paper processing.