Zircon (65% of Revenue). Forecast Annual Production 49,500 tonnes.
Zircon is a zirconium silicate, ZrSiO4, which originates in nature as an early forming accessory mineral in igneous rocks, particularly sodium-rich granites. Its hardness, high diamond-like lustre and reflectivity, corrosion resistance, high melting point and ability to absorb radiation are properties utilised in the manufacture of a variety of products in the ceramic, chemical, refractory and foundry industries. The proportion of zircon consumed in each of these industries is shown in Figure 1.
The Coburn zircon product is suitable for use in all of the above industries, although its iron oxide and titanium dioxide levels are slightly higher than the premium grade zircon cut-off levels of 0.1% and 0.12% respectively. Nevertheless, ceramic industry customers in Europe and Asia have advised that Coburn zircon can be blended with premium grade material for glazing of tiles, the principal ceramic use.
The radiation hazard level of Coburn’s zircon, expressed by its uranium and thorium (U+Th) content of between 320-450 parts per million, is quite low and compares favourably with the accepted international limit of 500 parts per million. Radiation levels in the zircon chemicals industry are particularly critical, as uranium and thorium are concentrated in the tailings during the manufacturing process, making it difficult and expensive to achieve safety requirements.