Keysbrook, Western Australia
MZI Resources Ltd owns and operates the Keysbrook Mineral Sands Mine, which hosts a major leucoxene deposit, located approximately 70 kilometres from Perth. Production commenced in late 2015, making Keysbrook one of the largest primary producers of leucoxene in the world.
The land is predominantly pastoral, used for dairy and beef cattle farming, with some pockets of degraded remnant native vegetation. The project sits within two Shires: the Shire of Murray and the Shire of Serpentine-Jarrahdale. Land titles in the Keysbrook area were granted prior to 1899 and consequently are freehold ‘minerals to owner’, meaning that the minerals are owned by the private landowner and not the State.
The deposit is dunal, with no overburden and low clay and rock content. The mining depth will average between 1m and 5m depending on dunal variations.
The deposit is approximately 1,406 hectares in area. It has an unusual heavy mineral suite, compared to other titanium and zircon operations in the south west of Western Australia, with leucoxene as its major constituent.
The Minister for Environment issued Ministerial Statement No. 810 in October 2009 pursuant to the provisions in the Environmental Protection Act. The Federal Minister granted approval under the EPBC Act on 16 February 2010.
The Development Approvals and Extractive Industry Licences were granted by both Shires on 15 March 2012 for a 6.5 year mine life. Ore Reserves are sufficient to support production at initial rates for +10 years, subject to securing the necessary additional approvals as operations progress, with potential for further extension based on existing resources.
Heavy mineral concentrate (HMC) product from Keysbrook is transported via the South West Highway to Doral Pty Ltd’s mineral separation plant (MSP), located in Picton, approximately 130km south from Keysbrook, for dry separation. MZI has an agreement with Doral to toll treat the HMC. A plant upgrade was undertaken at Doral’s MSP plant to enable it to treat the leucoxene-rich Keysbrook HMC.
Leucoxene is exported through the Bunbury Port, while zircon concentrate is exported in containers through the Port of Fremantle.
Mineral Sands Mining overview
The primary processing of mineral sands is a relatively simple one. Using water, spirals and gravity separation, the HMC product is separated from sand as follows:
Keysbrook is a 24-hour / 7-day per week mining operation, using articulated dump trucks and an excavator operation to provide MZI with operational flexibility.
After the HMC has been mined, all sand and other material is returned to the mining void and replaced with the stockpiled topsoil.
The HMC product is transported to Doral at Picton for dry separation into the leucoxene and zircon constituents using electrostatic and magnetic separation, and exported to customers in China and the USA.
Pastoral land disturbed by mining will be returned to its pre-mined state, with progressive rehabilitation requiring at least two growing seasons to re-establish prior to allowing grazing by animals. Rehabilitated native vegetation will be protected by fences from stock and will take several years to establish.
The process of clearing, mining and rehabilitating occurs progressively with a priority on minimising the open area of mining at any one time. No chemicals are used in the mining and wet concentration process apart from flocculants to remove clay from the water, allowing the water to be recycled on site. The flocculant is non-toxic and is often used in water treatment plants.
Unlike other forms of mining such as gold or iron ore, only a minimal footprint remains and any evidence of mining is almost undetectable following successful rehabilitation.