The Mt Weld Central Lanthanide Deposit (CLD) is one of the highest grade rare earth deposits in the world. Mt Weld also hosts the undeveloped Duncan (rare earth), Crown (niobium, tantalum, titanium, rare earths, zirconium) and Swan (phosphate) deposits.
Lynas processes the CLD ore at the Mt Weld Concentration Plant to produce a rare earth concentrate that is sent for further processing at the Lynas Advanced Material Plant (LAMP) near Kuantan, Malaysia.
The Mount Weld rare earths deposits sit in a two billion year old volcanic plug. It is estimated that approximately 1.8km of the volcanic plug has been weathered during this time to form a high grade supergene Rare Earth Oxide (REO) deposit.
The highest concentration of rare earths is found in the Central Lanthanide Deposit and is currently an open pit to a depth of 51m. The carbonatite, which is approximately 3 km in diameter, also hosts a number of other deposits including the undeveloped Duncan, Crown and Swan deposits.
The rare earths are hosted in secondary rare earths phosphate minerals that can contain up 60-70% REO. They are finely disseminated within various iron oxides, such as goethite and limonite. The rare earths phosphates within the CLD are predominantly light rare earths enriched, however heavy rare earths mineralisation in the form of crandallite and xenotime does exist in the Duncan Deposit.
Mt Weld Resources and Reserves
The Mt Weld Concentrator is a flotation plant designed to process 240,000 tonnes per annum of ore to produce up to 66,000 tonnes per annum of concentrate containing 26,500 tonnes of REO. The Mt Weld Concentrator was commissioned in May 2011 and has been exporting concentrate to the LAMP since late 2012.