Mount Weld, South-West Australia

Mount Weld is located 35 km south of Laverton, Western Australia (Fig. 2.8). The rare-earth-element deposit was discovered in 1988, but was not exploited for a long time, because China was supplying REE at low prices. When the so-called REE-crisis (see Chap. 6) came about in 2009, Lynas Corporation, the company owning the deposit, decided to exploit the rich REE-deposit. 

In January 2012, the Mineral Resource estimate for Mount Weld was 23.9 million tons, at an average grade of 7.9 % REO, for a total of 1.9 million tons REO. 

The Mount Weld carbonatite dates from the Proterozoic (approximately 2025 Ma ago) and is emplaced in the Yilgarn Craton (Hoatson et al. 2011). The carbonatite is covered by a thick lateritic soil, which in its turn is covered by lacustrine and alluvial sediments (Lottermoser 1990). The Mount Weld deposit occurs in the weathered layer. 

The primary igneous REE-bearing minerals are apatite, monazite, and synchysite (Willett et al. 1989 Lottermoser 1990). Secondary minerals containing REEs are 

8 The location of Laverton in SW-Australia. Modified after Google Maps (2015) 

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