Seabrook Rare Metals Venture – Western Australia
In October 2014, Lithium Australia NL (‘LIT’) announced that it had identified lithium-rich pegmatites on the shores of Lake Seabrook, approximately 60 kilometres (‘km’) northeast of Southern Cross in Western Australia (see Figure 1). LIT applied for an exploration licence covering most of the known pegmatite swarm.
Later that month, LIT entered into a strategic partnership with ASX-listed Tungsten Mining NL to explore for lithium and other metals in the Lake Seabrook area, on ground held by Tungsten Mining. The partnership significantly extends LIT’s interest to a 15-km strike potential and provides LIT with immediate access to granted tenure.
The Seabrook Rare Metals Venture provides LIT with the right to earn an 80% interest in all metals other than tungsten, the rights for which remain or are vested in Tungsten Mining. The summary terms of the agreement are as follows.
LIT is to manage the joint land package and be responsible for maintaining the tenements in good
- A declared area of influence around the Tungsten Mining tenements of 20 km.
- LIT alone to fund exploration to the commencement of a definitive feasibility
- On committing to a definitive feasibility study, conversion to an 80/20 (LIT/Tungsten Mining) contributing joint venture for developing non-tungsten
- Tungsten Mining retains a 100% interest in tungsten and the right to continue operations for the discovery and development of tungsten within the area of
- LIT to provide all exploration data to Tungsten Mining.
The Lake Seabrook tenure overlies a 15-km section of the Koolyanobbing shear zone, which is one of several northwest-trending, crustal scale, ductile shear zones in the Archean granitoid-greenstone terrains of the Yilgarn Craton. At Lake Seabrook, an area approximately 6 km wide of highly deformed granitoid rocks defines the shear zone. The lithium mineralisation appears to be associated with the Koolyanobbing shear zone and consists of pegmatites and metasomatically altered country rock. On the ground held by Tungsten Mining, the mineralisation manifests as tungsten-bearing skarns, which also contain a number of other rare metals, typical of the genesis associated with the pegmatites.
LIT now has significant experience in geochemical modelling of prospective lithium terrains, as well as the soils derived from pegmatites containing lithium micas, using hand-held X-ray fluorescence (‘XRF’) instruments. While the portable XRF does not read lithium directly, LIT has developed methods, using pathfinder elements, to map lithium signatures. Much early understanding of the use of these instruments to profile soil lithium responses was developed during trials at Lake Seabrook.
Hand-held laser-induced breakdown spectroscopy (‘LIBS’) is a novel technology that can provide real-time lithium assays. It was used to compare real-time lithium spectral data with various geochemical signatures generated with field portable XRF equipment from soil sampling along the tungsten-bearing skarns. The results show conclusively that patterns of lithium anomalism determined by hand-held LIBS are remarkably similar to the anomalism produced using the field-portable XRF.
LIT plans to extend its field evaluation of prospective areas and infill current geochemical surveys, to provide greater resolution of the existing anomalies.