The Hillside Lithium Project covers an area of approximately 65km 2 located in the Pilbara region of Western Australia, which is highly prospective for Lithium-Tin-Tantalum (Li-Sn-Ta) mineralisation.
The Hillside Lithium Project is located along strike and adjacent to the Trigg Hill and East Curlew lithium projects which are being actively explored by Eastern Resources Limited (ASX. EFE) where drilling has been ongoing at the Trigg Hill lithium project and EFE has reported high-grade rock-chip assays in extensive lithium-caesium-tantalum (LCT) pegmatites, with results up to 2.28% Li2O, 1,552ppm Cs2O, and 514ppm Ta2O5 .
The Hillside Lithium Project is located less than 4km NE of the Tambourah Project which is being actively explored by Riversgold Ltd (ASX. RGL) and the Tambourah North Project which is being actively explored by Trek Metals Limited (ASX. TKM).
The figure below highlights the strategic location of the Hillside Lithium Project which is located adjacent to and along strike of the Trigg Hill and East Curlew Lithium Projects (Eastern Resources). Also shown on the map is the location of the Tambourah Lithium Project (Riversgold) and the Tambourah North Lithium Project (Trek Metals).
Geology and Mineralisation
Regionally the Hillside Lithium Project is located within the East Pilbara granite-greenstone terrain, which is characterised by granitic rocks of the Shaw Batholith. Metamorphosed granitic rocks of the Archean Tambina, Split Rock and Callina Supersuites in the centre and southeast of the project area dominate the local geology. The granites have intruded older Archean rocks of the Pilbara Supergroup, composed of mafic and felsic volcanic rocks, with minor sedimentary and intrusive rocks. These units underly much of the western and northern parts of the tenure. The granitic rocks contain extensive swarms of late-stage pegmatites, the source of the tin and tantalum mineralisation in the area.
The geology of the Hillside project is largely rafts of amphibolitic and chloritic schists after basalts and dolerites, with some schistose metaperidotites, meta-dunnites and komatiitic metabasalts, between variably gneissic granitoid units of monzogranite, granite, granodiorite and tonalite. Siliceous metasediment units and greisen are also mapped on the Hillside project.
Pegmatite dykes related to the various granitic plutons have been intruded into the greenstone sequences and occur in swarms. These are variably fractionated and several have been located that fall at the end of the fractionation sequence in the Lithium- Caesium-Tantalum (LCT) category.
There are two types of pegmatites in the group. The first shows cassiterite, monazite and tanteuxenite, as sub-parallel swarms less than 0.5 metres wide dykes. The second are albite pegmatites, zoned with quartz cores, and containing beryl, formanite, lepidolite, muscovite, spodumene, yttrotantalite, and zinnwaldite.
The figure below outlines the geology of the Hillside Lithium Project.
The exploration potential of the Hillside Lithium Project is significant given the recent exploration success in the area. Geological targeting has identified several areas of high-priority exploration zones which will be followed up in the field. There are hundreds of pegmatite outcrops within the greenstones within the Hillside Lithium Project greenstone area. Whilst many of these are interpreted to be small to medium in size, there is significant potential for larger LCT pegmatite bodies to be identified particularly in areas of folded or faulted greenstones such as those that have been identified by Eastern Resources at the Trigg Hill Lithium Project, next door to the Hillside Lithium Project.
The pegmatites have potential for tantalum, REE, lithium and tin. The larger zoned LCT pegmatites will be more prospective for the presence of spodumene whilst lepidolite can occur in narrow dykes. Radiometric surveys (U) can also be used to locate larger tantalum pegmatites within greenstone hosts and some indications of subsurface pegmatites have already been located.
Exploration completed in the adjacent area at Trigg Hill and East Curlew by Eastern Resources Limited (EFE) has highlighted significant LCT-type pegmatite swarms that can be clearly traced on the Hillside Lithium Project, refer to the figures below.
The geological “Goldilocks Zone” was also utilised as an exploration targeting method for the Hillside Lithium Project which has identified zones of priority exploration areas which would be followed up in future field visits. The zones correlate with the Greenstone units at the Hillside Lithium Project and concentrate in areas that are adjacent to and along strike of Trigg Hill and East Curlew as well as on the western side of the tenements that comprise the Hillside Lithium Project, as shown in the figure below.