GreenTech Metals has confirmed spodumene as the dominant lithium mineral in a single rock-chip sample from its Osborne joint venture (JV) ground following x-ray diffraction (XRD) mineral characterisation analysis.
The bid to confirm the host mineral came after the company recently undertook wet chemical laboratory analysis for lithium in several samples from pegmatite-bearing zones within its adjoining Kobe and Osborne JV projects, south of Karratha in Western Australia’s Pilbara region.
One sample from its newly-discovered “southern trend” in the Osborne ground yielded the highest grade of all the samples taken to date from both the Ruth Well and Osborne JV tenure. Management was prompted to confirm the host mineral after it was found to be running a healthy 3.6 per cent lithium oxide.
The sample was taken close to another one that had previously assayed 2.3 per cent lithium oxide, making it the second-highest grade obtained in the entire sample suite and adding a further shine to the new southern zone.
XRD is a versatile, non-destructive technique used to analyse physical properties of substances, including rocks, such as phase composition, crystal structure and orientation, in powder, solid and liquid samples. It can enable differentiation of different minerals that might contain one or more of the same elements.
The biggest concentrations of lithium-containing minerals are found in hard-rock granitic pegmatites and the most important are spodumene and petalite. Spodumene is considered the most economically-viable source of lithium, with typical grades between 0.5 and 2.5 per cent lithium oxide.
Petalite also occurs in pegmatite host rocks, sometimes together with spodumene in the same occurrence, so it is important to differentiate the two minerals for exploration, metallurgical and processing purposes.
XRD confirmed the crystal lattice of petalite as being the key lithium component in concentrates from the Bikita deposits in Zimbabwe for the production of high-purity lithium carbonate. X-ray fluorescence (XRF) and wet chemical analyses show that the concentrate comprises oxides of lithium, silicon and aluminium as major components, with an average lithium oxide content of 4.1 per cent.
In a WA context, Venus Metals recently identified two neighbouring pegmatite outcrops during a mapping and field program at its Youanmi project, with visible coarse petalite running grades of up to 4.6 per cent lithium oxide.
GreenTech says it has identified several new potential lithium targets in its historic and new datasets.
Some targets, with grades of up to 1.65 per cent lithium oxide, are in the 7.5 km-long northern Kobe trend within its 100 per cent-owned Ruth Well tenements. Two solid hits of 1.7 per cent and 1.8 per cent lithium oxide have been picked up in eastwards extensions of the Kobe trend into the Osborne JV ground.
Meanwhile, the two biggest lithium hits of 2.3 per cent and 3.63 per cent lithium oxide were picked up in the new “southern trend” and strongly suggest a separate mineralised area about 3km to 4km south of and almost parallel to the Kobe trend.
Management says its priority exploration plans are aimed at launching its maiden lithium drilling at Ruth Well, with a program of works being approved for all tenements and a heritage clearance submission lodged with the Ngarluma Aboriginal Corporation. Other exploration plans include extending known pegmatite trends and identifying new trends.
The Ruth Well deposit lies some 20km south of the important regional hub of Karratha, offering GreenTech an extensive range of logistical and support facilities close to its projects.
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By Doug Bright
