By Business Reporter – Tuesday 11 February 2020
HARARE (Mining Index) – PROSPECT Resources Limited (ASX: PSC, FRA: 5E8) has identified significant caesium concentrations in satellite bodies to its lithium mine.
The first element to be discovered with a spectroscope, caesium was first unearthed in 1860 by a German chemist Robert Bunsen and physicist Gustav Kirchhoff. The primary use of caesium is in caesium formate brine used in high temperature or high pressure oil and gas drilling.
In a statement authorised by its Managing Director Sam Hosack, the lithium producer revealed it was “pleased to announce the presence of significant caesium concentrations in soil, from a number of satellite bodies to Arcadia, notably the Shabaash.”
Prospect’s ground holdings at Shabaash consist of a block of three mining claims, covering 50 hectares of open bushland. The Shabaash site is located 3km west of the planned Arcadia Pit.
“The identified caesium occurs within pollucite, a high value rare caesium mineral that forms in extremely differentiated Lithium-Caesium-Tantalum (“LCT”) pegmatite systems,” said Prospect Resources, adding that global supply is very constrained.
According to a study published in 2016 in the journal Frontiers in Surgery, caesium is currently being researched in treatment of several forms of cancer, including brain tumours.
Background to the discovery of caesium at Arcadia Lithium mine
The area is located within the east-west trending Arcturus limb of the Archaean age Harare Greenstone Belt. It consists largely of metabasalts of the Arcturus formation.
As part of its satellite exploration and ground sterilisation programme, 14,000 soil samples were collected from the area surrounding the drilled resource in 2017 – 2018. Soil samples were collected every 20m on 100m spaced lines, surveyed north-south, but due to time constraints, assayed only for Lithium, by atomic absorption at Zimlabs, Harare.
A number of lithium anomalies were defined, which were subsequently drilled in 2017 – 2018. All of these were subsequently drilled and proved to be mineralised pegmatites, albeit in some case too thin and low grade to be economic.
The anomaly at Bermersyde, in contrast, was successfully drilled and, is now part of the reserve, and is the epicentre of the planned Northeast satellite pit.
In December 2019, a small number (61) of stored pulps were selected for re-assay for caesium. These were selected from samples which had previously returned Lithium anomalies. These pulps were re-assayed successfully at UIS Analytical Services in Centurion, South Africa.
From a statistical analysis of the results, 13 of them returned caesium results > 100ppm, and four anomalous returned > 400pm. Of these results, one sample was located within the Company’s Shabaash Claim holding.
As indicated by an analysis of the correlation matrix, the caesium anomalies are related to, but not directly associated with the higher lithium values. The anomalies at Shabaash lie along the approx. 800m zone in Shabaash pegmatite area. It is strongly suspected that there is a swarm of east-west mineralised pegmatites (lepidolite + caesium bearing) lying under the agricultural field at Shabaash to the west.
The only significant natural mode of occurrence of caesium is in the zeolite mineral, pollucite. It can be safely concluded that there are least reasonable concentrations of pollucite around and within the Shabaash pegmatite.
A trenching programme into the pegmatite zone is planned by excavating at least 4 trenches, 30m long and 2-3m deep, across the strike of the anomaly. Although no statements as to the dimension and grade of the mineralisation can be made until it is followed up by trenching and / or drilling; the presence of pollucite is highly encouraging.
There is increasing evidence for large scale mineral zonation around the periphery of the 4.5km long Arcadia petalite-spodumene mineralisation.
The implications for the proceptivity of the greater Arcadia area, for hidden deposits (Cs/Ta/Sn) are immense. In addition, it is validation of the regional geological model, developed by our experienced successful exploration department, who continue to discover previously un-recorded deposits. ENDS// www.miningndex.co.zw
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