Greenstone Resources (ASX:GSR) report assays from 8 drillholes have all intercepted ‘highly-anomalous’ PGE mineralisation at the Mt Thirsty Joint Venture (50:50) with Conico (ASX:CNJ) in Western Australia.
The current phase one drill campaign is testing for extensions to the recent palladium-platinum-gold-copper-nickel (PGE) discovery by Galileo Mining (ASX:GAL) located less than 200m from the Mt Thirsty Project’s northern tenement boundary.
The company reports phase one drilling activities at the Mt Thirsty project continue on schedule with 12 holes now completed, will all holes intercepting ‘semi-massive’ or ‘heavily’ disseminated sulphides within the target horizon.
Assays have been received for the first 8 holes, testing approximately 3% of the modelled altered ultramafic target horizon.
All 8 holes intersected ‘highly anomalous’ PGE mineralisation including:
- MTRC003D- 27m @ 0.33g/t 3E, 0.12% Ni and 0.05% Cu from 198m.
- MTDD001D- 18m @ 0.29g/t 3E, 0.11% Ni and 0.01% Cu from 199m.
- MTRC009D- 10.2m @ 0.23g/t 3E, 0.09% Ni and 0.01% Cu from 199m.
The depth of mineralisation is consistent with the previously modelled target horizon however the initial geological interpretation of these results indicate a secondary control on mineralisation are likely influencing the local distribution of grade and continuity.
The confirmed presence of PGE mineralisation within the tenement, over 450m from the Callisto discovery suggests the prospectivity for future PGE discoveries remains.
Thickening was observed in the sediments to the south in holes MTRC0011AD (38m) and MTRC005D (49m). This thickening is interpreted to be a key control on mineralisation, being the source of both sulphur and fluid which may facilitate the local enrichment of PGE mineralisation.
Both MTRC0011AD and MTRC005D have been logged, cut, sampled, and submitted to the laboratory with assays expected in the next 4 to 6 weeks.
The company notes that despite the first 12 holes only intercepting thin mineralised horizons, results from these holes have been instrumental in refining the geological model by synthesising geochemical, geological and more recent geophysical data, to define the remaining Phase I drill campaign to areas which exhibit a similar signature to Callisto.
The current geological interpretation indicates that Callisto-style mineralisation may be hosted within a north-south trending zone of demagnetisation, resulting in localised alteration and remobilisation of mineralisation.
This interpretation is supported by the results which have been received to date from the northeast corner of the target area and geophysical interpretations.
Greenstone Managing Director Chris Hansen said the historical focus of Mt Thirsty has primarily focused on the near surface oxide resources, with the more recent PGE exploration occurring in largely untested geological horizons.
“Over the past weeks our geological understanding of the potential controls on mineralisation has evolved rapidly”
“Over the past weeks our geological understanding of the potential controls on mineralisation has evolved rapidly and we continue to dynamically adjust our exploration model to reflect this.
We are reassured to have received highly anomalous PGE mineralisation in all holes completed to date, and more importantly the two most recent holes, MTRC0011AD and MTRC005D, have intersected significantly thicker sedimentary packages, which are interpreted to be a key control on mineralisation.
With a further seven holes planned as part of the aggressive Phase I drill campaign, we look forward to testing the majority of the prospective strike horizon at Mt Thirsty over the next four weeks.
Following the completion of the PGE drill campaign the multipurpose drill rig will then move to the western margin to test the recently identified lithium potential where 8 pegmatite outcrops have been mapped over a 1,000m strike horizon.
We look forward to keeping shareholders updated on a regular basis as our understanding of the scale and nature of this new geologic system continues to develop.”
A continuous demagnetised has been interpreted to run the entirety of the Mt Thirsty JV licence, exhibiting a similar low magnetism geophysical signature similar to the Callisto host lithologies.
As ultramafic formations are ‘highly magnetic’, and this suggests a zone of ‘strong’ alteration and potential remobilisation of minerals.
With over 90% of the altered ultramafic target horizon remaining untested, and a large demagnetised zone remaining largely untested, the Mt Thirsty complex remains ‘highly prospective’ for additional PGE discoveries.
The remainder of the phase one drill campaign has been reprioritised and is expected to be completed within the next 4 weeks.
In addition to the untested PGE potential, Greenstone is also undertaking a detailed geological review, assessing the western margin of the Mt Thirsty licences for lithium-caesium-tantalum (LCT) potential, with historical drilling and mapping previously documenting pegmatites within the licence area.
Preliminary geological mapping in the area has identified 8 pegmatite outcrops on the western margin of the Mt Thirsty licences over a strike extent of 1,000m, with preparations for an initial 11 hole program (1,650m) already underway with drill pads having been prepared.
Some 150m to the west of licences held by Greenstone is the Mt Thirsty pegmatite where Galileo previously reported a series of steeply dipping, north-south trending pegmatites. Six grab samples of micaceous (lepidolite) pegmatite were sampled by Galileo returning an average assay grade of 2.3% Li2O, 1.87% Rb and 476ppm Ta2O54.
The Mt Thirsty Joint Venture is jointly held by Greenstone Resources and Conico, with both companies owning a 50% stake in the project.
The project is located 16km north-northwest of Norseman, Western Australia, and it contains a cobalt-nickel oxide deposit with a JORC Resource of 26.9Mt @ 0.126% Co, and 0.54% Ni. The project also hosts nickel sulphide mineralisation potential.
Images: Greenstone Resources Ltd