Shree Minerals Ltd (ASX:SHH) has planned a reverse circulation drill program to test a gold mineralised trend identified by soil sampling and rock chip sampling at Rock Lodge Exploration Licence that forms part of the Lachlan Fold Belt Project in southern NSW.
The gold anomaly generated is coincident with the northern area of induced polarisation (IP) chargeability at Rock Lodge.
With all approvals received, the company expects to begin the RC program of about 1,000 metres around mid-November 2021.
Soil sampling program
Soil sampling completed in September 2021 over the northern area of anomalous IP chargeability where previous drilling intersected gold mineralisation returned anomalous gold results to 1.29 g/t gold.
Sampling was conducted on a detailed 80 x 20-metre grid and generated 130 samples that were submitted to the laboratory for gold and pathfinder geochemistry.
Apart from 1.29 g/t gold, the best result also returned 1,615 parts per million (ppm) arsenic, 208 ppm bismuth and 240 ppm copper from close to historic workings.
Five samples were returned with more than 100 parts per billion (ppb) gold and the results have identified an approximate north-south trend coincident with the northern IP chargeability anomaly.
Results from this program correlate well with 17 rock chip samples taken in August 2021 that returned a maximum result of 7.3 g/t gold with 6,049 ppm arsenic and 446 ppm bismuth.
RC drill program
The upcoming drilling will be conducted on traverses with the intention of validating previous drilling and extending the mineralisation.
It will also test the southern IP anomaly that is about 1.6 kilometres to the south and has not been sampled or drilled previously.
Shree believes it is possible that the mineralisation is continuous between the northern and southern IP anomalies but this cannot be confirmed without drilling because of flat lying basaltic cover rocks.
A land access agreement has been signed with the landholder and approval for drilling has been given by the NSW Department of Planning, Industry and Environment while Shree has signed a contract with a drilling contractor.
Geological consultants Rangott Mineral Exploration Pty Ltd in Orange is assisting Shree with the program because of COVID related travel restrictions.
Possible IRGS system
Rock Lodge prospect has possible affinity with the Intrusion Related Gold System (IRGS) class of deposit that are commonly within a large hydrothermal system with potential for large-tonnage, low-grade gold mineralisation in disseminated systems or higher grades in vein systems.
Kidston Mine in Queensland is an example of an IRGS deposit that to 1990 had a total production of 23.7 million tonnes at 2.08 g/t gold, with an estimated remaining mineral resource of 42.6 million tonnes at 1.43 g/t gold, 1.85 g/t silver and a further inferred resource of 11.7 million tonnes at similar grades.
Characteristic features of IRGS mineralisation include sheeted veins containing gold with elevated bismuth, arsenic, silver, copper, lead and zinc.
The systems are commonly geochemically zoned around a central intrusion and can also have elevated sulphide which can be detected with induced polarisation (resistivity lows).
Shree is encouraged that many of these features are present at Rock Lodge.
Planned RC drilling will initially target the shallow veins but pending results deeper drilling is planned to test for an interpreted source intrusion at depth.
Several Silurian and Devonian aged intrusions have been mapped in the Rock Lodge area by the NSW Geological Survey.
Limited exploration
Rock Lodge, which is 35 kilometres south of Cooma and covers 163 square kilometres, has been explored by only two companies in the last 50 years.
These exploration programs progressed to RC and diamond drilling, but significant intersections were not followed up. In addition, consideration was not given to the prospectivity away from the old workings.
Several target areas generated from geochemical and geophysical surveys at Rock Lodge were not followed up, including the Monaro Prospect and the Bobundara Gold Mine.