Mamba Exploration identifies new sulphide anomalies at Black Hills project
As Lithium Australia advances its battery recycling technologies, the company continues progressing its exploration projects.
Results from recent surveys and drilling by Mamba Exploration (ASX: M24) at the Black Hills project in Western Australia have identified new geophysical anomalies of disseminated sulphides.
Down hole electromagnetic (EM) surveys located one weak in-hole conductor and several discrete off-hole conductors from two drill holes completed in 2021.
A previous surface EM loop failed to provide sufficient data as it could not be placed in the preferred orientation, due to access limitations, reducing the coupling between the loop and the downhole probes.
A drone survey was also completed over the interpreted mafic-ultramafic intrusion at the northern end of a mapped ultramafic and 2PGE (derived from platinum and palladium) anomaly trend.
The ultra-detailed survey and associated 3D inversion modelling of data identified several magnetic anomalies and a number of structural complexities.
Compelling targets
Managing director Mike Dunbar said the findings represent compelling follow-up drill targets.
“The down hole survey completed on the first two holes has identified several off hole conductors which is pleasing, given the EM loop configuration was not optimal due to access limitations,” he said.
“The drone magnetic survey and 3D inversion modelling was was not hampered by these limitations and has identified several anomalies and structural complexities which represent compelling targets.”
Disseminated sulphides
A December drilling program completed at Black Hills intersected disseminated to blebby sulphides and visual logging showed multiple zones of disseminated sulphide mineralisation.
An original VTEM (versatile time domain electromagnetic) anomaly was not able to be explained by the drilling as the sulphides were proven to be not interconnected.
The limited amount of sulphides intersected resulted in weakly anomalous nickel, copper and 3PGE (platinum, palladium and gold) intersections.
Highlights were 12 metres at 213 parts per million nickel, 103ppm copper and 55ppb 3PGE from 84m; 10m at 156ppm nickel, 124ppm copper and 13ppb 3PGE from 154m; 32m at 156ppm nickel, 138ppm copper and 44ppb 3PGE from 20m.
Also reported were assays of 18m at 153ppm nickel, 106ppm copper and 20ppb 3PGE from 111m; 6m at 340ppm nickel, 65ppm copper and 45ppb 3PGE from 142m; and 2m at 225ppm nickel, 322ppm copper and 52ppb 3PGE from 286m.
Individual assays up to 810ppm nickel, 551ppm copper and 130ppb 3PGE were intersected within broader zones of anomalism and coincided with zones of more sulphide identified in the detailed geological logging.
Nickel-copper grades
“The background nickel-copper grades within the intrusive rocks are very low for mafic-ultramafic rocks at around 110ppm nickel and 72ppm copper,” Mr Dunbar said.
“So the anomalism identified confirms that the likely source is the disseminated sulphides and not just from a background silicate source.”
He said the additional geophysical data would allow the company to better target the anomalies and learn more about the original EM responses, which are believed to be from a sulphide source.