Ausmex Mining Group (ASX: AMG) has announced a highly positive update on the initial drilling results at Princess Royal Prospect of Burra project in South Australia.
The company reported that the RC pre-collar drilling for deeper diamond core holes at Princess Royal prospect intersected REE and indicator minerals for a large alkaline, ultramafic mineral system above Conductive Target 1 (Drill holes BURC011 & BURC012).
These two pre-collar holes were drilled to ~ 240 m by RC as preparation for further drilling using diamond core to the target 400 m depth.
AMG said that the metal association of rare earth elements, yttrium, scandium, nickel, chromium, cobalt, and copper as well as gold, suggests the likely presence of a deeper alkaline ultramafic sourced mineral system corelating with the AMT Conductive Target 1.
The company said that from 150 m to ~250 m within hole BURCO11, total REE plus Y are positively correlated lying on a vector that extends at depth to target 1.
Independent Expert Emeritus Professor Ken Collerson has interpreted this as evidence that the distinctive mineral vector profiles are related to the conductivity anomalies (MT flares) identified in magneto-telluric data below Burra.
The company announced that deeper drilling with diamond tails planned to continue to target this potential higher grade mafic to ultramafic hosted mineralisation.
The Burra project is located near the historical copper mining centre of the same name in South Australia’s mid-north.
Some of the significant prospects include Princess Royal and Mullaby prospects.
Drilling at Princess Royal
The Princess Royal Prospect is located approximately 15 km south of Burra township.
AMG reported that seven RC pre collar holes totalling 1,562 m, have been completed for a deeper diamond drilling campaign into the Princes Royal conductive targets, with additional pre collar assays recently dispatched to ALS in Adelaide for analysis.
Assays received from 2 RC pre collar drill holes
In November 2019, the company announced the multielement assay data from the first two RC pre collar drill holes (BURC0011 and BURC0012) at Princess Royal prospect.
The RC pre collar holes BURC0011 and BURC0012 were drilled to a maximum of 246 m as preparation for deeper diamond core drilling targeting the Audio-Magnetotellurics (AMT) conductive zones.
It may be noted that this “MT flare” at Burra is similar in scale and character to a large MT conductive anomaly below Olympic Dam ~380 km to the northwest, interpreted by Heinson et al., (2018) to image the metal migration regime involved in formation of this world class IOCG system.
Review of assay data
The company announced that independent Expert Emeritus Professor Ken Collerson was engaged to review multielement assay data from the RC pre collar drill holes, BURC0011, and BURC0012, to assess the potential source of the conductive anomalies (MT flares) identified in the AMT magnetotelluric survey at Burra.
Key findings of review
AMG reported the key findings from the initial assay results and interpretation by Emeritus Professor Ken Collerson.
The professor said that the results indicated the possibility of the presence of a large alkaline, ultramafic mineral system above Conductive Target 1.
Collerson noted that the profiles showing variation in elemental abundances with depth are useful in showing compositional gradients in the vicinity of the computed conductive anomalies.
He said that, in BURC0011, there is clearly some near surface REE supergene enrichment. However, in the depth interval from 50 m to ~ 250 m, total REE plus Y concentrations are strongly positively correlated and defining a vector towards higher TREY values at Conductive Target 1.
The Expert Emeritus Professor reported that Ba, Th, U, Cr, and Sc, display virtually identical depth profiles indicating that the entire suite of metals is useful as geochemical vectors for targeting deeper mineralisation.
This is interpreted as evidence that the distinctive vector – depth profiles are in some way related to that the conductivity anomalies (MT flares) identified in magnetotelluric data below Burra. Thus, they are most likely the result of mineralisation.
The review concluded that the metal association of rare earth elements, yttrium, scandium, nickel, chromium, cobalt, and copper as well as gold, suggests the likely presence of a deeper alkaline ultramafic sourced mineral system at Conductive Target 1.
AMG announced that further work includes early stage exploration, DHEM, and follow up of any significant copper and/or gold anomalies, including additional interpretation of geophysics data, reviews and assessments of targets, and infill geochemical sampling of anomalies in preparation of follow up drill testing.
Ausmex Managing Director Matt Morgan said: “The initial assay results and interpretation within the Collerson Report have far exceeded our expectations yet confirm the prospectivity for Burra to host significant mineralisation associated with the AMT Conductive targets.
The combination of an AMT conductive target, with indicator mineral assemblage ratios increasing at depth towards the conductive unit, present highly prospective Diamond Drill targets.
This is further confirmed by Professor Collerson’s interpretation that the mineral assemblage may be associated with a deeper alkaline mafic source adds to the prospectivity.
The company will continue to update shareholders on further drilling results from Burra as we carefully evaluate all that we have learnt from the recent drilling program, we consult with our independent experts and advisors and as progress towards Diamond core drilling at Burra.”