Impact Minerals Limited announced that a diamond drill programme of up to 1,100m will commence this week at its newly named Yellowstone prospect and which is being funded by joint venture partner IGO Limited. The Yellowstone prospect is part of the greater Platinum Springs project area which lies at the southern end of the Moorkai Trend, a nine kilometre long ultramafic to mafic dyke and chonolith complex that is very poorly explored. Two diamond holes have been planned to test a significant electromagnetic (EM) conductor identified by IGO in an extensive ground EM survey completed across the project area earlier this year.

The EM plate is located approximately 1,000 metres southeast along strike from the main Platinum Springs Prospect where previous drilling by Impact returned a narrow intercept of high-grade massive sulphide mineralisation in PSD002 that returned: 0.6 metres at 11.5 g/t platinum, 25.6 g/t palladium, 1.4 g/t gold, 7.6% copper, 7.4% nickel, 44.3 g/t silver, 0.16% cobalt, 1.3 g/t rhodium, 1.7 g/t iridium, 2.0 g/t osmium and 0.8 g/t ruthenium from 57.1 metres down hole. A down hole EM survey of PSD002 indicated the massive sulphide had a high conductance greater than 5,000 siemens and similar to that modelled for the new conductor. The new EM conductor has been modelled to have a high conductance of about 8,000 siemens and with the top edge of the modelled EM plate centred at a depth of about 350 metres below surface.

It has a length of about 420 metres and extends for at least 85 metres down dip moderately to the south. Field checking by IGO identified ultramafic and mafic rocks that were possibly related to the target Moorkai Trend intrusion which is much younger (c. 825 Ma) than the majority of the rocks at Broken Hill (c. 1650 Ma). The Platinum Springs Prospect lies at the southern end of the Moorkai Trend, a nine kilometre long ultramafic to mafic dyke and chonolith complex that is very poorly explored.

Although high grade rock chips occur along the entire Trend, only the southern end has been explored in detail but with limited success prior to Impact's work in the area. This is because the mineralisation appeared to be discontinuous and erratic and the controls on its distribution were poorly understood. Work by Impact, including extensive drilling, identified high grades of nickel-copper-PGM's in a channel-like structure at the base of the ultramafic unit and which has yet to be followed up.

The channel-like structure was identified in close-spaced drilling using Impact's proprietary ratio for PGM mineralisation and was the first coherent zone of mineralisation defined in the area in over 30 years of exploration. This work led to a new geological framework within which to understand the Moorkai Trend (ASX Release 9th March 2021). The new EM conductor is located within a major structure to the southeast of the main outcrops of the Moorkai intrusive complex.

It is possible that the Moorkai Trend formed in a large (now folded) perpendicular structure between two major shear zone structures which bound the intrusive complex. These shear zones may be so-called "feeder zones" to the mafic-ultramafic rocks along the Moorkai Trend and also raise the possibility that the Trend continues to the south to southeast where similar strongly magnetic rocks occur under thin cover. Recently published scientific work, and by the CSIRO in particular, has shown that many chonoliths and other steeply dipping mafic-ultramafic intrusions that host significant massive sulphide deposits, commonly have mineralisation within conduits that act as feeder zones to the entire intrusive complex.

These feeder zones are priority target areas because the research work has also shown that within intrusions with strong vertical magma flow, massive sulphides are often deposited as the magma slows its ascent and drains back down into the main conduit. This "back flow" can cause deposition of massive sulphides in the feeder zone as proposed in a very elegant model for chonolith development developed by Professor Steve Barnes and co-workers at CSIRO. Impact has been using this model to help drive its exploration programme at Broken Hill.

Accordingly, the Company views the new conductor identified by IGO as a compelling target.