Impact Minerals (ASX: IPT) says indications are that it has a very large mineral inventory at the Rockwell prospect, part of its Little Broken Hill Gabbro (LBHG) project, after striking anomalous copper, nickel and platinum group elements (PGE).
LBHG lies about 25 km south of the town of Broken Hill in New South Wales and is the largest of a suite of mafic to ultramafic intrusions that occur in a 40km-long belt from Little Broken Hill in the south west to Red Hill, Darling Creek, Platinum Springs and Moorkai in the north east.
Reconnaissance drill holes and survey data show a strongly anomalous zone over at least 1.5km.
This follows the first ever drill program at the project’s ground.
Disseminated copper sulphide is present in zones up to 25m in true thickness, increasing to the south towards an interpreted feeder zone for magmatic nickel-copper-PGE sulphides
Disseminated nickel sulphide occurs in thick layers within the copper sulphide zones.
The company says that, while assays from key drill holes are still awaited, new assays and electronic surveys indicate the mineralisation appears to be increasing in thickness and grade from north to south into a priority target area with a possible feeder zone.
Similar to giant China deposit
Feeder zones are fault-controlled conduits through which hot magma migrates into a larger intrusion.
Impact noted that its work has shown LBHG to be of a similar size, age, chemical composition and in the same geodynamic setting as the giant Jinchuan nickel-copper-PGE deposit in China which comprises 500 million tonnes at 1.1% nickel, 0.7% copper and 0.5% PGE.
The company has completed 28 drill holes at Rockwell for 2,412m with assays from another 41 drill holes awaited.
Impact says extensive follow-up drilling is “clearly required” at Rockwell “and in all likelihood other places within the LBHG”.
Drilling will resume as soon as practicable in the first quarter of 2021 and the company is now in discussions with drilling contractors.
The mineralisation occurs mostly within an ultramafic unit at the base of LBHG.
Impact says this confirms the prospectivity of the whole 6km-long intrusion — as predicted from the company’s previous work in the area.