White Cliff Minerals (ASX: WCN) has identified ten anomalous electromagnetic responses from a technical review of historical high level airborne electromagnetic survey at its Merolia nickel-copper project in Western Australia.
The review by geophysical consultants Newexco found the EM responses coincide with either the basal contact of the Diorite Hill layered mafic-ultramafic intrusion or contacts between mafic and ultramafic layers within the intrusion.
Both positions are consistent with the optimal locations for the deposition of nickel and copper sulphides within layered mafic ultramafic intrusions.
Geochemical soil sampling targeting the EM responses and the basal contact has also been completed with results expected by the end of April.
This was designed to confirm the prospectivity of the areas of anomalous EM response and to identify any nickel-copper soil anomalies along the 30 kilometre long basal contact.
"Field exploration is rapidly advancing the Merolia nickel and copper project with the current geochemical survey expected to generate several new nickel-copper targets," managing director Todd Hibberd said.
"The geochemical survey will be followed by geophysical surveys that are expected to generate multiple defined EM conductors that will be drilled in the second half of 2014.
"The prospective parts of the project extend over 80 kilometres and are along strike from the Rosie and Camelwood nickel sulphide discoveries to the north and the Mulga Tank nickel discovery to the south."
Electromagnetic Survey Review
Newexco has identified seven priority one, two priority two and one priority three anomalous responses from the data.
It noted that due to noisy data it was difficult to confirm whether all or some of the anomalous EM responses were due to bedrock conductors.
Detailed ground electromagnetics will be required to confirm bedrock conductors and to provide sufficient detail to plan drill hole locations.
Based on the review, White Cliff has undertaken and completed a comprehensive 1350 sample geochemical soil sampling program covering the areas of anomalous EM response and along the basal contact of the Diorite Hill layered mafic ultramafic intrusion and the Rotorua ultramafic complex.
Assay results for the survey are expected in the coming weeks.
Merolia Nickel-Copper Project
The Merolia Project licences cover 771 square kilometres in the Merolia Greenstone belt, a region prospective for magmatic nickel and copper sulphides and orogenic gold deposits.
It contains extensive ultramafic sequences including the Diorite Hill layered ultramafic complex, the Rotorua ultramafic complex, the Coglia ultramafic complex and a 50 kilometre long zone of extrusive ultramafic lava's.
The Intrusive complexes are prospective for nickel-copper sulphide accumulations possibly with platinum group elements, and the extrusive ultramafic rocks are prospective for nickel sulphide and nickel-cobalt accumulations.
The project also contains extensive basalt sequences that are prospective for gold mineralisation including the Ironstone prospect where historical drilling has identified 24m at 8.6 grams per tonne gold.
Merolia is highly prospective for two types of nickel and copper sulphide mineralisation:
- Intrusive layered mafic-ultramafic related basal margin nickel and copper sulphide accumulations; and
- Extrusive lava channel Kambalda style nickel sulphide deposits.
At Diorite Hill, historical exploration including soil sampling and limited drilling has identified several areas with anomalous nickel mineralisation including one area containing 6 metres at 1.8% nickel in laterite overlying ultramafic portions of the layered intrusion.
Recent re-evaluation of the historical work has identified the basal contact on the south-west margin of the intrusion and the company is targeting this contact for nickel-copper accumulations of the same style as the Nova-Bollinger and Voisey Bay Nickel deposits.
Wide spaced historical soil sampling has highlighted two coincident copper-nickel anomalies on the basal contact.
No drilling or geophysics has previously tested the basal contact of the intrusion and White Cliff will carry out modern multi element soil sampling and geophysics across this contact to identify discrete drilling targets prior to drill testing.
The Rotorua ultramafic complex consists of a 10 kilometre by 1.5 kilometre intrusive ultramafic sill interpreted to be the feeder conduit of the Diorite Hill intrusion.
Virtually no historical nickel-copper exploration has been conducted over the complex except at the southern tip where there is a strong nickel in soil anomaly.
The company will carry out modern multi element soil sampling and geophysics across this contact to identify discrete drilling targets prior to drill testing.
Meanwhile, White Cliff is targeting nickel and copper sulphide accumulations along the basal contact of individual lava flow channels at the Coglia ultramafic complex, which covers a 7 kilometre by 2 kilometre area.
The complex consists of a sequence komatiitic lava flows dipping steeply to the west. The base of the flows consists of heavier crystals of cumulate textured olivine that have settled to the bottom due to their weight. This is the ideal location for the accumulation of nickel and copper sulphides that also settle to the bottom of lava flows due to their weight.
Historical drilling has identified extensive nickel mineralisation within the overlying laterite and saprolite profiles. Several discrete areas within the saprolite profile are highly anomalous in nickel, copper and platinum.
Due to the width of the komatiitic sequence and the large number of lava channels several target horizons have been identified.
Merolia also contains extensive mafic and felsic sequences, prospective for gold mineralisation, located in a region that contains the 2 million ounce Barnicoat gold mine, the Fish and Lord Byron gold deposits and the Brightstar gold deposit.
The most advanced gold prospect is the Ironstone gold prospect, where previous drilling intersected 24 metres at 8.6g/t gold from 113 metres.
Analysis
While nickel-copper exploration at the Merolia Project is still at its early stages, the rapid pace that White Cliff Minerals is setting should soon result in the generation of several drillable targets.
These will be drilled in the second half of 2014, giving the company a firm understanding of the nickel prospectivity of the project which hosts a number of extensive ultramafic sequences including Diorite Hill.
The prospective parts of the project extend over 80 kilometres and are along strike from Independence Group's (ASX: IGO) Rosie and Rox Resources'(ASX: RXL) Camelwood nickel sulphide discoveries to the north and Impact Minerals (ASX: IPT/Golden Cross Resources' (ASX: GCR) Mulga Tank nickel discovery to the south.
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