Summary:
The Sconi deposits are hosted in laterites which have formed on ultramafic rocks that include serpentinites, meta-gabbros and pyroxenites. These occur as lower crustal material rich in iron, magnesium and nickel. It is likely that these laterites formed following a period of prolonged weathering post the Cretaceous era.
Ultramafic rocks have a high background level of nickel and cobalt and the process of lateritisation has concentrated the nickel and cobalt to grades which have the potential to be exploited economically.
The laterite profiles are well preserved with the drill holes intersecting a complete laterite profile, from natural surface soil cover down to poorly mineralised bedrock. Each deposit varies with respect to geological profile and mineralisation, with Kokomo and Lucknow enriched in scandium, while Greenvale appears less enriched in scandium.
The Sconi project comprises three granted mining leases with the main deposit located at Greenvale together with two satellite deposits at Lucknow and Kokomo.
Greenvale and Lucknow
The Sconi Mineral Resource is contained within a saprolite, developed by weathering process over fragments of ultramafic basement rocks. Ni and Co have been enriched from the ultramafic rocks by both residual and supergene processes. Sc is less enriched at Greenvale than the other deposits, however higher Sc levels are recorded from drill samples obtained from the waste dumps, allowing these dumps to be assessed for inclusion in the Mineral Resource.
Serpentinites are interpreted as being formed in shear zones at the top edges of a meta-gabbro. Through the central regions of the deposit the serpentinite and resultant saprolite are generally flat lying at shallow depth and become steeper with several structures dipping up to 70° on the edges of the deposit. Weathering is preferentially superimposed on the softer serpentinite, resulting in the formation of limonite hosted nickel mineralisation and the formation of cobalt mineralisation, via the scavenging of cobalt by the accumulation of MnO near the base of the weathering profile.
Kokomo
The Kokomo Mineral Resource is contained within a laterite, developed by weathering process over fragments of ultramafic basement rocks. nickel, cobalt and scandium have been enriched from the ultramafic rocks by both residual and supergene processes.
The ultramafic complex and overlying nickel laterite form an elongated north-northeast trending body bounded by predominantly siltstones on the eastern and western margins. These margins display a marked increase in nickel, scandium and cobalt content.
Dimensions
The Greenvale Mineral Resource is approximately 2,700 m in strike length, between 150 m and 1,300 m in plan width, and extends to a depth of approximately 50 m below surface.
The Lucknow Mineral Resource is approximately 3,900 m in strike length, between 150 m and 350 m in plan width, and extends to a depth of approximately 50 m below surface.
The Kokomo Mineral Resource is approximately 4,800 m in strike length, between 330 m and 770 m in plan width, and extends to a depth of approximately 40 m below surface.