Pacifico Minerals has announced an initial exploration target for its Lorella Project in the McArthur Basin, Northern Territory, Australia.
The Project area contains high potential for significant additional tonnages of oxide copper mineralisation, a small section of which has been drilled by Sandfire Resources NL.
The Lorella Project lies within EL26939 of the Borroloola West Joint Venture (“BWJV”) which consists of 12 exploration licences and 1 mining licence (1,817 km2 ). The parties to the BWJV are 51% Pacifico Minerals Limited (“Pacifico” or “Company”) and 49% Sandfire Resources NL (“Sandfire Resources”) (ASX: SFR).
Data from drilling programs completed during 2010 and 2011 at the Lorella Prospect has been reviewed and reinterpreted. Intersections with significant oxide copper mineralisation are compiled in Appendix 1.
Drilling to date over the known oxide copper mineralisation only covers a small area of 350m x 400m (Figure 2). Considerable potential exists at Lorella for additional oxide copper resources along the strike extension of the subcropping stratabound mineralised horizon.
An Exploration Target of 5 to 10Mt of 0.8% Cu to 1.1% Cu of oxide copper mineralisation is estimated. The grades of the Exploration Target are derived from the grades of mineralised blocks defined by 18 RC and diamond holes in the drilled area of oxide copper mineralisation (Appendix 1). The tonnage estimates are based on an estimate of the occurrence of pods of oxide copper mineralisation over 12km of strike under shallow alluvial cover.
The oxide copper mineralisation consists of disseminations, veins and fracture fill of malachite and azurite within highly leached siltstone and fine grained sandstone. Using a 0.4% Cu cut-off, the drill intersections average 1% Cu and have an average vertical thickness of 8m (Appendix 1). The mineralisation is flat or gently dipping and beneath just 20 to 30m of unconsolidated alluvial overburden. The mineralisation is related to the base of the unconsolidated recent alluvium, and gently west dipping, stratabound horizons within the underlying Amelia Dolomite.
Preliminary acid leach test work recently carried out at SGS Metallurgy in Perth, returned highly positive results and indicates that leaching the oxide copper material could be economically viable. If further oxide copper mineralisation can be defined there is potential for a low capital and operating cost operation, to open-cut mine the unconsolidated alluvial overburden and weathered oxide copper mineralisation, and produce cathode copper from a solvent extraction, electrowinning plant (“SXEW”).
Planned Aircore Program
An aircore program (2000m) at Lorella is planned to commence late November to test strike extensions of the oxide copper mineralisation to the NW and SSE to validate the Exploration Target and increase the potential for oxide copper resources, prior to definition reverse circulation and diamond drilling after the wet season has passed in early 2018, which if positive could provide a maiden mineral resource. The upcoming 40 hole program will also test for significant indications of primary copper mineralisation to a depth of approximately 50 metres.