(Nickel-Copper, Zinc-Copper-Silver & Gold)
The Rockford Project is located in the highly prospective Fraser Range district of Western Australia and covers a total area of 2,378km2 (Figure 1). Exploration is primarily focussed on Nova-Bollinger style nickel-copper, along with volcanogenic massive sulphide (VMS) style zinc-copper-silver and Tropicana style structurally controlled gold mineralisation.
The Project comprises both 100% Legend owned tenure (238km2) and three separate joint ventures (2,140km2) involving Legend, Creasy Group (Creasy) and Independence Group NL (IGO) with varying interests (see ASX announcement 9 July 2019). Legend is the manager and operator of the Legend (70%)-Creasy (30%) joint venture covering 1,482km2 and non-manager of the IGO (70%)-Legend (30%) and the IGO (60%)-Creasy (30%)-Legend (10%) joint ventures over 658km2.
The Rockford Project comprises 12 contiguous granted exploration licences covering 2,378km2, located some 120km northeast of the Nova-Bollinger nickel-copper deposit. Importantly, the package covers a strike length of 100km over a regional gravity high “ridge” associated with dense mafic/ultramafic intrusive rocks of the Fraser Zone, within the larger Albany-Fraser Orogen. The Nova-Bollinger deposit and the recently discovered Silver Knight nickel-copper deposit, both of which lie within the Fraser Zone, are situated on a similar tenor gravity ridge to that of the Rockford Project, see Figure 2.
In 2015 Legend acquired an extensive exploration dataset over the entire Rockford Project, which is constantly being added to by Legend’s activities and reinterpreted/interrogated to identify specific areas for follow up exploration. These high quality datasets include:
- Project wide high resolution aeromagnetic data at 50m line spacing
- Detailed gravity data over an 800m/400m x 100m grid, comprising 35,600 stations
- Aircore drilling with multi-element analysis of bottom-of-hole samples
- Detailed petrological descriptions of bottom-of-hole aircore samples
- Project wide soil and calcrete geochemical sampling over an 800m x 400m grid.
Exploration activities completed by Legend over the Rockford Project since the commencement of the JV on 23 September 2015 include:
- Project wide aeromagnetic data interpretation
- 3D inversion modelling of the aeromagnetic and gravity data
- Moving loop electromagnetic surveys over 26 target areas, 233km2
- Fixed loop electromagnetic surveys over five target areas, 4.8km2
- Four diamond drillholes targeting EM conductors, totalling 2,652.1m
- Ten RC drillholes targeting EM conductors, totalling 2,266m
- Downhole electromagnetic surveys in six drillholes
- Aircore drilling 637 holes totalling 44,936m
- Two detailed infill aeromagnetic surveys, 534km2
- Three detailed gravity surveys, 10,294 stations
- Target selection and evaluation.
Exploration results to date have highlighted four priority prospects as shown on Figure 3. These include; magmatic nickel-copper sulphide style targets at Area D and Crean and VMS style zinc-copper-silver targets at Shackleton and Worsley. Legend’s regional exploration programmes involving aircore drilling and moving loop electromagnetic surveys are ongoing and designed to systematically test targets identified from the aeromagnetic and gravity datasets.
Follow up RC and diamond drill programmes will be undertaken as required.