This Study is primarily based on the mining and processing of the magmatic Ni-Cu-Co sulphide Resources hosted by the Savannah North Intrusion (SNI) located to the north of the Savannah Mine. The mineralised character of the SNI was identified by Panoramic in February 2014 when underground exploration drilling from the mine intersected broad zones of Ni-Cu-Co rich massive sulphide mineralisation 600m north of the mine beneath the surface expression of the SNI.
Exploration diamond drilling continued throughout most of 2014, with 16 surface drill holes and nine underground holes completed for a total of 27,700 drill metres. Resource diamond drilling at Savannah North commenced in April 2015, following completion of the 1570 Savannah North Access Drive, with a further 38 underground resource drill holes totalling 15,300 drill metres completed at Savannah North to September 2015.
Between February and July 2016, the Company completed a further program of Resource drilling at Savannah North to build on the 2015 programs. The 2016 drill program was undertaken from the 1570 Drill Drive and involved the completion of 27 new drill holes (KUD1573 to KUD1598) and the extension of two 2015 drill holes (KUD1550A and KUD1546), for a total of 13,407 drill metres.
The Savannah North deposit is predominantly composed of two discrete zones of mineralisation, the Upper Zone and Lower Zone. The Upper Zone relates to mineralisation developed on or about the basal contact of the SNI. The Upper Zone mineralisation strikes east-west and dips moderately to the north.
To the east of Section 5750mE, the Upper Zone mineralisation is dominated by massive sulphide mineralisation developed at the base of the SNI in contact with the underlying Tickalara Metamorphics (Figure 1). The massive sulphide mineralisation is typically 5-8m thick and dips between five and 40 degrees to the north. Post-mineralisation dykes frequently cut and dilate the Upper Zone mineralisation between 5800mE and 6100mE.
To the west of Section 5750mE, the Upper Zone mineralisation appears to be developed within the SNI and is typically underlain by a 20-30m thick contaminated chilled contact zone of noritic composition. Here the Upper Zone mineralisation is typically 15-20m thick and is dominated by strong matrix mineralisation (20-40% sulphides). The matrix mineralisation frequently contains thin zones of higher grade semi-massive to massive sulphide mineralisation.
The Savannah North Lower Zone relates to a consistent zone of higher grade, off-contact massive sulphide mineralisation (Figure 2). The Lower Zone mineralisation is predominantly developed within the Tickalara Metamorphics underlying the SNI and is interpreted to originate from the Upper Zone mineralisation. It is up to 15m thick and dips 50-60 degrees towards the northwest. In places, the Lower Zone mineralisation appears to coincide with dykes related to a possible link structure between the 500 and 900 Faults.
The Upper Zone mineralisation remains open to the east and west (Figure 3). The western extent of the Upper Zone is currently defined by surface drill hole SMD164 (5.05m @ 2.62% Ni) on Section 5400mE. This intersection is coincident with a very large, highly conductive down-hole electromagnetic response (DHEM), which previous geophysical modelling indicated may extend a further 1km to the west from SMD164 (refer to the Company’s ASX announcement of 25 August 2015). The latest surface drilling in this area on Section 5100mE (drill holes SMD167 and SMD167A) supports this interpretation, but also indicates that the orientation of the Upper Zone has adopted a more north-westerly trend in this area. To the east, recent drilling indicates the Upper Zone may extend to within 50m of surface drill-hole SMD170 (refer to the Company’s ASX announcement of 31 January 2017). The Lower Zone mineralisation is open down dip to the northwest.
Panoramic considers the Savannah North system to have significant upside, and notes the following:
- The 2016 Resource drilling program has not closed off the mineralisation;
- The potential strike length of the Upper Zone is currently understood to be approximately 2km based on the large, highly conductive on-hole EM responses identified in surface drill holes SMD164 on Section 5400mE and SMD167 and SMD167A on Section 5100mE and therefore less than 35% of the potential Upper Zone mineralisation has been tested by resource drilling; and
- The Lower Zone Resource remains open down dip to the northwest.
Figure 1 – Savannah North Cross Section 6100mE, showing Upper Zone mineralisation.
Note: drill-hole intersections are downhole thicknesses, not true width
Figure 2 – Savannah North Cross Section 5800mE, Upper Zone and Lower Zone mineralisation
Note: drill-hole intersections are downhole thicknesses, not true width.
Figure 3 – Plan view showing location of the Savannah and Savannah North Intrusions, Upper and Lower Zones, and possible extensions