K U M A  S O L O M O N  I S L A N D S

Porphyry Copper- Gold

Exploration Manager Jason Ward (right) with a local community member. 

Exploration Manager Jason Ward (right) with a local community member. 

SolGold has streamlined its in-country presence after significant drill testing reduced the prospectivity of the Fauro, Koloula and Malakuna tenements.  The exciting Kuma project in Guadalcanal has emerged as a significant porphyry copper-gold target upgraded by recent geochemical and spectral work by GEX in 2014-15.  

Kuma Project (100% owned application) 

Location:                37km south-east of the capital Honiara, Solomon Islands
Ownership:            100% owned
Tenement Area:      43km2
Primary Targets:     Copper gold porphyry deposits

The Kuma project lies just to the south-west of a series of major NW-SE trending arc-parallel faults. These faults are associated with numerous Cu and Au anomalies, including the Sutakiki prospect and the Mbetilonga prospect (formerly part of the Guadalcanal Joint Venture).  The project area overlies a 3.5‐kilometre wide, annular, caldera‐like topographic feature.  Annular and nested topographic anomalies in the region suggest the presence of extensive batholiths of the Koloula Diorite beneath the volcanic cover of the Suta Volcanics.  The prospect geology is dominated by a 4km by 1km lithocap. This extensive zone of argillic and advanced argillic alteration is caused by hydrothermal fluids that emanate from the top of porphyry copper-gold mineralising systems, and thus provides a buried porphyry copper gold target (Figure 1).  

Figure 1: N-S section showing conceptual model over the Kuma prospect, showing geochemical zonation and an alteration lithocap overlying a buried porphyry copper‐gold system

Figure 1: N-S section showing conceptual model over the Kuma prospect, showing geochemical zonation and an alteration lithocap overlying a buried porphyry copper‐gold system

The geochemically anomalous portion of the Kuma lithocap (northwest end) lies within the annular topographic anomaly.  Kuma, has a spectacular oxidized float boulder trail along the Kuma River and was traced to Alemba and Kolovelo creeks which lead to discovery of broad hydrothermal alteration zones and lithocap (Figure 2).   

Figure 2: Geological setting of the Kuma lithocap along Tabala Ridge (left) and the discovery of classical porphyry style leached cap and lithocap rocks at Kololevu and Alemba creeks (right).

Figure 2: Geological setting of the Kuma lithocap along Tabala Ridge (left) and the discovery of classical porphyry style leached cap and lithocap rocks at Kololevu and Alemba creeks (right).

Figures 3 and 4: Previous exploration completed at Kuma under the Guadalcanal Joint Venture between SolGold and Newmont included extensive geochemical sampling (BLEG, rock chip and channel samples), geological mapping, a magnetic survey and an electromagnetic survey.  Geochemical results define a central zone of manganese depletion (Mn < 200 ppm) inferred to indicate the destruction of mafic minerals by hydrothermal alteration.   Zinc > 75 ppm forms an annulus to this zone, and Molybdenum > 4 ppm lies along the margins of the manganese low indicating potential for porphyry Cu-Au mineralization at depth. TerraSpec spectral analysis of sieved coarse fraction soil samples covering the Kuma lithocap area, was completed at a commercial laboratory in Australia.  The results integrated with known geology in the prospect area has highlighted a primary porphyry target centre in the northern portion of the lithocap. 

Figures 3 and 4: Previous exploration completed at Kuma under the Guadalcanal Joint Venture between SolGold and Newmont included extensive geochemical sampling (BLEG, rock chip and channel samples), geological mapping, a magnetic survey and an electromagnetic survey.  Geochemical results define a central zone of manganese depletion (Mn < 200 ppm) inferred to indicate the destruction of mafic minerals by hydrothermal alteration.   Zinc > 75 ppm forms an annulus to this zone, and Molybdenum > 4 ppm lies along the margins of the manganese low indicating potential for porphyry Cu-Au mineralization at depth. TerraSpec spectral analysis of sieved coarse fraction soil samples covering the Kuma lithocap area, was completed at a commercial laboratory in Australia.  The results integrated with known geology in the prospect area has highlighted a primary porphyry target centre in the northern portion of the lithocap. 

The prospecting licence (PL 08/06) expired on 11 April 2015 and accordingly the carrying value of $0.31 million was considered to be impaired and an impairment charge of $0.31 million (2014: $nil) was recognised during the year.

Figure 5: Soil geochemical zonation over the Kuma prospect showing a central molybdenum high with coincident manganese depletion with an annular zinc halo (left), and simplified geology showing extent of mapped silica-clay-pyrite (right).

Anaconda style geological mapping is planned for the coming year so as to bring the project to drill ready status in 2016. Three steeply-inclined diamond core drill-holes, each about 800 m deep, are envisaged for an initial test of the target area.  Drill Sites will be located following Anaconda style geological mapping within and peripheral to the target area.  Silica ledges and dickite anomalies controlled by high level structure can be tested to provide vectors toward the centre of the Kuma porphyry gold-copper system and the identification and orientation of dikes (porphyritic felsic), veins (quartz and epidote) and fractures (containing chalcopyrite or magnetite). 

Figure 6: Combined imagery showing summary of interpreted hydrothermal alteration zones and geochemical anomalies, over RTP magnetics.

Figure 6: Combined imagery showing summary of interpreted hydrothermal alteration zones and geochemical anomalies, over RTP magnetics.