Nexus Minerals - Pinnacles Gold Project Returns Multiple Auger Soil Anomalies
Nexus Minerals Limited (ASX: NXM) has returned multiple auger soil anomalies over the Pinnacles Gold Project, with a maximum assay result of 1.55g/t Au. The anomalies are coincident with geological features and/or magnetic or gravity structures. Two of the anomalies have a strike length in excess of 2.4km and will be followed up in the next round.
HIGHLIGHTS
Pinnacles gold project Phase 1 regional auger soils exploration program completed:
- Maximum auger soil result of 1552 ppb Au
- 2.4km x 300m Au anomaly (GT5) – coincident over sheared ultramafic unit, aeromagnetic target and gravity low
- 2.5km x 1.5km coincident Au + As / Bi / Mo (Au pathfinder elements) anomaly
- Multiple auger soil geochemical anomalies identified
- Ground geological / structural mapping completed over auger soils coverage area
- Gravity survey over tenement package completed
Eastern Goldfields gold explorer, Nexus Minerals Limited (ASX: NXM) (Nexus or the Company) is pleased to announce the results of its auger soil geochemical sampling program, the regional gravity survey and ground geological activities over the highly prospective Pinnacles regional 100km2 tenement area.
Nexus Minerals tenement package is largely unexplored and commences less than 5km to the south of, and along strike from, Saracen Minerals (Saracen) >4Moz Carosue Dam mining operations, and current operating Karari underground gold mine.
Nexus holds a significant land package (100km2 ) of highly prospective geological terrain within a major regional structural corridor, and is actively exploring for gold deposits.
Auger Soil Geochemical Program
Auger sampling targeting calcareous soils (calcrete) has been successfully employed as the preferred geochemical sampling medium for gold exploration in the goldfields for the past decade. Mineralisation in the Carosue Dam district, including Karari, Whirling Dervish, Luvironza, Monty Dam and Twin Peaks deposits were all identified using this technique.
This phase 1 program (Fig. 2 and 3) has been designed to cover an area of prospective geological units, and north/south structures (Fig. 4) that also exhibit gravity lows (Fig. 6) – the “ingredients” of Carosue Dam style mineralisation. The program also traversed a number of aeromagnetic “area of interest” targets previously identified (Fig. 7).
988 auger samples were collected across the northern 25% of the tenement area. Samples were collected on a 400m x 80m grid and analysed for gold and 32 additional pathfinder elements to identify mineralisation and as a lithological mapping tool.
- GT5 – This is a high order 2.4km x 300m Au anomaly (max 61.7 ppb Au) showing good strike continuity across six of the 400m spaced survey lines. The anomaly is striking north-south within a sheared ultramafic unit. This area is located in a gravity low and had been highlighted previously as a zone of interest from Nexus regional aeromagnetic assessment and interpretation. Infill auger soil lines at 100m x 80m will be undertaken to better constrain the anomaly boundaries prior to planning drill activities.
- 1552 ppb Au auger soil result – This extremely high-level result, and a number of anomalous results immediately to the west, highlight the prospective nature of this ground. Only a small number of auger holes intersected the required calcrete sampling layer - and hence the sampling method in the majority of this area is considered ineffective. This eastern side of the auger program is in an area where the regolith profile, and the calcrete layer, has been largely stripped away and will require aircore drilling to determine its prospectivity.
- Broad anomalous zone – elevated in Au +As/Bi/Mo (Au pathfinder elements) – this 2.5km x 1.5km zone contains a gold anomaly (max 47 ppb Au) that surrounds a pathfinder element anomaly elevated in As, Bi and Mo. The structural setting is significant as it is located on the same fault that displaces the Karari and Whirling Dervish gold mines to the north east. Mapping has identified sheared and silicified tuff and volcaniclastic sedimentary units, with local felsic intrusive. Detailed mapping will be undertaken over this anomaly to better define geology and structure prior to further sampling programs.
- Triple/Double/Single sample site anomalies – multiple sample site elevated gold results >9 ppb Au, with a maximum of 20.8 ppb Au. With the initial broad 400m x 80m sample spacing providing significant scope to host significant mineralisation. These areas require ground geological truthing and infill auger soil lines to better define these anomalies.
Geology and Structure
The project tenements are underlain by a north-south trending Archaean greenstone sequence with the Carosue Basin volcaniclastic sediments dominating to the east of the Yilgangi fault. To the west of the Yilgangi fault a more mafic dominated package is observed consisting of volcaniclastic sediments intercalated with basalt and ultramafic rock units with minor units. This greenstone sequence is sandwiched between two ovoid Archaean granitoid plutons to the east and the west.
Structurally the region is cut by a series of north-south trending faults with offsets of tens to hundreds of metres. These faults are particularly common in this Carosue Dam region as the greenstone belt passes through a relatively narrow “neck” between the two granitoids. This is also the area where most of the known Carosue Dam mineralisation is concentrated.
Mineralisation is known to occur proximal to, and east and west of the Yilgangi fault. This fault is a major feature that dissects the Nexus tenement package for a strike distance of some 15km. It can clearly be seen as a “spine” feature on the gravity survey map (Fig. 6).
Another significant feature of the Carosue Dam style mineralisation is the presence of numerous quartz-poor igneous intrusions including lamprophyres, that have intruded the greenstone sequence. Lamprophyres are usually associated with voluminous granitoid intrusive episodes and are known to be spatially and temporally associated with gold mineralisation. They represent the injection of volatile rich magmas from deep sources along major structures – associated with gold mineralisation.
Encouragingly diamond drill core from the Pinnacles East resource area, completed December 2016, intersected a carbonate-chlorite-biotite altered lamprophyre (Fig. 5), confirming that the emplacement of this rock type continues through the Nexus tenement package
