The Sinclair Nickel Project includes an extensive 290km2 tenement package covering at least five known ultra-mafic volcanic sequences that are considered prospective for massive nickel sulphide mineralisation.
Numerous nickel occurrences have been identified through historical drilling, geochemical and geophysical surveys across the project, with key targets shown in the figure below.
Figure 1: Sinclair Nickel Project showing known ultra-mafic volcanic sequences considered prospective for massive nickel sulphide mineralisation over regional geology
The style of mineralisation likely to be found at Sinclair is Type-I Archean Komatiite hosted nickel sulphide deposits. These deposits, similar to those found throughout the greater Norseman-Wiluna Greenstone Belt, are accumulations of nickel sulphides at the base of Komatiite lava channel flows that occurred over 2.5-2.8 billion years ago. These accumulations of nickel sulphides are conductive and can be remotely detected by electro-magnetic (EM) surveys and geochemical analysis of overlying soils.
Following a detailed regional targeting program across the Sinclair Nickel Project and a high powered fixed loop electromagnetic (FLEM) survey at the Delphi Prospect, Talisman completed its maiden exploration drill program at Sinclair Nickel late in 2015. Five diamond drill-holes were completed across three prospects at Delphi North, Cody Well and Fly Bore for a total of 1,053 metres of diamond drilling and 1,960 metres of RC pre-collars.
Encouraging results were received in the first hole completed at Delphi. Detailed interpretation of results from this campaign will continue towards advancing the Talisman’s geological understanding of the prospects tested during this campaign and the prospectivity of the broader Sinclair Nickel Project.
This information will be used to refine the ongoing exploration strategy and future exploration programs.
The Delphi Prospect area, located 4km to the south of the Sinclair mine, has delivered historic high-grade nickel sulphide intersections in sparse historic drilling including:
- 0.44 metres at 5.43% Ni; and
- 0.32 metres at 2.99% Ni.
Reinterpretation of the geology extending south of Sinclair through the Delphi Prospect area has shown similarities in the ultramafic rock units to those seen at Sinclair Nickel. In addition, the recently completed geophysical program has identified EM anomalies are now interpreted to lie in favourable stratigraphic positions and are interpreted by Talisman to represent possible accumulations of nickel sulphide mineralisation.
Modern, high-powered geophysical moving loop electromagnetic (MLEM) surveys were recently completed at Delphi. Assessment of the results of the MLEM surveys has identified five high priority EM anomalies, three anomalies at Delphi North (constituting one target area) and two anomalies at Delphi South.
Figure 3: Plan view of Delphi geology showing geophysical EM anomalies, historic intercepts and planned drilling
The newly identified EM anomaly at Delphi North was modelled as a 200m x 200m plate with a late-time response at a very high conductance at a depth of 230m below surface (see Figure 3). The Delphi Prospect is the highest priority exploration target.
This EM anomaly sits parallel to, and below, two historical, re-interpreted down-hole EM anomalies generated from sparse historical drilling. Historical drilling adjacent to this new anomaly intersected a narrow zone of mineralised massive sulphides (0.32m @ 2.99% Ni).
Following the geophysical surveys, drilling targeting the interpreted MLEM anomaly, intersected a number of massive, matrix and breccia sulphide horizons in a deformed sequence of host ultramafic and basaltic rock units. Assays from this drill-hole returned an overall intercept of 2.2m @ 1.9%Ni from 397m in SND001.
The main sulphide intersection within the hole is represented by a total of 1.4 metres of massive, matrix and breccia sulphides within a 2.2 metre interval, with narrow zones of strongly foliated basaltic rocks from 396.9m to 399.1m down‑hole (true width not known at this time). The vertical depth of this intersection is approximately 348m below surface.
Drill-hole SND002, (see Figure 3) which was completed approximately 100m south of SND001, intersected a narrow zone of stringer sulphides within a highly deformed, complex sequence of ultramafic, basaltic and sedimentary rock units. While the stringer sulphides intersected by this hole are not interpreted to host significant mineralisation, the hole demonstrates the continuity of the fertile ultramafic horizon at Delphi North.
In conjunction with historical intersections at Delphi North, the recent drilling has now defined nickel sulphide mineralisation over a strike length of 600m. Talisman interprets these results to represent a fertile mineralised environment that has the potential to host significant mineralisation, and Talisman will continue detailed work to unlock this potential.
The first EM anomaly at Delphi South is modelled as a 570m x 150m plate with a late-time response at a moderate conductance, at a depth of 150m below surface (see Figure 3). This anomaly, originally defined in historical geophysical surveys, has been confirmed and refined by the recent MLEM surveys.
The anomaly is interpreted to lie in a prospective stratigraphic position and is considered to represent potential for massive sulphide accumulations. The second of these newly identified high priority targets is a surface MLEM plate located in the south western extent of Delphi South (see Figures 2 & 3). The EM anomaly is modelled as a discrete (i.e. not stratigraphic) 75m x 75m plate, with a late-time response at a very high conductance, starting at a depth of 150m below surface.
Talisman interprets that this target has the potential to open up a new mineralised horizon at Delphi and it may represent a continuation of the western ultramafic seen at the Sinclair Nickel Mine.
At Delphi Central, an historical drill intercept of 0.8m @ 1.27% Ni did not generate an EM anomaly in the recent MLEM survey, but Talisman believes this was due to its proximity to a stratigraphic conductor.
In conjunction with a planned DHEM program following the planned drill program, Talisman intends to re-enter and survey selected historical drill-holes where the application of high-powered DHEM surveys could generate vectors towards massive sulphide mineralisation in this area.
The Fly Bore Prospect is located ~15km north of the Sinclair Nickel Mine and hosts more than 10km of prospective ultramafic stratigraphy. As part of the exploration program, Talisman has completed two diamond drill-holes to target re‑interpreted geophysical anomalies identified as part of the project targeting review (See Figure 4).
Figure 4: Fly Bore Prospect showing interpreted geology, geophysical anomalies and location of drill-holes SND004 and SND005
Drill-hole SND004 was drilled to target coincident historic DHEM and FLEM anomalies that are interpreted to lie in a favourable stratigraphic position. The drill-hole intersected 0.5m of matrix and breccia-style sulphides on the contact between the ultramafic rocks and the interpreted basaltic footwall sequence.
Disseminated sulphides were also encountered over a zone of 36 metres within high magnesian ultramafic rocks above the matrix and breccia sulphides. Visual inspection of the sulphide mineralisation has identified pyrrhotite as the dominant sulphide mineral with accessory chalcopyrite also noted. No significant assays were received from the analysis of these samples.
Drill-hole SND005 was drilled to target a historic FLEM anomaly interpreted to lie in a favourable stratigraphic position. The hole intersected a sequence of sheared ultramafic rocks over approximately 10 metres but did not intersect any visible sulphide mineralisation.
Bedrock drilling across the Fly Bore Prospect remains very sparse with exploration of the area considered still to be at a very early stage. Talisman is encouraged by the intersection of sulphide mineralisation at the interpreted base of a significant ultramafic sequence and will use these recent results to advance the company’s exploration strategy for this area.
DHEM surveys will also be completed on these holes to help guide future exploration activities.
Other Fly Bore Prospects
At Fly Bore North and Fly Bore West there are two geochemical anomalies that are interpreted to lie in favourable geological positions (see Figure 4). Talisman intends to complete MLEM surveys over these areas as part of future planned geophysical programs prior to the end of the year.
The Cody Well Prospect is located approximately 3km north of the Sinclair Nickel Mine (see Figure 5).
One diamond drill-hole was completed at Cody Well to target a priority EM anomaly interpreted to lie in a favourable stratigraphic position along strike from the Sinclair deposit and an associated coincident geochemical anomaly.
Figure 5: Cody Well Prospect showing interpreted geology, geophysical anomaly and location of drill hole SND003
Other Regional Targets
On completion of the Delphi geophysical survey, Talisman completed a small fixed-loop electromagnetic (FLEM) survey at the Sinclair East Prospect, to test the interpreted up-dip extensions of the Sinclair host ultramafic unit and along strike of the Sinclair nickel sulphide mineralisation where there is limited historical drilling. This survey confirmed the existence of a discrete, late-time EM anomaly located on the interpreted Sinclair ultramafic contact. Detailed interpretation and modelling of this anomaly is ongoing.
The maiden exploration program at Sinclair Nickel Project represents the first phase of a larger exploration strategy for the project that will in the future utilise bedrock drilling to target new discoveries outside of the Sinclair Deposit.
High priority targets within the Sinclair Nickel Project remain to be tested at numerous prospects including Fly Bore and Delphi with ongoing exploration programs such as surface MLEM, geochemistry and bedrock drilling being developed for these areas.
Talisman anticipates that in the future it will complete DHEM geophysical surveys in the recently completed drill-holes. Detailed interpretation of the drill-holes completed in this exploration program will continue and is expected to provide further information towards greater definition and re-evaluating exploration targets across the project.