Laverton Downs Project

Located in the richly endowed Laverton region of Western Australia, the Laverton Downs Project (LDP) has demonstrated potential to host both gold and nickel sulphide mineralisation. The LDP commences just 20kms north of Laverton in the Eastern Goldfields where it occupies some high potential mineralised real estate. World-class neighbouring mines include; Granny Smith (Au), Sunrise Dam (Au), Mt Morgans (Au), Mt Windarra (Ni), Wallaby (Au), Rosemount/Garden Well (Au).

In 2019, CSA Global completed a project evaluation covering geochemistry, litho-structural, and mineral systems analysis and target generation – a similar program to the one completed over the Lake Wells (Yamarna) Gold Project that contributed to the Earn in Joint Venture with SBM. CSA concluded that the Project is prospective for both gold and nickel sulphide deposits, and that exploration is considered at an early stage.

Initial interest in the LDP came after the publication of regional scale prospectivity studies, primarily the pmd* CRC Y4 project. As a predictive tool for gold mineralisation, the Y4 project indicated that the LDP is highly ranked (Figure 1), containing many of the ingredients that other world-class gold deposits exhibit. APC has continued the mineral systems analysis through industry consultants CSA Global and distilled all available data into discrete targets, along with additional conceptual goals that have received little or no compelling exploration.

Figure 1

The LDP comprises six granted tenements, E38/2724, E38/3014, E38/3132, E38/3402, E38/3403, and E38/3404.

CSA Global has completed a desktop review the LDP that concluded:

  • 20 gold targets identified, ranging from high priority to conceptual;
  • 5 nickel sulphide targets identified based on the presence of olivine cumulate komatiites, and anomalous nickel-bearing iron sulphides;
  • Regional metallogenic context extrapolated from known mineralisation and regional datasets; and,
  • Considered early-stage exploration with many targets having little or no drilling.

Outcomes from the CSA Global review were generated from the following:

  • Detailed magnetic/geophysical data interpretation;
  • Analysis of bottom-of-hole geochemistry for lithology, alteration and mineralisation;
  • Structural interpretation combining the above datasets with a solid geology interpretation;
    • LDP straddles the Kurnalpi and Burtville Terrane boundary – both highly mineralised greenstone belts;
    • CSA also Infer both 2.7Ga (Kambalda equiv.), and 2.8Ga (Windarra equiv.) ultramafic units, enhancing the komatiite hosted nickel sulphide targets
  • Geochemistry;
    • Defined primary lithological classification, including rock types considered essential for gold mineralisation in the region;
    • Areas of moderate to strong alteration;
    • Geochemical gradients interpreted to be related to gold mineralisation;
    • Coincident gold pathfinder elements;
  • Litho-structural;
    • New solid geology map with correlation to known deformation framework;
    • Cross-sectional interpretation that provides 2.5D insight into the architecture of the project. 

Based on the work compiled by CSA, APC is highly encouraged to continue to explore the LDP, and the Company is actively seeking commercial solutions to fund the necessary exploration work.

 Nickel Prospectivity

Regional geology, including known nickel deposits, highlight the potential for nickel sulphide mineralisation within the LDP (Figure 2). 

Project evaluation by CSA Global utilised all available data including regional datasets, detailed magnetic data, and high precision geochemical assay results derived from bottom of hole drill samples. Targeting criteria for Kambalda-style nickel deposits is based on identifying nickel bearing ultramafic rocks in contact with sulphur rich sediments. The geochemical results confirm that the high MgO (>25%) ultramafic komatiite rock type is present within the LDP, and also confirms the presence of magmatic nickel sulphides through the relationship of Fe vs S.

Figure 2: Regional location of the Laverton Downs Project showing known nickel sulphide deposits. Regional RTP magnetic image as background.

VTEMTM Survey

Opportunistically in November 2020 a small portion of the project area was flown with an airborne Versatile Time Domain Electromagnetic (VTEMTM) (Figure 3). Covering 100 linear kilometres at 100 metre line spacing, with 50 metre infill lines over one target, the program was designed to detect massive nickel sulphide mineralisation within highly prospective rocks identified in the CSA Global project evaluation. VTEMTM is an airborne electromagnetic geophysical technique that is designed as a first pass massive sulphide detecting method (Figures 3 & 4).

The VTEMTM program was extremely successful with several very strong EM anomalies identified that show all the hallmarks of massive sulphide mineralisation consistent with the Kambalda-style komatiite-hosted massive nickel sulphide deposit model. Kambalda-style deposits are characterised by massive pyrrhotite-pentlandite sulphide mineralisation that is highly conductive and magnetic, meaning they are amenable to detection with electro-magnetic geophysics.

Figure 3: Helicopter-borne VTEMTM survey in action over the Laverton Downs Project

Priority targets generated from the VTEMTM survey are high amplitude, late-time, discrete anomalies.  Conductor plate modelling suggests the conductor sources to be shallow, starting from approximately 100-150 metres below surface. Despite being considered shallow, these targets are deeper than the deepest historical drill hole that targeted nickel and are consistent with the most recent mineralisation models for the style of deposit targeted.

The VTEMTM survey identified numerous high priority targets and six of these were chosen for detailed 3D modelling. Six modelled conductive plates comprising three separate high priority target areas (Figure 4) are determined to be suitable for immediate drill testing. If drilling intersects massive sulphide mineralisation, then additional EM surveying, including downhole, and data processing will be warranted, and additional targets may result from the existing dataset and any expanded area of survey.

Figure 4: Laverton Downs Project initial VTEMTM survey extent with modelled conductor plates. VTEMTM image is dZ45 HDV, where the pink colours are late time conductors.

Planning and approvals are well advanced for the drill testing of the identified targets.