2022 – 2023 Drilling Program

In February 2023, Cobalt Blue Holdings Limited (COB) completed a comprehensive drilling program to support various aspects of the Broken Hill Cobalt Project (BHCP) Definitive Feasibility Study (DFS).

The program included:

  • dedicated geotechnical drilling to inform pit slope stability analysis for mine design and optimisation at the Big Hill and Railway deposits;
  • investigation of zones of potential resource extension at the Big Hill and Railway deposits;
  • infill drilling targeting improved resource classification at the Big Hill deposit; and
  • drilling for waste rock characterisation at the Pyrite Hill, Big Hill and Railway deposits to inform detailed design criteria for the Integrated Waste Landforms (IWLs).

Seventy-eight (78) drill holes were completed for some 12,280 metres increasing COB’s cumulative drilling effort from approximately 28,500 metres to over 40,000 metres since 2017 (excluding drilling required for installation of groundwater monitoring equipment).

Figure 1. Metres drilled at the Broken Hill Cobalt Project since 1967 with COB completing over 40,000 metres since 2017.

Broken Hill Cobalt Project Diamond Drilling
Figure 2. Diamond drilling at Big Hill south.

Following drilling, the exploration team have completed site rehabilitation works and commenced routine monitoring of areas subject to surface disturbance to ensure fulfilment of rehabilitation objectives and completion criteria.

Continuing Technical Studies

  • Mineral Resource Estimation - the geological models for the Pyrite Hill, Big Hill and Railway deposits are currently subject to revision for the purposes of Mineral Resource estimation.
  • Mine / Processing Waste Management - waste rock samples (core) have been prepared and despatched with process tailings from the Demonstration Plant for further geotechnical and geochemical analysis as a precursor to kinetic testwork. This work will ultimately contribute to the optimisation of detailed design criteria for the proposed IWLs.
  • Pit Slope Stability Analysis - geotechnical analyses of the Big Hill and Railway deposits are progressing with the completion of:
    • further laboratory testwork to determine critical rock mass properties; and
    • downhole acoustic / optical imaging to both calibrate and supplement orientated structural information on features such as faults, fractures and bedding routinely derived from diamond (core) drilling.

Figure 3. Downhole acoustic / optical imaging of drillholes completed during the 2022 - 2023 program.