Assurance is implemented in terms of a three-tier system, aligned with the guidelines of Exxaro's Mineral Resource and Mineral Reserve reporting procedure, summarised as follows.
Mineral Resource and Mineral Reserve estimation is undertaken as per Exxaro's governance framework.
Sign-offs are required at each stage and the process is concluded in a formal sign-off session by a panel comprising Exxaro's lead Mineral Resource and Mineral Reserve Competent Persons and technical specialists. Technical assurance is managed in terms of dedicated standards.
Internal reviews are scheduled and planned for a
three-year cycle or when deemed necessary. The focus is on projects, and Resource and associated Reserve compliance with Exxaro's governance framework, while ensuring accountability and consequence management.
External audits are scheduled in a three-year cycle or at the discretion of the lead Competent Persons and entail a full review of the Mineral Resource and Mineral Reserve estimation process from drill hole logging to Mineral Reserve evaluation.
In 2022, tier 1 assurance was undertaken for the Belfast, Matla and Grootegeluk operations. Geological data validation, data analysis and subsequent updating of geological and structural models were concluded in the reporting period. These models were peer reviewed by geosciences central experts for the three operations and the models were signed off by the applicable Competent Persons and their supporting technical teams. Findings were incorporated in the model updates.
LoMPs were reviewed at our Belfast, Matla, Grootegeluk, Leeuwpan and Mafube operations.
Table 6 below indicates tier 2 technical assurances conducted on development projects with specific focus on the estimation that underpins these projects. Where technical findings were identified during reviews that may materially impact the business, remedial actions were recommended to ensure project robustness and shareholder return.
Internal Coal Resource estimation reviews measuring compliance to the Exxaro geosciences policy and the associated Coal Resource reporting and estimation procedures were conducted for Belfast and Grootegeluk mines. A formal review was done on OCCS reporting at Grootegeluk culminating in approval for use in LoM planning. A summary of findings is listed in Table 7.
On tier 3, PwC conducted an audit on our internal Resource and Reserve estimation process in 2022 and no critical findings were reported.
Table 6: Tier 2 technical assurances conducted in the reporting year with general points addressed
|Project name||Project description||Summary Resource actions||Summary Reserve actions|
|Grootegeluk complex AMS||Review various technology alternatives for the transportation of overburden material from the pit to the backfill system||The overburden (OVB) was modelled and levels of confidence assigned to the different geological zones. Additional drilling is required in specific areas.||The AMS study concluded that the base case trucking solution was the most economical mining solution as opposed to an overburden in pit crush and convey system.|
|Moranbah South assurance phase 1||Development, operating, processing and transport of coal for the associated Resource||Exploration to enhance geological structural interpretation as well as coal characterisation should proceed to inform the exploitation plan.||The assurance review highlighted technical aspects on gas, geological structure, geotechnical and mining height considerations that requires optimisation to reach the applicable stage gate.|
|Belfast pit 4 box cut||Develop and execute the pit 4 box cut, to access the pit 4 Reserves aligned to the Belfast LoMP||We performed exploration drilling to increase the level of confidence in the pit 4 area ensuring the correct placement of the box cut and delineate the Resource extent.||The layout was reviewed based on the updated geological model. The mine design was appraised, with various box cut layouts and designs evaluated to determine the optimised option.|
|Matla primary production equipment||Replacement and refurbishment of Matla's primary production equipment||We evaluated the Matla Seam 2 thickness based on the latest (2022) geological model.||Mining through areas where seam thickness is less than 1.6m will result in contamination as to accommodate the continuous miner and associated equipment.|
|Belfast LoM optimisation project||Project to enable Exxaro to optimise the full Belfast mining right||We updated the geological model.||Underground and surface mining methods were evaluated resulting in surface mining as the option going forward.|
Table 7: Tier 2 internal reviews findings
|Area under review||Finding||Conclusion and recommendation*|
|Belfast||Core photographs||Current core photographs to be labelled according to the drill hole number and depth range in sequence.|
|Core recovery||Core recovery to be captured for each drill run.|
|Sample mass records||All samples to be weighed and validated with laboratory measurement.|
|Wireline logs||Misalignments must be investigated and adjusted where required on an "if not, why not?" basis.|
|Grootegeluk||Sign-off of exploration plan||Surveyor and environmental manager to sign off on exploration plans for effective planning and compliance to authorisations.|
|Capture metadata||Optimise the capturing of metadata to enhance value add.|
|End of hole depth check||Record stick-up measurements in log sheet.|
|*||Findings are communicated and corrective measures are implemented.|