P-PRCP-100785954 · TNC MINING PTY LTD

Department foundThe PRCP assessment process is an iterative process whereby ongoing awareness and understanding of the site’s rehabilitation needs will lead to additions and variations to the draft PRCP schedule. Amendments proposed by the administering authority to draft the PRCP schedule is provided as an attachment to this information request notice to assist you in developing SMART criteria. Note, where the administering authority has not varied a criterion of the draft PRCP schedule, it is not intended to infer this criterion is accepted. Please review and amend the draft PRCP schedule in consideration of the additional information request items below. Overall amendments proposed: The administering authority proposed the inclusion of an additional rehabilitation area (RA) relating to levees, with a post-mine land use (PMLU) of Flood Protection Landform. Criteria for management milestones also don’t achieve SMART principles. Additional criteria have been proposed by the administering authority, with more specific surface requirement and geotechnical criteria required to demonstrate that the landform is geotechnically stable. Further specific requests are below.

Asked forReview the proposed amendments to the draft schedule and advise of agreement or comment otherwise to the amendments. The draft schedule in response to this information request is able to be provided in the word document format rather than the excel spreadsheet. It is the administering authority’s preferred approach that where the proposed amendments are agreed, that track changes of these amendments is accepted. Any agreement to any comments on the schedule is to be provided as subsequent comments. Any additional amendments or concerns are to be provided in track changes and/or comments.

Notice, page 3

Department foundA final landform design The final landform design provided in section 6.1 of the PRC plan does not comply with the requirements of section 3.6.1 and 3.6.3 of the PRCP Guideline, for example: • The information in section 6.1 states that detailed design of the final landform is yet to be completed and is currently conceptual in nature.

Asked forProvide a final landform design that meets the criteria within section 3.6.1 and 3.6.3 of the PRCP Guideline or consider adopting the proposed PRCP schedule conditions 15 and 16 and relevant milestone criteria.

Notice, page 4

Department foundAn appendix which refers to BioCondition benchmarks is required. The criteria proposed must: (a) Provide a benchmark to measure areas requiring revegetation to demonstrate that the area is on a trajectory to achieving stable condition. (b) Provide a benchmark to measure the achievement of revegetation for each regional ecosystem. In addition, criteria should be included to ensure non- native seed has not been used for the revegetation (except for sterile cover crops).

Asked forProvide a revised Schedule which includes BioCondition benchmarks for the relevant regional ecosystems which are the target PMLU outcome. Refer to the attached modified BioCondition benchmark framework and draft PRCP schedule to develop BioCondition benchmarks.

Notice, page 4

Department foundWith consideration of the PRCP Consultation Schedule provided in Attachment 2 of this Notice, the department considers that additional surface water and groundwater monitoring locations are necessary to adequately capture potential contaminant sources. Suggested monitoring locations have been outlined in Appendices 5 and 6 for your consideration.

Asked forReview the suggested monitoring locations provided in Appendices 5 and 6 and update the proposed surface and groundwater monitoring plan accordingly. Alternate monitoring locations may also be proposed. The revised monitoring plan should clearly identify the proposed locations, their rationale, and how they will address potential contaminant risks.

Notice, page 4

Department foundThe PRCP schedule outlines rehabilitation outcome criteria for surface water and groundwater limits, as specified in Schedule E of the EA, to demonstrate achievement of a stable condition aligned with the post-mining land use. To ensure these limits are effective, they must be fit for purpose (i.e., focused on closure rather than operation), site-specific, and informed by water quality objectives (WQOs), relevant guidelines, and background data. Where insufficient monitoring data exists to support site-specific limits, WQOs have been adopted, as shown in the attached PRCP consultation schedule. However, the PRCP NPM response does not provide sufficient groundwater quality data to establish appropriate values for the following dissolved quality characteristics: • Arsenic • Zinc

Asked forPropose appropriate site-specific parameters supported by sufficient data in the format specified (attached). Background data can be used to determine site- specific limits as follows: (a) For surface water, the 80th percentile of data for upstream/reference sites should be used for phys-chem indicators and the 95th percentile for toxicants. For groundwater, the 95th percentile of baseline data can be used to determine site-specific limits for all indicators. See DES 2021 Groundwater Guideline Using monitoring data to assess groundwater quality and potential environmental values Propose groundwater quality limits for Arsenic (dissolved) and Zinc (dissolved). The proposed limits must be supported by raw water quality data. Alternately, consider adopting the proposed surface and groundwater limits in the attached PRCP consultation schedule (Appendix 2).

Notice, page 5

Department foundFurther clarification is required regarding the current groundwater monitoring bore WYNGMB04A, which is located within the proposed disturbance area for the Project. Specifically, it is unclear whether this bore will remain accessible for monitoring purposes post mining.

Asked forProvide clarification whether WYNGWMB04A will remain accessible for monitoring purposes post mining.

Notice, page 6

Department foundWith consideration for the Draft PRCP Schedule provided in Attachment 2 of this Notice, provide a geotechnical setback distance for Improvement Area (IA) 1 associated with Pits 1, 2, 4/5 and 6.

Asked forProvide a geotechnical setback distance for Pits 1, 2, 4/5 and 6 in IA1.

Notice, page 6

Department foundWith reference to condition PRCP3 in Attachment 2 of this Notice, the department does not support the proposed changes to the date nominated for ‘available for rehabilitation’. This condition has been included to ensure that in the event land becomes available for rehabilitation earlier than the nominated dates in the PRCP schedule, that progressive rehabilitation commences as soon as practicable.

Asked forDisturbed land is considered available for rehabilitation if the land is not being mined and will be required to be rehabilitated unless it meets the requirements of section 126D(5) of the EP Act. Refer to condition PRCP3 in Attachment 2 of this Notice. Alternatively, provide evidence demonstrating how a 1-year timeframe aligns with the requirements of the EP Act and best practice standards.

Notice, page 6

Department foundWith reference to condition PRCP5 in Attachment 2 of this Notice, the department does not support the removal of PRCP5. This condition has been included to monitor known and emerging issues at the site prior to surrender. Its purpose is to ensure that adaptive management actions are implemented to achieve a stable condition, including the establishment of self- sustaining vegetation and water quality that demonstrates a clear trend towards a non-polluting outcome.

Asked forRefer to condition PRCP5 in Attachment 2 of this Notice. Alternatively, provide robust evidence to substantiate the removal of PRCP5, demonstrating how known and emerging issues will be effectively managed to achieve stable, self-sustaining conditions and non-polluting water quality outcomes.

Notice, page 6

Department foundWith reference to condition PRCP8 in Attachment 2 of this Notice, the department does not support the removal of PRCP8(b). This condition represents the minimum information required to demonstrate appropriate monitoring of rehabilitation milestones, providing a clear and enforceable framework from a compliance perspective. While the proponent may choose to undertake additional monitoring beyond these requirements, PRCP8(b) is essential to maintain regulatory oversight and accountability.

Asked forRefer to condition PRCP8(b) in Attachment 2 of this Notice. Alternatively, provide further evidence to substantiate the removal of this proposed PRCP condition.

Notice, page 7

Department foundWith reference to condition PRCP11 in Attachment 2 of this Notice, the department does not support the removal of PRCP11. This condition has been included to ensure that all relevant published materials are thoroughly considered when preparing and certifying technical aspects of the AQP designs, specifications, certifications, assessments and related documents.

Asked forRefer to condition PRCP11 in Attachment 2 of this Notice. Alternatively, provide justification to support its removal, demonstrating how the consideration and certification of all relevant published materials will be ensured in the absence of this condition.

Notice, page 7

Department foundWith reference to condition PRCP14 in Attachment 2 of this Notice, the department does not support the removal of PRCP14(b), which pertains to groundwater-dependent ecosystems (GDEs). It remains unclear how potential impacts to GDEs were addressed or approved during the Project approval process, as EA P-EA-100331581 does not specifically reference GDEs. Moreover, this condition is directly related to closure outcomes, rather than operational activities. It is critical to ensure that GDEs are not adversely affected following the closure of the Project.

Asked forRefer to condition PRCP14 in Attachment 2 of this Notice. Alternatively, provide robust evidence to justify the removal of PRCP14(b), ensuring that potential impacts to GDEs have been adequately addressed.

Notice, page 7

Department foundA durability assessment has been included within condition PRCP17 of Attachment 2 of this Notice for landforms identified by the department as high-risk, where either conceptual landform designs or no designs have been provided. Conditions relating to the durability assessment are deemed necessary or desirable to ensure that the final landform design is robust, well-developed, and informed by known material properties. This includes consideration of failure modes, monitoring requirements, and appropriate risk management strategies. The amended PRCP identifies that 15.38% of 91 waste samples exhibit potentially acid-forming (PAF) traits. However, section 6.6.4 of the report suggests that over 5% of total waste is likely to be PAF. Arsenic has been identified as a concern due to the potential for soluble salt leaching, and flood modelling highlights interactions between the floodplain and the WRD. Flood modelling also suggests the potential for interactions between 0.1% AEP and PMF flood events with Pit 4/5 and Pit 6. These interactions raise concerns about flooding impacts extending beyond the NUMA extent, potentially affecting areas required to achieve PMLUs and areas outside the mining lease boundary. As such, it is considered that both the WRD and the flood protection landforms proposed by the department to be included for Pit 4/5 and Pit 6 are high-risk landforms. It is considered that a durability assessment for high risk landforms is a key component in demonstrating that a stable condition can be achieved and maintained.

Asked forConsider the durability assessment conditions outlined in Attachment 2 of this Notice. Alternatively, provide final landform designs for high-risk structures (e.g., WRDs) that are well- developed, based on known material properties, and meet the criteria outlined in the PRCP Guideline.

Notice, page 8

Department foundWith reference to PRCP18 in Attachment 2 of this Notice, the department does not support its removal. The condition is critical to ensuring that the landform closure design report for high-risk landforms is fit for purpose, prepared in accordance with professional standards, and capable of delivering a stable landform in a post-closure context if constructed as specified.

Asked forRefer to condition PRCP18 in Attachment 2 of this Notice. Alternatively, provide detailed justification to support its removal – including evidence demonstrating how the objectives of ensuring high-risk landforms are stable, fit for purpose, and prepared in accordance with professional standards – will be achieved without this condition.

Notice, page 9

Department foundWith reference to PRCP20 in Attachment 2 of this Notice, the department does not support its removal. This condition is essential to ensure that the landform closure design report, including the durability assessment, is regularly maintained and updated as needed to guarantee that the relevant structures achieve and sustain a stable condition over the long term.

Asked forRefer to condition PRCP20 in Attachment 2 of this Notice. Alternatively, provide detailed justification to support its removal, including evidence demonstrating how the ongoing maintenance and updating of the landform closure design report – including the durability assessment – will be managed to achieve and sustain a stable condition for the relevant structures over the long term.

Notice, page 9

Department foundWith reference to PRCP23 in Attachment 2 of this Notice, the department does not support its removal. This condition is critical to ensuring that the flood protection landform design plan and report for any flood protection features are fit for purpose, prepared in accordance with professional standards, and aligned with the findings of the associated assessment.

Asked forRefer to condition PRCP23 in Attachment 2 of this Notice. Alternatively, provide detailed justification to support its removal – including evidence demonstrating how the flood protection landform design plan and report will be ensured to be fit for purpose, prepared in accordance with professional standards, and aligned with the findings of the associated assessment.

Notice, page 10

Department foundAs noted in item 1 above, the administering authority has proposed the inclusion of an additional PMLU, specifically a Flood Protection Landform associated with levees. Furthermore, amendments to PMLU naming have been suggested to align with Table G1 of the EA. If TNC agrees to these proposed changes, the final site design depicted in Figure 19 of the revised PRCP will need to be updated accordingly.

Asked forProvide a revised final site design which is inclusive of all proposed PMLUs for the Project.

Notice, page 10

Department foundAs noted in item 1 above, the administering authority has proposed amendments to the draft PRCP, resulting in changes to the proposed RAs. If TNC agrees to the proposed updates, the reference map shown in Figure 20 of the revised PRCP will need to be updated accordingly.

Asked forProvide a revised reference map which is inclusive of all proposed rehabilitation and improvement areas.

Notice, page 10

Department foundThe administering authority has proposed the inclusion of additional surface water and groundwater monitoring locations to appropriately capture potential impacts from mining activities. A figure is sought for inclusion in the schedule which identifies the nominated surface water and groundwater monitoring locations (Figure 3, 4, and 5).

Asked forProvide a new figure 3, 4 and 5 for inclusion in the PRCP schedule.

Notice, page 10

Department foundDuring the review of the initial draft PRCP schedule, TNC proposed removing the reference to the milestone criteria stating, “an independent AQP has certified the achievement of RM#-RM#.” The department is open to considering the removal of this reference where the associated rehabilitation activity is deemed low risk.

Asked forTo support any proposed changes, provide further information identifying which rehabilitation activities are considered low risk and therefore would not require certification by an independent AQP to confirm that the nominated milestone criteria have been achieved.

Notice, page 11

Department foundThe current flood modelling does not account for climate change, as required under section 41C of the Environmental Protection Regulation 2019 (EP Reg). Specifically, flood estimates must adhere to the Australian Rainfall and Runoff (ARR) 2019 guidelines, which incorporate climate change considerations, as detailed in ARR 2019 Book 1 (Scope and Philosophy). Consequently, the credibility of the flood model and its ability to address future flood risks remain unsubstantiated.

Asked forProvide updated flood modelling which is consistent with the Australian Rainfall and Runoff Guidelines and incorporates climate change considerations.

Notice, page 11

Department foundPit 6 lies fully within, and Pit 4/5 partly within, the 0.1% AEP floodplain. As outlined in section 3.6.1 of the PRCP Guideline, flood modelling must consider the Probable Maximum Flood (PMF) where flooding is a relevant factor. The application, however, does not include PMF flood modelling results. Given the significant flood risks identified for lower-frequency events, and the location of Pit 6 and Pits 4/5 within a flood plain, PMF modelling is essential to ensure a comprehensive and accurate risk profile assessment.

Asked forProvide PMF flooding assessment for Pit 4/5 and Pit 6.

Notice, page 11

Department foundIn accordance with the Manual for Assessing Consequence Categories (the Manual, ESR/2016/1933), a levee that prevents the ingress of clean floodwater is considered regulated if the pit is encroached by a flood event more frequent than or equal to the 0.1% AEP. Table 7 of the Manual requires that all regulated levees provide at least 1:1000 AEP immunity. Both the Manual and the Guideline Structures which are dams or levees constructed as part of environmentally relevant activities (ESR/2016/1934), require levees to be assessed for consequence. Furthermore, the PRCP Guideline requires that the PMF be considered when assessing the flood risk profile.

Asked forProvide a consequence category assessment (CCA) for approved levees, Pit 4/5 and Pit 6 under PMF.

Notice, page 12

Department foundNotwithstanding item 13 above as it relates to the durability assessment, the CCA has been conducted for the 0.1% AEP flood event, with the levee classified as having a ‘Low’ consequence rating in Table 9 of Appendix K. However, the long-term reliability of the modelling remains unverified, as the effects of climate change have not been incorporated into the 0.1% AEP flood estimate (per IR Item 21). Additionally, the CCA tables in Appendix K contain inconsistencies and potential errors. For instance, Table 10 for Pit 6 incorrectly references Pits 4/5 in the “Overtopping” and “Dam Break” scenarios. There is also insufficient evidence to substantiate claims of water quality “dilution” during flood events. No water balance modelling has been provided to demonstrate that overtopping will not occur. While water levels in the voids are expected to stabilise below ground level, the risks associated with flood ingress and the potential consequences of overtopping have not been adequately addressed. It is important to note that relying on dilution via overtopping as a management strategy is not appropriate. Overtopping poses a significant risk and should not be considered a mitigation measure. Over time, water quality in Pit 6 and Pits 4/5 is predicted to deteriorate, with potential increases in salinity and mobilisation of metals. This raises significant concerns about the long-term suitability of these areas for grazing or aquatic life, which remains uncertain.

Asked forProvide an updated CCA that includes the following: • Consideration of the effects of climate change; and • Revision of inconsistencies within Appendix K; and • Water balance modelling to demonstrate that overtopping of pits will not occur. Please note that if TNC proceeds with adopting the proposed flood protection landform as the PMLU, elements of this information request item may no longer be required.

Notice, page 12

Department foundSection 2.1.1 of the PRCP planning part identifies that “after the first pit is mined, it is intended to dump waste from subsequent pits into preceding ones…”. Section 6.6.4 of the PRCP planning part identifies that potentially acid forming (PAF) material is proposed to be either encapsulated within the waste rock dump (WRD) or placed in voids below groundwater table. The EA P-EA-100331581 does not authorise for the placement of waste rock within voids. Furthermore, the EA designates the voids as NUMAs, not as WRDs that would likely require capping upon closure.

Asked forProvide an updated rehabilitation planning part that describes waste management for the Project which is consistent with the approvals of the EA.

Notice, page 13

Department foundChanges to the Rehabilitation Planning Part may be required as a result of the information request items detailed above.

Asked forProvide an updated Rehabilitation Planning Part as necessary to provide consistency.

Notice, page 14