Data as at 14 September 2026 · from the Queensland EP Act public register
P-PRCP-100883071 · SOLOMONS GOLD PTY LTD
PRC plan P-PRCP-100883071 for SOLOMONS GOLD PTY LTD (EPML00772413), minerals. Current schedule final milestone 2057-12-10; 6 rehabilitation and improvement areas. 1 applications, including information requests and replies.
- Environmental authority
- EPML00772413
- Holders
- SOLOMONS GOLD PTY LTD
- Tenures
- ML1079
- Plan versions
- P-PRCP-100883071 (effective 2026-08-28)
- Current schedule final milestone
- 2057-12-10
- Areas in current schedule
- 6 · 228 ha
Schedule versions
| Version | Effective | Final milestone | Areas | Document |
|---|---|---|---|---|
| 1 (current) | 2026-08-28 | 2057-12-10 | 6 | Schedule PDF |
Rehabilitation and improvement areas
From the current schedule's tables. Land use categories are keyword groupings; the schedule's wording is shown beneath.
| Area | Activities | Hectares | Post-mining land use | First milestone | Page |
|---|---|---|---|---|---|
| RA1rehabilitation | Infrastructure, Stockpile Areas, Village and Exploration Areas, Access Tracks & Roads | 121.4 | GrazingLow Intensity Grazing | 10-12-2037 | 12 |
| RA2rehabilitation | Processing Plant and ROM Pad | 3.3 | GrazingLow Intensity Grazing | 10-12-2037 | 13 |
| RA3rehabilitation | Waste Rock Dumps | 24.1 | Native ecosystemGrassland | 10-12-2037 | 14 |
| RA4rehabilitation | TSF and Heap Leach | 73.6 | Native ecosystemGrassland | 10-12-2037 | 15 |
| RA5rehabilitation | Runoff Dam | 5.4 | Water, diversions and flood landformsWater Storage | 10-12-2049 | 16 |
| IA1improvement | Open-cut pits | NUMA or voidNUMA | 10-12-2037 | 33 |
Application A-PRCP-NEW-100883057
- Received
- 2022-03-28
- First information request
- 2022-05-27
- Response due
- 2022-11-30
- Extensions
- 2 (to 2024-03-29)
- Plan effective
- 2026-08-28
- Days from receipt to plan effective
- 1614
- Register
- Application record
30 documents on the register
- A-PRCP-NEW-100883057_ApplicationDocuments Other
- A-PRCP-NEW-100883057_ApplicationDocuments_Attachment_01 Other
- A-PRCP-NEW-100883057_ApplicationDocuments_Attachment_02 Other
- A-PRCP-NEW-100883057_ApplicationDocuments_Attachment_03 Other
- A-PRCP-NEW-100883057_ApplicationDocuments_Attachment_04 Other
- A-PRCP-NEW-100883057_ApplicationDocuments_Attachment_05 Other
- A-PRCP-NEW-100883057_InformationRequest_ExtNotice_01 Extension notice
- A-PRCP-NEW-100883057_InformationRequest_ExtNotice_02 Extension notice
- A-PRCP-NEW-100883057_InformationRequest_Notice_01 Information request
- A-PRCP-NEW-100883057_InformationResponse Information response
- A-PRCP-NEW-100883057_InformationResponse_Attachment_01 Response attachment
- A-PRCP-NEW-100883057_InformationResponse_Attachment_02 Response attachment
- A-PRCP-NEW-100883057_InformationResponse_V2 Information response
- A-PRCP-NEW-100883057_InformationResponse_V2_Attachment _01 Response attachment
- A-PRCP-NEW-100883057_InformationResponse_V2_Attachment _02 Response attachment
- A-PRCP-NEW-100883057_InformationResponse_V2_Attachment _03 Response attachment
- A-PRCP-NEW-100883057_InformationResponse_V2_Attachment _04 Response attachment
- A-PRCP-NEW-100883057_InformationResponse_V2_Attachment _05 Response attachment
- A-PRCP-NEW-100883057_InformationResponse_V2_Attachment _06 Response attachment
- A-PRCP-NEW-100883057_InformationResponse_V2_Attachment _07 Response attachment
- A-PRCP-NEW-100883057_InformationResponse_V2_Attachment _08 Response attachment
- A-PRCP-NEW-100883057_InformationResponse_V2_Attachment _09 Response attachment
- A-PRCP-NEW-100883057_InformationResponse_V2_Attachment _10 Response attachment
- A-PRCP-NEW-100883057_InformationResponse_V2_Attachment _11 Response attachment
- A-PRCP-NEW-100883057_InformationResponse_V2_Attachment _12 Response attachment
- A-PRCP-NEW-100883057_InformationResponse_V2_Attachment _13 Response attachment
- A-PRCP-NEW-100883057_InformationResponse_V2_Attachment _14 Response attachment
- A-PRCP-NEW-100883057_InformationResponse_V2_Attachment _15 Response attachment
- A-PRCP-NEW-100883057_V1_InformationResponse Information response
- A-PRCP-NEW-100883057_V1_InformationResponse_Attachment_01 Response attachment
Information request: 28 items
Department foundTable 6 of the PRC Plan identifies the presence of vertosol soils which are prone to erosion and collapsing. Such soils are difficult to manage, and minimising disturbance in this type of soils is desirable.
Asked forTable 6 of the PRC Plan identifies the presence of vertosol soils which may provide management challenges. Further information is sought regarding the likelihood of disturbance or use and if specific management measures are considered for these soils.
Applicant repliedAn EA Amendment was approved and took effect on 24 March 2026. The activity areas have been updated and the PRCP has been revised to align with the EA Amendment.
Department foundSection 3.2 of the rehabilitation planning part references extensive stakeholder engagement that was completed prior to the implementation of the PRCP framework in 2019. While a community consultation register table has been provided as part of the Yandan Stakeholder Engagement Plan in Appendix E, details of how community consultation has been considered in developing the PRC plan has not been included.
Asked forProvide a discussion of how the community consultation has informed the PRC Plan or carry out community consultation as per section 3.5 of the PRCP Guideline (ESR/2019/4964) and update the Rehabilitation planning part to reflect the outcomes of the consultation process. Provide an updated Rehabilitation Planning Part that includes a community consultation register which includes the commitments made by the applicant.
Applicant repliedThe PRCP and Schedule has been revised to include exploration disturbance. Existing disturbance associated with exploration (primarily seismic survey lines) have been included in the spatial package as polygons. The total area now aligns with Table F1 of the EA. These areas, along with any exploration bores, have been assigned to RA1 with a PMLU of ‘low intensity grazing’. Additionally, specific milestone criteria have been included for the rehabilitation of exploration activities (see RM1.4)
Department foundTable 11 and Table 13 show the maximum surface area for each disturbance type as approved in the EA. However, the total area of the rehabilitation areas and improvement areas (388.5ha) in the PRCP Schedule exceeds the maximum surface area authorised under the EA (295.6ha).
Asked forProvide an updated Rehabilitation Planning Part and PRCP Schedule that reflects the authorised disturbance in the EA or provide additional information to demonstrate that the PMLU and Non-Use Management Area (NUMA) areas in the proposed PRC Plan are consistent with the conditions of the EA.
Applicant repliedPRCP has been updated to align with the EA Table F1. The disturbance areas listed in this item have been included in RAs.
Department foundSection 3.1.2 of the PRC Plan provides some information on the rehabilitation activities that have been carried out and findings from rehabilitation monitoring. Details of the rehabilitation works that have been carried out and the success criteria of the rehabilitated areas is required to determine whether a rehabilitation or management milestone is achieved for all areas where rehabilitation has been conducted. Also, the Plan states that Cell A is trending towards an open woodland community whereas the PRCP Schedule identifies this area as having a PMLU of grazing. Section 3.5.1 refers to activities that need to be carried out for continued progress towards rehabilitation completion criteria for example: Cell A – re-development of water shedding landform profile (limited to small central zone only), Village Infrastructure area – removal of some remaining concrete footings, Water storage structures to be retained by the landholder will be cleaned and made safe prior to surrender.
Asked forInclude a description of all rehabilitation works previously carried out and when the rehabilitation works commenced and were completed. Provide information regarding the level of revegetation achieved with % foliage cover, plant heights, seedling, woody stems and other pertinent measures to demonstrate the PMLU has been met. Comparison to analogue sites should be carried out and justification given as to why rehabilitation is considered to have been achieved for the area. Where demonstration has not been provided of the specific milestone being met, milestone criteria must be included for each rehabilitation or improvement area to determine whether a rehabilitation or management milestone is achieved.
Applicant repliedAll open cut pits will be NUMAs. The PRCP has been updated to reflect this and to align with the EA.
Department foundThe PRC Plan refers to reference sites for comparison of milestone criteria for the areas to be rehabilitated to grazing land. No detail has been provided for the location of the reference sites or their suitability as representative sites for the rehabilitation areas.
Asked forClearly identify where the reference/analogue sites are located and provide justification for their selection as being suitably representative sites for monitoring rehabilitation success.
Applicant repliedSolomons propose inclusion of a void geotechnical stability assessment as a PRCP condition. The proposed condition is detailed in Section 9.5 of the PRCP. Criteria have also been included in the Schedule (MM1.1, MM1.2, MM1.5 and MM1.6).
Department foundPreliminary flood modelling has identified that some mining domains including the pit and heap leach pad will be inundated or in contact with floodwaters under 1% AEP and PMF events. However, information detailing how flood flow may interact with the final landform has not been included. An understanding of flood depth and velocity across the final landform is required and how this may influence the achievement and maintenance of a safe, stable and sustainable PMLU.
Asked forDemonstrate how all final landforms will achieve and maintain a stable condition under 1% AEP and PMF events. This includes investigating the effect that flood depth and velocity may have on the final landform.
Applicant repliedYandan – Main Pit and Suttor River characterisation – March 2024 Page | 56 Contents 1 Introduction ......................................................................................................................................................... 5 1.1 Background.......................................................................................................................................................................................... 5 1.2 Changes since the initial PRCP submission ................................................................................................................................. 5 1.3 Intent of this work package ............................................................................................................................................................. 5 1.4 Scope ..................................................................................................................................................................................................... 5 2 Yandan site profile .............................................................................................................................................. 6 2.1 Landscape and drainage setting .................................................................................................................................................... 6 2.2 Closure landforms profile ................................................................................................................................................................. 8 2.3 Elevation profiles ................................................................................................................................................................................ 9 3 Hydrology profile of the Suttor River and Yandan......................................................................................... 12 3.1 Nature of flow ................................................................................................................................................................................... 12 3.2 Flow regimes and magnitudes...................................................................................................................................................... 14 3.3 How connection occurs between the Suttor River system and the Main pit.................................................................... 14 3.4 Relationship between river connection at the Main pit to St Anns gauge ........................................................................ 14 3.5 River flow durations ......................................................................................................................................................................... 18 3.6 Observation of the 2023 flooding event .................................................................................................................................... 18 4 Flooding profile of the Suttor River and Yandan............................................................................................ 20 4.1 Modelled flooding extents and elevations for 1% AEP and PMF events............................................................................ 20 4.2 Indicative flow velocity profile during floods ............................................................................................................................ 22 4.3 Flooding elevation and depths ..................................................................................................................................................... 22 5 Risk assessment for landforms in major flood conditions ............................................................................. 25 6 References .......................................................................................................................................................... 27 Appendix A – RFI to work package map ................................................................................................................ 28 Yandan - Flooding profile characterisation for closure – February 2024 Page | 3 1 Introduction 1.1 Background GBM Resources Limited is currently in the process of a transitional Progressive Rehabilitation and Closure Planning (PRCP) for the Yandan mine with the Department of Environment, Science and Innovation (DESI). Yandan is a historical mine site with several legacy landforms, including two (2) pit voids (including the Main pit adjacent to the Suttor River and the focus of this assessment), a tailings storage landform, and a heap leach landform. With the initial Yandan PRCP submission early in 2022, subsequently DESI (former DES) issued a request for information (RFI) listing several queries around water-related risk and requests to clarify closure outcomes. As supplements to SBE (2022), additional packages of work are prepared to respond to the RFI around water-related risk, structured as three separate (3) technical updates: • Yandan site flooding profile characterisation (this report). • Main pit and Suttor River water system characterisation. • Yandan groundwater and conceptual model characterisation. 1.2 Changes since the initial PRCP submission As core additional information for PRCP and a related program for Estimated Rehabilitation Calculation (ERC), in 2023, GBM embarked on a robust data collection program to obtain representative and seasonal information, including additional groundwater wells and water storage monitoring. The additional data and information obtained over the past year provides a material step change in representative data, understanding and technical confidence of the Yandan water systems, and provides an excellent management tool for the site looking forward. Information and data gained to date is incorporated into this updated assessment. 1.3 Intent of this work package This report captures, expands, and assesses the flooding nature and risk profile for the Yandan site, including: • Mapping of Yandan site to elevations and nature of closure landforms. • Hydrology profile of the mid-Suttor River, including flow regimes, flow durations, and connections with the site, including validation of the working flow model through January 2023 flood observations. • Flooding profile of the mid-Suttor and Yandan in modelled flooding extents in major floods, including elevations and relationship to closure landforms. • Risk assessment of Yandan closure landforms in major flooding conditions, including how water will interact with each landform, water flow, quality mixing and contact with engineered structures. 1.4 Scope The scope of this work is to satisfy reasonable requirements of the Progressive rehabilitation and closure plans (Queensland Government 2023) for a historical site under transitional provisions by addressing and resolving key questions in the 2023 Request for Information (RFI). A map of RFI to responses is provided in Appendix A. This report should supplement SBE (2022) for overall site characterisation and further information. Yandan - Flooding profile characterisation for closure – February 2024 Page | 5 Appendix A – RFI to work package map
Applicant repliedAn updated hydrogeological assessment has been provided as Appendix H. This was completed in March 2026 and includes a void water balance assessment indicating that all the residual voids will act as sinks long- term. Groundwater quality has been discussed in Section 8 of Appendix H. Limited surface water monitoring data is available. It is acknowledged that at least 5 consecutive years of sampling data is required to propose site-specific quality limits. As such, it is proposed to include a PRCP condition to undertake the following: Surface Water Monitoring and Quality Limits The holder must, by 30 April 2037, submit a report to the administering authority that: • Proposes a revised surface water monitoring network for inclusion in Surface Water Monitoring Locations table; • Proposes surface water quality limits for inclusion in Surface water quality limits table based on at least 5 years of site-specific data. Limited groundwater monitoring data is available. It is acknowledged that at least 5 consecutive years of sampling data is required to propose site-specific quality limits. It is proposed to include a PRCP condition to undertake the following: Groundwater Monitoring and Quality Limits The holder must, by 30 April 2037, submit a report to the administering authority that: • Proposes a revised groundwater monitoring network for inclusion in Groundwater monitoring locations table; • Proposes groundwater quality limits for inclusion in Groundwater quality limits table based on at least 5 years of site-specific data.
Department foundA slope angle of 30% is proposed for the tailings storage dam (TSF) and 25% for the heap leach pad (HLP). Total groundcover (rock and/or vegetation) (C-value from RUSLE equation) used to calculate the erosion rates on both TSF and HLP embankment slopes is 65% to achieve 9.60 and 8.37 t/ha/yr respectively. These erosion rates are elevated and do not appear to apply a sufficient level of contingency planning in the event a 65% groundcover value is not achieved and maintained. It is noted that a reduction in targeted slope angle would have a significant influence on predicted erosion rates and may help to support the PMLU of low intensity grazing. Furthermore, final landforms need to be conducive to the PMLU and the PMLU for the heap leach pad and TSF have been identified as grazing. The slopes on the HLP and TSF pose potential challenges to the safe, stable and sustainable achievement of a grazing PMLU. The PRCP Schedule milestone criteria for Dams in RM4 requires a geotechnical assessment where landforms incorporate slopes greater than 17%, however the PRC Plan and supporting information do not identify areas in the dam landforms that would have a slope greater than 17%.
Asked forFurther information is sought regarding justification for the slope angles and how this meets the PMLU as well as how it will achieve geotechnical and erosional stability. Further information is sought regarding the slope angles for the dams and justification for the proposed slope angles and how the PMLU is met as well as how it will achieve geotechnical and erosional stability for these landforms.
Department foundSection 3.1.6 of the PRC Plan provides some information on groundwater levels and salinity. No detail has been provided on the interactions of the pit, tailings dam and heap leach pad with groundwater. Criteria that demonstrate these structures will be non-polluting has also not been included. Figures 27 and 28 do not provide context on orientation of the pit and river nor depths of strata and pit depth. The Suttor River alluvium mentioned in section 3.1.6 of the PRC Plan is also not represented. Increasing trends in arsenic have been identified in groundwater in the PRC plan and interactions of tailings and heap leach seepage with groundwater may be occurring. The prediction of water quality impacts from mining activities is necessary to determine appropriate measures for the containment and management of contaminants and the potential impacts on environmental values should they be released.
Asked forProvide an assessment of the hydrogeology of the site including all landforms and connected strata in accordance with 3.6.1 of the PRCP Guideline. An assessment of the interactions of the tailings and heap leach pad with groundwater must also be included in the PRC Plan. Provide detailed information regarding water quality and how it varies between depths and bores. Provide milestone criteria for groundwater quality to demonstrate all final landforms will be non-polluting.
Applicant repliedThe PRC Plan and schedule have been revised. Detailed responses are provided below: Milestone criteria have been revised. The Deep Lead Pit has now been designated a NUMA (IA1), in line with the EA. The disturbance area of NUMAs in the PRCP and spatial package now align with EA Table F1. PRCP and spatial package now align with EA Table F1. Rehabilitation Areas (RAs) have been revised and now cover the full extent of disturbance as authorised by the EA. WRDs are now under RA3, ROM pad and processing plant is now RA2, and topsoil stockpiles are RA1. The schedule has been revised to resolve timing inconsistencies and uncertainties. The schedule has been revised to resolve timing inconsistencies and uncertainties. RA5 now includes the Runoff Dam. Other water structures will be decommissioned and rehabilitated. The schedule has been revised to resolve timing inconsistencies and uncertainties. The TSF is now under RA4 and will be rehabilitated in one stage, beginning once operations have ceased. Timing for this has been included in the revised schedule. PRCP and Schedule criteria has been updated to remove reference to analogue sites. Vegetation coverage is now based on required cover to achieve adequate erosion minimisation as determined by erosion modelling (included with the PRCP as Appendix L). The PRCP and Schedule have been updated to align with the EA, including: • Pits as NUMAs • Pits act as groundwater sinks (see PRCP Section 6.9.2) Therefore, it is now not intended for water quality in the pits to achieve livestock drinking water quality.
Department foundThe PRC Plan and EA require that the pit lake level is to remain above 160mAHD. The Plan also considers that the pit will act as a groundwater sink. Figure 32 in the SBE 2022 report indicates that the groundwater levels in the bore SH3 fluctuate above 160mAHD. Figure 26 of the PRC Plan includes an indicative map of the potentiometric surface of the groundwater however the potentiometric surface does not extend to the pit area.
Asked forProvide a hydrogeological assessment that encompasses all landforms on the project area. Include supporting evidence that demonstrates how the pit will act as a sink.
Applicant repliedYandan - Flooding profile characterisation for closure – February 2024 Page | 28 Contents 1 Introduction ......................................................................................................................................................... 5 1.1 Background.......................................................................................................................................................................................... 5 1.2 Changes since the initial PRCP submission ................................................................................................................................. 5 1.3 Intent of this work package ............................................................................................................................................................. 5 1.4 Scope ..................................................................................................................................................................................................... 5 2 Summary of new information and learnings .................................................................................................... 6 2.1 Map of the overall Yandan water monitoring network ............................................................................................................ 6 2.2 Groundwater bores and system ..................................................................................................................................................... 6 2.2.1 Construction of new groundwater wells ..................................................................................................................................................... 6 2.2.2 Learnings................................................................................................................................................................................................................. 6 2.3 Surface water storage and system ................................................................................................................................................. 7 2.3.1 Installation of new level monitoring ............................................................................................................................................................. 7 2.3.2 Learnings................................................................................................................................................................................................................. 7 2.4 General influence of rain on water quality.................................................................................................................................. 11 2.4.1 Rainfall .................................................................................................................................................................................................................... 11 2.4.2 Tailings containment storage ......................................................................................................................................................................... 11 2.4.3 East Hill pit storage ........................................................................................................................................................................................... 14 2.4.4 Main Pit storage ................................................................................................................................................................................................. 14 3 Updated Yandan conceptual model ................................................................................................................. 17 3.1 Topography and catchments ........................................................................................................................................................ 17 3.2 Geology and groundwater framework ....................................................................................................................................... 19 3.2.1 Geology ..................................................................................................................................................................................................................19 3.2.2 Groundwater occurrence .................................................................................................................................................................................19 3.3 Site groundwater characterisation ............................................................................................................................................... 22 3.3.1 Groundwater levels over 2023 ...................................................................................................................................................................... 22 3.3.2 Groundwater potentiometric surface ......................................................................................................................................................... 22 3.3.3 Populations by chemistry................................................................................................................................................................................ 26 3.4 Characterisation of groundwater domains ................................................................................................................................ 26 3.5 Quality profiles across domains ................................................................................................................................................... 28 4 Domain conceptual models .............................................................................................................................. 32 4.1 Overview ............................................................................................................................................................................................. 32 4.2 Sandy Creek and Tailings Storage domain ................................................................................................................................ 32 4.3 Heap Leach through Mineralised area domain ........................................................................................................................ 33 4.4 Regional domain ..............................................................................................................................................................................34 4.5 Heap Leach to Yandan Creek domain ........................................................................................................................................ 35 5 Findings and recommendations ....................................................................................................................... 36 5.1 Technical confidence ....................................................................................................................................................................... 36 5.2 Characterisation of domains ......................................................................................................................................................... 36 5.3 Characterisation of quality ............................................................................................................................................................. 36 5.4 Conceptual model water system interactions and processes ............................................................................................... 37 5.5 Next steps .......................................................................................................................................................................................... 37 6 References .......................................................................................................................................................... 38 Appendix A – RFI to work package map ................................................................................................................ 39 Appendix B – Bore logs ............................................................................................................................................ 43 Appendix C – Bore chip photos ............................................................................................................................... 47 Appendix D – Driller logs ......................................................................................................................................... 49 Appendix E – Influence of density on groundwater effective head ..................................................................... 56 Yandan – Updated conceptual model for water performance – March 2024 Page | 3 1 Introduction 1.1 Background GBM Resources Limited is currently in the process of a transitional Progressive Rehabilitation and Closure Planning (PRCP) with the Department of Environment, Science and Innovation (DESI) for the Yandan mine, located in north Queensland inland, approximately 40km west of Mount Coolon. Yandan is a historical mine site with several legacy landforms, including two (2) pit voids (including the Main pit adjacent to the Suttor River and the focus of this assessment), a tailings storage landform, and a heap leach landform. With the initial Yandan PRCP submission early in 2022, DESI (former DES) subsequently requested information (RFI) listing several queries around water-related risk and requests to clarify closure outcomes. As supplements to SBE (2022), additional packages of work are prepared to respond to the RFI around water-related risk, structured as three separate (3) technical updates: • Yandan site flooding profile characterisation. • Main pit and Suttor River water system characterisation. • Yandan updated groundwater and conceptual model characterisation (this report). 1.2 Changes since the initial PRCP submission As core additional information for PRCP and a related program for Estimated Rehabilitation Calculation (ERC), in 2023, GBM embarked on a robust data collection program to obtain representative and seasonal information, including additional groundwater wells and water storage monitoring. The additional data and information obtained over the past year provide a material step change in representative data, understanding, and technical confidence of the Yandan water systems. They also offer an excellent management tool for the site looking forward. Information and data gained to date are incorporated into this updated assessment. 1.3 Intent of this work package This report captures, expands and assesses the nature of the Yandan water system to identify and characterise water domains as closure landforms, including: • Summary of new information and implications for the conceptual model. • Updates to the site setting and water system • Updated domain conceptual models for the Mineralised zone (Main Pit and East Hill Pit), Regional, Heap Leach and Tailings Storage Facility (TSF). 1.4 Scope The scope of this work is to satisfy reasonable requirements of the Progressive rehabilitation and closure plans (Queensland Government 2023) for a historical site under transitional provisions by addressing and resolving key questions in the 2023 Request for Information (RFI). A map of RFI to responses is provided in Appendix A. This update report should supplement SBE (2022) for overall site characterisation and further information. Yandan – Updated conceptual model for water performance – March 2024 Page | 5 • TD and HL (all wells) – Metamorphic rocks (phyllites), metasediments and quartzite of the Anakie Inlier. • ITD – tailings and ground surface of the Anakie Inlier, like hills, surround the TSF landform. Depths of tailings are as expected. Groundwater level adjustment for Main Pit wells As an exception and genuine learning for the project, the initial groundwater sampling event identified all bores in the Main Pit area as highly saline (25,000EC uS/cm and above). With no previous wells in the pit domain (only one distal well to the Main Pit previously, SH3), MP01-04 bores were designed to test and inform groundwater quality for the East and Main Pit mineralised areas. High salinity and high chloride levels are naturally associated with hydrothermal activity and mineralisation events, including high chloride levels. The effect of the salinity is to increase the density of the water, which means the effective head of saline water wells is higher than measured by simple standing water at atmospheric pressure. To compare relative groundwater levels with those of fresher water heads such as Main Pit or other groundwater wells as effective heads, saline well levels require density adjustment. The approach is explained in Appendix E, meaning that an additional 1.5m of the effective head was added to the measured relative water levels for functional purposes. 2.3 Surface water storage and system 2.3.1 Installation of new level monitoring Water level loggers were installed into three storages between April and November 2023 and continue to present: in Main Pit Lake, East Hill Pit Lake and the Tailings Storage containment dam. Logging aimed to track responses to rainfall and evaporation as a test for runoff factors and potential connection to groundwater. An additional function of logging salinity was installed into the Tailings Containment dam to test for salinity response to rainfall or over a dry season. As a record of installation, the loggers were field surveyed to obtain a relative level (mAHD) and adjusted for barometric pressure, as in Table 1. Table 1 - Surface storage logger details
Applicant repliedYandan – Updated conceptual model for water performance – March 2024 Page | 39
Applicant repliedThe PRCP and Schedule have been revised to align with PMLUs as pre-approved in the Land Outcome Documents (LODs). This includes the PMLU for the runoff dam which now has a PMLU of ‘Water Storage’ as RA5. Milestone criteria have been included in the Schedule for the ‘Water Storage’ PMLU in RM7.
Department foundTable 22 and Figure 32 show the available rehabilitation material on the project, however, does not provide a materials balance of resources required in the rehabilitation of each area. Several material sources are identified such as the dam embankment material as an available source of material; however, it is unclear if these materials are intended to be use in the rehabilitation given that these structures are proposed to remain in the existing landform. Furthermore, it is unclear where some of the available material volume shown in Table 22 has been obtained from and it does not appear that quality assessment has not been completed for all the available material identified in Table 22. 2022 SLSA soil survey (AARC 2022a) recommends mitigation measures for topsoil management, the development of a Topsoil Management Plan and topsoil amelioration, however topsoil placement and management has not been addressed in the PRC Plan. The 2022 SLSA soil survey (AARC 2022a) identifies the increased risk of erosion associated with the Sandy soil management unit (SMU). Given the Sandy SMU encompasses a significant area of the project, robust monitoring and mitigation strategies should be included in the rehabilitation planning part to demonstrate the achievement of the stable PMLU. Section 6.2 of the 2022 SLSA soil survey (AARC 2022a) recommends mitigation measures to reduce the risk and impacts of erosion, however it does not appear that these are included in the PRC Plan and PRC Schedule including the areas where each of these methods will be implemented.
Asked forProvide an assessment of the quality and suitability of all soil and capping material and for all the material that is proposed to be used in rehabilitation. Provide a materials balance that specifies material available, and materials required for rehabilitation for each of the structures. Provide an assessment on how the quality of all the materials available for use in rehabilitation activities are adequate in supporting the proposed PMLU. Include in the PRCP Schedule milestone criteria that relate to the management of erosion and topsoil to meet the PMLU and include supporting information in the PRC Plan. Refer to Appendix 2 of the PRCP Guideline for examples.
Applicant repliedFigures, including the Final Site Design (Fig 9-1) and Rehabilitation and Improvement Areas (Fig 9-2), have been revised and are now consistent with updates to the PRCP and Schedule.
Department foundSection 3.5.11 of the PRC Plan (Tailings and processing facilities) includes characterisation of tailings from Cell B only of the TSF. The PRC Plan supporting information in the RGS (2015) report identify that “Since placement, the sulfide minerals have undergone substantial or complete oxidation. This means that in the tailings, to at least 600 mm depth, essentially no residual sulfide minerals are present.” It is not clear what the likely future speciation and mobility of the constituent elements of the tailings beneath the 600mm upper layer would be. Additionally, the RGS (2015) report recommends in-situ core sampling of the tailings through the tailings profile in the deepest area of the TSF.
Asked forDetail in the PRC Plan how the characterisation of Cell B tailings relates to the characteristics of the tailings in Cell A, otherwise include details of characterisation studies carried out on Cell A. Include an assessment of the characteristics of the tailings material below the 600mm sample depth and how the material may interact with infiltration of rainfall to ensure the structure is non-polluting.
Applicant repliedThe PRCP has been updated with additional erosion modelling (section 6.5) including a WEPP erosion assessment (as Appendix L). Criteria have been included to ensure certification by an AQP that the land has achieved stable condition (RM8.4).
Department foundThe final landform design section of the rehabilitation planning part provides detail surrounding each of the residual voids that will remain as NUMAs on the project. This section of the planning part identifies further investigations that are yet to be completed and are required to inform management area milestone criteria. Main Pit A geotechnical assessment has not yet conducted on void batter angles, therefore residual void angle requirements are unknown. The rehabilitation planning part identifies that whether any rehabilitation milestones or management milestones to be completed under the PRCP schedule during the year have been met, and also requirements for an audit report for a PRCP schedule to include a statement about whether the holder has complied with the schedule during the audit period. As such, there is no requirement for a milestone criterion to duplicate the obligations under the EP Act 1994 in relation to the administering authority.
Asked forProvide further information to demonstrate that both the Main Pit and East Hill Pit will achieve a safe and stable condition as per section 3.6.3 of the PRCP guideline including, but not limited to, a geotechnical assessment and proposed final slope angles. Include all required milestone criteria in the PRCP Schedule to ensure the management of the NUMA’s to safe, stable, non-polluting landforms.
Applicant repliedMilestones in the PRCP schedule have been revised regarding criteria for erosion.
Department foundA number of rehabilitation milestone criteria use references such as ‘comparable’, ‘not significantly different’, and ‘evidence of’. Criteria needs to meet the SMART principles. ‘Evidence of’ must include measurable commitments. Please note that Section 6 and 7 of the SLSA outlines several details that could be translated directly into SMART milestone criteria or monitoring, maintenance and mitigation strategies including: Topsoil thickness Deep ripping depth Organic and fertiliser amelioration rates specific to various soil types High density seeding rates for the achievement of rapid stabilisation Hay mulching at specific rates until target groundcover achieved to reduce the risk and impacts of erosion
Asked forAll milestones must be written in a manner that delivers on SMART principles as per section 4.1 of the PRCP Guideline.
Department foundThe schedule refers to reference/analogue sites. Reference/analogue sites need to be identified in the planning part and justifications as to their representativeness and suitability given.
Asked forProvide specific reference sites that will be used in comparison to the rehabilitated areas for determining success of milestone criteria.
Department foundRehabilitation Area (RA) 5 of the PRCP Schedule indicates that existing rehabilitation of the South Pit, TSF Cell A, and Village infrastructure has occurred. However, no details on the rehabilitation works has been provided to support the completion of the rehabilitation milestones.
Asked forIn accordance with section 126C(1)(j) of the EP Act 1994, update the PRC Plan to Include the following details about any existing rehabilitation already completed at the time of submission of the proposed PRC Plan: a description of the rehabilitation works previously carried out when the rehabilitation works commenced and were completed whether the rehabilitation has been applied for or approved as progressively certified under the EP Act.
Department foundSome of the milestone completion dates in the PRCP Schedule do not align with the PRC Plan. For example, RA5 in the PRCP Schedule would indicate that 54.4 hectares of area currently meets the definition of available for rehabilitation and has been nominated that RM8 has been completed prior to 2022. However, the next milestone date (RM9) for the area is not due for completion until 2040, in approximately 18 years. The PRC Plan indicates that this milestone has a typical timeframe of 10 years to achieve RM9.
Asked forAlign milestone completion dates with the justification for the milestone completion dates proposed in the PRC Plan.
Department foundWhen determining when land becomes available for rehabilitation, future activities that have not been currently authorised in the EA cannot be taken into account. The PRC Plan indicates that Infrastructure areas are nominated to be retained for processing the material from other projects following the cessation of mining activities at Yandan.
Asked forReview and update the timing of milestone criteria completion to align with the definition of available for rehabilitation as per section 126D(5) of the EP Act 1994, considering that only activities currently approved or currently in application for an EA amendment can be considered in the PRCP Schedule.
Department foundMM1 for the pit areas states that “Final void high walls comply with maximum safe and stable slope angles as nominated in geotechnical stability assessment” however no milestone criteria has been included to undertake the geotechnical stability assessment for the pit areas.
Asked forInclude all milestone criteria relevant to achieve the final PMLU.
Department foundThe PRC Plan indicates that the Main Pit is expected to be inundated with flood waters and pass floodwater in to and out of the pit via spillways at certain river heights/flood levels to the Suttor River.
Asked forDiscuss how the objectives for the Main Pit achieve best practice management of the area and minimises risks to the environment from the passage of flood waters in to and out of the pit. Consideration should be given to the stability of the spillways to achieve the purpose of passing floodwater in to and out of the pit. Completion criteria for water quality must reflect releases from the main pit not causing environmental harm to land, surface waters or any recognised groundwater aquifer, other than the environmental harm constituted by the existence of the residual void itself.
Department foundFigures 9 and 10 of the SBE 2022 Report as part of the PRC Plan indicate spikes in Electrical Conductivity (EC) during flow events with an explanation provided as “…with the exception of short-term higher salinity experienced during the major regional flooding event in 2011. Comparison of upstream & downstream salinity would suggest an additional salt load entered the river during this significant event, similar to occurrences across the Queensland region for this event.”
Asked forProvide commentary on the timing of releases from main pit and how they correlate or not with the peaks in EC in the Suttor River
Department foundThe PRC Plan states that “For final closure, the existing permanent water cover and flushing pit design will be maintained using bunds.” The risk assessment also states that geotechnical assessment will be required for the main pit bund.
Asked forInclude detail in the PRC Plan to support the functionality of this flushing pit design. Include details of the bund structures, how they will be maintained and include completion criteria for the bunds that ensures these structures will meet the objectives of safe, stable and non-polluting.
Department foundThe PRC Plan states that “Additional monitoring infrastructure (monitoring bores around the Main Pit and a pit water level gauge) will be installed to obtain groundwater information and assist water balance modelling.”
Asked forInclude the installation of the additional monitoring infrastructure and the water balance modelling as completion criteria including appropriate timeframes for completion.
Department foundThe PRC Plan states that “minimal mixing is required with site or river water to meet receiving environment requirements.” However, no detail is included on what dilution is required to meet the receiving environment requirements or at what flow volumes the minimal mixing will occur.
Asked forProvide detail on the minimum mixing requirement to ensure no environment harm will be caused from releases of pit water to the receiving environment
Department foundMM3 identifies that the long-term pit water depth in the East Hill Pit will remain above the sandstone unit within the pit for the prevention of potential groundwater contamination, however the PRC Plan does not include details to support and justify the milestone.
Asked forUpdate the PRC Plan to provide information to support and justify the development of the proposed PRCP schedule.
Department foundSection 3.5.13 of the PRC Plan includes details of construction of a small (approximately 3 m) permanent landform bund to ensure that floodwaters do not enter the pit from the north during an extreme flood event (PMF event). No Improvement Area Rehabilitation Milestone has been included to consider this.
Asked forInclude the construction of the bund completion criteria including appropriate timeframes for completion.
Department foundThe milestone criteria for RM8 of the PRCP Schedule refers to “Seeding of target key species completed at a sowing rate of 6 kg/ha drawn from Table 23 Recommended species for revegetation (Yandan Gold Mine Transitional PRCP)”. Table 23 of the PRC Plan refers to Standard ABA Classification Criteria typically used for material classification.
Asked forUpdate milestone criteria to reflect correct referencing. It is recommended where possible to include the specifics for each Milestone Criteria instead of referring to tables and plans.
Department foundThe PRCP Schedule includes milestone criteria for: Standard barbed wire fencing erected around the perimeter of the residual void to prevent access by humans and fauna. Safety bund constructed around perimeter of the residual void. The Main Pit is expected to be inundated with floodwaters periodically.
Asked forProvide detail in the PRC Plan as to how this infrastructure will remain stable in the flooding conditions expected in proximity to the Main Pit.
Department foundThe PRC Plan refers to several reports such as R&D Environmental 1999; Chapman & Dwyer 1999; SRK Consulting 1999a; SRK Consulting 1999b, HLA EnviroSciences 2001, Forbes 1988, Ross Mining N.L 1992, Scott 2000 and RLA 2019 however these reports have not been provided in Appendix G.
Asked forProvide all technical studies and reports relied upon in the development of the PRC Plan.
Replies to requests not published on the register: 5
Request, as quoted by the applicantThe rehabilitation plan identifies that the Deep Lead Pit is to be backfilled to the surrounding landform however no details have been provided on the removal of water from the pit, backfilling methodology or final slope angles. This information is required to address quality assurance and quality control requirements and to provide milestones that meet the SMART principles.
Applicant repliedThe Deep Lead Pit has now been designated a NUMA (IA1), in line with the EA. The disturbance area of NUMAs in the PRCP and spatial package now align with EA Table F1.
Request, as quoted by the applicantRA2 includes the former waste rock dumps (WRDs) that are identified as ‘having been rehabilitated with varying success by previous mine owners’. The area for these WRDs has not been included in RA2 and no details have been provided on the achievement of each milestone criteria. If these WRDs are to be included in the PRCP schedule, and commencing at an advanced RM, evidence needs to be provided to demonstrate achievement of previous relevant RMs.
Applicant repliedThe PRCP and Schedule have been revised to include rehabilitation for all areas of the WRDs. There is limited information available regarding the commencement and completion of existing rehabilitation. For the purposes of the PRCP it is assumed that these areas may require further rehabilitation work and therefore, all the relevant rehabilitation milestones will apply.
Request, as quoted by the applicantAll activities and areas of disturbance are required to be included within a defined RA that includes rehabilitation milestones (RM) which describes the rehabilitation outcome and timeframes. Please note that disturbance areas to be retained by the landholder under a landholder agreement, need to be included in a RA with milestone criteria that identifies that the activities will achieve a stable condition.
Applicant repliedThe PRCP, Schedule and spatial submission have been revised to include all areas of disturbance. Rehabilitation now reflects the requirements of the EA (Table F1)
Request, as quoted by the applicantThe spatial imagery identifies that the active waste rock dump (WRD) 3 is encroaching into the area that is shown as part of the rehabilitated WRD. The schedule needs to include the extent of each activity that will occur at the end of mine life.
Applicant repliedThe PRCP and schedule have been revised to include rehabilitation for all areas of the WRDs as there is insufficient monitoring data to ascertain the progress or success of previous rehabilitation. It is assumed that all WRDs will require application of all relevant RMs.
Request, as quoted by the applicantRevision Date Comments 1.0 5 January 2022 Initial PRCP submission 3.0 29 April 2026 Response to additional PRCP RFI
Applicant repliedi Table of Contents 1.0 Introduction .................................................................................................... 1 1.1 Project Overview and History .................................................................................... 1 1.2 Relevant Legislation and Policies .............................................................................. 3 1.2.1 Mined Land Rehabilitation Policy .............................................................................. 3 1.2.2 Environmental Protection Act 1994 ........................................................................... 3 1.2.3 Environmental Protection Regulation 2019 ................................................................ 3 1.2.4 PRCP Guideline ........................................................................................................ 3 1.2.5 PRCP Application Form ............................................................................................ 3 1.2.6 Mineral Resources Act 1989 ..................................................................................... 4 1.2.7 Other Legislation ...................................................................................................... 4 2.0 Project Planning .............................................................................................. 5 2.1 Project Description................................................................................................... 5 2.1.1 Type of Operations ................................................................................................... 5 3.1.3 Duration Of Operation .............................................................................................. 5 2.2 Mining Tenements .................................................................................................... 6 2.3 Baseline Information ................................................................................................ 7 2.3.1 Climate .................................................................................................................... 7 2.3.2 Topography .............................................................................................................. 9 2.3.3 Geology ................................................................................................................. 11 2.3.4 Soils ...................................................................................................................... 13 2.3.5 Land Suitability Assessment ................................................................................... 15 2.3.6 Land Stability ......................................................................................................... 19 2.3.7 Ecology .................................................................................................................. 21 2.3.8 Surface Water ........................................................................................................ 29 2.3.9 Groundwater .......................................................................................................... 32 2.3.10 Existing and Surrounding Land Uses........................................................................ 37 2.3.11 Land Tenure ........................................................................................................... 38 2.4 Design for Closure .................................................................................................. 41 2.5 Rehabilitation Planning ........................................................................................... 41 2.6 Existing Rehabilitation ............................................................................................ 42 3.0 Post Mining Land Uses ................................................................................... 43 3.1 Pre-approved PMLUs .............................................................................................. 43 3.2 PMLUs ................................................................................................................... 44 3.3 Community Consultation ....................................................................................... 48 ii 3.4 Planning Scheme ................................................................................................... 48 3.5 Final Milestone Criteria ........................................................................................... 49 4.0 Non-use Management Areas .......................................................................... 50 4.1 Voids in Floodplains ............................................................................................... 50 4.2 Achieving Sufficient Improvement ........................................................................... 50 4.3 Community Consultation ....................................................................................... 51 4.4 Planning Scheme ................................................................................................... 51 4.5 Final Milestone Criteria ........................................................................................... 51 5.0 Community Consultation ............................................................................... 52 5.1 Community Profile ................................................................................................. 52 5.2 Community Consultation Register .......................................................................... 52 5.2.1 Ongoing Consultation ............................................................................................. 56 5.2.2 Native Title ............................................................................................................. 56 6.0 Rehabilitation and Management Methodology ................................................. 57 6.1 Final Landform Design ............................................................................................ 57 6.1.1 Landform Design Criteria ........................................................................................ 57 6.1.2 Landform Structures .............................................................................................. 57 6.1.3 Landform Construction .......................................................................................... 59 6.1.4 Quality Assurance .................................................................................................. 60 6.2 Hydrogeology ......................................................................................................... 61 6.2.1 Hydrogeological Conceptual Model ........................................................................ 61 6.2.2 Groundwater Distribution and Flow ......................................................................... 63 6.2.3 Groundwater Velocity ............................................................................................. 64 6.2.4 Recharge and Discharge ......................................................................................... 66 6.2.5 Groundwater Chemistry ......................................................................................... 66 6.3 Flooding ................................................................................................................. 68 6.4 Soil and Capping Material Assessment ................................................................... 70 6.4.1 Waste Rock Balance............................................................................................... 70 6.4.2 Soil Resources ....................................................................................................... 70 6.4.3 Topsoil Management .............................................................................................. 71 6.4.4 Topsoil Application ................................................................................................. 71 6.5 Erosion .................................................................................................................. 72 6.5.1 Erosion Assessment ............................................................................................... 72 6.6 Waste Characterisation .......................................................................................... 75 6.6.1 Methodology .......................................................................................................... 75 iii 6.6.2 Geochemical Analysis Results ................................................................................ 76 6.6.3 Summary of Waste Rock Characterisation .............................................................. 84 6.7 Cover Design .......................................................................................................... 85 6.8 Tailings Storage Facilities ....................................................................................... 85 6.8.1 Tailings Characteristics .......................................................................................... 88 6.8.2 TSF Water Quality ................................................................................................... 88 6.8.3 TSF Capping and Rehabilitation Strategy ................................................................. 89 6.9 Void Closure Plan ................................................................................................... 91 6.9.1 Options for Minimising Size and Volume of Residual Voids ....................................... 91 6.9.2 Void Water Balance ................................................................................................ 91 6.9.3 Source-Pathway-Receptor Assessment .................................................................. 94 6.10 Underground .......................................................................................................... 96 6.11 Water Management ................................................................................................ 96 6.12 Revegetation .......................................................................................................... 96 6.12.1 Objectives.............................................................................................................. 96 6.12.2 Species Selection ................................................................................................... 97 6.12.3 Seeding Methodology ............................................................................................. 98 6.12.4 Soil Treatment ........................................................................................................ 98 7.0 Mine Closure Risk Assessment ....................................................................... 99 7.1 Principles and Methodology .................................................................................... 99 7.2 Risk Matrix ........................................................................................................... 101 8.0 Monitoring and Maintenance ......................................................................... 108 8.1.1 Rehabilitation Milestones ..................................................................................... 111 8.1.2 Rehabilitation Area Milestone Monitoring and Schedule ........................................ 111 8.1.3 Rehabilitation Monitoring Phases .......................................................................... 111 8.1.4 Major Monitoring Methods .................................................................................... 113 8.1.5 Desktop Monitoring .............................................................................................. 113 8.1.6 Landform and Erosion .......................................................................................... 113 8.1.7 Soil and Spoil ....................................................................................................... 114 8.1.8 Vegetation ........................................................................................................... 114 8.1.9 Surface Water ...................................................................................................... 114 8.1.10 Receiving Environment ......................................................................................... 114 8.1.11 Groundwater ........................................................................................................ 114 8.2 Rehabilitation and Closure Maintenance and Management ................................... 115 8.3 Rehabilitation Trials .............................................................................................. 116 iv 9.0 PRCP Schedule ............................................................................................ 117 9.1 Final Site Design ................................................................................................... 117 9.2 Rehabilitation/ Improvement Areas ....................................................................... 119 9.3 Milestones and Milestone Criteria ......................................................................... 121 9.4 Available for Rehabilitation and Completion Timeframes ....................................... 129 9.5 Conditions ........................................................................................................... 130 10.0 References .................................................................................................. 131 Tables Table 2-1 WGM Mining Tenements ....................................................................................... 6 Table 2-2 Representative Soil Profiles .................................................................................13 Table 2-3 Rehabilitation Related Chemical Properties .........................................................13 Table 2-4 Land Suitability Classes .......................................................................................15 Table 2-5 Summary of Land Suitability Classes for Beef Cattle Grazing .................................16 Table 2-6 Summary of Land Suitability Classes for Rainfed Broadacre Cropping ...................16 Table 2-7 Soil Erosion Susceptibility ....................................................................................19 Table 2-8 Erosion Hazard (IECA, 2008).................................................................................19 Table 2-9 RUSLE Calculations .............................................................................................20 Table 2-10 Regional Ecosystems ...........................................................................................21 Table 2-11 Threatened fauna within a 10 km radius of WGM ...................................................24 Table 2-12 Matters of National Environmental Significance - Ecological Communities ............25 Table 2-13 Matters of National Environmental Significance that may occur within 10 km ........26 Table 2-14 Surface Water Monitoring Points ..........................................................................29 Table 2-15 Surface Water Quality Monitoring Values ..............................................................29 Table 2-16 Surface Water Chemistry (2021-2023) ..................................................................30 Table 2-17 Monitoring Bores Details ......................................................................................33 Table 2-18 Baseline Groundwater Data August 2021 – August 2023 (Appendix H)....................36 Table 2-19 Land Tenure ........................................................................................................38 Table 2-20 WGM Rehabilitation Planning ...............................................................................41 Table 3-1 EA approved PMLUs .............................................................................................44 Table 3-2 PMLUs and Applicability .......................................................................................44 Table 3-3 Requirements of a PMLU ......................................................................................45 Table 4-1 NUMAs at WGM ...................................................................................................50 Table 5-1 Community Stakeholders ....................................................................................52 Table 5-2 Community Consultation Register ........................................................................55 v Appendices Appendix A: EA (EPML00772413), 24 March 2026 Appendix B: Soils and Land Suitability Assessment Appendix C: Community Consultation Management Plan Appendix D: Flood Hazard Overlay Assessment Appendix E: Vegetation Survey Report Appendix F: Wirralie TSF Rehabilitation Strategy Appendix G: Wirralie Gold Mine Waste Rock Characterisation Appendix H: Hydrogeology Report Appendix I: Wirralie Gold Mine Concept Closure Methodology and Water Balance Model Appendix J: Waste Rock Characterisation Supporting Letter - Cadmium and Selenium Appendix K: Waste Rock Characterisation Supporting Letter – Salinity Appendix L: PRCP RFI Erosion Modelling Appendix M: PRCP Schedule v3.0 viii Table 5-2 Community Consultation Register