based on data availability and will be appropriate to support the particle tracking that is proposed as part of Phase I. Note, the numerical groundwater flow model will be updated and calibrated to represent “current conditions” for groundwater based on observed hydraulic heads and available groundwater quality data (2025/2026 data). The calibration of the “current conditions” model will ensure that the model provides an appropriate and defensible representation of existing hydrogeological behaviour prior to being used for predictive scenario simulations. The updated model will then be used to simulate future flow conditions and provide particle tracking simulations to assess potential groundwater flowpaths and inferred contaminant migration pathways near and within the footprint of the proposed Upper Mundic Gully TSF. These simulations will be used to address DETSI information request 13(e) and to support evaluation of groundwater containment performance. The key objective of these simulations is to demonstrate that hydraulic containment of the dissolved constituents in groundwater impacted by seepage from the Upper Mundic TSF can be achieved once the TSF has been constructed. The updated groundwater model and supporting CHM will be documented in a modelling report. 6.6.9.2 Phase II Model Update The Phase II model update will involve updating the site-wide groundwater model and developing a solute transport model as part of that effort. The key objective is to simulate the movement of selected constituents, e.g., sulphate and/or selected metals, in groundwater within the mine site (including from the proposed UMG TSF) and to simulate the contaminant loads to the Dee River and other receiving areas. This modelling would be undertaken as part of a larger scope of work to better understand the improvements in local groundwater quality and the water quality of the Dee River as a result of the Mount Morgan Tailings Processing & Rehabilitation Project. Ecology Previous EA amendment applications submitted to DETSI over the years have presented desktop information obtained from Protected Matters Search Reports and MSES search reports. As the Upper Mundic Gully TSF footprint was mapped as intersecting mapped high risk areas for protected flora, there was sufficient justification to undertake detailed ecological assessments to support this amendment application with reference to the following guidance material: ∕ Terrestrial Vertebrate Fauna Survey Guidelines for Queensland; ∕ Flora Survey Guidelines – Protected Plants; and ∕ Methodology for surveying and mapping regional ecosystems and vegetation communities in Queensland. 6.7 6.7.1 Desktop Assessment A comprehensive desktop assessment was undertaken on the 10 February 2025 to identify potential environmental values, constraints, and potential impacts within the Project area to enhance understanding of the ecology of the area and its relationship to and connectivity with the surrounding landscape. The desktop assessment results are discussed in Section 3 of GHD’s Ecological assessment report (Appendix E). An additional updated desktop assessment was conducted by Wulguru Technical Service (WTS) in the fauna survey report in September 2025 and the information sources used are summarised in Table 43 and the results of the assessment are discussed in Section 3 of WTS’s Fauna Survey Report.
Project number: 25B061
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