this section, consideration is given to all catchments and mine features within the mining lease and not just the Upper Mundic Gully TSF footprint as the purpose of the CSM is primarily to conceptualise how groundwater can migrate to environmental receptors. The hydraulic gradients and inferred groundwater flow contours correlate well with pre-mining topography (GHD, 2017). Overall, the interpreted groundwater flow direction is towards the southeast and the Dee River and is not anticipated to change significantly due to seasonal variations in groundwater levels (GHD, 2017). Based on the geological conditions and soil properties of the Upper Mundic Gully area, the underlying geological units include colluvium/alluvium, saprolite underlain by fractured bedrock and bedrock. GHD (2017) provided a detailed summary of groundwater flows at the Mount Morgan Mine following review of previous RGI (2003, 2005, 2010 and 2011) groundwater reports. Mine affected water created from seepage or surface runoff is currently accumulated in numerous facilities including Shepherds Holding, No 2 Mill, Frog Hollow and Mundic West structures. Once collected, the seepage and/or surface runoff is either left to evaporate or pumped back into the OCP, with this location being the primary storage location for contaminated water. Most seepage currently reports to either the seepage sumps and subsequently the Sandstone Gully TSF and the OCP. This water treatment system is owned and managed by the DNRMMRRD. Existing seepage from the mine waste / tailings areas, inclusive of the Mundic Creek area and main discharge points for subsurface and groundwater flow is summarised as a source-pathway- receptor model in Table 38. Groundwater and sub-surface flows to for each catchment including to sumps and receiving environment simulated by RGI (2011) are presented in Table 39. Simulated groundwater flow per catchment is provided in Table 40.
Project number: 25B061
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