4.2 Topography and Drainage The Mount Morgan Mine is located west of the Mount Morgan Township, lying within the Dee Range. The Dee Range runs SE/NW and separates the coastal plains from the interior plains. The Dee River is the immediate receiving water body adjacent to the site, situated on the southern boundary of the mine lease, between the mine and the town. The Dee River enters a vast flat-lying alluvial plain at the margin of the Biloela Basin, ultimately flowing into the Don River and then the Fitzroy River, where it reaches Rockhampton and the coast. The Mount Morgan mine area is characterised by rugged, deeply incised terrains developed on competent bedrock units, with prominent ridgelines, escarpments and incised drainage features that reflect long term the landscape evolution. This natural geomorphological setting has been modified by more than a century of mining activity, resulting in a complex legacy of landforms comprising open pits, steep gullies, waste rock dumps, tailings storage facilities and altered drainage pathways. The proposed TSF is located within a natural topographic basin, with ground elevations across the footprint varying significantly. The lowest point of the proposed TSF footprint occurs at approximately 322 m AHD, while the surrounding ridgeline rises to elevations of up to approximately 405 m AHD. The current drainage features and receiving waterbodies are displayed in Figure 15. The landform has been highly modified primarily by the creation of the OCP which many catchments now drain into and influenced by the placement of latent tailings and waste rock within naturally occurring valleys. The evidence that the landform is highly modified is illustrated well by comparison with the pre-mining drainage network provided in Figure 16. As depicted in Figure 16, prior to mining activities occurring at the Mount Morgan Mine, the headwater of the Mundic Gully flowed north to south before flowing in an easterly direction towards the Dee River. The Mundic Gully headwaters now drain into an ephemeral dam that is connected via a tunnel to Dam 8.
Project number: 25B061
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