Mine Feature
Operational Activities – Collection and monitoring of seepage within new embankment. Construction of tailings dam wall – Previously disturbed areas to be used for workshops, administration areas and support services.
Mining Contractor (Services) Yard
Haul Roads Powerlines
– Mining Support Infrastructure – Mining Support Infrastructure
Non-Potentially Acid Generating (NPAG) Stockpile
– Source of TSF embankment and rehabilitation materials.
Slag Stockpiles
– Source of TSF embankment and rehabilitation materials
3.1 Latent Tailings Temporary Processing A significant volume of latent tailings must be relocated in order to prepare Sandstone Gully for the construction of Sandstone Gully Tailings Storage Facility (TSF), which is a proposed modern TSF where all processed tailings created during Heritage Minerals operations are intended to be disposed. During the life of the Mount Morgan Mine, prior to Heritage Minerals obtaining an EA, latent tailings were deposited into several naturally occurring gullies/valleys throughout the site. It has been discovered through recent geotechnical investigations that the legacy condition of Sandstone Gully is not as expected. Latent tails are proposed to be removed from Sandstone Gully and transported to the Process Plant for processing. The processed tails are proposed to be disposed into the OCP for a maximum period of 3 years which is sufficient time build the Sandstone Gully TSF. All processed tailings will be deposited into the Sandstone Gully TSF once constructed. Mining activities will only be conducted between 7AM and 10PM as per the allowable noise limits provided in Table D1 of EPML00433013. Mining activities will only occur from Mondays to Fridays with no work undertaken on weekends. The assessment of likely impact determined that the proposed activity does not present an increased risk of adverse impact to the site’s environmental values. Environmental aspects of the proposed activity that required detailed assessment to ensure continued protection of the site environmental values include water quantity (water balance) and water quality. The updated Water Balance Model shows that the OCP can accommodate and additional two (2) million dry weight tonnes of processed tailings, resulting in a maximum discharge of six (6) million dry weight tonnes of processed tailings, and risks of overtopping events are unlikely.The starting storage level applied at the commencement of the modeling was inputted at 269.2m AHD. The spill level of the OCP is at 273.52 m AHD and the simulations show that there is negligible spill risk due to the declining water level. The receiving OCP is of a lesser water quality than the processed tailings proposed to be temporarily discharged. Geochemical mixing model predicted results showed an overall improvement in the OCP water quality after adding new tailings slurry from the processing plant under pH 9.6 and 0.61 volume to volume mixing ratio of new tailings to OCP water. There were negligible changes in all other anion and cation concentrations. 4. Management methods and controls 4.1 Hierarchy of Waste To manage waste with minimal impact and full consideration of sustainability, best practice and conformance to all legislative requirements, waste is intended to be managed in accordance with the following hierarchy: 1. Waste avoidance – avoid unnecessary resource consumption
GHD | Heritage Minerals | 12626510 | Waste Management Plan
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