7.5.4 Impact Assessment The proposed operations at Mount Morgan will result in the reduction of contaminant sources via the excavation and placement of historical ARD generating mine waste and redeposition into the Sandstone Gully TSF, the OCP and (if approved) the Upper Mundic Gully TSF and rehabilitation of operational areas utilised by Heritage Minerals in accordance with the State Rehabilitation Plan (Unger et al, 2003) and Phase 3 Agreement leaving the site in an improved condition. Potential impacts on land from construction and operation of the Upper Mundic Gully TSF and ancillary infrastructure are unlikely given the significant existing disturbance within the area associated with the Western Dump placement and previous construction and operation of the water diversion tunnel. The construction of the Upper Mundic Gully TSF will likely improve impacts to land as the currently exposed face of the Western Dump will be sealed. The risk of exacerbating onsite and offsite contamination will also be minimised through the implementation of rigid TSF design, surface water controls associated with the TSF inspection regimes and groundwater monitoring. Through implementation of rehabilitation measures the Upper Mundic Gully TSF and ancillary infrastructure will achieve a final landform that is: ∕ Safe to humans and wildlife; ∕ Non-polluting; ∕ Stable; and ∕ Able to sustain an appropriate land use after rehabilitation or restoration. Management Practices The primary objective for Project land management will be to facilitate progressive tailing reprocessing and Mount Morgan Mine rehabilitation and remediation in accordance with the State’s Rehabilitation Plan (Unger et al, 2003) and Phase 3 Agreement. 7.5.5 The major waste stream generated from the proposed amendments are mineral wastes in the form of tailings that have been processed to remove contaminant mass. Permanently storing tailings in a bespoke managed TSF is considered best practice and is a better environmental outcome than the current setting whereby latent tailings (and waste rock) provides a source of contamination that continues to impact the environmental values of receptors, particularly the Dee River. In addition to these, the Heritage Minerals Soil and Hazardous Substances Procedures provide standard controls for various Project activities including chemical and hazardous material storage, spill response and soil management.
Project number: 25B061
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