Executive Summary
Wulguru Technical Services (WTS) was engaged by Heritage Minerals Pty Ltd (Heritage Minerals), the
owners and operators of Mount Morgan Mine, to prepare supporting information for an amendment to
Environmental Authority (EA) EPML00433013.
The purpose of this document is to describe existing environmental values and assess potential
environmental impacts that may arise from the proposed amendments. The proposed amendments
relate to:
• Authorise Upper Mundic Gully Tailings Storage Facility (TSF) by inclusion as a mine feature
in the EA;
• Update Table A1, and associated Schedule I Figure 1, to address to be determined (TBDs)
associated with the pipe corridor and exploration mine features; and
• Fix minor erroneous issues in the EA that impact on the processed tailings volumes for
discharge into Sandstone Gully TSF.
The Heritage Minerals Project will ultimately result in improved environmental outcomes at the Mount
Morgan Mine through the excavation and treatment of historical Acid Rock Drainage (ARD) generating
mine waste and redeposition of processed tailings into the Sandstone Gully TSF, Open Cut Pit (OCP)
and the Upper Mundic Gully TSF (if approved). This will result in the removal of the source of ARD
generating material from across the site reducing recharge of and seepage from mine waste structures.
This will reduce impacts from the Mount Morgan Mine to the receiving environment including the Dee
River in accordance with the State’s Rehabilitation Plan (Unger et al, 2003) and Phase 2 Agreement.
The Upper Mundic Gully TSF approval will provide a more resilient tailings/water management strategy
that can better accommodate more extreme climatic conditions and further reduce water balance risks.
Approval and operation of the Upper Mundic Gully TSF will provide further comfort to key project
stakeholders including the Independent Technical Expert (ITE) and the Department of Natural
Resources and Mines, Manufacturing and Regional and Rural Development (DNRMMRRD) by
reducing the likelihood of overtopping events from structures potentially impacting offsite environmental
values and reducing operational pressures on the Water Treatment Plant (operated by the
DNRMMRRD) that adjoins the OCP.
The Upper Mundic Gully TSF footprint is highly modified and surrounded by previous authorised mining
disturbances that have reduced environmental values. Potential impacts to environmental values from
the construction and operation of Upper Mundic Gully TSF have been fully identified. Mitigation and
management measures for reducing environmental harm for unavoidable impact to some
environmental values have been proposed.
The proposed amendment has been determined to be of negligible risk to all environmental values.
Existing controls can continue to be implemented to maintain the level of risk to as low as reasonably
possible.
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Wulguru Technical Services Pty Ltd – Supporting Information Report
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