Mount Morgan Mine Upper Mundic Gully TSF EA Amendment

SGME T-02 Memorandum

Date

13 February 2026

To

Tim Shiplin

Pete Mellor, Damien Tol, Mike Gowan

Cc

From

Lachlan McQuire

Subject

Mount Morgan Mine TSF Closure Plan for TMP

Dear Tim, We understand that you require the current closure plan for Sandstone Gully TSF, Upper Mundic Gully TSF and the OCP to inform the tailings management plan (TMP). Authorisation for Heritage Minerals to discharge up to six million dry weight tonnes of newly created tailings into the OCP is provided under condition W13 of Environmental Authority (EA) EPML00433013. As the OCP is not a feature authorised for mining activities in the EA, there is no requirement for Heritage Minerals to rehabilitate

and close this feature. As such, the closure plan provided herein does not mention OCP. This memo has prepared on the basis that it can be directly imported into the TMP.

1. Closure Plan 1.1 General

Under the QLD Government Mined Land Rehabilitation Policy, land disturbed by mining activities will be rehabilitated progressively as it becomes available to minimise the risks of environmental impacts and reduce cumulative areas of disturbed land. Land disturbed by mining activities is considered to be rehabilitated when it can be demonstrated it is safe, stable, does not cause environmental harm, and is able to sustain the post- mining land use (PMLU) or achieve a non-use management area (NUMA) in accordance with the approved Progressive Rehabilitation and Closure Plan (PRCP). Heritage Minerals submitted a PRCP for the Mount Morgan Mine site on 30 May 2025 to respond to a Not Properly Made notice. At the time of this TMP development, the PRCP application was deemed properly made and a request for information had been issued to Heritage Minerals. Although the PRCP schedule is not approved, TSF specific rehabilitation methods from the PRCP have been relied upon to inform this TMP. PRCP schedule approval is not anticipated until 2027 at the earliest. The rehabilitation and closure strategy for Sandstone Gully TSF and Upper Mundic Gully TSF will be mostly similar on the basis that the tailings originate from the same processing plant. Both TSFs shared similar geometries in that they are valley TSFs that ultimately reduce stability risks as they leverage existing landforms as buttresses whilst limiting seepage of surrounding historically placed waste material. As the mine plan is subject to further optimisation, this closure plan does not consider TSF closure timings or closure cost estimates. 1.2 Regulatory requirements The overarching rehabilitation goal for Sandstone Gully TSF and Upper Mundic Gully TSF is that they are to be rehabilitated to achieve a land outcome that is: Safe to humans and wildlife; Non-polluting;

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