Mount Morgan Mine Upper Mundic Gully TSF EA Amendment

Mine Domain

Mine feature

Mining Lease

Location (MGA94, zone 55)

Maximum Disturbance Area (ha)

Latitude (GDA94)

Longitude (GDA94)

ML5660 Justification for the changes described in Figure 7 are as follows: ∕ Inclusion of the Upper Mundic Gully TSF in Table F1 is required to authorise the mine feature as an operational activity. The proposed operational activities are intended to match Sandstone Gully TSF however are updated to reflect better nomenclature in that a “tailings dam wall” should be called a “tailings dam embankment”. Justification for the changes described in Table 7 are as follows: ∕ As described in Section 6.6.8, the installation of additional groundwater monitoring bores is proposed to further characterise the groundwater around UMG TSF; ∕ The rationale for each monitoring location is further described in Section 6.6.8. Generally, locations have been proposed to confirm bedrock conditions, confirm groundwater levels at both shallow and deep occurrences and assess potential seepage pathways; ∕ Proposed locations are provided for planning purposes only and the exact locations and target depths must be determined in consultation with the geotechnical engineers responsible for designing the TSF and conducting the necessary geotechnical assessment of the TSF foundation; and ∕ Access to each proposed drilling location must also be confirmed by staff from Heritage Minerals, as some areas of the Upper Mundic Valley are steep and not easily accessible with a drill rig and the supporting equipment needed to install the proposed monitoring bores. As such, TBDs have been provided for in Table 7 with a time bound date by which the EA holder must provide an update to the administering authority. Table 7 Proposed Table W1 – Groundwater monitoring locations and frequency

Monitoring Point(s)

Latitude (GDA 94)

Longitude (GDA 94)

Surface RL (m)

Monitoring frequency

MB2

-23.636

150.376

278.48

Monthly

MB3

-23.642

150.369

278.48

Monthly

MB5SD

-23.645

150.378

223.17

Monthly

MB7D

-23.656

150.372

211.87

Monthly

MB8D

-23.636

150.381

225.89

Monthly

MB9

-23.631

150.3837

238.06

Monthly

MB14

-23.640

150.374

276.13

Monthly

TBD

TBD to be provided by 30 June 2027

TBD to be provided by 30 June 2027

TBD to be provided by 30 June 2027

Monthly

Project number: 25B061

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