Original EA Amendment

Table 3.1

Summary of assumed maximum pump rates in the updated water balance modelling

GHD (2022a) Model - ML/d

July 2025 Update - ML/d

July 2025 Update - ℓ/s

SUBJECT

DOR WTP Discharge Flow Rate Phase 1 – Month 0 - 11: SSG being dewatered to OCP, OCP discharging via WTP.

1.5 (only for 3 months each year)

0 for month 1 and

11.57

Phase 2 – Month 12 - 51: OCP is the TSF. Phase 3 – Month 52 - 73: UMG is the TSF.

1.5 (only for 3 months each year)

4.8 after one month

55.55

1.5 (only for 3 months each year)

4.8

55.55

Phase 4 – Month 74 - onwards: UMG is the TSF.

1.5 (only for 3 months each year)

4.8

55.55

Return Water to Plant Phase 1: -

-

-

-

-

± 6.3 and 8.4 after 12 months

97.22

Phase 2: from OCP (Phase 2)

1.2

7.8

84.49

Phase 3: from UMG (Phase 3)

8.08

7.8

84.49

Phase 4: from UMG (Phase 4)

1.103

1.103

12.77

Phase 2 – 4: Ore moisture (Phase 2 - 4)

0.4

0.4

4.63

Phase 2 – 4: Dam 8

0.4

Other Pump Flow Rates

0.0

3.85

44.45

SSG to OCP (Phase 1) - Dewatering

0.0

0.5

5.79

OCP to UMG Transfer (Phase 3 and Phase 4)

1.2

Variable depending on sump

Variable depending on sump

Seepage Pump Back

12624987 | Heritage Minerals EA Amendment Application – Updates to Water Balance Model July 2025 (Final) 7

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