Overview
Stage | Production |
Mine Type | Open Pit & Underground |
Commodities |
|
Mining Method |
- Truck & Shovel / Loader
- Sub-level open stoping (SLOS)
- Paste backfill
|
Production Start | ...  |
Mine Life | 2040 |
The Cowal operation is currently an open pit and underground stope mining operation.
Cowal achieved a major milestone during the second half of FY23, mining and processing the first underground stopes. Remaining underground infrastructure milestones are expected to be reached early in FY24 to facilitate full commercial production levels expected by early in the second half of FY24.
The Open Pit Continuation (OPC) Project This project will extend open pit mining by ~10 years and Cowal’s mine life by ~2 years to 2042. The Feasibility Study for the Open Pit Continuation Project continues to progress to schedule. |
Source:
p. 2,135
Company | Interest | Ownership |
Evolution Mining Ltd.
|
100 %
|
Indirect
|
Evolution Mining (Cowal) Pty Ltd.
(operator)
|
100 %
|
Direct
|
Evolution Mining (Cowal) Pty Limited (Evolution) is the owner and operator of the Cowal Gold Operations (CGO). All mining activity occurs within Mining Lease (ML) 1535 and ML 1791. Evolution Mining Ltd. is wholly owned by Evolution Mining (Cowal) Pty Limited.
Contractors
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Deposit Type
- Mesothermal
- Vein / narrow vein
- Epithermal
Summary:
Mining at Cowal currently centres on the E42 deposit, with underground development of the GRE46 deposit underway, and studies ongoing for the E41 and E46 Open Pits. The gold deposits occur within the 40km by 15km wide Lake Cowal Volcanic Complex. The deposits occur within a 5km (n-s) by 2km (e-w) trend known as the Gold Corridor.
The gold deposits, E42, E41, E46 and GRE46 are structurally hosted, epithermal to mesothermal gold deposits occurring within and marginal to a >500m thick dioritic to gabbroic intrusion (Muddy Lake Diorite) doming the stratigraphically upright andesitic and dacitic volcaniclastic rocks and lavas. The CGO tenements also host the copper-gold porphyry prospect at Marsden/E43, and the volcanogenic-massive sulphide prospect at Decoy/E35.
Gold deposits aligned along a north-south orientated corridor within the bounding Booberoi Fault on the western side and the Reflector Fault on the eastern side. The area is commonly referred to as the Gold Corridor. The current architecture and associated mineralisation within the Gold Corridor is related to a succession of intrusions exploiting pre-existing zones of weakness, most likely the Cowal Shear Zone. The intrusions have domed the camp, resulting in a faulted anti-form that plunges shallowly to the north-northeast.
Gold mineralisation is associated predominantly with extensional, dilatant and shear quartz-carbonate veining with pyrite and a later base metal assemblage consisting ........

Mining Methods
- Truck & Shovel / Loader
- Sub-level open stoping (SLOS)
- Paste backfill
Summary:
The Cowal operation is currently an open pit and underground stope mining operation utilising conventional drill and blast, load and haul methodologies, mining nominally 9m blast benches as 3 x 3m flitches for the open pit and sublevel long hole open stoping underground with past backfill. Open pit mining commenced in 2005 and processing started in 2006 and Underground production commenced in 2023. Mining is carried out with a fleet of company-owned, hired and contract mining equipment. Ore is hauled by truck to either an ore stockpile area or directly fed into the primary crusher.
Mining at Cowal currently centres on the E42 deposit, with underground development of the GRE46 deposit, and studies ongoing for the E41 and E46 Open Pits.
Open Pit
The Open pit ore reserve consists of E42 Stage H and the currently unapproved E42 Stage I, E41, GR and E46 open pits. E42 Stage I, E41, GR and E46 will be mined through conventional truck and excavator mining methods with similar mining rates and constraints as the operational E42 Stage H pit.
Minimum mining widths for benches were based on 45m and are generally exceeded in all pit stages. However, in the E42 Stage I cutback where the cutback stays inside the existing Stage H pit, the mining width reduces to about 30-35m, or the width of the Stage H ramp. To account for operational delays in these narrow areas, operational efficiencies were lowered by reducing the productive hours of excavators by 5 ........

Source:

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Flow Sheet:
Summary:

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Production:
Commodity | Units | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 |
Gold
|
oz
| ......  | ......  | ......  | ......  | ......  | 257,951 | 263,015 |
Silver
|
oz
| ......  | ......  | ......  | ......  | ......  | ......  | ......  |
All production numbers are expressed as payable metal.
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Operational Metrics:
Metrics | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 |
Waste
| ......  | | | | | |
Ore tonnes mined
| ......  | ......  | ......  | 2,817 kt | 6,114 kt | 7,770 kt |
Waste OP
| ......  | ......  | ......  | 165 kt | 1,436 kt | 1,574 kt |
Total tonnes mined
| ......  | ......  | ......  | | | |
Tonnes processed
| ......  | ......  | ......  | 8,486 kt | 7,936 kt | 7,795 kt |
Plant annual capacity
| ......  | ......  | ......  | 9 Mt | | 7.5 Mt |
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Reserves at December 31, 2022:
Mineral Resource: Open pit cut-off 0.35 g/t; Underground cut-off 1.50.
Ore Reserve: Open pit cut-off 0.45 g/t; Underground cut-off 0.55/1.80.
Category | Tonnage | Commodity | Grade | Contained Metal |
Proven
|
27.4 Mt
|
Gold
|
0.47 g/t
|
414 koz
|
Probable
|
102.1 Mt
|
Gold
|
1.19 g/t
|
3,915 koz
|
Proven & Probable
|
129.5 Mt
|
Gold
|
1.04 g/t
|
4,329 koz
|
Measured
|
29.5 Mt
|
Gold
|
0.46 g/t
|
440 koz
|
Indicated
|
204.9 Mt
|
Gold
|
1.03 g/t
|
6,793 koz
|
Inferred
|
38.8 Mt
|
Gold
|
1.29 g/t
|
1,607 koz
|
Total Resource
|
273.3 Mt
|
Gold
|
1.01 g/t
|
8,840 koz
|
Pipelines and Water Supply
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Corporate Filings & Presentations:
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