Overview
Stage | Production |
Mine Type | Underground |
Commodities |
|
Mining Method |
- Longhole stoping
- Paste backfill
|
Processing |
- Gravity separation
- Centrifugal concentrator
- Carbon re-activation kiln
- Consep Acacia Reactor
- Smelting
- Crush & Screen plant
- Concentrate leach
- Agitated tank (VAT) leaching
- Carbon in leach (CIL)
- Carbon in pulp (CIP)
- AARL elution
- Carbon adsorption-desorption-recovery (ADR)
- Solvent Extraction & Electrowinning
- Cyanide (reagent)
|
Source:
p. 16
Company | Interest | Ownership |
Evolution Mining Ltd.
|
100 %
|
Indirect
|
Evolution Mining Mungari Pty Ltd.
(operator)
|
100 %
|
Direct
|
Evolution operates wholly-owned mine Mungari in Western Australia.
Evolution Mining Ltd (EVO) operates the Mungari Gold Operations (MGO) including the Frog’s Leg and White Foil gold projects.
Evolution Mining (Mungari) Pty Ltd is a wholly owned subsidiary of Evolution Mining Limited.
Summary:
Mineralisation at Frog’s Leg is hosted within a number of steeply dipping NNW-SSE structures that are vertical or dipping steeply (~80 degrees) to the west. Surface and underground drilling intersect the mineralisation at an angle to minimise bias.
The Frog’s Leg deposit is located in the southern portion of the Kundana mining area, within the Achaean Norseman-Wiluna greenstone belt of the Eastern Goldfields Province. The Kundana gold deposits are structurally related to the Zuleika Shear Zone, a regional NNW-trending shear zone that juxtaposes the Ora Banda domain to the east and the Coolgardie domain to the west. The Frog’s Leg deposit is located on the sheared contact between the porphyritic “cat rock” (regionally known as the Victorious Basalt) and volcaniclastic rocks of Black Flag Beds.
The ore lodes are between 2m and 20m thick and occur as sub-parallel lodes.
Mining Methods
- Longhole stoping
- Paste backfill
Summary:
At underground mine, Frog’s Leg mining methodology is top-down long hole stoping, with paste fill.
Access:
- 5m x 5.5m decline from portal in pit, then twin declines from 125 metres below surface (mbs) to access north (Mist) and south (Rocket) sections. Deepest current level is 700mbs.
Flow Sheet:
Processing
- Gravity separation
- Centrifugal concentrator
- Carbon re-activation kiln
- Consep Acacia Reactor
- Smelting
- Crush & Screen plant
- Concentrate leach
- Agitated tank (VAT) leaching
- Carbon in leach (CIL)
- Carbon in pulp (CIP)
- AARL elution
- Carbon adsorption-desorption-recovery (ADR)
- Solvent Extraction & Electrowinning
- Cyanide (reagent)
Flow Sheet:
Summary:
Three stage crushing, ball mill, gravity and carbon-in-pulp (CIP).
Recovery: 90 - 93%.
Leaching:
- Leaching: 2 x 1,140 m3 tanks;
- Adsorption: 6 x 750 m3 tanks;
- Elution: split AARL;
- Electrowinning: 3 x Consep tanks [2 x carbon-in-leach (CIL), 2 x gravity].
Gravity circuit:
- Concentrator: 2 x Knelson;
- Intensive Leach: Consep Acacia.
Recoveries & Grades:
Commodity | Parameter | 2020 | 2019 | 2018 |
Gold
|
Head Grade, g/t
| ......  | ......  | 5.32 |
Production:
Commodity | Units | 2020 | 2019 | 2018 |
Gold
|
koz
| ......  | ......  | 105 |
All production numbers are expressed as metal in ore.
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Operational Metrics:
Metrics | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 |
Ore tonnes mined
| ......  | ......  | 391 kt | 462 kt | 693 kt | 563 kt |
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Reserves at December 31, 2020:
The Underground Ore Reserve reported at a cut-off of 2.9 g/t.
The Underground Mineral Resource reported at a cut-off of 1.8 g/t.
Category | Tonnage | Commodity | Grade | Contained Metal |
Probable
|
0.3 Mt
|
Gold
|
3.57 g/t
|
35 koz
|
Measured
|
0.34 Mt
|
Gold
|
5.09 g/t
|
56 koz
|
Indicated
|
1.78 Mt
|
Gold
|
3.25 g/t
|
187 koz
|
Inferred
|
2.58 Mt
|
Gold
|
2.46 g/t
|
204 koz
|
Total Resource
|
4.71 Mt
|
Gold
|
2.95 g/t
|
448 koz
|
Financials:
| Units | 2020 | 2019 |
Capital expenditures
|
M AUD
| ......  | ......  |
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Aerial view:
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