Overview
Stage | Production |
Mine Type | Open Pit & Underground |
Commodities |
|
Mining Method |
- Truck & Shovel / Loader
- Longhole open stoping
|
Production Start | ...  |
Higginsville Gold Operation (HGO) comprises open pit and underground gold deposits, the 1.6 Mtpa gold processing facility, and in addition, Karora acquired the 1.0 Mtpa Lakewood mill in July 2022. Mining in 2022 was mainly conducted at the Spargos open pit in the Higginsville Greater area and at the Aquarius and Two Boys underground operations in the Higginsville Central Area. |
Latest News | MMS brings in Cat wheel loaders for Higginsville ROM assignment October 23, 2023 |
Source:
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Karora's principal asset are its 100% interest in HGO (represented by a 100% interest in Karora Australia Pty Ltd.)
Contractors
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Deposit Type
- Vein / narrow vein
- Mesothermal
- Paleoplacer
- Sediment-hosted
Summary:
The characteristics of the gold deposits at Higginsville are consistent with the greenstone-hosted quartz-carbonate vein (mesothermal) gold deposit model.
Throughout the Higginsville Gold Operations, a significant proportion of gold deposits are hosted by sediments within Southern Palaeochannel networks. Mineralised zones comprise both placer gold, normally near the base of the channel-fill sequences, and chemically-precipitated secondary gold within the channel-fill materials and underlying saprolite. These gold concentrations commonly overlie, or are adjacent to, primary mineralised zones within Archaean bedrock. Outcrop is generally poor, due to extensive ferruginisation, calcareous soils, aeolian sands and extensive areas of remnant lacustrine and fluvial sediments. The result is a complex, layered regolith, with considerable chemical re-mobilisation and re-deposition (Lintern et. al., 2001).
Higginsville is located almost entirely within the well-mineralised Archean Kalgoorlie Terrane, between the gold mining centres of Norseman and Saint Ives. The Archaean stratigraphy has a general northward trend comprising multiply deformed ultramafic – gabbro – basalt successions adjoined by sediments to the west and east. Shearing and faulted contacts are common. The units have been structurally repeated by east over west thrust faulting.
The HGO can be sub-divided into six major geological domains:
- Trident line-of-lode;
- Chalice;
- Lake Cowan;
- Southern palaeochannels;
- ........

Mining Methods
- Truck & Shovel / Loader
- Longhole open stoping
Summary:
Mining in 2022 was mainly conducted at the Spargos open pit in the Higginsville Greater area, which commenced operations late in 2021, and at the Aquarius and Two Boys underground operations in the Higginsville Central Area.
Higginsville Central
Trident
The Trident deposit has three distinct mineralised zones called Western Zone ("WZ"), Eastern Zone ("b") and Athena Lodes ("AL"). The Trident deposit is to be exploited by underground mining methods with access gained from the previously mined Poseidon South open pit and underground workings.
Trident has some key, narrow mineralised zones yet LHOS will not be feasible due to the flat dipping nature of these zones. Air leg room and pillar stoping is proposed and planned in these zones.
The Trident underground mine is accessed via an established portal and declines within the open pit, located close to the Higginsville plant and mining offices.
The mine is accessed by portals and a series of declines throughout the mine. The declines are typically 5.5 m width (W) x 5.8 m height (H), with a standard ore drive size of 4.5 mW x 4.5 mH. Lateral development profiles are well matched to the mobile fleet. Ore is hauled from the underground to surface via the decline where it isthen transported via a separate surface haulage fleet to the processing facility.
The main method will be a top down, mechanised LHOS is the primary stoping method proposed for Trident whilst some flatter dipping, high-grade zones, can be exploited by air ........

Source:

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Flow Sheet:
Summary:

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Production:
Commodity | Units | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 |
Gold
|
oz
| ......  | ......  | ......  | ......  | 55,958 | 84,595 | 91,371 |
All production numbers are expressed as metal in doré.
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Operational Metrics:
Metrics | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 |
Annual processing capacity
| ......  | | 1.4 Mt | 1.4 Mt | 1.3 Mt | 1.3 Mt |
Ore tonnes mined
| ......  | ......  | | | 784,004 t | 952,576 t |
Tonnes processed
| ......  | ......  | 580 kt | 989 kt | 1,189,400 t | 1,232,184 t |
Waste
| ......  | ......  | 5,366,911 t | | | |
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Reserves at January 31, 2022:
Effective date HGO Gold Mineral Reserves is September 30, 2020.
Cut-off grades for open-pit mineral reserves vary from 0.50g/t to 0.85g/t. Uderground mineral reserves cut-off grades vary between 1.6g/t (modified and diluted grade) to 2g/t (modified/diluted grade).
Gold Mineral Resources were estimated using variable cut-off grades taking into account variable operational costs: Higginsville Underground (Chalice, Trident and Aquarius) - 1.3g/t, Higginsville Open Pits (excluding Mt Henry Project) – 0.5g/t, Mt Henry Project – 0.4g/t, Spargos uses a 0.5 g/t Au cutoff grade above 300mRL and 1.6g/t below 300mRL.
Category | Tonnage | Commodity | Grade | Contained Metal |
Proven
|
8,503 kt
|
Gold
|
1.3 g/t
|
362 koz
|
Probable
|
9,249 kt
|
Gold
|
1.6 g/t
|
483 koz
|
Proven & Probable
|
17,752 kt
|
Gold
|
1.5 g/t
|
845 koz
|
Measured
|
15,449 kt
|
Gold
|
1.3 g/t
|
657 koz
|
Indicated
|
16,262 kt
|
Gold
|
1.8 g/t
|
930 koz
|
Measured & Indicated
|
31,711 kt
|
Gold
|
1.6 g/t
|
1,587 koz
|
Inferred
|
6,372 kt
|
Gold
|
2.1 g/t
|
428 koz
|
Source:

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HME Type | Model | Size | Quantity | Status | Leased or Contractor | Ref. Date |
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Grader
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Existing
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Jun 10, 2023
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Loader
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Existing
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Oct 6, 2023
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Loader
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