Overview
| Stage | Production |
| Mine Type | Open Pit & Underground |
| Commodities |
|
| Mining Method |
- Truck & Shovel / Loader
- Longhole open stoping
|
| Production Start | ...  |
In line with the Growth Plan presented in 2021, Karora has completed Phase I of the mill upgrade at Higginsville Processing Plant, with advanced engineering in progress for the Phase II mill expansion, increasing throughput to 2.5 Mtpa by 2024, which is fed at capacity from Karora’s underground Beta Hunt mine and Higginsville mines.
Currently, Karora is mining from the Spargos open pit mine in the Higginsville Greater area and the Aquarius and Two Boys underground operations in the Higginsville Central Area. |
Source:
p. 36-49
The Higginsville Gold Operation comprises 219 tenements (live and pending) covering approximately 1900 km2 which is owned by Karora through its wholly owned subsidiaries Avoca Resources Pty Ltd (Avoca), Polar Metals Pty Ltd (PMT) and Avoca Mining Pty Ltd (AMG).
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;
Mining Methods
- Truck & Shovel / Loader
- Longhole open stoping
Summary:
Currently, Karora is mining from the Spargos open pit mine in the Higginsville Greater area and the Aquarius and Two Boys underground operations in the Higginsville Central Area.
HGO mined 855,000 tonnes during 2021 at an average grade of 1.61 g/t containing 44,247 ounces of gold. Details of production by source is provided below:
HIDDEN SECRET
Hidden Secret continued to perform well during the fourth quarter, with mining of high-grade areas as per schedule. Mine production from Hidden Secret totalled 182,000 tonnes containing 8,155 gold ounces. Hidden Secret was the main ore source for processing throughout the quarter but will be replaced in the first quarter of 2022 with production from the Spargos open pit which commenced its production during the fourth quarter of 2021. Mine production from Hidden Secret is scheduled to be completed in the first quarter of 2022, with an extensional drilling program planned once mining ceases.
SPARGOS
The initial pre-strip development was completed at Spargos during the fourth quarter of 2021, with mine production and ore extraction commencing during the same quarter. Spargos infrastructure is in place to support mining of the Stage 1 open pit. Dewatering planning and approvals, in preparation for Stage 2 of the open pit mining (extension at depth), are in progress with completion of two dewatering bores and a management plan submitted for licence approval. The next stage of exploration drilli ........
Source:
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Flow Sheet:
Summary:
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Production:
| Commodity | Units | 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 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 |
|
Ore tonnes mined
| ...... | | | 784,004 t | 952,576 t | 1,015,459 t |
|
Tonnes processed
| ...... | ...... | 989 kt | 1,189,400 t | 1,232,184 t | 1,114,145 t |
|
Annual processing capacity
| ...... | ...... | 1.4 Mt | 1.3 Mt | 1.3 Mt | |
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Reserves at January 31, 2022:
Updated Gold Mineral Reserve estimate expected by end of Q4 2022.
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 |
|
Measured & Indicated
|
31,711 kt
|
Gold
|
1.6 g/t
|
786 koz
|
|
Inferred
|
6,372 kt
|
Gold
|
2.1 g/t
|
428 koz
|
Corporate Filings & Presentations:
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