Australia

Leonora Operation

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Overview

Mine TypeOpen Pit & Underground
StatusActive
Commodities
  • Gold
Mining Method
  • Truck & Shovel / Loader
  • Longhole open stoping
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SnapshotThe cornerstone of Leonora Operations, Gwalia mine, is the deepest underground trucking mine in Australia. Its depth is over 1,600 metres below surface.

Following the acquisition of St Barbara’s Leonora operations (Gwalia underground mine, Gwalia Mill, Tower Hill Project, and other Projects), Genesis is focused on unlocking the significant unique synergies available by pairing the new, shallow Admiral and Ulysses development projects with the Gwalia mine to fill the 1.4Mtpa Gwalia mill.

Admiral open pit - First ore delivered in the September 2023.

Ulysses underground - Now ready for underground development, mining planned from the March quarter 2024 using surplus equipment and labour from the re-set “quality over quantity” Gwalia mine.

Genesis is now focused on delivering a five-year outlook to the market in March 2024, cornerstoned by a long life, ‘margin over ounces’ Leonora business plan.
Related AssetUlysses Project

Owners

SourceSource
CompanyInterestOwnership
Genesis Minerals Ltd. 100 % Indirect
On July 3, 2023, Genesis Minerals Limited completed the acquisition of St Barbara’s Leonora assets, including the Gwalia underground mine, 1.4Mtpa Leonora mill, Tower Hill project, Zoroastrian project, and the Aphrodite and Harbour Lights refractory projects.

Contractors

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Deposit type

  • Vein / narrow vein

Summary:

Gwalia mine
Gold mineralisation occurs as a number of en echelon, moderately east dipping foliation parallel lodes within strongly potassic altered mafic rocks and extends over a strike length of approximately 500 m and to a vertical depth of at least 2,300 m. Four primary lodes (Main Lode, South West Branch, South Gwalia Series and West Lode) have been identified and the geometries summarised below.

Mineralisation domains are defined by abundance of quartz and quartz/carbonate veining, the presence of distinctive laminated veining (quartz/sericite/sulphides +/- au), strong potassic alteration, abundance of sulphides (commonly >3% pyrite) and elevated gold grade (>0.5g/t).

The mineralised zone strikes 15 degrees east of true north over a distance of 500m and plunges 45 degrees to the southeast. The mineralised zone consists of several stepped or en echelon style foliation parallel lodes disposed in plan in a “horse-shoe” shape with the limbs converging at the southern end. The mineralised zone and individual lodes dip east at 35 to 45 degrees and are conformable with the foliation of the Mine Sequence mafic schists. Individual lode widths vary from 2m to 30m true width. Mineralisation has been tested to approximately 2,300m below surface and remains open.

Admiral Group
The Admiral Group of deposits lies within the Archaean-aged Norseman to Wiluna greenstone belt. Host rocks comprise a sequence of dolerite and basalt units. Gold mineralisation is associated with a strongly altered, distinctive assemblage of biotite-sericite-albite-pyrite±carbonate alteration and quartz veining located within regionally extensive NS trending shear zones which take the same name as the deposit they are located on. Depth of complete oxidation varies from 1m to 30m with depth to fresh rock varying from 5 to 50m.

Within the shear zones, discrete zones of mineralisation are typically 2-8m in thickness and dip at 30-50° to the east. A number of horizons of magnetic dolerite sills occur within the mafic stratigraphy at ABCDK. Where the main shear cuts through these units, local thickening and increased grade are evident. The zones are visually distinct and typically display sharp boundaries to the mineralisation.

On the northern contact of the dolerite sill with the pillow basalts at Admiral, Clark and Butterfly there is an intense zone of shearing which runs parallel to the lithological contact dipping at 50-60° to the north. This shear is mineralised over 1.5km strike from the Admiral deposit in the west through Clark to Butterfly in the east. The mineralisation on this contact is referred to as the Hercules shear.

Mineralisation within the Hercules Shear is typically 5m to 12m wide and hosted within highly foliated basalts with intense quartz/carbonate/sericite alteration and associated sulphides.

Drilling in the area extends to a maximum depth of 300m below surface. The mineralisation has been interpreted and estimated to that depth and the mineralisation remains open over much of the 1.5km strike length of the deposits.

Ulysses deposit
The Ulysses deposit lies within the Archaean-aged Norseman to Wiluna greenstone belt. Host rocks comprise a sequence of dolerite and basalt units. Gold mineralisation is associated with a strongly altered, distinctive assemblage of biotitesericite-albite-pyrite ± carbonate alteration and quartz veining located within a regionally extensive WNW trending shear zone termed the Ulysses Shear. Depth of complete oxidation is approximately 30m to 40m with depth to fresh rock occurring approximately 45 to 60 meters below surface.

Within the Ulysses shear zone, discrete zones of mineralisation are typically 1-8m thick and dip at 30-50° to the northeast. A number of horizons of magnetic dolerite sills occur within the mafic stratigraphy at Ulysses. Where the main shear cuts through these units, local thickening and increased grade are evident and form plunging shoots with good continuity of grade and thickness over considerable plunge lengths. These high-grade plunging shoots are visually identifiable due to the strong pyrite-albite-biotite. They have been separately modelled and estimated to properly reflect the observed the high-grade continuity.

Drilling at Ulysses extends to a maximum depth of 520m below surface. The mineralisation has been interpreted and estimated to that depth and the mineralisation remains open over much of the 2.7km strike length of the deposit.

Reserves

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Mining Methods

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Comminution

Crushers and Mills

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Processing

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Production

CommodityUnits20232022202120202019201820172016
Gold oz  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe220,169268,428265,057276,278
All production numbers are expressed as metal in doré.

Operational metrics

Metrics20232022202120202019201820172016
Plant annual capacity  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe1.4 Mt
Ore tonnes mined  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe625 kt679 kt790 kt924 kt
Waste UG  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe
Tonnes milled  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe652 kt711 kt828 kt1,027 kt

Production Costs

CommodityUnits202320222021202020192018
Credits (by-product) Gold AUD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe -2 / oz   -2 / oz  
Cash costs Gold AUD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 703 / oz   572 / oz  
Total cash costs Gold AUD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 746 / oz **   613 / oz **  
All-in sustaining costs (AISC) Gold AUD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 1,027 / oz **   802 / oz **  
** Net of By-Product.

Financials

Units2023202220212020201920182017
Growth Capital M AUD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 11.1  
Sustaining costs M AUD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 44.2   33.8   30.2  
Capital expenditures M AUD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 115   70.6   -47.5  
Revenue M AUD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 392.7   461.3   441.9  
Gross profit M AUD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 237.4   303.3   298.8  
Pre-tax Income M AUD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 162  
EBITDA M AUD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 221.8   285.2   281.5  

Heavy Mobile Equipment

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Personnel

Mine Management

Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required Nov 6, 2023
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....................... Subscription required ....................... Subscription required Subscription required Feb 8, 2024
....................... Subscription required ....................... Subscription required Subscription required Nov 6, 2023
....................... Subscription required ....................... Subscription required Subscription required Nov 6, 2023
....................... Subscription required ....................... Subscription required Subscription required Nov 6, 2023

EmployeesContractorsTotal WorkforceYear
...... Subscription required ...... Subscription required ...... Subscription required 2022
...... Subscription required ...... Subscription required ...... Subscription required 2021
...... Subscription required ...... Subscription required ...... Subscription required 2020

Aerial view:

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