Guinea

Siguiri Mine

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Overview

Mine TypeOpen Pit
StatusActive
Commodities
  • Gold
Mining Method
  • Truck & Shovel / Loader
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SnapshotSiguiri is a multiple open-pit gold mine. Gold- bearing ore is mined from several pits (generally three pits at any one time). Mining occurs primarily at Kami and Bidini pits in Block 1, as well as Saraya pit in Block 2, and a satellite pit was reopened at Foulata in the fourth quarter of 2023 to account for a shortfall in production.

Owners

SourceSource
CompanyInterestOwnership
Government of Guinea 15 % Indirect
AngloGold Ashanti plc. 85 % Indirect
Société AngloGold Ashanti de Guinée S.A. (operator) 100 % Direct
Société AngloGold Ashanti de Guinée S.A. (“SAG”), has title to the Siguiri mine in the form of a mining concession. SAG is co-owned by AngloGold Ashanti (85%) and by the government of Guinea (15%).

The Republic of Guinea holds a 15 percent free-carried/non- contributory interest.

Contractors

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Deposit type

  • Vein / narrow vein

Summary:

Geology
Siguiri is situated in the northern part of the Siguiri Basin of Guinea, and is underlain by Lower Proterozoic rocks of the Birimian metasedimentary and volcano-sedimentary formations. Where exposed, the sediments consist of a well-bedded turbiditic sequence of greenschist facies siltstones, sandstones, greywackes and minor conglomerates, with some brecciated and possibly volcanic members. However, stratigraphic relationships in the area are poorly understood due to poor exposure and a thick lateritic duricrust covering large portions of the lease.

The Siguiri mineralisation occurs as secondary gold in alluvial or colluvial gravel in lateritic cover and primary vein-hosted mineralisation. The veins are quartz dominant and display various styles and orientations, with a sub-vertical northeast-trending conjugate quartz vein set predominating in most of the open pits, irrespective of the bedding orientation. Auriferous quartz veins show a robust lithological control and are best developed in the sandstone/greywacke units.

The primary structural and lithological trend in the current mining area of Block 1 changes from a north-south orientation in the south to a northwest-southeast orientation in the north.

The geology of Block 2 differs from Block 1 as it is mainly underlain by metavolcanic and volcanoclastics. However, mineralisation styles appear similar to those in Block 1, with Saraya appearing to be located on a north-south orientated structure.

Deposit type
Three main sedimentary packages are recognised in the Siguiri district, the Balato, Fatoya and Kintinian Formations. The basal Balato Formation is dominated by shale, siltstone, and greywacke centimetre-scale alternations. The overlying Fatoya Formation consists of metre-scale beds of greywacke fining towards the west. The Kintinian Formation is a thick package of shale and sandstone with a basal clast-supported conglomerate. The orebodies are structurally controlled, and the area has undergone at least three distinct phases of deformation, with initial north-south compression developing minor folds. The second and largest deformation event is associated with east-west to the east-northeast and west-southwest directed compression leading to north-south structural architecture. The third event was a northwest and southeast compression that refolded existing structures. A deep oxidation (weathering) profile is developed in the region, varying between 50 and 150m.

Mineralisation style
Primary gold mineralisation occurs in all three lithostratigraphic units of the Siguiri region, although most of the known mineralisation is found in the central and more competent Fatoya Formation. In some deposits, the mineralisation shows strong lithological control and is preferentially developed in coarsergrained units with higher fracture or vein densities than finegrained rocks. The mineralisation dominantly follows sub-vertical north-south thrusts, northeast to southwest dextral shear zones, and west-northwest to east-southeast sinistral faults associated with the main (D2) deformation event. The mineralised veins are remarkable for the relative consistency of their northeast orientation, despite the highly variable orientation of bedding and significant structures.

Mineralised veins are more intensely developed along major structural trends, with quartz-carbonate- sulphide veining developed along structures. Some of these structures have developed as incipient faults and are represented by discrete stockworks of mineralised quartz-carbonate veins occurring along a trend instead of clearly defined continuous structures.

Mineralisation characteristics
Two styles of primary mineralisation have been recognised at Siguiri. The first is characterised by precipitation of gold-bearing pyrite associated with proximal albite and distal carbonate alteration and opening of carbonate-pyrite veins. The second style corresponds to east-northeast to west-southwest trending native gold-bearing quartz veins with carbonate selvages which cross-cut carbonate-pyrite veins and show arsenopyrite (pyrite) halos.

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

Gold production at Siguiri decreased by 21 percent in 2023. Gold production was lower year-on-year mainly due to lower ore tonnes processed due to the CIL tank failure during the second quarter of 2023, which impacted metallurgical recoveries, and lower grades mined.
CommodityUnits202320222021202020192018201720162015
Gold koz  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe251285381305300
All production numbers are expressed as metal in doré.

Operational metrics

Metrics202320222021202020192018201720162015
Annual processing capacity  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe
Tonnes processed  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe8.8 Mt10.5 Mt11.6 Mt12.1 Mt11.8 Mt
Stripping / waste ratio  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe2.07
Total tonnes mined  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe20,508 kt

Production Costs

CommodityUnits2023202220212020201920182017
Total cash costs Gold USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 1,091 / oz **   844 / oz **   725 / oz **  
All-in sustaining costs (sold) Gold USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 1,176 / oz **   930 / oz **   796 / oz **  
All-in costs Gold USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 1,252 / oz **  
** Net of By-Product.

Financials

Units2023202220212020201920182017
Sustaining costs M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 15  
Capital expenditures M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 22.3   96.5   82  
Revenue M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 349   365  
Gross profit M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 34  
Operating Income M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe 22  
After-tax Income M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe 1   56  
EBIT M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 25  
EBITDA M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 62  

Heavy Mobile Equipment

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Personnel

Mine Management

Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required May 31, 2024
....................... Subscription required ....................... Subscription required Subscription required May 31, 2024
....................... Subscription required ....................... Subscription required Subscription required May 31, 2024
....................... Subscription required ....................... Subscription required Subscription required May 31, 2024
....................... Subscription required ....................... Subscription required Subscription required May 31, 2024
....................... Subscription required ....................... Subscription required Subscription required May 31, 2024
....................... Subscription required ....................... Subscription required Subscription required May 31, 2024

EmployeesContractorsTotal WorkforceYear
...... Subscription required ...... Subscription required ...... Subscription required 2023
...... Subscription required ...... Subscription required ...... Subscription required 2022
...... Subscription required ...... Subscription required ...... Subscription required 2021
...... Subscription required ...... Subscription required ...... Subscription required 2020
...... Subscription required ...... Subscription required ...... Subscription required 2019
...... Subscription required ...... Subscription required ...... Subscription required 2018
...... Subscription required ...... Subscription required ...... Subscription required 2017
...... Subscription required ...... Subscription required ...... Subscription required 2016
...... Subscription required ...... Subscription required ...... Subscription required 2015
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Aerial view:

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