Overview
| Stage | Production |
| Mine Type | Open Pit & Underground |
| Commodities |
|
| Mining Method |
- Truck & Shovel / Loader
- Shrinkage stoping
- Longhole open stoping
- Alimak
|
| Production Start | ...  |
| Mine Life | 2033 |
Bogoso Prestea Mine is an established gold mining operation located within West Africa’s premier Ashanti Gold Belt. Bogoso Prestea Mine is one of the largest and most famous gold mines in Ghana.
Bogoso Prestea has been producing gold for over 100 years comprised of both open pit and underground operations. |
Source:
p. 1
The gold producing Bogoso Prestea Mine, was acquired in October 2020 from Golden Star Resources by Blue International Holdings Limited, through its locally (Ghana) registered entity, Future Global Resources Bogoso Prestea Limited (FGRBPL).
Per the acquisition, FGRBPL owns 90% of Bogoso Prestea Mine, with the Government of Ghana holding the remaining 10% interest. Blue International Holdings Limited is a UK registered company, although its corporate operations are led out of its Accra Office which it shares with its subsidiary FGRBPL.
Contractors
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Deposit Type
- Vein / narrow vein
- Orogenic
- Mesothermal
Summary:
The Prestea-Bogoso area occurs at the southern termination of the Ashanti Belt, where the gold deposits, mined or under exploration, are localised principally along two steep to subvertical major crustal structures referred to as the Ashanti trend and the Akropong trend. The principal structures are graphitic shear zones and mineralised fault filled quartz veins. The Bogoso Prestea section of the Ashanti Trend shows a range of mineralisation styles associated with graphitic shear zone, which represents the principal displacement zone of a regional-scale shear zone that defines the mineral belt. These styles include laminated quartz vein deposits containing free gold, highly deformed graphitic shear zones containing disseminations of arsenopyrite as the principal gold bearing phase (e.g. Buesichem, Chujah-Dumasi and Bogoso North) and disseminations of sulphides in mafic/intermediate volcanic rocks generally found in the footwall of the main shear zone.
The Bogoso Prestea deposits can be classified as a lode gold deposits or orogenic mesothermal gold deposits, which are the most common gold systems found within Archean and Paleoproterozoic terrains. In the West African shield, orogenic gold deposits are typically underlain by geology considered to be of Eburnean age and are generally hosted by volcanosedimentary sequences. The Ashanti belt is considered prospective for orogenic mesothermal gold deposits and hosts numerous other lode gold deposits such at the Obuasi ........
Mining Methods
- Truck & Shovel / Loader
- Shrinkage stoping
- Longhole open stoping
- Alimak
Summary:
Mining activity includes both underground using mechanized shrinkage mining and longhole open-stoping, and a recent significant investment in open pit operations feeding both refractory and non-refractory processing plants.
The Bogoso Prestea gold mine resumed open-pit oxide mining in February 2021.
Underground
The planned mining method is mechanized shrinkage mining. This method uses mechanical raise climber technology (Alimak) together with longholes drilled from the raise climber. The method is an advance in terms of safety and productivity from conventional hand-held shrinkage mining. Safety is greatly enhanced both in raise development and stoping operations by having miners protected from rockfalls and removed from working on the broken muck pile. The productivity (per miner) is enhanced by introducing short longholes for stope production.
A typical cycle for Alimak stoping is:
- Raise development in the centre of a stoping block;
- Raise hangingwall rock support;
- Drilling of longhole blast rings;
- Relocation of the raise climber infrastructure to the top of the stoping block, blasting of longhole rings and swell mucking; then,
- Final draw-down mucking and possible waste backfilling.
Small diesel and electric 2 m3 LHD’s will be used for rock haulage from the base of the stoping panel. Mine development will be by hand held drills with LHD mucking. Tramming of ore and waste along the two ma ........
Source:
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Flow Sheet:
Summary:
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Production:
| Commodity | Units | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 |
|
Gold
|
oz
| ...... | ...... | ...... | ...... | 75,087 | 130,331 | 89,673 |
All production numbers are expressed as metal in doré.
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Operational Metrics:
| Metrics | 2021 | 2019 | 2018 | 2017 | 2016 |
|
Plant annual capacity
| ...... | | | | |
|
Waste
| ...... | 767,106 t | 928,457 t | 3,522,451 t | 4,039,768 t |
|
Ore tonnes mined
| ...... | 646,254 t | 502,266 t | 1,494,347 t | 1,499,656 t |
|
Tonnes processed
| ...... | 719,449 t | 1,301,976 t | 1,632,979 t | |
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Reserves at December 31, 2019:
Mineral Reserve Break-even cut-off grade estimates for the Prestea Underground Gold Mine 7.5 g/t Au.
Prestea Underground Mineral Resource has been estimated below the $1,500 per ounce pit shell of Prestea South down to 3,800 m elevation using a gold cut-off grade at 6.84 g/t Au.
| Category | Tonnage | Commodity | Grade | Contained Metal |
|
Probable
|
856 kt
|
Gold
|
11 g/t
|
302 koz
|
|
Indicated
|
24,942 kt
|
Gold
|
3.27 g/t
|
2,624 koz
|
|
Inferred
|
2,348 kt
|
Gold
|
6.93 g/t
|
523 koz
|
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Corporate Filings & Presentations:
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