Overview
Stage | Preliminary Economic Assessment |
Mine Type | Underground |
Commodities |
|
Mining Method |
- Longhole open stoping
- Transverse stoping
- Longitudinal stoping
- Paste backfill
|
Mine Life | 11 years (as of Jan 1, 2020) |
Wassa Mine of Golden Star Resources made full use of the processing capacity of the existing concentrator, and obtained the open-pit mining licenses in Benso I Area and DMH Area in July and November 2022, respectively, which quickly provided supplementary ore for the concentrator and provided the foundation and guarantee for the further development of Wassa Gold Mine. |
Source:
p. 22
Golden Star holds a 90% interest in the Wassa gold mine through its 90% owned Ghanaian subsidiary, Golden Star (Wassa) Limited. The remaining 10% interest in Wassa is held by the Government of Ghana in accordance with applicable laws.
Contractors
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Deposit Type
- Orogenic
- Vein / narrow vein
Summary:
The Wassa property lies within the southern portion of the Ashanti Greenstone Belt along the eastern margin of the belt within a volcano-sedimentary assemblage located at proximity to the Tarkwaian basin contact. The eastern contact between the Tarkwaian basin and the volcanosedimentary rocks of the Sefwi group is faulted, but the fault is discrete as opposed to the western contact of the Ashanti belt where the Ashanti fault zone can be several hundred meters wide. Deposition of the Tarkwaian sediments was followed by a period of dilation and the intrusion of late mafic dykes and sills.
The Wassa lithological sequence is characterized by lithologies belonging to the Sefwi Group and consisting of intercalated meta-mafic volcanic and meta-diorite dykes with altered meta-mafic volcanic and metasediments which are locally characterized as magnetite rich, banded iron formation like horizons.
The Wassa mineralization is subdivided into a number of domains: F Shoot, B Shoot, 242, South East, Starter, 419, Mid-East and Dead Man’s Hill. Each of these represents discontinuous segments of the main mineralized system which extends approximately 3.5 km along strike from surface and is still open at depth. The SAK deposits are located approximately 2 km to the southwest of the Wassa Main deposit on the northern end of a well-defined mineralized trend parallel to the Wassa Main trend. The SAK deposits are also located on the western side of a major regional east dippin ........

Mining Methods
- Longhole open stoping
- Transverse stoping
- Longitudinal stoping
- Paste backfill
Summary:
The Southern Extension will be accessed from existing underground workings via two declines, one on each side of the production panels.
The large mineralized footprint in the southern zone is accessed from two declines, east and west of the mineralization. The distribution of mineralization varies between the upper (4-6) and lower (7-8) panels. The layout of the production blocks is also different in the upper and lower panels.
- Panels 4-6: Three large production blocks on the east side with numerous smaller production blocks to the west. Blocks are spread across and along strike of the deposit, creating multiple independent production blocks.
- Panels 7-8: Reasonably uniform and continuous blocks on both sides of the deposit, merging at depth. More consistent geometry could be influenced by relatively wide spaced drilling (all of the Southern Extension classified as Inferred Resource), but panels 7 and 8 have the lowest drill hole density). However, should the geometry break apart with further drilling, the mining and access strategy is flexible in that the modular production blocks, with access from the two declines, can be moved around to match the geometry of the defined mineralization.
The majority of stopes in the Southern Extension zone will be mined using bottom-up, transverse Long Hole Open Stoping, with occasional longitudinal stopes where deposit widths are less than 15 m. Nominal stope lift dimensions are 20m along strike, up to 3 ........

Flow Sheet:
A four-stage fine crushing circuit is employed incorporating an open circuit primary jaw crusher followed by secondary, tertiary and quaternary cone crushers with the secondary and tertiary crushers operated in closed circuit with sizing screens. A single secondary, two tertiary and four quaternary crushers give a nominal crushed product size from the crushing circuit of 80% <8 mm.
Two independent milling circuits, each comprising a 5.03 m diameter x 6.7 m long ball mill fitted with 3 MW motors feeding individual clusters of classifying cyclones. Reported mill product size is around 70% <75 µm.
Flow Sheet:
Summary:

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Projected Production:
Commodity | Units | Avg. Annual | LOM |
Gold
|
koz
| 294 | 3,456 |
All production numbers are expressed as metal in doré.
Operational Metrics:
Metrics | |
Daily mining rate
| 8,791 t * |
Daily ore mining rate
| 6,826 t * |
Daily processing capacity
| 7,400 t * |
Annual ore mining rate
| 2.7 Mt * |
Annual processing capacity
| 2.7 Mt * |
Waste tonnes, LOM
| 10,668 kt * |
Ore tonnes mined, LOM
| 29,632 kt * |
Total tonnes mined, LOM
| 40,299 kt * |
Tonnes processed, LOM
| 29,632 kt * |
* According to 2020 study.
Reserves at December 31, 2020:
For Panel 4-Panel 5 cut-off grade is 2.3 g/t Au.
For Panel 6-Panel 8 cut-off grade is 2.9 g/t Au.
Category | Tonnage | Commodity | Grade | Contained Metal |
Inferred
|
30 Mt
|
Gold
|
3.8 g/t
|
3.6 M oz
|
Corporate Filings & Presentations:
Document | Year |
...................................
|
2021
|
...................................
|
2020
|
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