Overview
Stage | Permitting |
Mine Type | Underground |
Commodities |
|
Mining Method |
- Sub-level shrinkage
- Longhole open stoping
|
Processing |
- Gravity separation
- Flotation
- Concentrate leach
- Agitated tank (VAT) leaching
- Carbon in leach (CIL)
- Elution
- Solvent Extraction & Electrowinning
|
Mine Life | 10 years (as of Jan 1, 2018) |
During FY19, the Government of Ghana approved and issued a new Environment Authority Permit for the redevelopment and recommissioning of Bibiani. |
Latest News | Resolute Mining Ltd.: Sale of Bibiani Gold Mine for US$105 million in cash December 15, 2020 |
Source:
p. 48, 148
Bibiani is owned by Mensin Gold Bibiani Limited, a wholly owned subsidiary of Resolute. Resolute currently owns 100% of Mensin Gold Bibiani Limited through its wholly-owned subsidiary, Resolute (Bibiani) Pty Ltd. The Government of Ghana is entitled to a 10% dividend following the commencement of production.
Deposit Type
- Breccia pipe / Stockwork
- Vein / narrow vein
- Mesothermal
Summary:
The Bibiani deposit is hosted within a thick sequence of fine-grained graded turbidites with localised thin interbeds of fine to medium- grained turbiditic sandstones. The orebody is a mesothermal lode type deposit which is similar to the lode deposits in the Konongo Axim belt hosting the significant Obuasi deposit. The Bibiani orebody geometry is structurally controlled by a steep, north to north-east trending shear corridor 200 - 400m wide, within Lower Birimian sediments and close to the \ eastern contact of the Upper Birimian. The shear zone includes quartz infill as massive veins and quartz stock works. In the widest parts of the orebody, two and locally three individual quartz reefs or lodes can be identified. Two highly graphitic fault zones, historically referred to as pug seams or fissures, are associated with the major shear zone on footwall and hanging wall sides.
In general, the orebody dips east at 60 - 80°, crossing the regional structure at acute angles. At the centre of the mine the orebody alignment is 030 - 035° which changes to around 020° at the northern end of the mine. The strike of the bedding cuts across the strike of the ore body at acute angles. Traditionally the ore body has been divided into a northern and southern part based on the location of the central shaft, which lies on section line 5400N. Despite this the orebody is essentially continuous.
The southern ore zone is around 180m long and consists of a composite vein of quartz and mineralised country rock dipping about 60° to 70° to the east. The northern orebody consists of the continuation of the west lode and of the east and central lodes, which are less distinct toward the south. The latter reef lodes consist of more massive laminated smokey quartz with phyllite partings. Milky white quartz is also present, but is generally barren.
The northern ore zone has been mapped at 20 - 40m width near the surface and widens substantially at depth. At around 100 – 120m relative level (“mRL”) (the underground 4 and 5 Levels) horizontal widths exceed 100m. The dips are generally near vertical at surface, but the eastern boundary flattens moderately at depth to less than 65° around 150mRL. The lodes merge approximately 400 - 500m north of the central shaft. Further to the north the orebody narrows and continues as one near-vertical reef 15 - 25m in width.
The length of the main historic underground mining zone extends to 1,800m while the total strike length of the Bibiani mineralised trend is around 4,000m. The mineralisation remains open at depth.
Mineralisation is related to emplacement of quartz veins, which occur as either sheared, stockwork veins with quartz-ferroan dolomite, or as larger, up to 20m wide, locally stylolitic quartz reefs. Both veins types are associated with pyrite +/- arsenopyrite. Fine-grained disseminated Fe-carbonate and sericite alteration with pyrite +/-arsenopyrite occurs adjacent to the veining.
Mining Methods
- Sub-level shrinkage
- Longhole open stoping
Summary:
Mining will be undertaken by long hole open stoping (LHOS) mining methods. A trade-off study of various LHOS methods was undertaken and the selected mining methods were:
• The main mining method will be LHOS with pillars. This method was applied to the majority of the mining areas, where the stope blocks are less continuous, occur in multiple lodes and vary in width.
• In the lower southern portion of the mine, there is a large continuous block of ore at lower COG of approximately 2g/t Au, with widths of up to 25m. In this area, the sublevel shrink method is preferred. This method is currently used at Resolute’s Mt Wright mine at Ravenswood in Queensland, Australia.
The mine design covers a strike length of 1.2km and focuses on the ore located between 5,000 and 6,200m N. Due to the strike length of the design, two declines will be developed at depth, each servicing a 600m strike length of ore.
Development dimensions have been designed to suit the selected equipment. Declines will be 5.5m W x 5.8m H, being the typical dimensions for 60t to 65t trucks. Lateral development requiring truck access will have dimensions of 5.5m W x 5.5m H, reducing to 5.0m W x 5.0m H in the level access areas and 4.5m W x 4.5m H in the ore drives.
The ore drives will be designed to fit mid-sized 14t loaders and drill rigs capable of drilling 89mm diameter blastholes.
The optimum schedule has been selected in accordance with Resolute project objectives:
• Early ore production.
• Production rate of approximately 1.0Mtpa ore and recovered ounces of 100koz per annum.
• Ten-year mine life producing 1.0Moz
Processing
- Gravity separation
- Flotation
- Concentrate leach
- Agitated tank (VAT) leaching
- Carbon in leach (CIL)
- Elution
- Solvent Extraction & Electrowinning
Flow Sheet:
Summary:
The ore will be processed through the existing Bibiani processing plant that is currently on care and maintenance.
The plant has a nominal capacity of 3Mtpa. This will be reduced to 1.1Mtpa to treat Bibiani underground ore only.
The plant was designed around a standard carbon-in-leach ( CIL) process to extract the gold from the ore. To enhance the process, rather than rely on CIL with gravity, the overflow material from the SAG mill is floated and then re-ground to increase yield. Testwork has shown that the mineralogy of the deposit favours targeted regrinding of gold-associated sulphide minerals in order to achieve optimal leach extraction.
The mineralogy of the deposit favours targeted concentrate regrinding of these gold-associated sulphide minerals to achieve an optimal leach extraction. The process will produce a sulphide concentrate by flotation at a primary grind size of P80 106 µm. Concentrate is then fine ground to P80 25 µm prior to intense c ........

Recoveries & Grades:
Commodity | Parameter | Avg. LOM |
Gold
|
Recovery Rate, %
| ......  |
Gold
|
Head Grade, g/t
| 3.4 |
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Projected Production:
Commodity | Units | Avg. Annual | LOM |
Gold
|
koz
| 100 | 974 |
All production numbers are expressed as metal in doré.
Operational Metrics:
Metrics | |
Total tonnes mined
| ......  |
Waste tonnes, LOM
| ......  |
Ore tonnes mined, LOM
| ......  |
Annual processing rate
| ......  |
Annual processing capacity
| ......  |
Annual mining rate
| ......  |
* According to 2018 study.
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Reserves at December 31, 2019:
Category | Tonnage | Commodity | Grade | Contained Metal |
Probable
|
6,400 kt
|
Gold
|
3.3 g/t
|
660 koz
|
Indicated
|
13,260 kt
|
Gold
|
3.5 g/t
|
1,490 koz
|
Inferred
|
8,440 kt
|
Gold
|
3.7 g/t
|
1,010 koz
|
Total Resource
|
21,690 kt
|
Gold
|
3.6 g/t
|
2,500 koz
|
Mine Management:
Job Title | Name | Profile | Ref. Date |
.......................
|
.......................
|
|
Apr 8, 2020
|
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Staff:
Total Workforce | Year |
|
2019
|
Aerial view:
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