The Ashanti Belt is the most prolific Gold producing district in West Africa.
The Obuasi gold deposit is located 180 km NW of Accra in Ghana, West Africa (#Location: 6° 12′ N, 1° 41’W). The Obuasi deposit represents the largest single Precambrian gold deposit discovered in the world to date, exclusive of the Witwatersrand paleoplacer. The Ashanti Belt of southwest Ghana hosts a gold district that contains a significant number of world class hydrothermal gold deposits and the giant Obuasi deposit that hosts over 60 million ounces of gold. These deposits are spatially associated with the Ashanti Fault and other major shear zones in the Birimian Supergroup or along the contact between the Birimian and Tarkwaian units. The overlying Tarkwa Basin is also host to the Tarkwa paleoplacer that contains over 40 million ounces of gold.
Obuasi:
Shear hosted Orogenic Gold Deposit
Strike length of 8km
Orebody to 3 km deep
Quartz vein 4m width @ 60g/t
Open pit mining 40m width @ 7g/t
Gold production: 33 Moz
Mineral Resource: 34.05Moz @ 7.30g/t*
The giant Obuasi gold deposit (also named the Ashanti mine) is the largest deposit in western Africa, with more than 60 Moz of gold. The deposit extends for 8 km along strike and is 1.6-km-deep, with active exploration continuing below this depth. The deposit is located at the contact between the Kumasi volcano sedimentary basin and the Ashanti greenstone belt. It contains more than 20 individual ore shoots within a corridor between graphite-rich fault planes belonging to the Ashanti fault. There are two distinct gold mineralization styles; 1. sub-microscopic gold contained within arsenopyrite and, less commonly, in pyrite, 2. visible gold contained within micro-fractures, hosted in quartz veins which border the graphite-rich fault rock.
The highest grade ores at Obuasi are contained within quartz veins as thick as 4-m-wide. These ores are characterized by visible gold in microfractures cutting through, but contained entirely within the quartz veins. The quartz veins usually dip to the west and are very close to the graphitic shears. Several quartz veins may be present in the same ore zone. The veins comprise quartz, minor ankerite, and host rock fragments. The quartz can have a smoky, milky, or glassy appearance, but only the first two categories are associated with elevated gold grades. Within the microfractures, gold is accompanied by muscovite, graphite, galena, chalcopyrite, sphalerite, bournonite, boulangerite, and aurostibite.
For over ten decades there have been no other large-scale mining activities in the Obuasi area other than the operations of Anglogold Ashanti formerly Ashanti Goldfields Company . Artisanal gold mining, which predates mechanized gold mining by over 500 years, still goes on, even though AGA had concessionary rights over the entire area. The vast concession originally left no prospecting grounds for outside competitors. Very recently Anglogold relinquished over 250 square kilometers of land back to the government of Ghana for claim staking by local Ghanaian mining companies. Gold Cedi has carefully acquired mining concessions on these structures including the highly prospective Binsere trend, and the main Ashanti shear zone that is host to more than 50 million ounces of gold.
Currently, the leading gold producing country in Africa and sixth in the world is Ghana. The country’s gold production amounted to a total of 117.6 tons in 2021. This comprises roughly 90% of the West African country’s total mineral exports and 49% of its total export value. Ghana is considered one of the most prolific regions of gold discoveries in the world, with its Ashanti Gold Belt hosting many multi-million-ounce gold deposits.
Gold Cedi – Obuasi District Mine Sites
Achiasi
Akorokyere (Akrokerri)
Anyankyerim
Ayinabirim
Brenkaso
Benkasi
Kotopre
Kokoteasua
Mammiraiwa 1&2
Patakro
Roroso
Sansu South
Tema North