A Booming Bauxite Mining Industry of Guinea and Future Prospects
Abstract:Guinea with bauxite potential of about 40 billion tons is the largest aluminium ore exporter in the world today. During 2019, the country exported about 70 million tons of bauxite, which is likely to exceed 110 million tons by 2021. This may substantially change the present bauxite market and significantly affect other bauxite producing countries of the world. Guinea exports one of the best and low-cost metallurgical grade bauxite in the world today. The ore is natural low silica (2.5%), medium alumina (44-46%) gibbisitc bauxite, where reactive silica is only 1.2 to 1.5%, which makes this one of the best aluminium ore in the world. The present paper describes bauxite geology, basic characteristics, current and future bauxite mining, infrastructure developments and export from Guinea with details of various mining companies active in this country. About 8 bauxite mining companies have put forward their plans to set up greenfield alumina refineries in Guinea and some of them are in the feasibility stage. In the past also, several attempts were made for value addition within the country, however, none of them materialized. Now, this is an appropriate time for the Government of Guinea to push mining companies to set up new alumina plants in the country. In order to have sustainable bauxite mining development and prepare local technical manpower for alumina refinery, Guinea must set up Bauxite-Alumina Institute and prepare/train locals to effectively run this vital industry.
1. Introduction
Guinea, a small West African country with a population of 12.4 million and an area of 245,857 square kilometres, is the largest bauxite exporter in the world today. The bauxite mining industry is booming in this country and at the same time, the necessary infrastructure for export is also being developed here. The metallurgical grade bauxite resources in Guinea is estimated to be about 40 billion tons and thus occupies the top position in the world. Guinea’s bauxite industry is flourishing on the back of major miners- SMB, CBG, RUSAL, GAC/EGA, CHALCO, Alufer and scores of other bauxite exploration-mining companies. During 2019, the country exported about 70 million tons of bauxite, which is likely to be about 90 million tons during 2020. Guinea exports one of the best and low-cost metallurgical grade bauxite in the world today. Bauxite mainly occurs in low-lying flat-topped plateaus at an elevation of 200 to 400m above MSL (mean sea level). Laterite-Bauxite starts from the surface with thin soil cover (<0.5m) and low overburden (about 1m). The average thickness of the bauxite ore zone is about 6 to 8m, which makes mining operation quite simple and cost-efficient. Guinea ore is natural low silica (2.5%), medium alumina (44-46%) gibbisitc bauxite, where reactive silica is only 1.2 to 1.5%, which makes this one of the best aluminium ore in the world. The present paper describes the current status of bauxite mining and export from Guinea with details of various mining companies active in this country. Varying quality of metallurgical grade bauxite is being produced in the mines of Guinea and some companies have even started beneficiating the ore. The bauxite mining scenario is fast changing with the entrance of several companies from all over the world and it is expected that during the 2021 period bauxite production in Guinea may exceed 100 million tons per annum. This may substantially change the present bauxite market and significantly affect other bauxite producing countries of the world.
2. Bauxite Geology and Ore Characteristics The lateritic bauxite deposits of Guinea occur at low levels (200 to 400 m above MSL) in the flat-topped plateaus with practically negligible soil and overburden. The bauxite is underlain by a stacked pile of argillite, siltstones and minor sandstone intercalations of the Lower and Upper Members of the Faro Suite, widely intruded by sills and dykes of Mesozoic dolerites. A typical laterite bauxite profile of Guinea is shown here (Figure-1).
The Boke bauxite belt is the most prolific in Guinea and here average thickness of bauxite zone is about 8 to 10 meters with little soil cover and iron-rich cap of about 1 to 2 m. Bauxite forms as a result of intense tropical weathering and made up essentially of hydrated aluminium and iron oxides. One of the interesting features of Guinea bauxite is the natural low silica content (~2.5%) and about only 50% is reactive (~1.2%), which makes this ore most favourable for alumina production by low-temperature digestion. Alumina content in bauxite varies from medium (40%) to as high as 54% and, on average, have 45-46% alumina (about 40-41% available alumina). Further lateritic bauxite of Guinea is gibbisitc in nature with about 2% alumina is in the form of boehmite, particularly in the Boke region and this is mainly concentrated on the top layer of profile. Only high-grade Sangaredi sedimentary bauxite of CBG has high monohydrates, however, this is fast depleting now. Bauxite deposits, occurring near the coastal belt of Guinea sometimes have relicts Andalusite and Pyrophyllite minerals, which reduces the available alumina content in the ore.
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