INTRODUCTION
In recent years, the extractive industry has played an increasingly important role in the country's economy, contributing around CFAF 190 billion to the state budget in 2016 and CFAF 274.29 billion in 2019.[1]. Export earnings from mining products in 2016 amounted to 1023 billion and 1540 billion in 2018.[2]. Since 2009, gold has been the country's leading export. This is due to the country's immense geological and mining potential.
I. PRESENTATION OF BURKINA FASO'S MINING POTENTIAL
- Precious metals
Law 036-2015/CNT of 26 June 2015 on Burkina Faso's mining code includes the following precious metals: gold, silver, platinum and platinoids such as iridium, osmium, palladium, rhodium and ruthenium in their crude state, as well as any concentrates, residues and amalgams containing these metals.
Gold and silver are the only precious metals mined in Burkina Faso. They are found in the Birimian greenstone belts, which cover around 22% of the country. These include the Houndé, Boromo, Banfora, Loumana, Goren, Bouroum-Yalogo, Oudalan-Goroual and Djibo furrows. These furrows are associated with sixteen (16) gold mines operating in the country, semi-mechanised operations and several advanced projects (see attached table).
Fine gold production in 2022 is estimated at 57.674 tonnes for 7.328 tonnes of silver.[3] Most of this production comes from the mines at Essakane (Oudalan), Houndé (Tuy), Mana (Balé), Wahgnion (Léraba), Bissa (Namentenga), Boungou (Tapoa), Karma (Yatenga), Youga (Boulgou), Sanbrado (Ganzourgou) and recently the Bomboré project (Ganzourgou), which came on stream in the last quarter of 2022.
All in all, from 2007 to 2022, more than 500 tonnes of fine gold have been extracted in Burkina Faso. In 2020, analysis of the technical reports updating the gold reserves of the projects shows gold reserves of more than 600 tonnes for resources of more than 1,000 tonnes for all the projects already in place. Theoretically, if gold prices remain stable, this should keep Burkina Faso's mining sector going for at least two (02) decades. Considering the twenty or so advanced projects with resource calculations, this should enable Burkina Faso to consolidate its position as a gold-producing country.
2. Ferrous metals
Burkina Faso has significant ferrous metal potential. The most important of these are the deposits of Manganèse of Tambao (Oudalan) with a resource of around 107 million tonnes[4] and Kiéré (Mouhoun). In addition to manganese, the country is known for its NickelThese include the lateritic nickel mineralization at Bonga (Sanguié) and the nickel-PGE mineralization at Dablo (Sanmatenga), both of which are being extensively researched by geological and mining research companies. Other ferrous metal showings include Iron-Titanium-Vanadium deposits have been identified in Burkina Faso, with the largest resources located in the Sahel region. These are the vanadiniferous magnetite deposits at Tin Edia and Gouba, with resources estimated at 45 million tonnes and 16 million tonnes of ore with an iron content of 35% and 0,7% of vanadium[5]. A few unassessed showings are found nearby. These include the Gountouwala, Kolel, Hoka and Pwiga showings. In the Sanmatenga region, similar mineralisation has been observed in the Ouga-Yarcé zone. It is distinguished by a combination of low-grade copper.
3. Non-ferrous metals
Non-ferrous metals found in Burkina Faso include zinc, copper, lead, antimony, aluminium and rare earths.
If zinc is currently being exploited, this is not the case for other substances where research is still ongoing. In Burkina Faso, the only non-gold mine is the Perkoa zinc mine (Sanguié), interpreted by some authors () as being of the Volcanogenic Massive Sulphide (VMS) type. Production began in 2013, and after seven (07) years of operation was estimated at 6,900,000 tonnes[6] in 2019 at a concentrate grade of around 50%. Similar mineralization has been identified in the Tiébélé area (Loubel, Nabénia and Koubongo showings) near Po, and at Kwademen (Sanguié), and is being developed through geological and mining research.
Copper has a long history of research in Burkina Faso. Between 1931 and 1938, a copper lentil from 5,000 tonnes at an average grade of 8% was mined at the Gongondy prospect (Poni) by Compagnie Equatoriale des Mines (CEM)[7]. Continued research in the area by successive mining companies has revealed a copper potential of almost 973,661 tonnes which is associated with a gold resource of around 105,9 tonnes in the Gongondy and Diénéméra prospects[8]. The same potential is highlighted in the Wayen, Goren and Sartenga prospects, where copper mineralisation is combined with gold, molybdenite and silver in the latter. Most of these deposits have a low grade, offset by high tonnages. Mineralization of this type is very common in the geological context of Burkina Faso.
TheAntimony and the lead are substances often observed in the company of other substances such as zinc, particularly in VMS-type mineralisation. This is the case, for example, in the Perkoa and Koubongo mineralisations, where lead is associated with zinc mineralisation. In addition to these associations, lead lenses have been found in the form of galena (PbS) in the Gan locality (Sourou), while the Mafoulou locality (Sanmatenga) is known for its antimony showings in the form of N-S oriented lenses of stibine (Sb2S3).
Thealuminium is fairly widespread in the country in the form of bauxite, particularly in the towns of Kaya, Kongoussi and Bobo Dioulasso, although it is not currently producing economic concentrations. This is also the case for rare earths where showings were found in the localities of Zoungou (Ganzourgou), Mangodara (Comoé) and Kangounadeni (Comoé) in association with columbite-tantalite.
4. Precious and semi-precious stones
In Burkina Faso, the search for precious stones has been limited to diamonds. Diamond showings have been identified in the watersheds of the Mouhoun, Comoé, Léraba and Sissili rivers (Castaing et al., 2003). These are alluvial diamonds whose primary source has yet to be discovered. On the other hand, in the locality of Barsalogho (Sanmatenga), some indices micro-diamond primaries were discovered in 1972 by the BGR and BUVOGMI in ultrabasic rocks of the meta-dunite and meta-peridotite type.
In addition to diamonds, brownish hints of alluvial corundum of centimetre size were observed in Matiakoali. While in Kangouandeni (Comoé), some stony beryls are found in muscovite pegmatite (Jonquet, 1962). In addition, it is important to add garnets associated with the pegmatites found throughout the country. The same applies to spodumene (lithiniferous pyroxene) which appears as centimetric crystallisations in the pegmatites of Touo-Godo (Ganzourgou)[9].
All of these minerals may be semi-precious, but no studies have yet been carried out in this area.
5. Non-metallic substances
Non-metallic substances include phosphates, carbonate materials, fire clays and kaolin, silica sands and ornamental stones.
The deposits of phosphates constitute the main mineral potential of the Volta Basin. Most of the country's major deposits are found in this area. These are the Arloub-djouma (Tapoa), Arly (Tapoa) and Kodjari deposits. The Kodjari deposit, with estimated reserves of 60 million tonnes to 27.5% of P2O5[10]is the largest. It is operated by the Société d'Exploitation de Phosphate du Burkina (SEPB), which processes the phosphate into fertiliser for local farmers.
The carbonate materials are made up of limestone and dolomitic limestone. Large deposits of pure limestone with rare dolomitic intercalations are found in the Tin Hrassan (Oudalan) and Tin Dioulaf (Oudalan) areas, where a mining permit has been granted for open-cast mining as a raw material for cement manufacture. In the Bobo Dioulasso area, on the other hand, the limestone is dolomitic, and is found in the localities of Tiara, Samandéni, Koua, Dandé, etc. It is used in the manufacture of limestone. It is used to make lime.
Kaolin and refractory clays are widespread in Burkina Faso. They are derived from the supergene alteration of Birimian or Neoproterozoic terrains. They are traditionally used for pottery and house building. Deposits that have been exploited include those at Tikaré (Namentenga), Titao (Loroum), Koréba (Houet), etc.
Significant potential in silica sand has been identified in the locality of Borodougou (Houet), at the entrance to the town of Bobo Dioulasso. The potential is almost 370,000 tonnes which was highlighted by BUMIGEB's work. The deposit is currently being mined using traditional methods.
Ornamental stones include granite, laterite, feldspar, quartz, dolomitic limestone and tuff. These materials are used to make bricks, aggregates, tiles, etc. In 2019, around 535,022 tonnes of granite, 86,942 tonnes of tuff[11] which have been mined for ornamental stone. An assessment of the potential is currently being carried out by the Direction Générale des Carrières (DGC) in partnership with the Bureau des Mines et de la Géologie du Burkina (BUMIGEB).
6. Energy substances
Traces of energetic substances are found in Burkina Faso. Evidence ofuranium have been identified by BUMIGEB's geophysical work. Studies are underway to confirm these indications. In addition, the presence of peat is reported in the Sourou river valley, while hydrocarbon indications (oil, natural gas) are suspected in the Gondo plain, an area that shares the same geological contexts (Neoproterozoic to Cenozoic sediments covered by the terminal continental shelf) as the hydrocarbon indications found in Mali and Mauritania.[12]
[1] Specialised Perception/MMC
[2] MMC Statistical Yearbook 2018
[3] DGMG data for 2022
[4] MMC Statistical Yearbook 2019
[5] Castaing et al, 2003
[6] MMC Statistical Yearbook 2019
[7] Castaing et al., 2003
[8] SRK technical report, 2013
[9] Cachau, 1963
[10] WAXI, 2013
[11] MMC Statistical Yearbook 2019
[12] Zhilong et al, 2008. Petroleum systems of Taoudeni Basin, West Africa (Systèmes pétroliers du bassin de Taoudeni, Afrique de l'Ouest).
