BURKINA FASO

Burkina Faso is a landlocked country in West Africa. Most of the country consists of a peneplain, forming a gently undulating landscape. In some areas, a few isolated hills represent the last vestiges of a Precambrian massif. Burkina Faso is relatively low lying, with an average elevation of 400 m; the differential between the highest and lowest points not exceeding 600 m. The south-west of the country forms a sandstone massif, where the highest peak, Ténakourou (749 m), is located. The massif is bordered by vertical cliffs rising up to 150 m.

Three major climatic zones can be defined:

(i) The Sahel in the north typically receives less than 600 mm of rainfall annually and has temperatures in the 5–47°C range;

(ii) The Sudan–Sahel region is a transitional zone as regards rainfall and temperature;

(iii) The Sudan–Guinea zone farther to the south receives more than 900 mm of rainfall annually and has cooler average temperatures.

Burkina Faso has a range of mineral resources, including limestone, manganese, marble, phosphates, pumice, salt and several small gold deposits.

Agriculture represents 32% of GDP and occupies 80% of the working population. Much of it involves livestock rearing. In addition, corn, cotton, groundnuts, pearl millet, rice and sorghum are also grown, primarily in the south and south-west [5.1].

3.5.1. Geology

Burkina Faso is predominantly underlain by rocks of the Guinea Rise, which borders the Gulf of Guinea and extends from Sierra Leone in the west to Ghana in the east (Fig. 3.8). The rise is generally characterized by granitic gneisses, and north to northeasterly trending belts of metasediments and metavolcanics.

The oldest rocks in Burkina Faso are pre-Birimian migmatites, gneisses and amphibolites underlying the Birimian rocks. In southwestern Burkina Faso the Birimian deposits can often be divided, similarly as in neighbouring Ghana, between predominantly clastic (flysch) formations and volcano-clastic formations.

The clastic sequence consists of intensely deformed pelitic and psammitic metasediments. There are three major Birimian greenstone belts in the south and the west of the country, in which volcano-sedimentary sequences are dominant, and a fourth in the central and northeastern regions, besides numerous other smaller greenstone belts, which are found throughout the country. Granites and granodiorites occupy the spaces between the greenstone belts. Proterozoic conglomerates and sandstones of the Tarkwaian Group rest unconformably on Birimian rocks around Essakane in the NE of Burkina Faso. The margins of a large sedimentary basin of Neoproterozoic to Ordovician age emerge at the western border of Burkina Faso.

These rocks consist of basal sandstones with overlying shales and dolomites, sometimes carrying bauxite mineralization [5.2].

FIG. 3.8. Regional geological setting of Burkina Faso. For the general uranium occurrence legend see Fig. 2.1b.

A general global geological legend is shown although not all geological units necessarily occur on this particular map.

Mining contributes only a small amount to Burkina Faso’s GDP. The main mineral produced is gold, much of which is extracted by artisanal gold miners. Gold is primarily mined from Proterozoic rocks and alluvial/eluvial deposits.

Burkina Faso has important Neoproterozoic phosphate deposits in the extreme south-east of the country, close to the borders with Benin and Niger. The reserves of the various phosphate rock deposits were, in 1986, estimated at: Aloub Djouana (224 million t at 15% P2O5), Kodjari (80 million t) and Arly (4 million t) [5.2].

3.5.2. Uranium exploration

In the 1960s, France’s Atomic Energy Commission conducted some exploration in the Bobo-Dioulasso, Djibo and Yako areas. There were no significant results.

In 2008, Crosscontinental Uranium Ltd completed a detailed airborne radiometric and magnetic survey of the Oursi area. The Oursi project tenements, in the north-east of the country, cover a combined area of 500 km² and include a 50 km strike length of an unconformity structure that is considered prospective for uranium mineralization. Known uranium mineralization occurs 50 km along strike and west of the Oursi tenements.

The magnetic data defined the unconformity structure and a number of cross-cutting fault structures. The spectrometer data indicate several discrete uranium anomalies in a favourable geological setting, warranting ground follow-up and investigation. One uranium anomaly is approximately 8–9 times the radiometric background. Ground follow-up was expected to commence as soon as field access could be arranged.

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3.5.3. Uranium resources

Burkina Faso does not report uranium resources in any category. In 1983, a review of the IUREP estimates reported a range of <1000 tU of speculative resources [5.3].

The UDEPO database does not list any known deposits for Burkina Faso.

3.5.4 Comments

No uranium has been produced in Burkina Faso and there are no plans to develop nuclear generating capacity. No report has been submitted to the Red Book.

References to Section 3.5

[5.1] CENTRAL INTELLIGENCE AGENCY, The World Factbook: Burkina Faso, Washington, DC (2008), https://www.cia.gov/library/publications/the-world-factbook/index.html

[5.2] SCHLÜTER, T., Geological Atlas of Africa, 2nd edn, Springer, Berlin and Heidelberg (2008) 50–52.

[5.3] INTERNATIONAL ATOMIC ENERGY AGENCY, Speculative Resources of Uranium, A Review of IUREP Estimates 1982–83, IAEA, Vienna (1983).

3.6. BURUNDI

Burundi is one of Africa’s smallest countries. It is a landlocked country located towards the centre of the continent and forms part of the Albertine Rift, which is the western extension of the Great Rift Valley.

The country comprises a rolling plateau, with an average elevation of 1700 m, descending to lower elevations at its borders. The highest peak, Mount Heha (2690 m), lies to the south-east of the capital, Bujumbura. The River Nile is a major river in Burundi and Lake Tanganyika is an important source of water.

The climate is equatorial, with two rainy seasons: hot and humid in the Ruzizi valley (23°C average temperature; 800 mm annual rainfall) and temperate in mountainous regions (16°C average temperature;

up to 1200 mm annual rainfall).

Burundi’s largest economic sector is agriculture, with subsistence activities accounting for 90% of the total. Its most important source of revenue is coffee. Other agricultural products include bananas, cotton, maize, manioc, sorghum, sweet potatoes and tea, as well as beef, milk and hides. Some of Burundi’s natural resources include cobalt, copper, nickel, platinum and uranium [6.1].

3.6.1. Geology

Burundi’s geology is mostly made up of rocks belonging to the Mesoproterozoic Kibaran Belt and the Neoproterozoic Malagarasian Supergroup (Fig. 3.9). Tertiary and Quaternary sediments fill parts of the Western Rift at the northern tip of Lake Tanganyika.

Rocks belonging to the Mesoproterozoic Kibaran Belt are widespread in Burundi and are locally termed as the Burundian Supergroup. Generally, the Burundian Supergroup is subdivided into three units. The base of the lower Burundian consists of a quartzitic sequence, which overlies directly the Archean basement. The upper part of this unit contains locally a tuff horizon of intermediate composition. It is overlain by schists of considerable thickness, whose lower part consists of graphitic schists, which are interbedded with quartzitic horizons of minor importance. Higher up, the quartzitic horizons are interbedded with grey schists, sometimes containing volcanic intercalations.

FIG. 3.9. Regional geological setting of Burundi. For the general uranium occurrence legend see Fig. 2.1b. A general global geological legend is shown although not all geological units necessarily occur on this particular map.

The middle Burundian begins with a sequence of quartzites overlain by schists and green phyllites, which are particularly well-represented in the western part of the country, and which in this region contain basic volcanic intercalations overlain by acidic volcanic horizons. These pelitic key horizons are overlain by black graphitic and ferruginous schists, which progress gradually towards the upper Burundian. The upper Burundian is generally characterized by poorly sorted sediments, often containing arenites. Within these arenites occur numerous lenticular conglomeratic bands. Frequently present is an intraformational conglomerate near the base of this formation, which is characterized by the presence of ferruginous lenses.

The rocks of the Burundian Supergroup are intruded by granites, and along a 350 km long narrow zone by mafic and ultramafic intrusions [6.2].

Neoproterozoic rocks are represented by members of the Malagarasian Supergroup. The contact between the Neoproterozoic Malagarasian Supergroup and the underlying Burundian sedimentary rocks is either unconformable or faulted. The relatively flat lying and unmetamorphosed Neoproterozoic formations of south-eastern Burundi comprise epicontinental sediments associated with basic igneous rocks. The Malagarasian n Burundi has an overall thickness of about 2000 m and has been subdivided into five units:

(i) The lowest group is the Kavumwe Group, the sediments of which accumulated in local basins and consist of quartzites, sandstones, argillaceous sandstones and shales;

(ii) The Nkoma Group consists of conglomerates, quartzites and sandstones;

(iii) The Musindozi Group contains dolomitic limestones, calcareous shales, lavas, sandstones, quartzites and conglomerates;

(iv) In the Mosso Group, silicified dolomitic limestones and lavas occur;

(v) The top of the Malagarasian Supergroup is represented by the Kibago Group, which is characterized by sandstones, quartzites, shales and a basal conglomerate.

Mostly Neogene sediments fill parts of the Western Rift at the northern tip of Lake Tanganyika and along various rivers [6.2].

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3.6.2. Uranium Exploration

Uranium exploration started in Burundi in 1969 when, at the request of the Government of Burundi, the United Nations Development Programme initiated a project of mineral exploration using funds provided by the United Nations and facilities provided by the Geological Survey of Burundi. The programme was divided into four phases:

(i) Phase 1 (1969–1972): General reconnaissance studies and interpretation of geological structures using photogeology and results from an airborne spectrometer survey conducted by Hunting Surveys Ltd;

(ii) Phase 2 (1972–1977): Completion of a combined magnetometer and radiometric airborne geophysical survey covering part of the country by Hunting Surveys Ltd and detailed exploration of specific occurrences;

(iii) Phase 3 (1977–1981): Car-borne radiometric surveys used for infill of areas not covered by airborne surveys and ground follow-up of anomalies. Airborne (electromagnetic and magnetic spectrometer) surveys carried out by German’s Bundesanstalt für Geowissenschaften und Rohstoffe. Detailed exploration of specific occurrences located by the airborne survey;

(iv) Phase 4 (1982–1984): Priority given to the delineation of cobalt, copper, iron, nickel, titanium and vanadium mineralization, as well as to feasibility studies. At that time, uranium and rare earth prospects were not regarded as very promising.

From 1981 onwards, France’s Bureau de Recherches Géologiques et Minières (BRGM) conducted extensive field work in north-eastern Burundi. The Bundesanstalt für Geowissenschaften und Rohstoffe assessed the potential of the Gakara/Karonge bastnaesite (rare earth) deposit.

No major uranium occurrences are known in Burundi, although a number of small anomalies have been found:

(a) The Kiganda occurrence: Assay results of up to 500 ppm U associated with high copper and zinc values were obtained from trenches on radiometric anomalies in an area underlain by Burundian metamorphics at the western periphery of the granite–gneiss Kiganda complex;

(b) The Musigati occurrence: Assay results of up to 578 ppm U were obtained from trenches over radiometric anomalies in an area underlain by Burundian and Ruzizian metamorphics (schists and gneisses) and pegmatites. The uranium mineralization occurs as pockets of autunite, irregularly distributed within or at the contact of the partly brecciated and limonite stained pegmatites. The drilling results were not encouraging;

(c) The Mparamirundi and Kigambi occurrences: Assay results of up to 2000 ppm U were obtained from trenches over radiometric anomalies in an area underlain by Ruzizian metamorphics and pegmatites. No visible uranium mineralization was reported;

(d) The Matongo occurrence: At Matongo, a uraniferous carbonatite, mainly considered for its phosphate potential and probably related to the syenite complex of the Kayanza granite–gneiss complex, yielded assay results of up to 3300 ppm U in its weathered capping. Uranium recovery as a by-product of phosphate mining was considered, but further investigation indicated that the higher grade uraniferous pockets were too small and too sparsely distributed to warrant further effort.

No recent exploration activities have been reported in Burundi.

3.6.3. Uranium resources

There is no official estimate of uranium resources in Burundi. In 1983, the IUREP Orientation Phase Mission to Burundi estimated that speculative resources could range from 300 tU to more than 4100 tU [6.3, 6.4].

The UDEPO database does not list any known deposits for Burundi.

3.6.4. Potential for new discoveries

Speculative uranium resources may possibly be associated with potential vein-like deposits of the Lower Burundian. Other speculative uranium resources could be associated with granitic or peribatholithic environments, possibly in areas of low to medium grade metamorphism or at the faulted contacts between sedimentary arkoses and gabbroic intrusives.

3.6.5. Comments

There has been no uranium production in Burundi. Burundi has no nuclear power plants. No reports have been submitted to the Red Book.

References to Section 3.6

[6.1] CENTRAL INTELLIGENCE AGENCY, The World Factbook: Burundi, Washington, DC, https://www.cia.gov/

library/publications/ the-world-factbook/index.html.

[6.2] SCHLÜTER, T., Geological Atlas of Africa, Springer, Berlin and Heidelberg (2008) 54–57.

[6.3] OECD NUCLEAR ENERGY AGENCY–INTERNATIONAL ATOMIC ENERGY AGENCY JOINT STEERING GROUP ON URANIUM RESOURCES, World Uranium: Geology and Resource Potential, Report on Phase 1, International Uranium Resources Evaluation Project (IUREP), Miller Freeman Publications, San Francisco (1980) 524 pp.

[6.4] GEHRISCH, W., CHAIGNE, M., IUREP Orientation Phase Mission Report: Burundi, IAEA, Vienna (1983) 124 pp.

3.7. CAMEROON

Cameroon is located in western central Africa, bordering the Bight of Biafra, between Equatorial Guinea and Nigeria. It also has borders with the Central African Republic, Chad, Congo and Gabon. Cameroon exhibits all the major climates and vegetation of the African continent: mountains, desert, rainforest, savannah, grassland and ocean coastland, and can be divided into five geographic zones.

Cameroon’s coastal plain extends 15–80 km inland from the Gulf of Guinea to the edge of the South Cameroon Plateau. The coastal belt is heavily forested and is one of the world’s wettest locations. It is extremely hot and humid. The South Cameroon Plateau, which rises from the coastal plain and is dominated by tropical rainforest, has an average elevation of 450–600 m and is less humid than the coast.

In western Cameroon, the topography comprises an irregular range of mountains, hills and plateaux. This region enjoys a moderate climate and contains some of the country’s most fertile soils, notably around the volcanic Mount Cameroon. From the forested southern plateau the land rises northwards to the grassy, rugged Adamaoua highlands. Extending across Cameroon from the mountainous western area, the Adamaoua forms a barrier between the north and the south. Its average elevation is 1035 m and its climate is equable. The northern savannah plain extends from the edge of the Adamaoua to Lake Chad. Its characteristic vegetation is scrub and grass. This is a region characterized by sparse rainfall and high temperatures.

Cameroon’s natural resources tend to be in agriculture and forestry. An estimated 70% of the population farms and agriculture contributed an estimated 45% to GDP in 2006. Crops include coffee, sugar and tobacco. The southern rainforest has major timber reserves, estimated to cover 37% of Cameroon’s total surface area. Cameroon also possesses substantial mineral resources (bauxite, iron, petroleum), but these are not extensively exploited. Petroleum extraction has fallen since 1985, but still remains a substantial sector [7.1].

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3.7.1. Geology

The oldest Precambrian rocks, the Lower–Middle Proterozoic, have not been differentiated by their age (Fig. 3.10). They consist of gneisses, mica schists and migmatites. The Ayes, Lom, Mbalmayo-Benglois and Poli rock groups are considered to be of Lower Proterozoic age and form a folded complex consisting of amphibolitic schists, lavas and quartzites intruded by granitic bodies. The areas underlain by these rocks could have some potential for uranium, particularly because certain basement granites exhibit relatively high levels of radioactivity along tectonic and altered zones.

The Lower Dja Series, which have been correlated with the Franceville Series of Gabon, contain quartzites, sandstones and shales and could host uranium deposits, despite the lack of success of past surveys.

FIG. 3.10. Regional geological setting of Cameroon showing the distribution of selected uranium deposits and occurrences. For the general uranium deposit and uranium occurrence legend see Fig. 2.1b. A general global geological legend is shown although not all geological units necessarily occur on this particular map.

The Cretaceous Garoua sandstones (Continental Intercalaire) are present in sub-horizontal beds in a large area on both sides of the Benue River in north Cameroon. Generally, they overlie Precambrian granitic rocks. However, in some localities they are in fault contact with the Precambrian. The sandstones are intruded by volcanic rocks, mainly trachytes. The Garoua is at least 400 m thick and usually has a basal conglomerate overlain by sandstone beds with lenticular shale intercalations. Silicified wood is present in the Garoua sandstone. Uranium deposits could have formed in this geological environment [7.2, 7.3].

3.7.2. Uranium mineralization

Uranium exploration in Cameroon was initiated in 1959 by France’s Atomic Energy Commission. During the period 1959–1969, an area of 59 280 km² was investigated by airborne and ground surveys. Anomalies

were followed up on the ground at 230 different points. Geologically favourable areas for uranium were detected at several locations. Areas evaluated include: granites and syenites in the basic migmatite complex (Pan-African); areas along the Cretaceous basins in the north of the country; and the formations of the Dja Series in the south-east, which are possibly equivalent to the Franceville System in Gabon and known for its uranium deposits. No significant mineralization was discovered by the Atomic Energy Commission, but a private prospector identified an occurrence at the point of contact with a syenite intrusion, 8 km south of Poli, at Goble.

During the period 1970–1975, the IAEA provided assistance in prospecting an anomalous zone in the Poli–Garona area of northern Cameroon. A total of 277 m was drilled. Small, lenticular occurrences were found to be economically unattractive. Uranium resources of 240 tU metal at 0.1% U were discovered.

Also during this period, the Canadian International Development Agency conducted an aeromagnetic survey, not including radiometry, over 168 000 km² (Table 3.4).

TABLE 3..4. URANIUM EXPLORATION DATA [7.4]

Airborne radiometric

surveys (km²) Other surveys (km²)

Drilling

In 1976–1983, three exploration surveys were conducted for metalliferous deposits, including uranium:

(i) Under a United Nations Development Programme project, ground, airborne spectrometry, very low frequency electromagnetics and geochemical surveys were undertaken under an exclusive permit covering 65 000 km² of the Lower Dja Series, which shows great resemblance to the uranium bearing Franceville Series in Gabon and represents a potential target for future exploration;

(ii) The Bureau de Recherches Géologiques et Minières (BRGM) conducted helicopter-borne spectrometry and ground surveys in south-west Cameroon, mainly on a syenite stringer trending E–W and located east of Lolodorf. Anomalies were revealed in a syenite formation lying parallel to the interface with the Old Eratan, possibly a syenite intrusion. Mineralization in the form of uraninite and uranothorite associated with chalcopyrite, galena and molybdenite were discovered.

In 1983, BRGM started drilling to a depth of 50–80 m into a fault crossing the syenite stringer.

The mineralization appeared to extend irregularly downwards and was estimated to contain 1000 tU at a grade of 0.1% U;

(iii) German’s Federal Institute for Geosciences and Natural Resources carried out a survey on uranium mineralization at Goble in the Poli area. The investigations consisted of two short missions, one on granite and syenite intrusions and the other focused on continental Cretaceous basins in northern Cameroon.

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The uranium anomalies of the Lolodorf syenite were first discovered during fieldwork undertaken by BRGM in 1979. The arcuate late tectonic syenite occurs in a narrow band along the north-western edge of the Archaean Ntera Complex. It is 2–5 km wide and about 60 km long. On the ground, some samples contained uraninite and uranothorite, associated with minor chalcopyrite, galena, molybdenite and pyrite.

Grades of up to 0.1% U have been reported. The mineralization appears to be restricted to a particular layer of fine-grained syenite, parallel to the foliation, and flanked by coarser syenite.

The uranium mineralization at Goble in northern Cameroon (Poli district) was discovered in 1958 by a private prospector and re-examined by IAEA experts between 1970 and 1975. A regional airborne

The uranium mineralization at Goble in northern Cameroon (Poli district) was discovered in 1958 by a private prospector and re-examined by IAEA experts between 1970 and 1975. A regional airborne