Barytes occur in Nigeria as vein infilling materials associated with lead-zinc lodes and veins in the both Pre-Cambrian basement and Cretaceous sedimentary rocks of the lower and middle Benue valley.
The mineral commonly occurs as white, reddish-brown and clear varieties with specific gravity varying between 3.5 and 4.4. The width of the veins ranges from a few centimetres to 5.3 metres. Lengths of veins also vary from a few metres to 4,500 metres.
A survey carried out in 1959 put the estimated reserve at 41,000 tonnes for the Benue valley deposits. Also the Nigerian Mining Corporation estimated a resource of 70,000 tonnes in the Azara deposit in Nasarawa State. Recently the Nigerian Geological Survey Agency embarked on the evaluation of newly reported deposits in Cross River, Benue, Nasarawa, Plateau and Taraba States. The inferred resource estimated for four of the states (Benue, Cross River, Nasarawa and Taraba) where mining is considered viable is 21,123,913 metric tonnes.
Investment opportunities abound in the following areas:
- Applying for mineral titles with a view of wholly owning the mining rights for the barytes deposit
- Partnering with existing title holders for detailed exploration as consultants and specialists
- Partnering with existing title holders in a joint venture agreement to explore, mine and market the barytes resources
- Legal transaction in barytes won in quarries and operations for export
The barytes resource of Benue State is hosted in the igneous-metamorphic rocks of the Pre-Cambrian as well as in sandstones and shale of the Benue trough sedimentary formations. Mineralisation is in form of fissure filling with hydrothermal solutions depositing barytes in fissures formed by the closing in of the Benue trough during the Santonian.
The mineral occurs as white, reddish-brown and clear varieties with specific gravity varying between 3.7 and 4.4. Chemical analysis show that most samples contain between 76% to 87% BaSO , impurities of between 5% and 21% silica and up to 3% iron oxide.
Veins exposed do not persist over long distances in the area and width of 3 meters and above are common. The inferred resource of barytes for the state is 307,657 metric tonnes based on an average specific gravity of 4.0 and depth of vein to 20 metres.
Cross River State
Barytes veins in Cross River State are hosted in both hard and soft rocks. Of the 35 mineralised locations in the state, 11 are in sedimentary areas. This study divided the mineralised areas into the north, comprising of Obubra, Ikom and Yala local government areas (LGAs), and the south, consisting of Biase and Yakkur LGAs. Barytes is hosted more by sedimentary rocks in the north while in the south only 2 out of 18 locations are in sedimentary rocks.
The veins’ width are often between 2.5 and 5.3 metres (veins with width less than 0.2 meters were not considered). Specific gravity ranges between 3.5 and 4.4. Total vein length varied between 1,000 and 6,000 metres.
Inferred resource for the entire state is 8,612,880 metric tonnes distributed almost evenly between the north and south. Resource extraction is easier in the northern zones as a result of soft host rocks. Resource estimate in this report is likely to increase as new veins are located in the future.
The resource is hosted by assorted sedimentary rocks (shale, mudstone, siltstone, limestone). The barytes occur in the form of veins having a width varying between a few centimeters to 3.5 metres. Veins persist along strike for distances varying between just under 1,000 metres to over 4,000 metres.
Laboratory studies conducted on samples from the state show that specific gravity of mine materials varies between 3.9 and 4.4. This is within specification of the American Petroleum Institute (API). However, some samples have specific gravity values of less than 3.6. Such samples are silica rich varieties not suitable for use unless beneficiated. The impurities indicated by analytical data are quartz, celestite and iron oxide.
The inferred resource of barytes in the state is 3,243,376 metric tonnes calculated using an average specific gravity of 4.0 and a vein depth projected to 20 metres.
Barytes resources in Taraba State are located in five LGAs: Sardauna, Karim Lamido, Yoro, Lau and Ibi. The resources are hosted in porphyritic granites and fine grained sandstones. Vein lengths are persistent over distances varying from 3,500 to 5,000 metres and width from 3.5 to 5 meters. Impurities consist of quartz and sulphide minerals such as galena.
The figure obtained for the inferred resource is 8,960,000 metric tonnes to depth of 20 metres. Quality of resource is good with most specific gravity values close to 4.2. Considering the size of individual veins, investment in heavy equipment to mine at greater depth is considered worthwhile.
Most of the locations in the state previously reported to have barites mineralisation were found to be veins of calcite and celestite with lower specific gravity values. The latter may be an impurity in the barytes thus lowering the specific gravity.
The location with the best quality barytes in the state is Faya where a prominent well developed vein was estimated to contain about 500,000 metric tonnes of resource with specific gravity varying between 4.0 and 4.2.
Some sections reportedly contain fluorite as impurities. The vein is hosted by sandstones of the Keana Formation of Cenomanian age.
New exploration information
Recent investigations by the Nigerian Geological Survey Agency and private exploration/mining companies have continued to shed more light on the endowments and the potentials of the country in barytes mineralisation.
Between the years 2006 and 2008 the Nigerian Geological Survey Agency has carried out evaluation and assessment of key commodities nationwide. Barytes is one of the strategic commodities given priority. Beyond the known areas of barytes mineralisation, some three other states (Adamawa, Gombe and Zamfara), with favourable geological settings for barytes mineralisation or proximal to the Benue trough system, were considered in the evaluation.
Barytes occurrence in Adamawa State is notable around Gban and Mayo-Kpoki areas. The geology of the barytes is associated with fissure and cavities infilling by hydrothermal fluids associated with faults and fracture zones of the Upper Benue trough.
The colour of the mineral varies from white to pink and some have vitreous luster with specific gravity values varying between 4.0 and 4.36. The inferred resource of the state is 332,130 metric tonnes.
The mineral is being hosted in gneiss-migmatite complex and coarse sandstone of the Benue trough. The mineralised areas in the state are Gombe and Liji hills located 10 kilometres north-east of Gombe town.
The thicknesses of the veins vary between 0.3 metres and 1.2 metres and some reaching 1.5 metres; others can be traced along strike for up to 400 metres.
The colour of the barytes is creamy to grey-white with specific gravity between 4.09 and 5.3. Gangue minerals associated with the mineralisation are fluorite, quartz and chalcopyrite. Major element analysis gives BaO content to be between 45.00% and 59.5%. The inferred resource estimate for the two locations is 352,800 metric tonnes.
Barytes mineralisation in the state is linked to epigenetic hydrothermal fluids, which leached barium from adjacent rocks and precipitated in the vein.
The vein deposits show great variations in their properties, especially thickness. The veins have variable widths from a few centimetres up to several metres, and lengths of longer than 100 metres. The majority of veins have probably formed from rising hydrothermal solution which precipitated the barytes in the veins.
Barytes occur in the following locations:
- Dareta near Anka, Anka LGA
- Rekebu near Chafe, Chafe (Tsafe) LGA
- Yarkatsina (Gidan Saro), Bungudu LGA
- Tofa forest reserve, Gusau LGA
The barytes are large to granular with uneven fractures and the colour varies from white to the reddish-brown type.
Investors interested to invest in barytes mining and exploration should contact the Mining Cadastre Office at [email protected]