AFRICA SPECIAL — Northern Ghana’s potential begins to attract attention

More than a dozen companies have acquired prospecting licences in northern Ghana, testifying to the region’s mineral potential.

Activity in the country’s northern, upper western and upper eastern regions has focused mostly on historic gold mining sites.

According to Yakubu Iddrisu and T.M. Akabzaa of the University of Ghana’s geology department, northern Ghana is underlain by cratonic rocks (of Birimian and Tarkwaian suites) known for their gold-bearing potential.

Diamonds, manganese and bauxite have also been found in this geological environment, and more than half of the northern region is underlain by Voltaian sedimentary rocks which host industrial minerals such as limestone, sodium chloride (salt) and barite.

Most of the companies exploring for gold in the north are focusing on areas with historic mining sites, such as Dakupe and Kibilma in the Bole district, Nangodi Zag and Duhsi in the Bolgatanga district, and Zoasi and Widenaba in the Bawku district. Initial exploration programs have tended to target the Bole, Nangodi and Lawra belts.

Although the excitement over gold in the north outweighs interest in diamonds, there have been isolated diamond finds by the Geological Survey of Ghana, notably in Gambaga and the Sicili Valley. The largest diamond ever found in the West African country weighed 7.5 carats and was picked up along the White Volta River. Many geologists believe a major source of alluvial diamonds exists somewhere in the north.

Major iron ore finds identified in the north include the Sheini and Pudo deposits in the northern and upper west regions, respectively. By far the largest of these is the Sheini, with reserves estimated at 1,270 million tonnes grading 4.7% iron. Despite having received substantial attention from government, development is hindered by the lack of infrastructure and distance to the nearest port.

At the Pudo iron ore deposit, which is smaller and less studied, reserves are estimated at 4.5 million tonnes containing 33% Fe203 and 39% TiO2. It is unique for its high content of titanium and manganese. Other minor deposits have been recorded at Mirigu in the upper eastern region, and at Dutukpene and Nkwanta in the north.

Manganese potential

Manganese deposits of economic interest occur in four locations in the Bole district: Kalimbi Hill (total reserves of 6.2-8.5 million tonnes grading 14.33% manganese); Kapila (110,000 tonnes); Three Hills, near Ntrereso (2.5 million tonnes at 30% manganese); and Sere (no calculations available).

Occurrences of copper, lead and nickel have been reported in the Birimian and Voltaian rocks in the north, though no economic deposits have been established to date.

Three areas in the north are noted for substantial deposits of limestone. The Buipe deposit, for example, is the largest occurrence of carbonate rocks known to exist in the region, with total reserves of quality limestone estimated at 6 million tonnes, plus 144 million tonnes of dolomite.

The Bongo-Da deposit, on Nalerigu-Tendi Road near Bongo-Da, contains some 15 million tonnes of high-quality limestone and 20-30 million tonnes of dolomite. It has been found to be suitable for quick lime and cement manufacture.

Easily accessible by road from Tamale is the Doboya deposit, where quality limestone reserves are estimated at 162,000 tonnes, suitable for small lime production. There is also a dolomite resource.

Minor occurrences of limestone, suitable for small-scale production, have been found in the Salaga-Yeji area and the Du-Walewale area in the northern region.

Deposits of barite have been identified along the banks of the White Volta River, near Daboya in the northern region.

A salt deposit at Dabaya is in the form of a brine-bearing horizon (43-100 metres) with average salt content estimated at 7 grams per litre during the dry season; the yield is about 22,000 litres per hour, amounting to 4.5 tonnes of salt per day. Another deposit exists at Tibogona, 16 km from Dabaya.

The recent extension of the electricity grid in the northern areas (part of the National Electrification Program) has come at an opportune time and has helped bring about the development of hitherto dormant deposits.

— The author is a freelance writer based in Ghana.