Talking Drums

The West African News Magazine

Digging Deeper for Manganese in Ghana

Poku Adaa

Manganese ores have been mined in Nsuta in the Western region of Ghana for over a century. POKU ADAA delves into the history of the mine and questions the rationale of the then military government of Ghana to take over a virtually exhausted mine in 1975, and in the light of the nature and use of the ores being mined now, unravels the reasons behind new equipment and installations now on site at the mine.
The western part of Ghana which is enclosed between the river Pra and the Ivorian border, lies in the valleys of the Tano and Ankobra and populated by an admixture of several ethnic societies, mainly the Nzima, the Ahanta, the Aowinn, the Shawi and the Wassa.

The area is known, for her mines and her lumber bringing into mind such settlements as Samreboi, Prestea, Tarkwa, Awaso, Bonsaso, Enchi and Nsuta, and of course for her noisy, rickety, smoky, slow trains, all-time remnants of British colonialism which for over a century carried the area's wealth to berthing ships at Takoradi for onward transmission to Her Majesty's dominions.

To Nsuta then we go, 65 kilometres from Takoradi, to the small town where mining may be older than the most elderly person in town. To the town where mining is and has always been a tradition, a way of life.

The Mine was established in 1936 and constituted a major supplier of manganese ores for the British Empire. For a brief period, it ranked fifth on the world scale in terms of quality, tonnage exported and future reserves and by the latter part of the 1950's, production peaked at around 700,000 tonnes. Then the mine was under the ownership and management of Union Carbide Corporation.

The military government of Ghana from 1972-1979 took over complete control of the mine in 1975 and from then the Ghana National on Manganese Corporation was born. From then on the output of the mine slumped considerably, so much that by the end of that regime in 1979, output was nearly one-third of its peak production, at about 275,000 tonnes. This may have been explained away as due to the general economic malaise of the country, the usual sing-song of lack of foreign exchange and spare parts and bad market prices and so on.

Why did the government take over the company at that particular time? Was the government pressurised in any way to take over the company at that particular time? Did the government know the state of the mine at the time it took over? What has given rise to the current spate of rehabilitations and restructuring of the company at this time?

Manganese is a metallic substance that exists in the earth's crust mainly in the form known as Pyrolusite, a black solid which finds use principally in the manufacture of dry cell batteries. A typical dry cell battery consists of graphite rod immersed in a jelly of manganese dioxide, ammonium and zinc chlorides and starch held in a zinc casing.

The manganese dioxide which must be of a particular crystal type protects the graphite rod against being coated with gas bubbles and by so doing prevents its deterioration and ensures stability and effective working of the whole battery. Only the pyrolusite form of manganese such as was available from the Nsuta mine could be useful for this purpose in dry ice manufacture. Hence one could easi appreciate the interest of Union Carbide Corporation in the mine. well... that is as long as that unique manganese ore was available to be mined.

As it turned out, however, by the time the Acheampong administration took over the Nsuta mine, this very important manganese ore type had been almost completely exhausted, an estimated 20 million tonnes, leaving an estimated token of about 3½ to 4 million tonnes. Union Carbide had no use for the mines then. Ghana took over 'an empty pot' as it were, with only the dredges to gather. That also meant that the lucrative dry cell battery manufacturing outfit as a market was no longer relevant to the mine.

This did not spell out doom for the mine though. There were still some reserves of manganese, though not of the battery-making type. They were a mixture of low grade ores which could only be marketed on the world market if it was turned into a form suitable for the iron and steel making industries and that required new equipment and machinery to process and handle. This is the reason for the current spate of rehabilitations and new structures at the mine.

This processing involves what is technically known as 'calcination' that is the low grade ores in which the manganese are present in a 'carbonate' is subjected to high temperature treat- ment in a specially built kiln or furnace whereby the carbonate breakdown to liberate the manganate compound which is salable to the iron and steel trade.

The use of manganese here is to remove impurities from molten steel. About 10% of the manganese toughens steel making it useful for the manufacture of armour plate, steel, helmets, safes, etc.

What the Mine required then were new equipment and facilities to cope with the new phase of the mine. Luckily, the civilian government of the Peoples National Party had a keen interest in the mining sector and coupled with a stubborn determination of the Mine management, financial and technical agreements were entered into with foreign companies to upgrade facilities at the mine.

Consequently C74 million a rehabilitation project was launched two years ago spearheaded by the Fuller Company of Catasauqua, USA as a major contractor at a cost of C25 million. The design and construction of civil, mechanical and electrical work was awarded to Taylor Woodrow International Limited. The contract was for the construction of a 'Nodulising Plant', that is the kiln to burn and convert the carbonate ores to the relatively pure forms of the manganese and process it into nodules or ingots for export.

The project has been reported to have been completed and ironically the ruling PNDC has taken so much pride and credit for it that an annual expected revenue from it of $24.8 million was a strong point of the last government budget. With the new structures in place, about 400,000 to produce about 255,000 tonnes of the ferro-manganese alloy per year.

Already, international markets are opening up speedily. The Rumanian Import & Export Company has signed a two year agreement to buy 10,000 tonnes of the alloy per year, while Japanese imports of Ghana's manganese, according to the Anglo-Japanese Economic Institute, has jumped from 24,548 tonnes in 1981 to over 46,125 tonnes in 1982, an increase of about 47%. A new twenty-five year loan from the European Economic Community has just been announced, worth $5.2 million to continue the restructuring exercise and already the Mine management have been quoted as saying that plans are being drawn up to move further ahead to convert electrolytically the low grade ores to the manganese dioxide, the battery making type of ore.

That seems rational, since at the moment, the price of the alloy is going to depend completely on the already depressed and collapsing state of the international iron and steel trade. Besides, one of the problems the mine is facing now is the poor transportation from the mines which had effected shipment. While production in 1982 was about 223,146 tons it fell to 159,946 tons in 1983, and the new nodulising plant has yet to make any impact on the overall level of productivity at the mines.

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