Anyone who has spent a few months in Ghana cannot fail to notice the important role that gold plays in the economic and cultural life of its people. Indeed, it would not be an exaggeration to say that Ghana and gold are synonymous literally and metaphorically. The colonial name of Ghana, ‘Gold Coast’ was based on the fact that when visitors from outside Africa first arrived on the shores of the Gulf of Guinea they could literally see and pick gold from the sand. Today it is not impossible to do so, although it may require more effort. I am inclined to think that it is the gold more than anything else that initially attracted the Portuguese, the Danes and the British to invest so much in castles and forts along the coast of Ghana.

By its sheer geographical location, Ancient Ghana was the meeting point for the traders from the North and the traders from the South. The King levied taxes on both sellers and buyers of gold. The Empire on the other hand offered the traders the needed protection because of the stable political climate. At the height of its prosperity the capital of the Ghana Empire, Kumbi Saleh, was supposed to have a population of 15,000. Old traditions also speak of a movement of some of the people of ancient Ghana southward to occupy the present middle belt of modern Ghana. If indeed this movement occurred, it means that the ancestors of the people who occupy the present Ghana had seen gold as a source of wealth and also as currency. Among the Akans and non-Akans who occupy the middle and the coastal region of modern Ghana, the name for gold is Sika Kokoo that literally means ‘red money’ or currency. In pre-colonial Ghana, the currency for trading activities was either gold or cowry, the latter being shells of a marine snail. Cowry is white hence the need to distinguish gold from it by describing gold as ‘red’. Gold and cowry were demonetized in 1889 after colonial Gold Coast had been established by the British in 1874.

Another factor that makes the metal precious is that it is relatively scarce in the earth’s crust. The percentage abundances of some useful elements are given in the following table. It can be seen that gold is ten million times as rare as iron, for example.

[M]ost of Ghana lies within the Precambrian Guinea Shield of West Africa, the main rock units being the metamorphosed and folded Birimian, Tarkwaian and Dahomean systems, the Togo series and the Buem Formation. The Precambrian rock are overlain by later Proterozoic to Paleozoic epicontinental sandstones, shales and mudstones termed the Voltaian System. The Birimian, about 2000 million years old, is the host rocks for deposits of gold and other precious minerals such as diamonds, bauxite, manganese and iron.

A mineral map of Ghana shows that there is gold everywhere in Ghana except perhaps the Volta Basin.

(i) reef or vein type,

(ii) surface ore,

(iii) alluvial deposits.

Surface Ores. These may be hard rocks at or near the surface containing gold deposits. The hard rocks may have been formed as a result of volcanic activities. The sulfide-laden rocks, when exposed to the atmosphere, become what are termed oxidized ores. The sulfur and the arsenic are converted by the weathering process into sulfates and arsenates respectively. The chemical equations for the weathering processes may be as follows:

Examples of goldmines that exploit this type of ore are Tarkwa Gold Field, Teberebie Goldfields and Ghana Australian Gold Fields near Tarkwa.

Alluvial Deposits. These deposits are found in the streams or rivers that run over the areas with Birimian rocks. They are derived from the primary veins. The gold is finely divided and is found in riverbeds, riverbanks, dry valleys, gravel beds, beach gravels and sand. The ore at Konongo, mined by Konongo Southern Cross Mining Company (partly owned by an Australian company) is lateritic. AGC also mines this type of ore. Concessions given to the small-scale miners in the Central, Eastern Ashanti, Upper East and Upper West Regions involve this type of deposit.

One of the actions taken by the former Provisional National Defense Council (PNDC) Government to revive the mining industry was to set up a Minerals Commission (MC) in 1989 whose main responsibility was to promote and oversee the orderly development of the industry. In 1989, on the advice of the MC, the government of Ghana decided to regularize small-scale gold mining by individuals or small groups of individuals. Up until 1989 gold mining by individuals had been illegal. The main reason for allowing individuals and small groups to mine was that the exploitation of alluvial gold in particular is not attractive to the big companies which normally use sophisticated machinery. A law compels these small scale miners to sell their gold to the Precious Minerals Marketing Corporation.

- Crushing and grinding of the ore (communition or scrubbing);

- Concentration which involves the separation of the ore into characteristic products;

- Disposal.

Alluvial Gold. The crushing and grinding of the ore is done by nature. The powdered material is transported by river or by rainwater. In the course of time some rivers dry up. In dry areas the vegetation is removed. A mixture of sand and pebbles contained in a basket is washed (sluiced) in the river or in artificial ponds to concentrate the ore. This concentrated ore is poured over a stretched, sloping blanket or some similar material. The gold gets stuck to the material while the sand and other impurities run off. The gold is scraped into a container; a few drops of mercury are added to extract the gold by almagam formation. The excess mercury is drained off and the amalgam is heated to evaporate the mercury leaving behind the gold. Gold recovery is about 20-30 percent by the small scale miners and about 70-80 percent at the Dunkwa Goldfields on River Offin.

Surface Ore. The vegetation and topsoil are removed if necessary to expose the rock or laterite. The rock is chipped with a hammer or chisel; the broken pieces are ground with a mechanical crusher (or manually with metal mortar and pestle) into a fine powder. Laterite is also ground to give a powder. The powder is washed to concentrate the gold, which is isolated by amalgamation or by heap-leaching. Heap-leaching is used by the big companies, and it is normally suitable for low grade ores.

Heap Leaching. Heap leaching is practiced at Konongo, Teberebie, AGC and Ghana Australian Gold Field, Tarkwa. The crushed ore is mixed with cement and made into pellets that are heaped on a leach pad covered with high-density polythene sheets 0.2 in. (or 0.5 mm) thickness. The heap is continuously sprayed with cyanide solution at pH 11 for about 30 days. The gold dissolves as the cyanide solution percolates gradually through the heap. The gold solution drains eventually into a collection pond and metallic gold is recovered by one of several methods available. Gold recovery is above 80 percent.

(a) Addition of Zinc Powder: Zinc in the form of powder added to the solution dissolves and replaces gold in the complex union. Gold metal precipitates out of the solution. The crude gold is purified by electrolysis, using impure gold as the anode and a strip of pure gold coated with a thin layer of graphite as the cathode.

(b) Carbon in Leach and Carbon in Pulp Methods: A solution of the gold cyanide complex is obtained as described before. The complex union is absorbed onto an activated carbon. After filtration the complex union is stripped off the carbon by chemical means and the resultant solution electrolyzed using steel wool as the anodes.

There is serious water pollution in the mining areas. Rivers and other water bodies that serve as the source of drinking water for the communities in the mining area or downstream from it complain of serious water pollution because of the mining activities. Recently there were reports of ‘galamsey’ operators having dug very close to railway lines somewhere in the Eastern Region, thus putting the entire operation of the Accra-Takoradi railway services into jeopardy. Galamsey operators also nearly destroyed a forest and game reserve in the Upper East Region. In the last two cases it took the intervention of the government, the police and the army to halt the operations.

Air pollution is another serious side effect. Gold mines that are located underground usually harvest the vein-type deposits. Gold in these deposits is associated with sulfur and arsenic and to some extent nitrogen compounds. These elements consume cyanide, the chemical that separates gold from its impurities. They must therefore be expelled before the cyanidation, and this is done by roasting the powdered ore. The heating converts the arsenic, nitrogen and sulfur into gaseous oxides that are contained in the emissions from the stacks of the furnaces.

Bio-leaching technology has been introduced in the past six years. If it catches on, this method hopefully will eliminate the need to roast ores. In the bio-leaching process some special bacteria are fed into the powdered ore; the bacteria feed on the sulfur and arsenic and give out quite harmless sulfate and arsenate products as their waste.

Ghanaians use not more than 15 percent of the total gold produced; the rest is exported for foreign exchange. We may assume that the difference between total production and total export is what is used locally (see Table 1).

The export earnings for a five-year period (1990-1995) from gold and other commodities are given in Table 2 on the next page. It is clear that since 1992 gold has been fetching the nation more foreign exchange than any other exportable commodity. Can we do without the foreign exchange from gold? The answer really depends on how much of this income stays in the country. My own guess is that at the moment not much stays because investors have to recover their costs and also to transfer their profits. The situation would have been different if there were major indigenous companies in the gold industry.

Total Gold 541,408 845,908 998,195 1,261,424 1,430,845 1,708,531 1,586,094

Production

Total Gold 539,110 844,922 997,763 1,210,474 1,435,475 1,689,47 1,584,380

Export

Export of 17,233 10,437 15,145 32,518 93,922 139,535 112,220 Small Scale

Mining

Source: Minerals commission, Accra

Cocoa Products 36.80 33.08 25.6 35.41 25.22 28.42 --

Gold 201.65 304.44 343.41 433.95 548.62 647.27 694.71

Diamond 16.55 19.24 19.33 17.27 20.37 14.76 13.11

Timber & 117.99 124.22 113.80 147.38 165.36 190.57 --

Timber Products

1990 1991 1992 1993 1994 1995 1996

Cocoa Beans 1,309.00 1,289.70 1,273.00 950.00 1,238.00 1,521.78 --

-$/tonne

Gold 383.10 364.60 345.00 358.50 382.20 383.12 432.00

- $/ounce

Diamond 26.00 29.00 28.00 31.20 28.40 22.88 23.42

- $/craft

The world gold price compared to other commodity prices has experienced relatively less decline in the last decade, and in Table 3 we can see the variation in prices of gold and cocoa over a five-year period: 1990-1995. However, the current price of gold at 318 US dollars per ounce is very low, to the extent that mines in South Africa are operating at a loss. One wonders how far Ghana is from their situation.

Gold is used locally mainly for jewelry, since other industries that use gold as raw material are not functioning in Ghana. The use of gold for jewelry is universal, and recent reports indicate that gold consumption in India and China has gone up considerably. Indeed, there is the potential for higher growth if the laws governing jewelry shops are relaxed in China.

Gold for jewelry links the past of Ghana to the present. The tribes that constitute modern Ghana had once fought one another over ownership of land reputed to be rich in gold. In pre-colonial times, especially in the eighteenth century, the Ashanti State in particular fought and conquered a number of other states to the south, north, east and west for their gold, among other things. The conquest to the south was critical because it enabled the Ashantis to gain access to the coast in order to trade in gold with Europeans.

Can consumption of gold for cultural purposes constitute a vibrant, self-sustaining, commercial exploitation of Ghana’s gold deposits? It can if we bring gold down to the reach of the average Ghanaian. Chiefs in Ghana cannot conspicuously consume any more gold than they are doing now since the metal is heavy. But more Ghanaians might be encouraged to wear gold. There is no overt cultural disrespect to the priority of the chief’s consumption of gold provided no one wears more of it than he does on festive occasions when the chief is in his regalia.

What we need, above all, is to learn the modern methods of mining and to adopt them. It is likely that we shall be kinder to our own environment than others would be, and also that we shall keep the earnings in the country for the national good.

1. Basil Davidson, F.K. Buah and J.F.A. Ajayi, The Growth of African Civilization — A History of West Africa 1000-1800 (London: Longman, Green and Co., 1966).

2. Handbook of Chemistry and Physics, 53rd edition, 1972-73 (Ohio: Chemical Rubber Publishing Co.)

3. K. Barning, "Mineral Investment Policy in Ghana and its Impact on the Mining Development," Proceedings of symposium on gold mining in Ghana (Accra: Minerals Commission, 1992).

4. P.C. Acquah, "Emerging Trends in the Gold Ore Processing and Some Related Environmental Issues in Ghana," Accra: Minerals Commission; "The Use of Processing Equipment in Gold Exploration in Ghana," Proceedings of symposium on Gold Exploration in Tropical Rain Belts in Southern Ghana, K. Barning (ed.) (Accra: Minerals Commission); "Cyanide Heap Leaching of Low Grade Ores in Ghana," paper delivered at the Biennial Conference of the Ghana Chemical Society, April l990.

5. K. Ameyibor and M.B. Wiredu, Chemistry for Senior Secondary Schools (London: Macmillan, 1990).

6. P.C. Acquah, op.cit.

7. P.C. Acquah, "Cyanide Heap Leaching of Low Grade Ores in Ghana," op.cit.

8. Daily Graphic, August 18, 1997 (Accra: The Daily Graphic Corporation).

9. S.K. Amasa, (1975) Environmental Health Perspective, 12, p. 131; E.H. Amonoo-Neizer and M.K.E. Amekor, (1993) Environmental Health Perspective, 101, p. 46; D. Nyamah, E.H. Amonoo-Neizer and K. Acheampong, (1994) Ghana Journal of Chemistry, 1. 10, pp. 431-435; D. Nyamah and J.O. Togbor, (1986) Water Resources, 20, p. 1341.

10. K. Amasa, op.cit.

11. Daily Graphic, August 19, 1997 (Accra: The Daily Graphic Corporation).

12. The ceremony by which a chief is formally recognized is called an enstoolment. In certain respects the chief’s stool may be loosely regarded as the Ghanaian counterpart to the British king’s crown.