Guide To African Mining
Botswana
Botswana has many of the geological characteristics of South Africa, and geologists have sought extensions of the Witwatersrand reefs and Bushveld complex across the country. Gold and platinum exploration have not resulted to date in the finding of commercially viable deposits, what has been found is significant diamond bearing kimberlites. Over 200 kimberlites have been identified. With much of the country thickly covered by Kalahari sand and calcrete geophysical exploration techniques used elsewhere are almost useless. As such, kimberlites are sought by searching for indicator minerals brought to the surface by termites.
Botswana is heavily dependent on diamonds for its GDP and exports, with gem diamonds representing about 80 % of exports. Diamond mining is undertaken by Debswana, a joint venture between the government and De Beers. It operates three mines, Orapa, Jwaneng and Lethakane, and has a capacity of up to 20 m carats. Jwaneng is the world's richest diamond mine. Other than diamonds, few minerals are produced - Bostswana RST at Selebi Pikwe produces 40,000 tpy of copper/nickel/cobalt. There are large coal reserves of 27,000 mte mined at Morupule colliery. Molopo Mining and Botswana Diamondfields are involved in exploration.
Namibia
Namibia's principal diamond wealth has been the onshore ancient beach deposits stretching 150 km north from the Orange River mouth. The best of these deposits are now exhausted. As a result of the 1923 Halbescheid Agreement, De Beer/Consolidated Diamond Mines has an exclusive right to prospect and mine for diamonds in the Sperrgebeit - 100 km wide stretch of coastline stretching from the Orange River to 70 km north of Luderitz.
The sea diamond deposits off the coast of southern Namibia and the northern part of South Africa's west coast are now attracting interest. The occurrence of marine diamond deposits is believed to be derived from the erosion of kimberlite pipes intruded into the Kaapvaal craton during the cretaceous period. It is estimated that up to 1.5 km of the vertical lithology has been removed from the central plateau of southern Africa since the cretaceous period, liberating some 10 bn carats. The diamonds, estimated to total some 1.5 bn to 3 bn of mainly gem quality stones, were washed out to sea from the inland kimberlite bodies along the ancient and current river courses of the Orange, Vaal, Buffels and Oliphants rivers over millions of years. This was the same process of alluvial erosion that deposited the huge quantities of high value stones onshore between Luderitz and Oranjemund which have been mined over the past 75 years. The diamonds occur in seabed terraces of the continental shelf from shallow water immediately adjacent to the coastline out to depth of some 125 m, their distribution having been determined by changes in the river systems and sea levels over millions of years.
Africa: Diamond Mining
Overview
Africa is the world’s largest producer of diamonds, producing as much as 50% of global production. To date, Africa has produced over 75%, in value, of the world's diamonds with more than 1.9 billion carats worth an estimated $US 158 billion mined. Mining activities are centered around South Central Africa, with diamonds being produced primarily from kimberlite mines (South Africa, Angola, Ghana, Tanzania, Lesotho and Botswana), followed by alluvial dredging operations (Angola and South Africa) and offshore marine diamond activities (South Africa and Namibia). Most of West Africa’s diamond production in the area originates from fluviatile placers and only on a minor scale from eluvial deposits or from altered kimberlite pipes. Virtually all mines are relatively small-scale operations mainly run by artisanal miners, except for the Akwatia mine in Ghana and the Aredor project in Guinea.
Main artisinal production is centered around the following areas:
- East-central C.A.R., centred around Mouka, Ouadda and Yalinga,
- south western CAR,
- the Birim Diamond Field in Ghana,
- the Yengema area in Sierra Leone,
- south-central Guinea around Gbenko and
- the Lofa River in north-western Liberia.
In most cases, the primary sources of these alluvial diamonds have not been traced yet, therefore making an attractive exploration target.
The discovery of potential diamondiferous kimberlites in Mauritania by Rex Diamonds and Ashton is rated as exciting discoveries and could yield potential. The continuing conflict in Angola between Unita rebels and Angolan Government troops (MPLA) is beginning to spill over into neighboring Namibia and Zambia. As a result, legitimate efforts to produce diamonds in Angola proved yet again impossible, with Ashton, DiamondWorks and Southern Era struggling. The United Nations wishes to prohibit the purchase of the Angolan stones by the CSO in order to strangle the diamond trade in Angola, which apparantly bankrolls Unita’s war effort.
South Africa
South Africa produced 10.7 million carats in 1998, primarily from De Beers operated mines and offshore marine operations. Southern Era’s mining operations at its Klipspringer operation continue well now that the Marsfontein issue has been settled with De Beers earning 60% and Southern Era the remaining 40%.
Botswana
Botswana has the strongest economy in Africa, and also has the highest GDP / person in Africa. The dependence on diamond mining activities on Botswana’s economy is great. Debswana (De Beers Botswana) is a joint company with the Botswana Government. Debswana currently operate three large open cast operations, which produce nearly all of Botswana’s 20 million carats per year.
Namibia
Diamond mining is one of Namibia’s main export products, contributing $US 390 000 per annum. This represents a total of 1.5 million carats, most of which were produced by De Beers, Namibian subsidiary, Namdeb. However, new producers in Namibia are Canadian listed Namibian Mining Corporation (Namco) which has made impressive progress with its marine mining operations. ODM also has significant operations in Namibia, producing 57 000 carats in 1998. An estimated 1500 million carats of reserves are located in the marine environment. Recent improvements in marine mining methods, led by De Beers Marine, Namco and Benco, will make these operations more lucrative. The entire coastline of Namibia is currently being explored / exploited for marine diamonds deposits. With the rapid influx of diamond exploration companies, in particular marine operators, Namibia has legislated a new Diamond Act, which will further control and regulate the production and sale of rough diamonds.
Angola
Endiama, Angola’s state run company still produce a majority of Angola’s diamonds, although large amounts of production are still being produced by UNITA and artisinal workers (of which some production is purchased by UNITA). Several foreign companies are involved in the development or exploration of potential kimberlitic and alluvial deposits. Unfortunately the security situation has not assisted in this process. It is not known when hostilities will cease, if at all. Angola produced just over 5 million carats in 1998, at an average price of $US 136 /carat.
Democratic Republic of Congo (DRC)
Diamond production from the DRC continues with 21 million carats being produced in 1998 making the DRC the second largest producers of diamonds after Botswana. Artisinal production contributes more than two thirds of production.
Mining Companies active
De Beers is the largest diamond mining and marketing company in the world and is active with 19 operational mines in Botswana, Namibia, South Africa and Tanzania. Mining methods range from underground (as at Finsch in South Africa) through open pit (Venetia) to alluvial and marine mining methods. De Beers Marine has 8 marine mining and exploration vessels, of which 6 are in active in Namibia with the remaining in South African waters. These mines between them account for around half of the world's output of rough gem diamonds by value. De Beers has concluded a deal with Venetia mine in South Africa where it purchased Avmin’s 87.5% share in the Saturn Partnership (which entitles 50% of pre tax profits).
A relative newcomer to South Africa, Southern Era has rapidly become the producer of the best quality diamonds in the world from its operations at the Klipspringer mine in South Africa. Although high grade, the life of mine on Klipspringer is not known. Its Angolan operations, however, have been halted due to the worsening security situation in Angola. The development of the Camafuca pipe in the diamond rich Lunde Norte area of Angola (the world’s largest economic kimberlite at 160ha) is being developed via a 50% share in the project.
A planned merger between Ocean Diamond Mines (ODM)and Trans Hex International has been completed. Between the two, an annual production of around 240 000ct is envisaged. Trans Hex has acquired Gem Diamonds a South African black empowerment company. Acquisition by Namco of ODM in what could turn hostile has been in the air for some time. Trans Hex is primarily carrying out alluvial operations in Namibia and South Africa. Recent marine terrace deposits have been located along the Skeleton Coast in Namibia.
Benguela Concessions (Benco) is solely operating in offshore marine diamond mining just south of the Orange River mouth in South African waters. Benco produced 25 000 carats in 1998 fetching an average price of $US 140 / carat. The fully equipped diamond mining and recovery vessel the Moonstar has been in operation for a coupe of years and has had several teething problems. Merger discussions between ODM, Transhex and Benco in 1999 failed.
Rex Diamonds has mining concerns in South Africa and Sierra Leone, with discoveries of kimberlite in Mauritania. Rex’s mines produce good quality stones, on average fetching around $US 220 / carat.
Petra Diamonds has a diversified range of interest in diamonds in South Africa and Angola. Petra won the tender to control Alexcor (which produced 130 000 carats at an average price of $US 260 / carat) the state owned marine diamond mining company at Alexander bay, near the border of South Africa and Namibia.
Firestone Diamonds has made some successful finds along their palaeo Orange River operations in South Africa. The company’s Namaqualand marine operation is continuing.
Falconbridge / De Beersare currently investigating the low grade Gope deposit in the Central Kalahari. Environmental issues are paramount here, as the deposit is located within the Central Kalahari Game Reserve.
Approval of the construction and modification of a second mining vessel will see Namco’s production increase to 500 000ct/year. Namco is rapidly emerging as the second largest marine diamond mining company after De Beers Marine.
Diamond Fields International (DFI)has some small-scale shallow workings with sampling being carried out over other concessions, particularly along the northern coast of Namibia.
DiamondWorks has extensive diamond mining operations in Angola, Sierre Leone, CAR and Lesotho. The company has two producing operations in Angola with bulk sampling of a major kimberlite in progress. It also operates Sierre Leone’s only diamond mine. Sierra Leone produces some of the world’s best quality diamonds. However, operations in the country have been erratic due to the continuing civil war. DiamondWorks has teamed up with Lyndhurst (controlling interest in CAMCO and CADCO who produce most of Central African Republic’s diamonds) to assess and exploit some of the CAR’s high quality alluvial diamonds.
Ashton, the operator of the world’s largest producer, Argyle Diamond mine in Australia, is developing a mine in Angola and has projects in Mauritania, Cameroon, Mali and South Africa. New Mining Corporation / Letseng Diamonds Guernsey are re-opening Lesotho’s only mine previously owned by De Beers, making the project one of the world’s highest altitude diamond mines.