document: The Jwaneng mine , on the fringes of the Kalahari desert in Botswana , is known as ' a gem in the world of gems ' because it almost certainly is the richest diamond mine in the world - at least in terms of the value of the stones it yields . Jwaneng 's position is being reinforced by a USDollars 160m expansion programme at present being completed three months ahead of schedule and under budget . Meanwhile , 160km west of Kimberley in the northern Cape Province of South Africa , another diamond mine , the Finsch , where operations started in 1964 , has been given a new lease of life . Having dug an open pit 423 metres deep , miners have now gone underground . Mr Simon Webb , the general manager , says that the underground development has given it another 35 to 40 years of life . All this goes to show that De Beers , the South African group that dominates world trade in rough -LRB- uncut -RRB- diamonds , still has complete faith in its ability to maintain stability in the diamond market despite short-term difficulties such as those the company is experiencing with Russia . It also remains intent on maintaining its diamond output even though its 100-year-old mines at Kimberley are now running down . The South African group believes that its control of at least 50 per cent of world diamond production gives it a powerful base from which to negotiate with the other producers who have marketing contracts with De Beers ' Central Selling Organisation , In Botswana De Beers controls half of Debswana , the company that owns the Jwaneng mine , with the government owning the rest . The value of Jwaneng to Botswana can not be overstated . It , and the country 's two other -LRB- smaller -RRB- diamond mines , between them account for 50 per cent of the government 's revenue and 40 per cent of the country 's gross domestic product . No wonder Jwaneng 's company slogan is Re phtas imisa Botswana , which translates as ` We make Botswana sparkle ' . Production started at Jwaneng in 1982 . Now a so-called fourth stream is being completed which is adding one-third to processing capacity . In turn , this means a 21 per cent rise in the number of carats produced . Last year the mine treated 5.8 m tonnes of ore which yielded 8.546 m carats of diamonds , well below the 1992 output when the 5.77 m tonnes treated gave up more than 9m carats . Jwaneng 's open pit has reached a depth of 190 metres . Already it is 2kms long and 1km wide . Mr Loz Shaw , chief geologist , says drilling down to 600 metres shows there are still plenty of diamonds at that depth and so the pit will go down at least that far . Mr Derrick Moore , the general manager , says this indicates mining in the open pit will last another 35 years - ` and then we might go underground ' . If experience at De Beers ' wholly-owned Finsch mine in South Africa is anything to go by , planning the underground development at Jwaneng might already have started . Planning for the underground mine at Finsch started in the 1970s and the first work began in 1979 . Yet the bottom of the Finsch open pit - 423 metres - was not reached until 1990 . Unfortunately , things did not go completely as expected when underground mining started , to some extent because the development was designed by a management whose expertise was mainly in open pit mining . However , Mr Mark Button , mining superintendent , says : ` Finsch has come of age as an underground mine after two years . Our costs compare with the best in the group . ' Among the innovations that have helped Finsch achieve its objectives are some remote-controlled LHD -LRB- load-haul-dump -RRB- trucks which are similar to radio-controlled toy vehicles or boats . Using VHF radio signals , a driver can stand back and send a truck on its own to dig out material from areas between the old pit wall and the underground development that would not otherwise be mined because of the dangers involved . When , as occasionally happens , rock crashes on to the LHD trucks , it is relatively simply to haul the vehicles out virtually undamaged . Mr Webb says the objective is to mine down to a depth of 830 metres , at which point there are not enough diamonds left in the ground to make recovery viable . Finsch - named after the discoverers , Messrs Fincham and Schwabel , who stumbled across the kimberlite pipe containing the diamonds when actually they were looking for asbestos - is one of the victims of the present turmoil in the diamond market caused mainly by uncertainties about Russian exports . About 500 of its 1,900 employees were laid off in August 1992 . It is mining only five days a week at present and processing on four days . Last year Finsch mined 2.68 m tonnes and recovered 2m carats of diamonds compared with 4.7 m tonnes mined and 3.446 m carats in 1992 . Mr Webb suggests 1994 output will be similar to last year 's . But when market conditions improve , production can be brought back up to previous levels in about six months .
extractive_keyphrases: jwaneng mine south african group diamond output world diamond production central selling organisation diamond mines underground mine russian exports botswana de beers
abstractive_keyphrases: wholly-owned finsch mine