As the world ’ s largest diamond mine by area , the Orapa diamond mine is located 240km west of Francistown city in Central Botswana . The open-pit mine is estimated to contain 85.7 million carats of diamond reserves . Orapa commenced production in 1971 and underwent expansion in 1999 to double its previous capacity . Owned and operated by Debswana , a partnership between the De Beers Company and the government of Botswana , the site is the oldest of the four diamond mines operated by Debswana .

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