Tanzania only has one operating diamond mine at Mwadui, south east of Mwanza. The Williamson diamond mine is operated and owned by De Beers (70%) and the Tanzanian government. The Mwadui kimberlite was one of the world’s largest producing kimberlite pipes. The mine has been in operation since the 1930’s and has produced as much as 2Mct. Production has dropped significantly, due to flooding of the mine coupled with exhausted ore reserves. The mine produced 166,000 carats in 2003 an increase from 2002 but a decline from the 320,000 cts in 2000.

Exploration teams are looking for other economically viable kimberlites in Tanzania before the Mwadui pipe is exhausted. From 1940 – 1970, Williamson Diamonds undertook an extensive exploration program covering nearly all of Tanzania. More than 300 kimberlite pipes were found, of which 60 were found to be diamondiferous. However, details on methods employed in locating and determining the grade and quality of the kimberlites is poor. Hopefully modern methods of locating and evaluating kimberlites should accelerate the discovery of more diamondiferous kimberlites.

Participating Organisations
De Beers Investments

De Beers has a 70% share (Tanzanian Government 30%) in the Williamson Mine located near Mwadui in north central Tanzania.