At 146 hectare in area at surface level, it ranks as the largest economically exploitable diamond-bearing volcanic pipe in the world.

The diamond industry of Tanzania in the 1930s was characterized by a scattering of very small mining operations that were insignificant in the economic makeup of the country.

In 1940 he discovered the Mwadui kimberlite pipe;[1] over the next several years he developed the mine, although he was hindered by difficulty in procuring equipment and raising funds due to World War II.

Williamson's heirs sold the mine[1] for about £4 million GBP to an equal partnership between De Beers and the colonial government of Tanganyika on August 13, 1958.

Although details are unknown, De Beers and other diamond industry players speculate that mine performance deteriorated significantly in the 1980s under government management.

Since 1994, De Beers has acted to improve the performance of the Williamson diamond mine by trimming the work force, making capital investment in equipment, and bringing in expertise in technology, technique, and exploration.

In September 2008, Petra Diamonds Ltd agreed to acquire the Williamson Mine from De Beers and completed the acquisition in February 2009.

These included public swimming pool, tennis and squash courts, soccer field, athletics track, golf course and yacht club.

The hospital used to treat the mine employees for free, and poor people from neighbouring areas could take treatment there at nominal charges.

[6][7] NGO RAID claimed evidence of harm by contracted guards who shot locals on the concession, including 10 killings and 50 injuries since 2009.

[9] Initial internal investigations found record of only one live-fire incident during the alleged window, alongside other use of "reasonable force" against illegal miners.