The Williamson diamond mine, also known as the Mwadui mine, is a diamond mine in Tanzania. It was well-known as the first diamond mine outside of Africa. This mine was established by Dr. John Williamson of Canada in 1940. It has produced 19 million carats of diamonds since its inception. The mine is currently 75% owned by Petra Diamonds and 25% by the Tanzanian government.
The mine is currently 300 feet deep, employs 1100 people and is considered the “largest economically exploitable diamond-bearing volcanic pipe in the world”.
Currently, the mine produces six carats of diamonds per hundred tons of ore. At the beginning, the mine produced sixty-two carats per hundred tons. A 54 carat flawless pink diamond was found at the Williamson Diamond mine.
In 1938, Dr. Williamson used the Mabuki diamond mine as his base for prospecting diamonds in the area. By the 1950’s, the Williamson diamond mine expanded into the largest diamond mine in Tanzania with a large labor force and state-of-the-art mining equipment. He managed the mine until his death in 1958 at the age of 50.
On August 13, 1958, Williamson’s heirs sold the mine for 4 million GBP in an equal partnership between DeBeers and the government of Tanganyika.
In 1971, “the government nationalized the mine”. It was not as productive in the 1980’s under the government leadership.
In 1994, DeBeers bought 75% of the Williamson mine. Today, the mine is considered a “marginal performer” but DeBeers has found some avenues for development which will make the mine viable well into the future.