The Williamson diamond mine in Tanzania – in which Petra Diamonds and the Tanzania government hold 75% and 25% stakes, respectively – has posted a 53% increase in revenue for the year ending in June 2010 according to a report published by the diamond company last week.

AllAfrica.com reports that the Williamson mine generated $14.4 million in the year reported compared to $9.4 million in the year ending June 2009 – a fact attributable to increased diamond recovery. Production for the period reported stood at 91,901 carats of rough diamonds compared to 75,045 carats for the previous year. Diamonds from the Williamson mine sold for an average per-carat price of $157.

Petra Diamonds CEO Johan Dippenaar said that the company was pleased with the quality of diamonds mined at Williamson and hoped that a new plant and processing techniques would contribute to greater diamond recovery and revenue. Expansion work on the mine has begun and production is expected to reach 180,000 carats annually.

The Williamson diamond mine is based on the Mwadui kimberlite, the largest continuously mined pipe in the world. The kimberlite has been yielding diamonds as an open pit mine since 1940.