Petra Diamonds Limited has released a sales and production trading update for the year ended June 30. Full financial results will be released on September 20, 2011. According to the newest numbers, the company's gross mine revenue is up 24% to $220.6 million from the previous year's $178 million. Excepting the sale of the $35 million Cullinan Heritage diamond in 2010, revenue is up 55%. The increase is attributed to the growing price of rough diamonds. The gross carats sold were up 4% to 1,174,825.

However, gross production was down 4%. The company attributes the lack of growth to its shift in focus from volume to value; the planned cessation at the main pit at Williamson; the planned depletion of high-grade optical sort plant material at Cullinan; unexpected lower volumes from Kimberly Underground; and heavy rainfall.

An agreement reached with De Beers for Petra to acquire the Finsch diamond mine in South Africa is expected to double the company's annual carat production, increasing the resource base to more than 300 million carats valued at approximately $56.5 billion.

Meanwhile, the company reports that it is on track to reach its goal of doubling production in the fiscal year 2012, with its targets climbing to 4 million carats in 2014 and 5 million by 2019.