251 The largest diamondiferous kimberlite in the world, page-76

"In Angola, production at Somiluana, in which Trans Hex holds a 33% stake, amounted to 72 041 carats (2013: 41 313 carats) due to an increase of 20,9% in volumes treated and a 44,2% increase in grade. Total sales amounted to US$32,4 million at an average price of US$478 per carat (2013: sales of US$14,9 million at an average price of US$352 per carat). Somiluana’s operating margin was 32% (2013: -20%) and the Mine generated net profit of US$10,5 million (2013: loss of US$3,0 million). Repayments of US$1,0 million were made to Trans Hex against the outstanding investment amount and the balance of cash generated was retained to develop the Mine."

http://www.transhex.co.za/images/stories/pdf/THG Annual Results 31 March 2014.pdf

32m Sales
10.5m Profit
1 million payed back.

At that rate it will take around 30 years.