African Diamonds’ shares added 3.4%Tuesday, after it announced a potential increase in the value of its AK6 diamond mine in Botswana.

According to the Irish Times, the diamond miner said the latest assessment of the diamond mine stood at $162 per carat – $23 a carat higher than that used in its current studies. The valuation further indicated a possibility for a $200-a-carat value at production. African Diamonds said the project is on target for a late 2011 start-up.

Africa Diamond further said it was instating several changes to its diamond processing plant in order to minimize diamond breakage and allow the recovery of diamonds up to 350 carats in size.

A valuation of 1,760 carats of diamonds from AK6 was undertaken in Geneva by Mercury Diamonds: “Overall the diamonds from AK6 are deemed to be of very good quality and very attractive to diamond buyers. Colors are generally very white, and the samples showed numerous examples of ‘blocky’ makeable and strong crystal forms that tend to lead to strong polished yields and demand a premium,” said the report.

African Diamonds has a near 30% stake in AK6.