The company said it sampled 58 tons of ‘fresh high-interest kimberlite’ and 62 tons of kimberlitic material from a residual stockpile, known as 'Dump E'.
A total of 87 macro diamonds were recovered from the fresh kimberlite with a modelled grade of 50 carats per hundred tonnes, while 24 macro diamonds came from Dump E with a modelled grade of 16 carats per hundred tonnes.
"This bulk sampling campaign, which was carried out with the company's royalty mining contractor Eurafrican Diamond Corporation, had two objectives,” James Campbell, Botswana Diamonds' managing director said in a statement.
“The first was to test the grade of the fresh kimberlite and the second was to confirm the grades of one of the mine dumps. Both were achieved, and proof of the fresh kimberlite grade paves the way for further exploration work on Marsfontein to target potential blows.
“The kimberlite grade is aligned with those achieved at Klipspringer mine and Thorny River, which are both nearby, indicating the considerable extent of the kimberlite dyke system.”
Campbell added that the company will investigate options for the exploitation of the dumps, once the nationwide coronavirus lockdown is lifted and “a sense of normality” returns to diamond markets.