Diamond exploration intensifying close to mine that paid for itself in 3.5 days

London- and Botswana-listed Botswana Diamonds, which is funding diamond exploration on three sites in South Africa, expects to declare an inferred resource by year-end at its Thorny River project in Limpopo, which is located very close to the Marsfontein mine that had an astonishing three-and-a-half-day payback. The De Beers Southern Era Marsfontein joint venture of 1998 to 2000 had an average grade of 172 carats per hundred tonnes (cpht) and a diamond value of more than $200/ct – but it was only 0.4 ha in size.