The two parcels were recovered by then license holder Auridiam Botswana in 1999 and 2000 and they suggest that relatively large stones can are present in the BK16 samples.
Tsodilo transferred the stones to I. Hennig & Company in Gaborone for counting and weighing after they had been kept in a safe deposit box at First National Bank's main office in Botswana’s capital since their recovery.
Parcel 1 consisted of 25 diamonds weighing 4.93 carats with 4 stones weighing more than 0.5 carats each, accounting for 2.96 carats or 59% of this parcel's weight. The stones were recovered from five 12.25 inch diameter holes via reverse circulation drilling.
Parcel 2 consisted of 83 stones weighing 16.98 carats including 3 stones weighing 1.69, 1.12 and 0.98 carats each. These stones were retrieved at 30 meters depth into the kimberlite body via a mining shaft into the highly diluted basalt breccia which, covers part of the pipe.
"We are fast tracking the evaluation of the BK16 kimberlite having just finish the diamond core drilling program of 3,600 meters only a few months after being granted the license. We are currently completing the geological model in order to plan for the large diameter drilling (LDD) program scheduled for later in the year. We have also acquired a mobile dense media separation ('DMS') treatment facility in Letlhakane which we will be upgrading over the next few months. Our plan is to obtain an initial sample of some 2,500 to 3,000 tonnes to ascertain grades of the different kimberlite phases and to acquire more stones for valuation purposes. To view these previously recovered stones is very exciting and while one cannot attach too much significance to the results of these limited samples, it is important to take notice of the presence of relatively large stones in the BK16 samples", said Tsodilo’s president and COO, Dr. Michiel de Wit.
The BK16 pipe is part of the Orapa Kimberlite Field (OKF), which is made up of at least 83 kimberlite bodies, varying in size from insignificant to the 110 hectare AK1 kimberlite which is the Orapa Mine.
In 2014, the Orapa Kimberlite Field produced 13,355,292 carats and over the past decade, Botswana diamond mines have produced an average of 27 million carats annually. Botswana is the world's largest producer of diamonds by value.