Recommendations for wire-line calipers

During the first quarter of 2005, a due diligence study on caliper techniques, was conducted at a De Beers<br>operation. The purpose of the study was to determine the accuracy and precision of a newly acquired GeoVista 4<br>arm caliper for down-hole measurements. The survey was conducted in one of the large diameter drill holes (LDD)<br>drilled as part of the Resource Extension Project currently underway at the operation. These holes are being used for<br>resource evaluation, with the grade analysis performed on samples in the range of 1 tonne. The reason for acquiring<br>the caliper was to obtain more accurate estimations of down-hole sample volumes, which has the effect of<br>increasing confidence in grade values.