Petra Diamonds Limited Alto Cuilo – operations update Petra Diamonds Limited (“Petra” or “the Company”), the AIM quoted diamond mining group, announces an operations update with regards to the Alto Cuilo project in north eastern Angola. Project update Since the Company’s last Alto Cuilo update announcement on 8 September 2004, diamond core drilling has continued at a further fifteen sites in the area of the Mussunuige-Luangue river interfluve (“the ML Complex”). All fifteen sites have intersected kimberlitic material, with total drilling in excess of 2,571 metres having been undertaken since the last update, giving a total of 5,110 metres drilled to date. Core samples from these additional sites have also been analysed by an independent expert from Rhodes University, South Africa. As per the previous samples sent for analysis from other drill sites, these were confirmed as kimberlitic in nature. Over one thousand kilogrammes of kimberlitic material has been collected for further diamond analysis work at a Canadian research facility. Authorisation for the export of this material has been requested from the Angolan authorities.The drilling has resulted in intersections of kimberlitic material ranging from 33 metres to 160 metres in true thickness. The drilling will continue with the objective of further delineating the size of the kimberlitic deposit.The drilling carried out to date on anomalies 4 and 13 has led to the Company calculating a deposit of kimberlitic material of approximately 115 million tonnes. It is expected that the continuing drilling programme will increase the size of this deposit. This is only an estimate of tonnage potential based on wide spaced drilling and does not constitute a reserve or resource for mining. Sampling for macro diamond grade potential of this body still has to be undertaken. Sampling of the alluvial deposit and adjacent kimberlitic exposures has produced many gem quality diamonds. The kimberlitic exposures are not connected to the kimberlite currently being drilled.The total number of known kimberlite occurrences in the ML Complex, on which activities are currently focused, is now twelve. The ground geophysics work carried out in August has been processed by independent experts in South Africa. Their interpretation suggests a kimberlitic complex of approximately 70 hectares in area existing around anomalies 4, 13 and 14 within the ML complex. The diamond recovery plant (MB100 and DMS) was commissioned on 23 September 2004. The plant has run from that date with steadily improving results. Since commissioning, alluvial gravels from the Luangue river, as well as kimberlitic material from the AC2 complex, have been treated by the plant and as of 23 November 2,665 macro diamonds have been recovered with a total mass of 679.8 carats. This includes numerous gem quality diamonds, including stones of 10.35 and 9.61 carats from kimberlitic material. The bulk sampling work on the alluvial deposits will enable the Company to determine a representative diamond value and grade for the alluvial deposits in the current area of focus. Kevin Dabinett, Chief Executive Officer of Petra, comments, “As we have said in the past we believe that at Alto Cuilo we are working on a major diamond deposit. Anomalies 4 and 13 are proving to be a large body of kimberlitic material and recently dispatched samples will help with an understanding of the diamond potential. We will now move forward to ascertain the economic value of the alluvial deposits, progress the drilling and sampling work on the kimberlite complex and commence the exploration programme on the rest of the Alto Cuilo concession outside of the ML Complex area.” ~ Ends ~ For further information, please contact: Kevin Dabinett / David Abery Petra Diamonds Tel: +27 11 467 6710 Justine Howarth / Cathy Malins Parkgreen Communications Tel: +44 20 7493 3713
