Petra Diamonds Regulatory News (PDL)

20 Dec 2006 13:09

Petra Diamonds Ld20 December 2006 For Release 20 December 2006 Petra Diamonds Limited Alto Cuilo; Bulk Sampling Update Petra Diamonds Limited ("Petra"), the AIM-quoted and ASX-listed diamond mininggroup, announces an update with regards to the bulk sampling campaign at projectAlto Cuilo ("Alto Cuilo") in Angola. The bulk sampling campaign is an importantpart of the exploration programme at Alto Cuilo as it will provide key datarelating to grade and value per carat. Highlights • The first microdiamond results from representative drill cores sent for external specialist analysis have given encouraging microdiamond counts • Ongoing laboratory analysis of drill core from additional kimberlites continues to give diamond indicator mineral chemistry ('minchem') results consistent with some of the world's economic kimberlites • Taking into account the minchem results available to date, the ranking of kimberlites has been revised for the large diameter ("LD") drilling campaign which is underway • Core drilling at Alto Cuilo continues at the same time as the LD drilling programme and has made further solid progress, with the discovery to date of 71 kimberlitic occurrences (31 October 2006: 62 occurrences) out of 80 targets drilled, an exceptional success rate Bulk sampling A second technical target prioritisation meeting was recently held where allminchem results received to date were tabled and kimberlites re-prioritised forLD drilling. The revised ranking is as follows:Kimberlite Current Ranking Previous Ranking Surface area (hectares) estimated from aeromagnetic signatures (20.12.06) (20.6.06)AC 63 1 - 20AC 60 2 1 30AC 98 3 2 175AC 71 4 - 32 To date, 71 kimberlites have been intersected and the minchem results receivedin respect of 35 of those kimberlites. The minchem results received for certainof the kimberlites recently analysed have highlighted new occurrences of highinterest. It is significant to note that where there is corresponding microdiamond datafor representative kimberlite material (the lead time for microdiamond analysisbeing much longer than that for the minchem analysis), the microdiamond datacorroborates the minchem result. For AC63 and AC98, which have been highlyranked on minchem, the microdiamond results are also encouraging andcorrespondingly kimberlites with poor minchem have also reported a poormicrodiamond result. Based on the relationship between minchem and microdiamondresults, AC63 has now been ranked as priority number 1 in the LD drillingcampaign. As more results are accumulated, revisions to the priority rankingscan be expected. Drilling at AC16, the first kimberlite to be accessed by the LD drill rig, hasbeen successfully completed. Eight sites were successfully drilled to depths inexcess of 350 metres. All samples have been stockpiled and await commissioningof the 10 tonne per hour Dense Media Separation ("DMS") sampling plant laterthis month. On completion of the LD drilling at AC16, the drill rig was serviced andcalibrated by a Prakla engineer and relocated and set up at AC63, where drillingcommenced last week. Although AC16 has now been relegated in priority withregards to minchem data and does not now rank in the top as a high prioritytarget, it was drilled first as the LD drill needed to be tested on a kimberlitethat offered straightforward logistical conditions and good infrastructurallocation to ensure proper commissioning, learnings and operational testing. Ends Notes 1. The information in this update that relates to Exploration Results, MineralResources or Ore Reserves is based on information compiled by Jim Davidson, Pr.Sci Nat (reg No 400031/06), who is a Member of the Geological Society of SouthAfrica, a 'Recognised Overseas Professional Organisation' ('ROPO'), included ina list promulgated by the ASX from time to time. Jim Davidson is a full-timeemployee of the Company and has sufficient experience which is relevant to thestyle of mineralisation and type of deposit under consideration and to theactivity which he is undertaking to qualify as a Competent Person as defined inthe 2004 Edition of the 'Australasian Code for Reporting of Exploration Results,Mineral Resources and Ore Reserves'. Jim Davidson has given his written consentto the inclusion in this announcement of the matters based on his information inthe form and context in which it appears. Jim Davidson is the Qualified Personfor the purposes of the AIM Guidance Note on Mining, Oil and Gas Companies datedMarch 2006 2. It should be noted that the potential quantity in this report is conceptualin nature, there has been insufficient exploration to define a Mineral Resourceand it is uncertain if further exploration will result in the determination of aMineral Resource. For further information, please contact: Parkgreen Communications, London Cathy Malins / Annabel Leather Tel +44 20 7851 7480 This information is provided by RNS The company news service from the London Stock Exchange