Reserve & Resource Increase

Petra Diamonds Ld 08 October 2007 For release 8 October 2007 AIM: PDL Petra Diamonds Limited South Africa - substantial increase in Reserves and Resources Petra Diamonds ('Petra' or 'the Company' or 'the Group') announces an updated statement of the Group's South African reserves and resources. The statement has been prepared in accordance with JORC and is in respect of the Koffiefontein, Helam, Sedibeng and Star mines. Highlights • Updated carat base of 9.33 million carats attributable (11.38 million carats gross), an increase of 101% on previous statement (May 2005: 4.64 million carats attributable) • In-situ value of US$1.5 billion attributable (US$1.9 billion gross) • JORC compliant attributable reserves increase 66% to 2.95 million carats (May 2005: 1.77m carats) • JORC compliant attributable resources increase 123% to 6.38 million carats (May 2005: 2.86m carats) • Increase due to the acquisition of Koffiefontein and additional kimberlite fissure units included in the total mineral resource SUMMARY OF ATTRIBUTABLE RESERVES AND RESOURCES COMBINED SOUTH AFRICAN OPERATIONS Contained Contained Tonnes Grade Diamonds Diamonds May Category October 2007 October 2007 October 2007 2005 (millions) (cpht) (millions) (millions) Ore/Diamond reserves Proven 18.397 8.3 1.524 0.558 Probable 1.993 71.3 1.422 1.217 Sub-total 20.390 14.5 2.946 1.775 Diamond resources Measured 40.674 2.9 1.169 - * Indicated 12.774 9.5 1.218 - * Inferred 31.036 12.9 3.994 2.864 Sub-total 84.484 7.6 6.381 2.864 Total 104.874 8.9 9.327 4.639 * Refer to Note 4 below regarding the treatment of measured and indicated resources of the fissure mines. The resource statement, in compliance with the AIM Guidance for Mining Companies, is shown below in total for the Group's South African operations and then shown split out as to Koffiefontein and the fissure mines (Helam, Sedibeng and Star combined). This statement does not include any contribution from Kimberley Underground which will only form part of Petra's assets when the conditions in the corresponding acquisition agreement are met. SUMMARY OF RESERVES AND RESOURCES BY STATUS - COMBINED SOUTH AFRICAN OPERATIONS Category Gross Net attributable Operator Tonnes Grade Contained Tonnes Grade Contained (millions) (cpht) Diamonds (millions) (cpht) Diamonds (millions) (millions) Ore/Diamond reserves per asset Proven 25.860 7.3 1.886 18.397 8.3 1.524 Refer summaries below Probable 2.105 69.0 1.453 1.993 71.3 1.422 Refer summaries below Sub-total 27.965 11.9 3.339 20.390 14.5 2.946 Diamond resources per asset Measured 58.105 2.9 1.670 40.674 2.9 1.169 Koffiefontein JV Indicated 18.248 9.5 1.740 12.774 9.5 1.218 Refer summaries below Inferred 43.787 10.6 4.632 31.036 12.9 3.994 Refer summaries below Sub-total 120.140 6.7 8.042 84.484 7.6 6.381 Total 148.105 7.7 11.381 104.874 8.9 9.327 SUMMARY OF RESERVES AND RESOURCES BY STATUS - KOFFIEFONTEIN Category Gross Net attributable Operator Tonnes Grade Contained Tonnes Grade Contained (millions) (cpht) Diamonds (millions) (cpht) Diamonds (millions) (millions) Ore/Diamond reserves per asset Proven 24.436 4.4 1.080 17.105 4.4 0.756 Koffiefontein JV Probable - - - - - - Sub-total 24.436 4.4 1.080 17.105 4.4 0.756 Diamond resources per asset Measured 58.105 2.9 1.670 40.674 2.9 1.169 Koffiefontein JV Indicated 18.248 9.5 1.740 12.774 9.5 1.218 Koffiefontein JV Inferred 42.263 4.6 1.960 29.584 4.6 1.372 Koffiefontein JV Sub-total 118.616 4.5 5.370 83.031 4.5 3.759 Total 143.052 4.5 6.450 100.136 4.5 4.515 Koffiefontein; reserves and resources have been taken from De Beers June 2005 internal scorecard classification (considered to be a conservative classification) and depleted by mining conducted by De Beers from July 2005 to March 2006 and by Petra to September 2007. Reserves and resources have been re-classified in compliance with JORC 2004. SUMMARY OF RESERVES AND RESOURCES BY STATUS - FISSURE MINES COMBINED (HELAM, SEDIBENG, STAR) Category Gross Net attributable Operator Tonnes Grade Contained Tonnes Grade Contained (millions) (cpht) Diamonds (millions) (cpht) Diamonds (millions) (millions) Ore/Diamond reserves per asset Proven 1.424 56.6 0.806 1.292 59.5 0.768 Petra/Sedibeng Mine JV Probable 2.105 69.0 1.453 1.993 71.3 1.422 Petra/Sedibeng Mine JV Sub-total 3.529 64.0 2.259 3.285 66.7 2.190 Diamond resources per asset Measured - - - - - - Indicated - - - - - - Inferred 1.524 175.3 2.672 1.452 180.6 2.622 Petra/Sedibeng Mine JV Sub-total 1.524 175.3 2.672 1.452 180.6 2.622 Total 5.053 97.6 4.931 4,737 101.6 4.812 Fissure mines; grades and fissure widths are extrapolated downwards below working levels from detailed historical records collected over many decades of mining, with confirmation of fissure continuity by diamond drilling where necessary. For further information, please contact: Justine Howarth / Louise Goodeve Telephone: +44 (0) 20 7851 7480 Parkgreen Communications, London Adrian Hadden Telephone: +44 (0) 20 7523 8000 Collins Stewart, London Ends Notes 1. The information in this update that relates to Exploration Results, Mineral Resources 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 South Africa, a 'Recognised Overseas Professional Organisation' ('ROPO'). Jim Davidson is the Qualified Person for the purposes of the AIM Guidance Note on Mining, Oil and Gas Companies dated March 2006. Jim Davidson is a full-time employee of the Company and has sufficient experience which is relevant to the style of mineralisation and type of deposit under consideration and to the activity which he is undertaking to qualify. Jim Davidson has given his written consent to the inclusion in this announcement of the matters based on his information in the form and context in which it appears. 2. 'Operator' is name of the company that operates the asset; 'Gross' are 100% of the reserves and/or resources attributable to the licence whilst 'Net attributable' are those attributable to the AIM company; 'cpht' is carats per one hundred tonnes. 3. The previous JORC compliant statement of resources and reserves published by Petra was dated 26 April 2005. It was prepared by Snowden Mining Industry Consultants ('Snowden') as part of the documentation required when Petra merged with Crown Diamonds NL in May 2005. At that time the resources and reserves were only in respect of the Helam, Sedibeng and Star fissure mines. The current reserves and resources have been updated using the same parameters applied as per the Snowden 2005 report. 4. Fissures - measured resources are classified as one level below the base of the deepest workings, indicated resources as two levels below the base of the measured resources, and inferred resources as three levels below the base of the indicated resources. Measured and indicated resources have been converted to proven and probable reserves by applying historically derived waste rock dilution and in-stope loss factors to in-situ kimberlite tonnages and grades. Resources converted to reserves have been subtracted from the overall resource figure and reported separately. Due to in-stope loss factors of 10% for shrinkage mining (carried out at Helam and Sedibeng), reserve carats will be less than resource carats on conversion and this adjustment has been included in the statements above. Glossary 'mineral resources' - a concentration or occurrence of material of intrinsic economic interest in or on the earth's crust in such form, quality and quantity that there are reasonable prospects for eventual economic extraction. 'inferred mineral resource' - that part of a mineral resource for which tonnage, grade and mineral content can be estimated with a low level of confidence. It is inferred from geological evidence and assumed but not verified geologically and/ or through analysis of grade continuity. It is based on information gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes which may be limited or of uncertain quality and reliability. 'indicated mineral resource' - that part of a mineral resource for which tonnage, densities, shape, physical characteristics, grade and mineral content can be estimated with a reasonable level of confidence. It is based on exploration, sampling and testing information gathered though appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes. The locations are too widely or inappropriately spaced to confirm geological and/or grade continuity but are spaced closely enough for continuity to be assumed. 'measured mineral resource' - that portion of a mineral resource for which tonnage, densities, shape, physical characteristics, grade and mineral content can be estimated with a high level of confidence. It is based on detailed and reliable exploration, sampling and testing information gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes. The locations are spaced closely enough to confirm geological and/or grade continuity. 'ore reserves' - those portions of mineral resources which, after the application of all mining factors, result in an estimated tonnage and grade which, in the opinion of the competent person making the estimates, can be the basis of a viable project, after taking account of all relevant modifying factors. 'probable ore reserve' - the economically mineable part of an indicated, and in some circumstances measured mineral resource. It includes diluting materials and allowances for losses which may occur when the material is mined. Appropriate assessments and studies have been carried out, and include consideration of and modification by realistically assumed mining, metallurgical, economic, marketing, legal, environmental, social and governmental factors. These assessments demonstrate at the time of reporting that extraction could reasonably be justified. 'proven ore reserve' - the economically mineable part of a measured mineral resource. It includes diluting material and allowances for losses which may occur when the material is mined. Appropriate assessments and studies have been carried out, and include consideration of and modification by realistically assumed mining, metallurgical, economic, marketing, legal, environmental, social and governmental factors. These assessments demonstrate at the time of reporting that extraction could reasonably be justified. This information is provided by RNS The company news service from the London Stock Exchange

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