Kono project - update

Petra Diamonds Ld
20 September 2007


                            Petra Diamonds Limited

                             Kono project - update

Petra Diamonds Limited ('Petra') announces an update concerning the Kono diamond
project in Sierra Leone. Petra's interest in the Kono project is 51%, with its
joint venture partner Stellar Diamonds Limited ('Stellar'), a 68.5% owned
subsidiary of Mano River Resources Inc (AIM: MANA, TSX-V: MNO), holding the
remaining 49%.


Highlights

     •    The development programme makes further solid progress, with test 
          shafts delivering highly encouraging results

     •    Trial mining commenced on three shafts where in-situ grades of between 
          50 and 80 carats per hundred tonnes ('cpht') have been achieved
     
     •    Petra believes that the test shafts have a high likelihood of 
          developing into economic production operations
          
     •    2,809 diamonds totaling 241.7 carats recovered from trial mining to 
          date (February 2007: 638 diamonds, 58.8 carats)
          
     •    The increase in diamond recoveries is due to the better quality 
          kimberlite now encountered, more consistent kimberlite fissure and 
          better fissure widths; all very positive signs for the future 
          development of economic operations

Adonis Pouroulis, Chairman of Petra, commented; 'We are pleased to report the
further positive progress at the Kono project. The trial mining is going well
and whilst further work is required in order to infer a representative grade and
value, the results to date support our expectations for the Kono project and we
progress with confidence into the next phase of the development. The quality,
consistency and width of the kimberlite now encountered are all positive signs
for the future development of economic operations.'

Stellar's CEO, Karl Smithson, commented: 'We are very encouraged by the news
given by Petra Diamonds from the Kono operations.  We would like to commend
Petra, our partners, on their diligent and effective management of the project.
Petra is the world leader in underground kimberlite fissure mining and they have
assembled a first class operational team that we are confident can bring success
to the Kono project.'

Test Shaft Development

The development programme at Kono has achieved some highly encouraging results
in recent months with potentially economically viable kimberlite fissures having
been opened. Diamond yields, fissure widths and the underground mining and
geological conditions have enabled Petra to concentrate test shaft efforts on
three very promising diamondiferous kimberlite fissure targets.

To date five shafts have been sunk, each to a depth of 30 metres. Three of these
shafts are now at the trial mining stage on the 30 metre level and have been
returning satisfactory in-situ kimberlite grades of between 50 and 80 cpht.
These shafts display a consistent, near-vertical dipping fissure line with very
encouraging in-situ shaft sinking grades; fissure widths vary between 40
centimetres ('cm') and 200cm with satisfactory mining conditions experienced to
date. Two shafts were discontinued because diamond recoveries during the shaft
sinking and trial mining phases did not match the potential of the other three
shafts.

The test shafts are at advanced levels of development and the processing of the
limited amount of weathered, diluted and mixed diamondiferous kimberlitic
material extracted during shaft sinking has yielded 2,809 diamonds totaling
241.7 carats. The ten largest diamonds ranged in size from 0.65 carats to 7.2
carats. Although the diamond yields are highly encouraging from the small amount
of material processed, Petra is of the opinion that the scale of the test work
conducted is presently too limited to arrive at any representative grade or
value and accordingly will report on further findings when available.

The next phase of the project will excavate approximately 100 metres of
kimberlite along strike of ore body at each shaft, so as to process
approximately 1,000 tonnes of clean kimberlite and obtain acceptable run of mine
grades and diamond values to be used in proposed business plans. It is
anticipated that this next phase programme will be completed by March 2008.

Exploration Development

During shaft sinking operations Petra found that, due to the highly saprolitised
nature of the rocks in this locality, the silicate and spinel kimberlite
indicator minerals have been destroyed, in many cases to depths of up to 20
metres. It has further been ascertained that ilmenite-deficient kimberlites
exist in the area. These conditions may mean that kimberlite pipes were
overlooked during mining and exploration operations carried out by previous
operators in the area. Petra is therefore considering the flying of a low-level
helicopter borne electro-magnetic survey over the licence areas so as to
prospect for these potential deposits.

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.   It should be noted that the potential quantity in this report is conceptual
     in nature, there has been insufficient exploration to define a Mineral 
     Resource and it is uncertain if further exploration will result in the 
     determination of a Mineral Resource.


For further information, please contact:
Justine Howarth / Louise Goodeve                 Telephone: [phone]
Parkgreen Communications, London


Adrian Hadden                                    Telephone: [phone]
Collins Stewart, London



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