BHP Billiton Joint Venture

Petra Diamonds Ld
14 September 2004

14 September 2004



                             Petra Diamonds Limited

                     Joint Venture signed with BHP Billiton


Petra Diamonds Limited ('Petra'), the AIM quoted diamond mining group, announces
that it has agreed terms for a Joint Venture ('JV') with BHP Billiton World
Exploration Inc ('BHP Billiton') regarding the Alto Cuilo diamond project in
north eastern Angola.


Under the terms of the JV, BHP Billiton can, by investing up to US$60 million in
the JV vehicle ('Vehicle') which it is intended will hold Petra's share in Alto
Cuilo, acquire shares of up to 75% of the Vehicle.


Petra has to date focused its work on the area around the Mussunuige-Luangue
river interfluve ('the ML Complex') in which Petra, along with its Angolan
partners Endiama and Moyoweno, has already established the presence of a
substantial diamondiferous kimberlite and alluvial complex. Under the terms of
the JV, BHP Billiton will undertake regional exploration on the balance of the
concession and may work with Petra to develop the ML Complex further.


Other terms of the JV are:


•   BHP Billiton will acquire its first interest in the Vehicle once it
    has invested US$7.5 million in the JV Vehicle and from that point will 
    acquire further shares in the Vehicle as its investment increases


•   Should BHP Billiton acquire 75% of the Vehicle, it may elect to buy a
    further 5% of the Vehicle from Petra. The value of that 5% would be 
    determined based on accepted mining valuation principles applied by 
    independent mining consultants appointed by agreement between Petra and BHP 
    Billiton


•   Once Petra's total project expenditure on the ML Complex reaches US$20
    million, which is expected within the next six months, BHP Billiton may 
    elect to take up the sole funding, as part of the US$60 million investment, 
    of exploration and development on the ML Complex. Should BHP Billiton at 
    that point not take up sole funding on the ML Complex, Petra will continue 
    to finance the ML Complex. BHP Billiton may elect to participate at a later 
    stage and BHP Billiton will then pay Petra a back-in amount of four times 
    Petra's expenditure over and above US$20 million


•   Once BHP Billiton has invested US$60 million in the Vehicle, the
    parties will fund any further development and mine construction in 
    proportion to their shareholdings in the Vehicle. If requested by Petra, BHP 
    Billiton will arrange debt financing for Petra's share of the funding 
    requirements of the Vehicle



The JV terms, which are legally binding, are subject to the execution of the
formal Joint Venture documentation and the obtaining of all required consents.
Ultimately development of a mine on the project will depend on the results of a
feasibility study and approval of a Mining Licence by the Angolan authorities.
The Vehicle is currently a 100% owned subsidiary of Petra.



On the execution of the formal Joint Venture documentation, which is expected to
occur before 31 October 2004, BHP Billiton will pay the US$1.5 million (which
was deposited in escrow in February 2004) to Petra which will convert into Petra
shares based on the average of the closing mid-market price of Petra's shares
for the ten dealing days prior to execution.



Adonis Pouroulis, Chairman of Petra Diamonds, commented, 'We are delighted to
have announced the terms of our JV with BHP Billiton and we are confident that
through this partnership we can realise the true potential of Alto Cuilo.  This
partnership is a great step forward in the development of Petra Diamonds and
acts as an endorsement of our commitment to Angola.'



 Ends



For further information, please contact:

Adonis Pouroulis / David Abery        Cathy Malins / Annabel Leather              Frank H. Moxon
Petra Diamonds                        Parkgreen Communications                    Williams de Broe Plc
Tel: [phone] /                Tel: [phone] /                     Tel: [phone]
     [phone]                       [phone]






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