Diavik approval of new dike

Rio Tinto PLC
06 December 2004


Diavik approves construction of new dike

The owners of the Diavik diamond mine (Rio Tinto 60%) today announced approval
for the construction of the A418 dike, and funding for further study of the
viability of underground mining, including the construction of an exploratory
decline.

Construction of the A418 dike is expected to cost US$190 million and will
commence in the summer of 2005.  First production from the A418 pit will be in
early 2008.

The exploratory decline will provide access to the A418 pipe and both the North
and South A154 pipes to provide data to support feasibility studies into
underground mining of the three diamond ore bodies.  These studies will be
completed in the first half of 2007.  The cost of the feasibility studies,
including the exploratory decline, together with a process plant optimisation
programme, is expected to be US$75 million.

The development of the A418 open pit and, subsequently, the underground mines
will enable Diavik Diamonds to capture the additional value due to better than
anticipated process plant performance and higher than anticipated diamond
values.


For further information, please contact:
LONDON                                       AUSTRALIA

Media Relations                              Media Relations

Lisa Cullimore                               Ian Head
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Investor Relations                           Investor Relations

Peter Cunningham                             Dave Skinner
Office:  [phone]                Office:  [phone]
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Richard Brimelow                             Susie Creswell
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Website: www.riotinto.com

Background

The Diavik Diamond Mine, located in the sub-arctic region of Canada's Northwest
Territories, is an unincorporated joint venture between Rio Tinto's Diavik
Diamond Mines Inc (60% interest) and Aber Diamond Corporation (40% interest).

Diavik currently has a number of diamond-bearing bodies called kimberlite pipes,
including those designated A154South, A154North and A418 referred to in this
release, located under Lac de Gras.  Commercial production commenced in early
2003 following an investment of C$1.3 billion and two years of construction,
involving innovative engineering, to allow temporary access to the lake bottom.

Diavik was built after significant environmental study and local community
consultation, and today is providing local northern and aboriginal communities
with significant benefits in the form of training, employment and new business
opportunities.

Diavik produced 3.8 million carats in 2003 and production in 2004 will be well
over seven million carats.  Production in 2005 is expected to be over 8.5
million carats.

Diavik's annual production is expected to be between seven and nine million
carats until at least 2010.  The Diavik mine life is projected to be 20 years.

US dollar amounts in this release are based on a US dollar/Canadian dollar
exchange rate of 0.73.


                      This information is provided by RNS
            The company news service from the London Stock Exchange