Diavik Diamonds Project - Environmental Agreement.

Business Editors

LONDON--(BUSINESS WIRE)--March 9, 2000

Diavik Diamond Mines Inc, (DDMI) a wholly owned subsidiary of Rio Tinto (NYSE: RTP) announced the signing of the Environmental Agreement for the Diavik Diamonds Project on March 8, 2000. In addition to DDMI, the Parties to the Diavik Environmental Agreement include the Government of Canada represented by the Department of Indian Affairs and Northern Development (DIAND) and the Government of the Northwest Territories, represented by the Department of Resources, Wildlife and Economic Development. Representatives of the Dogrib Treaty 11 Council, the Lutsel K'e Dene First Nation, the Yellowknives Dene First Nation, the North Slave Metis Alliance and the Kitikmeot Inuit Association participated in the negotiations. The above-mentioned Aboriginal Groups are expected to become Parties to the agreement following ratification by their respective leaderships.

The Environmental Agreement sets out the environmental monitoring and reporting requirements for the project. The agreement also sets out conditions for the reclamation security deposit requirements for the Diavik project. The agreement is the first of its kind in Canada having the following combination of key components:

- Majority representation by Aboriginal Groups on the project's

Environmental Advisory Review Board;

- Progressive reclamation of mine workings to achieve

incremental abandonment in a manner consistent with

sustainable development;

- Mechanisms for proponent participation in a Regional

Cumulative Effects Management Forum; and

- The provision of environmental security consistent with

life-of-mine closure costs and progressive reclamation as well

as additional security to meet the Government of Canada's

requirements for adequate funding in the event of premature

mine closure. The maximum security required is forecast to be

approximately C$180 million, taking into consideration credits

for progressive reclamation.

The conclusion of the major milestone should now enable the timely issuance of the final project authorizations. In the interim, DDMI plans to remobilize its workforce at its existing camp facilities and utilize the balance of the 2000 winter road season. The extent to which full use of the remaining winter road will be possible is dependent upon DIAND issuing appropriate land use permits. The impact of the mobilization delay on the overall project time-line will be dependent, among other factors, on the weather-sensitive winter road schedule.

The Diavik Diamonds Project is an unincorporated joint venture between DDMI (60%) and Aber Diamonds Mines Ltd. (40%). Both companies are headquartered in Yellowknife. DDMI is a wholly owned subsidiary of Rio Tinto plc of London, England, and Aber Diamond Mines Ltd. is a wholly owned subsidiary of Aber Resources Ltd. of Toronto, Ontario.