Rio Tinto offer for Alcan – 90 per cent threshold reached

Rio Tinto today announces that approximately 90.2 per cent (339,339,000 shares) of the
outstanding common shares of Alcan Inc. (“Alcan”) have been validly deposited and taken up
under the offer by Rio Tinto Canada Holding Inc. (“RTCH”) to acquire all of the shares of Alcan (the “Offer”).

RTCH is now entitled to acquire all the remaining Alcan shares by way of compulsory
acquisition under the Canada Business Corporations Act. RTCH will exercise these rights
promptly after the expiry of the Offer.

All additional validly deposited shares during the balance of the Offer period will be taken up daily and payment for such shares will be made to the depositary within two business days of take-up. Shares covered by notices of guaranteed delivery will be taken up when the
certificates representing them are delivered to the depositary. The Offer expires at 6:00 p.m.
(Canadian Eastern Time) on November 8, 2007.