In this Feb. 14, 2006 file photo, a close-up of the chest patch of a worker at Barrick's Ruby Hill Mine, outside Eureka, Nev., is shown. Barrick Gold Corp. lost more than US$3 billion in the fourth quarter after taking a massive writedown on its copper business in Africa, the company announced Thursday along with plans to make major changes in the way it does business. THE CANADIAN PRESS/AP, Douglas C. Pizac