Diavik Diamond Mines (DDMI) owns Rio Tinto's interest in and manages the unincorporated Diavik diamonds joint venture in the Northwest Territories of Canada. Mining takes place in the lake bed at Lac de Gras with water held back by a dike made of rock fill. With approximately 800 employees, Diavik is instrumental in making Canada the world’s third largest diamond producer by value. Diavik has won awards for its sensitive management of environmental and community issues.