This week Harry Winston Diamond Corporation announced a new mine development plan for the Diavik Diamond Mine own jointly by Harry Winston (40% ownership) and Rio Tinto (60% ownership). The plan involves a $218 million investment by Harry Winston and $327 million by Rio Tinto, both over the next two years.
Since the Diavik Diamond Mine started production in 2003, operations have been open pit mining and have produced 35 million carats of diamonds. The new development plan will facilitate the start of underground operations starting in 2009, which would extend the life of the mine to beyond 2020. The total estimated reserves for the mine were about 110 million carats, meaning that there are about 80 million carats yet to be mined.
The Diavik Diamond Mine is located 300 kilometers northeast of Yellowknife, capital of Northwest Territories in Canada. Situated on a 20 square kilometer island in Lac de Gras, the mine employs approximately 725 workers. The mine extracts ore from three kimberlite pipes, designated A154 North, A154 South, and A418, which contain higher than average content of readily marketable diamonds. The three pipes are all located beneath the waters of Lac de Gras so operations required construction of a dike to surround each pipe so the water could be removed before mining could begin. The lake freezes from October to June with an average thickness of 1.5 meters.
The physical plant (processing, maintenance, powerhouse, workers accommodations, etc.) are located on the island with enclosed walkways connecting the major buildings. All supplies to keep the mine operating must be trucked in over a 600 kilometer long ice road constructed each winter from February to April. The Diavik Mine requires about 4,500 truckloads a year to maintain the operations year around.