2010 Mining Explorers: Diavik Diamond Mines Inc.

(Rio Tinto plc. and Harry Winston Diamond Ltd.)

DDMI President and COO: Kim Truter

DDMI Superintendent, Geotechnical Engineering: Sarah Greer

DDMI Chief Geologist: David Eichenberg

The Diavik Diamond Mine is an unincorporated 60/40 joint venture between Diavik Diamond Mines Inc., a subsidiary of London-based Rio Tinto plc, and Harry Winston Diamond Mines Ltd., a subsidiary of Toronto-based Harry Winston Diamond Corp. Both companies have headquarters in Yellowknife, Northwest Territories. Diavik Diamond Mines manages the mine, which began diamond mining underground in February, with production expected to continue beyond 2020. Open pit mining, which began in 2003, is expected to cease in 2012. Diavik’s reserves are primarily contained in three kimberlite pipes, A154 North, A154 South, and A418, located beneath the waters of Lac de Gras, just offshore of East Island in Northwest Territories. A fourth pipe, the A21 pipe, is being reviewed to determine its viability for mining. While small compared to the world average, these diamond ore bodies contain a higher-than-average content of readily marketable diamonds. The mine’s reserves are located on part of four mining leases, totaling less than 2 percent of Diavik’s mineral holdings. The JV also is focused on exploring for additional reserves on its remaining holdings, which cover nearly 240,000 hectares, or 578,400 acres. Through ongoing exploration, Diavik has discovered about 70 kimberlites on the claim block, about half of which are diamond bearing. In 2010, open pit mining from the A-418 kimberlite pipe supplemented by the A-154 South kimberlite pipe was expected to be the primary source of 1.8 million metric tons of ore. About 500,000 metric tons of underground ore was expected to be sourced from the A-154 South and A-154 North kimberlite pipes. Total mine production was projected to total about 7.8 million carats.

To extend production beyond 2022, the mine’s owners hope to bring additional resources and exploratory tonnages into the reserves category. In addition to new mining techniques aimed at reducing unit cost and increasing mining velocity in the underground operation, exploration work has identified extensions at depth to the A-418 and A-154 North kimberlite pipes. Harry Winston said the inclusion of these extensions in ore reserves will be largely dependent upon the costs of new underground mining techniques currently under review. In April, Diavik also reported that its work force achieved 2 million hours without a lost time injury over an 11-month period. Diavik’s workers achieved the safety milestone over a period of 11 months.

In July, Harry Winston reported an agreement to buy back from Kinross Gold Corp. a direct equity stake of about 22 percent in Harry Winston and a 9 percent indirect interest in the joint venture that owns the Diavik Diamond Mine for about US$220 million in cash, common shares and debt. Harry Winston sold the interests to Kinross in 2009 for C$150 million. At July 31, Harry Winston had unrestricted cash and cash equivalents of US$125 million and working capital of US$386.2 million. Rio Tinto, a multinational mining conglomerate, reported underlying profits of $5.8 billion in the first six months of 2010, reflecting ample liquidity and resources. The company is traded on the London Stock Exchange.

P.O. Box 2498, Stn. Main • 5007 - 50th Ave.

Yellowknife, NT, Canada X1A 2P8

Tel: 867-669-6500 • Fax: 867-669-9058

www.diavik.com