Mining

An open pit mine gives Diavik access to the diamond-bearing kimberlite ore beneath Lac de Gras. Diavik mines three kimberlite pipes, called A154 North, A154 South and A418 by open pit mining methods. A fourth pipe, A21, was bulk sampled in 2007 to assess whether it should be included in the reserve.

Along with open pit mining, all three kimberlite pipes will eventually also be mined from underground. Diavik expects that the transition to total underground mining of the pipes will be completed around 2012. In order to determine how best to proceed with underground mining, Diavik is conducting test mining of the two richer ore bodies: A418 and A154 North, with plans to undertake underground mining of the A418 pipe as part of Diavik Phase 2. Approximately 2,900 meters of the main decline tunnel for underground mining has been completed, with another 500 meters required prior to completion.

A range of heavy duty equipment is used to mine for diamond-bearing ore. These include:

• Komatsu 830E haul trucks, each with a 218 tonne payload;
• Hitachi EX 3600 excavator with a 20m3 bucket and a 35 tonne payload;
• Hitachi EX 1900 excavator with a 12m3 bucket and a 22 tonne payload;
• Terex RH200 hydraulic excavator with a 21m3 bucket;
• LeTourneau front-end loader, with a 20m3 bucket and a 35 tonne payload;
• D75EX Driltech blasthole drills;
• Komatsu HD785 haul trucks, each with a 90 tonne payload; and
• Bulldozers, wheeldozers, graders, backhoe and loaders.