Diamonds are the ultimate prize in all projects operated by Diavik Diamond Mines Inc. in the North of Canada. Diamonds are located in volcano necks beneath a large lake, the Lac des Gras, in the North West Territories, 200 kilometres south of the Arctic Circle. In order to mine them to a depth of
300 meters, the dams around the volcano neck are sealed against the lake by means of diaphragm walls driven into the bedrock. When the water has been pumped out of the interior, mining can begin.
The first work was carried out in the summer months of 2001 and 2002 using a Bauer trench cutter, four diaphragm wall grabs and two complete jet grouting units. The project marked a first for the Bauer engineers: the heavy construction equipment was transported from Yellowknife on an ice road across the lakes to the site . This had to be done in the winter months, before the lake ice began its spring melt.
Scope of work:
Planning and execution of a 3 km dike and cut-off wall works in the year 2000;
32,000 m² Cut-Off Wall (COW), 80 cm width, Plastic concrete.
12,000 m² jet grout cut-off into the weathered rock with grout curtain.
Vibro-densification in the center of the dike - 300,000 m³ cut-off wall excavation through back-fill material, till with high boulder content, and permafrost, into the bedrock with cutter and grabs. Jet grout operation for tie-in with the bedrock under extrem arctic weather conditions.
Manpower workforce on the COW 100 people of which 30 are Bauer employees.