Grouting and Jet Grouting for Soil and Rock Impermeabilization under Extreme Conditions at the Diavik Diamond Mine’s A21 Project: The Point of View of the Contractor

A new dike will be constructed around the fourth kimberlite pipe, named A21, of the Diavik Diamond Mine in the Canadian North West Territories. In August 2015 BAUER Foundations Canada, a subsidiary of BAUER Spezialtiefbau GmbH, based in Schrobenhausen, Germany, received a major contract with a value of around 65 million euros to create a cut-off wall for the Diavik Diamond Mine in Canada. Jet grouting and permeation grouting with cement based grouts will be carried out to form part of the water tightening core structure of the dike. This paper describes the permeation grouting techniques as well as the approach that will be used for the jet grouting for the sealing of the soil layers underneath the cut-off wall (Bauer CSM) and of the weathered rock zone, down to the partially fissured bedrock. Almost 70% of the grouting works have been completed within the end of 2016. The jet grouting site tests for season one have been completed in October 2016. Some aspects related to design and methods, the lessons learnt as well as the main challenges the have been faced within season one of the works (December 2016) are described into this paper.