Project Case Study – Composite Soil Cover for Sulphide Tailings at Mine Site in Northeastern Ontario, Canada

During the Fall of 2006, the Ontario Ministry of Northern Development and Mines tendered a construction project to provide a soil cover over the North Impounded Tailings (NIT) area at the abandoned Kam Kotia Mine site in Northeastern Ontario, Canada.  The soil cover would effectively impede the entry of water and oxygen into the high sulphide tailings, substantially reducing acid generation and metal leaching effects from within the tailings.  The final design incorporated waste rock, sand, gravel layers, a Geosynthetic Clay Liner (GCL), clay and granular cover soils.  During the Fall of 2006 and Winter of 2007, Hazco E&D Services implemented the construction of this design.  Overall, 800,000 m² of GCL was deployed and covered.  Deployment of the GCL was undertaken by Terrafix under the supervision of Earth Tech Engineering. This paper summarizes the design and construction of this composite soil cover system.