October 5, 2016

Field Identification and Mitigation of Geosynthetic Clay Liner Seam Separation in a Tailings Impoundment Composite Liner System

Peter E. Kowalewski, P.E.; Tierra Group International, Ltd.1; Kevin Sessions, P.E.; Tierra Group International, Ltd. (former, now at Barrick Goldstrike Mine)2; Justin Knudsen, P.E.; Tierra Group International, Ltd.3; Adrien Butler, P.E.; Tierra Group International, Ltd.4; Andrew Jung; CETCO5

ABSTRACT: The use of geosynthetic clay liners (GCLs) as a component of composite liner systems in landfills, ponds, heap leach facilities, and tailings impoundments has increased significantly over the past five to ten years. Field observations (Thiel and Richardson, 2005 and Koerner and Koerner, 2005) and laboratory testing (Thiel et al., 2006) have indicated that under specific unconfined and exposed conditions, seam separation may potentially occur due to several different mechanisms, including tension necking or shrinkage due to repeated wetting and drying cycles. During the construction of a raise to an existing tailings storage facility in the western United States, it was suspected that the GCL secondary liner had experienced seam separation in a limited area of the previous stage of impoundment construction. A field investigation was conducted to identify affected areas, a root cause analysis was completed, and measures were developed and implemented to repair the identified affected seams. New installation procedures and both destructive and non-destructive testing protocols were developed to prevent future occurrences.

Download Article