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GCLs and hydraulic equivalence

June 1, 2009

By Timothy D. Stark Q: Are GCLs hydraulically equivalent to a compacted low permeability soil liner? A: A good, but difficult, question. GCLs are hydraulically equivalent to low permeability soil liner in terms of advective flow. However, GCLs are not hydraulically equivalent to low permeability soil liner in terms of diffusive flow unless a natural …

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The effects of heat on Subtitle D composite liner systems

By Timothy D. Stark Q: What effect does heat have on a Subtitle D composite liner system? A: Heat can have many detrimental effects on a Subtitle D composite liner system. For example, heat can adversely affect the compacted low permeability soil liner by reducing its moisture content, leading to an increase in hydraulic conductivity …

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Design strength for GCLs

By Timothy D. Stark Q: What design strength should be used for GCLs? A: If the GCL is not encapsulated between two geomembranes, the slope design should/must assume that the GCL will be fully hydrated at a low normal stress (e.g., 5–10 psi for a liner system). If the GCL will be encapsulated between two …

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GCL shrinkage: A possible solution

February 1, 2009

By Richard Thiel and Chris Thiel Introduction A potential industry-wide concern for GCL shrinkage was identified by Thiel and Richardson (2005) at the January 2005 Geo-Frontiers conference in Austin, Texas, based on observed problems at several sites worldwide. All of the known problems were for installations where an exposed geomembrane/GCL composite installation was left unballasted …

CETCO introduces new geosynthetic clay liner product

October 1, 2008

CETCO has introduced a new geosynthetic clay liner product that combines the benefits of its needlepunched GCLs with the pricing of its adhesive GCLs, according to a company press release. Bentomat 200R is manufactured with a 3.5oz-per-yd2 nonwoven polypropylene cap fabric that is needlepunched into a 3.2oz-per-yd2 woven polypropylene base. The new product contains 0.75lbs …

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Geomembrane thickness

April 1, 2008

From the GMA Techline Subject: Geomembrane thickness— We have been designing an ash pond for a thermal- electric plant, where we intend to use an HDPE geomembrane for the lining system. Can you recommend what thickness we should use for safety reasons, as our project is located near Halong Bay [in northeast Vietnam]? Do you …

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GCLs and slope stability

From the GMA Techline Subject: GCLs and slope stability — I’d like to find out what the current thinking is on designing for slope stability with GCLs … perhaps summarize the current stateof- the-practice regarding residual strength of reinforced GCLs used in bottom liners at landfills. (Myron, Washington) Reply: Of course, there are ongoing tests …

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Geocomposite cover for sulfide tailings

February 1, 2008

By Bruno Herlin, P.Eng. Abstract In autumn 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 east-central Ontario, Canada. The soil cover would effectively impede the entry of water and oxygen …

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Using geosynthetics to rehabilitate Fisher Cañon Dam and Reservoir

August 1, 2007

Installation of a reservoir liner restored more-efficient irrigation to a Colorado resort By Richard A. Millet, P.E., Jennifer L. Williams, P.E., Dennis A. Minchow, John B. Heap Introduction Fisher Cañon Reservoir is an off-channel storage facility that supplies irrigation water to the golf courses at the legendary Broadmoor Resort near Colorado Springs, Colo. The Fisher …

Use of geosynthetics in the mining and mineral processing industry

By Karin Renken, David Mchaina, Ernest Yanful Introduction This article gives a brief overview and a summary of the results of research work conducted under the 2003 North American Geosynthetics (NAGS) Award of Merit. The NAGS awards were initiated in 1989 as an industry sponsored program to recognize excellence in the state of the art …