The GMA Techline

August 1, 2020  |  Q&A: GMA Techline

Seaming dissimilar geomembranes Q: I kindly request your technical support in the questions below: A nonpolyethylene geomembrane was used in phase 1 of the tailings dam waterproofing system of a gold mine. For the expansion (phase 2), the use of a high-density polyethylene (HDPE) geomembrane is bei…
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The GMA Techline

June 1, 2020  |  Q&A: GMA Techline

Moderated by George R. Koerner Minimum sediment thickness Q: We are going to construct some evaporation ponds on existing sediment on top of a Hypalon geomembrane. The sediment looks to be predominantly fine. The subgrade condition below the liner is not known for sure. In such conditions, can you r…
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The GMA Techline

April 1, 2020  |  Q&A: GMA Techline

Moderated by George R. Koerner and Y. “Grace” Hsuan Welding Rod Q: This question is in regard to the welding rod intended for welding of geomembranes (both high-density polyethylene [HDPE] and linear low-density polyethylene [LLDPE]). Are there any GRI GM13- or GM17-based requirements for weldin…
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The GMA Techline

February 1, 2020  |  Q&A: GMA Techline

Moderated by George R. Koerner and Y. “Grace” Hsuan DARCIAN PERMEABILITY Q: I am aware of the section in your book regarding geomembrane “permeability” and get from it that it aims to calculate an equivalent Darcian permeability using vapor diffusion via Fick’s law. Can one use the derived…
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The GMA Techline

August 1, 2019  |  Q&A: GMA Techline

Moderated by Robert M. Koerner, George R. Koerner and Y. “Grace” Hsuan A geotextile for unpaved driveway/road? Q: Is there any point in using a 150 g/m2 (4.4 oz/yd2) nonwoven geotextile in building an unpaved gravel driveway or gravel road? If so, what should be the most important characteristic…
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The GMA Techline

June 1, 2019  |  Q&A: GMA Techline

Who is doing the testing? Q: This question relates to the number of rolls to be selected as the lot sample for specification conformance testing and refers to ASTM D4354. When I look at this standard, it appears the values in Table 1 of GRI’s White Paper #10 refer to the number of units to &hellip…
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The GMA Techline

April 1, 2019  |  Q&A: GMA Techline

Vegetation causing gases under geomembrane? Q: I have a site where we are installing a high-density polyethylene (HDPE) liner in an existing pond. Because of some residual heavy metals in the top layer of soil, I would like to strip off the top 3–6 inches (7.6–15.2 cm) of soil and vegetatio…
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The GMA Techline

February 1, 2019  |  Q&A: GMA Techline

Geomembranes for canal lining Q: Our company is an international member of the Industrial Fabrics Association International (IFAI). Our government is planning to line their water canals with a geomembrane to prevent water seepage into the soil. We have been approached by many to suggest the most sui…
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The GMA Techline

October 1, 2018  |  Q&A: GMA Techline

Toxicity of nonwovens? Q: Are there any comprehensive tests (or a general synopsis) of the environmental toxicity of leachate from nonwoven polypropylene fabrics when aged in a freshwater or saltwater solution? Regulatory and municipal bodies in Europe and New Zealand are requesting more info about …
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August 1, 2018  |  News, Q&A: GMA Techline

UV Weathering of Geotextiles Q: My firm is providing construction quality assurance services for a landfill cell expansion. We are having an issue with our contractor and are going to be in a position of having 8 ounces/square yard (271 g/m2) of nonwoven geotextile exposed for a period of time, whic…
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