Innovative Geosynthetic Liner Design Approaches and Construction in the Mining Industry

Abstract

Geosynthetics are used in the design and construction of various mining facilities for process solution containment (heap leach pads, solution ponds and tailings impoundments), foundation stabilization and support, and reclamation. Due to the nature and location of mining projects, the performance envelope of geosynthetic materials is often pushed beyond the limits of typical design procedures, testing, and construction methods. Common issues addressed in mining applications include: (1) Geomembrane liner and plastic pipe performance under very high loads (in excess of 3 Megapascals [MPa]); (2) Solution containment liner systems founded on compressible fills; (3) Liner construction under harsh environments; and (4) Foundation stabilization over historic mine workings. To cope with these harsh conditions, innovative testing, design and construction approaches have been developed. A non-standard laboratory liner-load testing frame is used to define the performance of the liner under high loads. This test frame is also used to evaluate the performance of the over- and under-liner materials. High-load interface shear tests are also used to assess stability of the liner system. The performance of plastic pipe under high loads is evaluated using a modified analytical method that accounts for arching effects in the over-liner material and acceptance of high deformation in the pipe cross-section. Methods to evaluate liner foundation deformation are also discussed with an emphasis on construction/stabilization. In addition, considerations for liner deployment and placement in harsh climatic conditions are discussed.