Presented at the Pan-American Conference on Soil Mechanics and Geotechnical Engineering, Cancun, Mexico, Nov 2019.
Sketch of the drainage system location in a mining structure.
In mining facilities, the system responsible for capturing, collecting and conducting solutions from seepage, leached solutions or acid rock drainage (ARD), is of utmost importance. Such a system is generally composed of granular material drains, flexible high-density polyethylene (HDPE) pipes and geosynthetics (e.g. geotextiles or geomembranes). Increased production rates, combined with limited availability of areas within mining facilities, has led to designing structures such as tailings dams, heap leach pads and waste dumps of over 200 m height. Therefore, understanding the behavior of drainage pipes in these structures, where they are subjected to high confinement pressures, is critically important. In the present study, results of five laboratory large-scale compression tests are presented. The tests were designed to analyze pipe behavior under high confinement pressures, simulating the effect of a 200 m (3.6 MPa) fill above the pipe crown. The tests were carried out using the configuration of a typical collection system, composed of compacted foundation soil, a geomembrane and a HDPE double wall corrugated pipe of 10 cm (4”) diameter, surrounded by granular material. The main objective of the study was to analyze the structural integrity of the pipes under high loads when placing different granular materials, identifying their influence on the pipe performance. Granular materials with different gradings curves, densities, and geological origins were used for testing.