Leakage through Holes in Geomembranes below Saturated Tailings

AbstractExperiments conducted to quantify potential leakage from holes in two geomembranes [1-mm-thick linear low-density polyethylene (LLDPE) and 2-mm-thick high-density polyethylene (HDPE)] placed on a silty-sand [underliner hydraulic conductivity (kUL), 1.1×10−7≤kUL≤1.2×10−5  m/s], or pea gravel (kUL=1×10−2  m/s) underliner (foundation/subgrade) and covered with saturated fine tailings at 65% initial solids content are discussed [tailings hydraulic conductivity (kT), 2.9×10−8≤kT≤1.6×10−6  m/s]. Tests results show that the overlying tailings, with a kTgeomembrane hole and had a larger effect on flow through the hole than the underliners examined. For the tested conditions, leakage through 10 and 20-mm-diameter holes were essentially the same whereas the leakage through a 1.5-mm-diameter hole was three orders of magnitude lower. Introduction of a 580  g/m2 nonwoven needle-punched geotextile (GTX) layer between the geomembrane and tailings increased the flow by approximately 60%. A gap be...