A TALE OF TWO CONDITIONS: HEAP LEACH PAD VERSUS LANDFILL LINER STRENGTHS

Heap leach pad and solid waste landfill facilities are among the largest manmade fill structures in the world. A unique attribute of these structures is that they are often founded on a geomembrane liner system, which can potentially compromise their slope stability. One of the most important aspects of these fill structures for stable exterior fill slope conditions is the interface strength of the underlying geomembrane liner system, as related to the construction and operation of the facilities. The interface of the geomembrane liner in contact with the underlying and overlying soil or synthetic materials generally results in a planar low-strength condition at the more critical downhill toe limits of the fill structures. This planar liner interface strength is generally less than the strength of the stored containment fill materials above the liner system, as well as the subgrade foundation materials beneath the liner system. This paper presents an overview of the general similarities and differences in heap leach pad versus solid waste landfill liner designs and operations with respect to liner strength conditions and the development of stable slope conditions over the life of the facilities