a method and liner for a reserve earthen pit for use in onshore drilling operations has a foamed polymeric composition . at least one layer of the continuous foamed polymeric composition is applied to the interior surface of the reserve earthen pit , preferably after the native soil has been compacted , thereby forming a sealed liner barrier between the native soil and the interior of the pit . the composition is resistant degradation from the drilling muds that are stored within the pit . uv protectants may also be added to the pit liner composition .