In March 2016, U.S. Department of Energy Office of Legacy Management (LM) conducted an annual inspection of the Mexican Hat Disposal Cell. During the Inspection, LM discovered surface depressions on the cover of the northeast side slope of the cell. In response to this discovery, LM began investigating the extent of these depressions to determine a possible cause and evaluate corrective actions.

Betwen 2016 and 2018, LM performed multiple field investigations, during which the depressions were detected and monitored. In summer 2019, LM replaced a 20,000-square-foot area of the northeast side slope with an Interim Cover Protection (ICP). The ICP was designed to restore the side slope back to its original design specications and limit further erosion, until a permanent desighn solution can be implemented. This page will feature information from the studies conducted since the initial observations of the depressions in March 2016 as well as other media relating to the monitoring and maintenance of the disposal Cell.