ACER prepared a Backfill Specification which detailed the removal of previously backfilled soil in an area where a mat foundation was proposed for a telecommunications site. In order for the foundation to be constructed, ACER recommended removing all previously excavated soil down to virgin soil or bedrock.  Upon confirming the proper depths and completing an inspection of the excavation, backfilling activities commenced.  The backfill material was clean stone that was graded with sizes of stone that are between ¼” and 1.5”.  The backfill was free of any sod, brush, roots or other perishable or organic materials.  The backfill was installed in horizontal layers with a maximum thickness of eight inches (8”) before compaction.  Compaction was accomplished by three (3) passes with a vibratory plate compactor mounted to an excavator.  Eight inch (8”) lifts were installed until a depth of nine feet (9’) below the existing ground elevation was met.  A total of 4.5 trucks of stone, totaling approximately 100 tons was utilized.