AECOM Analysis Cites 'Slime' As Factor in TVA Coal-Ash Spill

摘要

An unstable and weak slime-like foundation was the primary factor behind the Dec. 22, 2008, catastrophic failure of a coal-ash pond at Tennessee Valley Authority's Kingston plant near Knoxville, Tenn., says a root-cause analysis released last week by AECOM Technology Corp. TVA hired the firm after the accident to determine why dikes holding coal-waste slurry failed, flooding 300 acres around the plant and the Emory River with 5.4 million cu yd of coal ash.rnLos Angeles-based AECOM's analysis determined the dikes' angle and setbacks, increased loads because of recent high fill and loose, wet ash contributed to the failure. But the main factor appears to be a 6-in. layer of very small, round-particle fly ash and silt at the bottom of the failed foundation that AECOM calls "slime." AECOM's findings were peer-reviewed by a member of the National Academy of Engineering.