The likely cause of the Dec. 22, 2008, collapse of a coal-ash pond at a Knoxville, Tenn., powerplant that contaminated a stretch of river differs from what the plant’s owner and hired engineer disclosed last month, according to independent engineering analyses and reviews. The new studies point to other factors, including mismanagement and water pressure, as more likely catalysts than the reason cited by the Tennessee Valley Authority.
In a July 28 report, Marshall Miller & Associates, a Raleigh, N.C. engineering firm, says the “root-cause” analysis of the accident released last month by AECOM Technology Corp., Los Angeles, for TVA, focused “disproportionately” on a low-strength “slime” layer. The firm was hired by TVA’s inspector general to peer review the AECOM report.
