Fort Knox Mine Dam Under Scrutiny After Accident in Hungary

Dan Bross, KUAC – Fairbanks

The dam failure and toxic sludge release last week at ore processing plant in Hungary, has raised questions about similar potential at other mine facilities. The Ft. Know Gold Mine northeast of Fairbanks maintains a large dam that holds back a 300-acre tailings pond. The 4,000-foot long, over 300-foot high dam built in the 1990’s, is the largest in the state.  Alaska Department of Natural resources Dam Safety Engineer Charlie Cobb says it was designed and constructed to high integrity standards, and there’s minimal risk of the kind of catastrophic failure that occurred in Hungary.

Cobb says the dam that failed in Hungary was a much older communist regime-era structure that likely bares little design comparison with Ft. Knox.

Cobb says the state requires annual inspections by a consulting engineer, as well as daily
surveillance by the mine’s operator.  A seep was found under the Ft. Knox dam in 2006, but it was determined to be water from a sub dam fissure in the bed rock, and no tailings solution was released.   A monitoring system below the dam detects any seepage.  The state is currently taking public comment on Ft. Knox plan to raise the dam height 52 feet to accommodate additional tailings and waste fluid.

The sludge released from the Hungarian facility is from aluminum processing and contains lead and other heavy metals that have killed nine and sickened many others. Ft. Knox Environmental Manager Delbert Parr says the slurry stored in Ft. Knox is much less toxic.

The Ft. Knox gold mine’s tailings pond contains about 16 million gallons of slurry far less than the Hungarian sludge reservoir, which released 200 million gallons. The Ft. Knox facility is located in a valley, 25 miles northeast of Fairbanks, more remote than the Hungarian site. The state’s Cobb says even if there was catastrophic dam failure at Ft. Knox, the impacts would not be like what’s happening Hungary.

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