HARRIMAN, Tenn. — Three months after a massive coal ash spill, the Tennessee Valley Authority has begun dredging the ashen byproduct of coal-generated electricity from the Emory River.
The first hydraulic dredge began sucking up ash from the river Thursday, TVA officials said during a news briefing and tour Friday.
It could be several more weeks, however, before the coal ash actually leaves the Kingston Fossil Plant site, about 40 miles west of Knoxville. TVA and environmental regulators haven't decided where to send it.
Still, TVA's top environmental officer Anda Ray called the start of dredging a major milestone in the cleanup of one of the worst ash spills in the country's history — a recovery that TVA estimates could cost more than $800 million and take months, or even years, to complete.
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"We have been stabilizing and sampling and now we can take all of that pre-work, and we are ready to take the ash out of the river," Ray said.
Some 5.4 million cubic yards of ash breached earthen walls holding back a 60-foot-high landfill-like pile of ash at the Kingston plant three days before Christmas.
More than a dozen homes were damaged or destroyed as the gray muck spilled out over a 300-acre area, covering a cove and flowing into the river, filling a navigation channel up to 27 feet deep.
Tim Hope, TVA's recovery project manager, said about 3 million cubic yards went into the Emory. This first phase of dredging will recover a little more than half of that, he said. A layer of ash about 5 feet deep will be left on the bottom for dredging later.
The dredging will start slowly as TVA determines how to do it with the least disruption to residents and the environment. Dredge engines, pumps and compressors are being muffled. Floating water monitors look for signs the ash is being stirred up. "Turbidity curtains" are ready to drop into the water to prevent ash from flowing downstream. Half a dozen air monitoring stations are checking air quality.
"Obviously, dredging the river is a proven activity. We know dredging will absolutely get it all out," Hope said. "The time frame associated with that and the amount of dredging, that is what the pilot project will determine."
TVA expects to know in about a month what is involved, and be able to award a dredging contract about a month later. That will probably pick up the pace. TVA is starting with daytime-only dredging, but wants to go 24/7 if it can.
The ash will be pumped to a temporary holding area about three-quarters of a mile away at the Kingston plant. The area can hold about 200,000 cubic yards.
Ray said TVA is studying several options for disposing of the ash, including building a new off-site landfill, putting it into a coal mine reclamation project or dumping it into existing municipal landfills.
TVA also hasn't determined how best to ship it. Truck, rail and river barge are all being considered.
"The big picture challenge for us right now is getting this ash out of the river," Hope said. "That is first and foremost for us right now ... getting it out in a timely manner."