Duke Energy to ship Riverbend coal ash to NC clay mines

Duke Energy, in a novel use for coal ash in North Carolina, plans to ship nearly 3 million tons to reclaim clay mines used by the brick industry in Chatham and Lee counties.

Plans filed with environmental regulators Thursday describe the first step in what will be a long process to dispose of 108 million tons of ash now steeping in 32 open ponds.

Excavation of 1 million tons of ash at Duke’s Riverbend power plant, on Mountain Island Lake west of Charlotte, could begin by March.

Most of the Riverbend ash will be sent to the Brickhaven Mine in Moncure, an open-pit clay mine southwest of Raleigh, with a second mine in Sanford as a backup.

About 10 percent of the Riverbend ash will become an ingredient in cement made by a firm in Troutville, Va. The plant’s ash isn’t suited to making concrete locally, Duke said, but can be used for the cement that goes in concrete. North Carolina has no cement makers, the company said.

The fate of the other 3.6 million tons stored at Riverbend is unclear, but a proposal to bury ash at Charlotte’s airport won’t be part of the initial phase.

Duke had initially proposed sending the ash to a landfill at Charlotte’s airport. The airport balked, but Charlotte officials later offered Duke a land swap for a site elsewhere on city property.

Duke is under a legislative mandate to close the ponds by 2029, but details of getting rid of all that ash has remained unclear.

A newly created Coal Ash Management Commission, which will oversee the process, will meet for the first time on Friday.

The new filings met a Nov. 15 deadline to get started that Gov. Pat McCrory set in an August executive order. They address four power plants under orders to excavate ash by 2019: Riverbend; Dan River in Eden, scene of a February ash spill; Asheville; and Sutton in Wilmington.

“All this is intended to get us moving to meet the 2029 deadline,” Duke spokeswoman Paige Sheehan said.

Duke said it will move 5.1 million tons of ash, about 30 percent of the total stored at the four plants, in an initial phase. The work will be done within 12 to 18 months of receiving state permits, it said.

Like the other plants, Riverbend’s ash is poised near a water supply. That and the relatively small scale of the ash stored made the four plants top priorities for excavation.

It’s still uncertain how ponds at 10 other Duke plants in the state will be closed. Some deemed of low risk may be simply drained of water and capped.

Ash hasn’t been previously used in North Carolina to reclaim mines, but it was allowed in legislation passed in August.

State law requires synthetic liners be placed under the ash to protect groundwater. Layers of clay in the mines will also keep ash from infiltrating groundwater, experts say.

John Daniels, chairman of civil and environmental engineering at UNC Charlotte, called mine reclamation a good use for Riverbend’s ash.

“Your options are either to build a landfill at Riverbend or put the ash to beneficial use,” he said.

Ash and gypsum, another power-plant byproduct, have been used to reclaim surface mines in Pennsylvania and Ohio, Daniels said. Duke’s plan is also consistent with legislation that requires protective liners and groundwater monitoring for so-called structural fills, he said.

The Southern Environmental Law Center, which has sued Duke over ash contamination, called mines a good option if liners are used.

“This is the first step in that we have been moving toward for months, moving from unlined pits along waterways to lined storage,” said attorney Frank Holleman.

Duke will pay a contractor, Charah Inc., to excavate, haul, and store the ash at the mines. Charah will own the ash.

The Riverbend ash will initially travel to the mines by truck – Duke estimates 120 to 142 truckloads a day – and then by rail once loading facilities are built in a few months.

Two million tons of ash from the Sutton plant will also go to the clay mines.

Nearly 1 million tons of ash from Duke’s Asheville plant will continue to be taken to a lined landfill at Asheville Regional Airport, Duke said. More than 1 million tons of ash from the Dan River plant will go to an existing landfill in Jetersville, Va.

“At first blush (the plans) appear to be well thought out,” said Drew Elliot, spokesman for the Department of Environment and Natural Resources. “What we’ll be looking for are what permits are called for based on the plans, and ensuring that the right permits are issued.”

Filling mines with ash, for example, requires different permits than typical mine reclamation. Ash contains heavy metals that can be toxic in high concentrations.

Duke increased its estimates of the total ash stored in North Carolina to 152 million tons. The new figure includes 30 million tons in landfills and 14 million tons elsewhere on power plant property.

This story was originally published November 13, 2014 at 10:28 AM with the headline "Duke Energy to ship Riverbend coal ash to NC clay mines."