The troublesome pipes that ran beneath the Duke Energy coal ash ponds at the Dan River plant caught the eye of third-party inspectors at least as far back as 1986.
Five-year reports filed with the state Utilities Commission show the pipes were no secret to Duke, which hired the private inspectors for the facility, which dates back to the 1940s. A 1986 report pointed out one of the pipes was made out of corrugated metal and so would have a shorter longevity.
Subsequent reports recommended that water coming out of the pipes should monitored for signs of leaks, and twice recommended sending video cameras into them to check for leaks. Duke indicated it was monitoring the outflow from the pipe.
On Feb. 2, it was discovered that a corrugated metal pipe collapsed, sending 27 million gallons of wastewater and 39,000 tons of coal ash sludge into the Dan River. Duke has said those are the only two pipes that are beneath their 14 storage sites in the state. The other pipe is made of concrete, but was also leaking.
Duke also said the Dan River site was the only one with a corrugated metal pipe, but later said there were eight others elsewhere.
The Utility Commission reports were posted online by an independent journalist working on a project about coal ash. Her website is http://www.coalashchronicles.com/.
In other Duke coal ash news
State environmental regulators on Thursday continued their highly visible, stepped-up scrutiny of Duke Energys coal ash storage ponds.
Faced with criticism that the N.C. Department of Environment and Natural Resources has been lax in its oversight of the ponds, the agency has been issuing almost daily news releases about its crackdown on the utility.
On Thursday, the news was that DENR has cited Duke Energy for problems inspectors found at two coal ash basins at the Cliffside Steam Station, which straddles Rutherford and Cleveland counties.
DENR found problems with the facility, including a corrugated metal pipe that had deteriorated and was taking in groundwater.
The agency directed Duke to repair the pipe, seed an embankment to grow erosion-reducing grass, and remove trees and bushes that could lead to internal erosion.
If Duke doesnt come up with a schedule of repairs by April 7, DENR can take enforcement actions.
DENR also announced on Thursday that Duke has paid a $500 yes, $500 penalty for a mercury discharge that occurred while the company built a new discharge system at the Mayo Steam Electric Plant in Person County.