This is a developing story and will be updated as more information becomes available.
Coal ash from a structural fill site entered an unnamed stream after a sinkhole formed in Mooresville, state regulators announced today.
The sinkhole was in a parking lot built on top of a coal ash structural fill site off NC Highway 150. The North Carolina Department of Environmental Quality did not specify which fill site was affected, but state records show a previous sinkhole in a parking lot of the Terry K Smith Highway 150 project.
This site contains 45,833 tons of coal ash, sourced from Duke Energy’s Marshall Steam Station, located on nearby Lake Norman.
DEQ said in a press release that a stream culvert pipe collapsed under a coal ash structural fill during heavy rains on Thursday, Sept. 17, that caused a previously repaired sinkhole in a parking lot to reopen.
DEQ said it has been monitoring the sinkhole since becoming aware of it during a site inspection in July of 2019. The property owner had previously repaired the sinkhole in 2018 and 2019.
During site visits after the storm, sediment containing coal ash was observed in the stream bed of the unnamed tributary where it emerges south of Highway 150.
DEQ staff collected water quality samples from the stream and is conducting ongoing monitoring. The location is in the area of a state Department of Transportation expansion project, and DEQ has discussed necessary next steps with the property owner and NCDOT. DEQ also alerted county and state emergency management authorities.
There are dozens of known coal ash structural fill sites in North Carolina, and more that have been reported but not documented.