BRUNSWICK COUNTY –– Brunswick County Commissioners are seeking the assistance of a geotechnical engineering firm to determine what, if any, impacts may result from a sand mine in operation within its well fields supplying the Highway 211 groundwater treatment plant.
Located just a quarter-mile west and across Highway 211 from the St. James entrance, the Mirasol Family Mine, operated by Jones Holdings NC LLC, may already have interconnectivity to the Castle Hayne aquifer.
This aquifer feeds water to 14 wells within the vicinity of the mine from a depth of as shallow as 96 feet to as deep as 280 feet. About 20% of the county’s water supply is sourced from these wells, treated at the nearby plant capable of delivering up to 6 million gallons of finished water per day. St. James, Oak Island, Caswell Beach, and Southport receive blended water from the 211 groundwater treatment plant and the county’s surface-water sourced Northwest Water Treatment Plant, according to Brunswick County.
One of the public wells is actually located on a corner of the private mine property; this well’s confining layer is either thin or nonexistent. The Castle Hayne aquifer itself is semi-confined, meaning some areas of the expansive groundwater wellspring are naturally contained by limestone and some are not. As the most productive aquifer in the state, it spans the entire coastline.
Brunswick County is aiming to garner more information about the possible interconnection to the sand mine.
“That’s what we’re trying to do, is just find out what our implications are,” public utilities director John Nichols said Thursday. If the county’s consultant finds the mine presents a significant concern for the county’s groundwater supply, the county may embark on additional testing to determine its effects on the wells.
“We just don’t know. We need to look into it and see if there are any real impacts or not. They’re stating there likely already is an impact,” Nichols said, referring to the mine’s consultant.
Jones Holdings NC LLC is seeking to ramp up its sand mining activities on 138.9 acres, which borders mainland Oak Island town limits. The company previously applied for a rezoning –– from commercial low density to commercial intensive conditional –– set for planning board review in April.
After county officials flagged potential issues with the operation’s apparent interconnection with the public water supply, the company stalled its rezoning application in May before pulling it altogether ahead of its scheduled slot in the June meeting. A hydrogeology report prepared by geologist Chris Reinhardt in May on behalf of the mine’s Florida-based property owner, Malcolm Jones, noted an existing sandpit on the property is about 40 feet below land surface (BLS).
The observed water level in the pit was about 12 to 14 feet BLS, “indicating there may be a hydraulic connection between the bottom of the sandpit and the top of the aquifer the County draws from,” the report states. Later in the report, the hydrogeologists’ assessment of the connection is more concrete when presenting an alternative solution to the permitting issue:
“[I]t is apparent the existing sandpit already has a connection to the aquifer and there has been no mention that this connection has had any impact on the county wells. Given that the hydraulic connection already exists, I and my client ….propose a comprehensive groundwater sampling event of each county well and the surface water in the existing pit.”
An interconnection may actually help recharge the county well field (meaning, fill it back up with water), reducing stress on the aquifer, the report concludes. Once proposed mining activities cease, the county could tap into a vast, 85-acre lake, possibly capable of delivering 250 million gallons of surface water into the aquifer as a reservoir, according to the report.
The apparent connection also presents a host of concerns.
“From a water quantity perspective, it probably would help,” Nichols said. “But if that’s happening, we would have additional water quality concerns because we’re getting water from the surface then that has some potential to be contaminated.”
It is not clear whether the sand mine actually caused the identified interconnection or if it pre-dates excavation activity (the mine’s consultant did not return a request to comment). The county raised the issue that mining could cause an adverse impact to the wells, a concern that “appears to have some validity,” the mine’s consultant noted, “based on the lowered water table in the existing pit and the borehole log showing a lack of a restrictive aquitard between the surficial aquifer and the limestone aquifer.”
Previously dreamed to be the Mayfaire of Brunswick County, the property’s five-year approval window for “Mirasol” shut last year. A commercial real estate agent who previously represented the property told Port City Daily they tried to pitch it to retailers but the market wouldn’t line up.
After the planned development go-ahead expired, Jones then applied for a rezoning to commercial intensive, which the planning board denied in November 2020. Jones appealed to commissioners and the applicant eventually opted to amend the application to a conditional zoning, sending the request back to the planning board for the latest attempt.
The land has operated as a sand mine for years, according to Brunswick County planning director Kirstie Dixon.
It previously functioned as a North Carolina Department of Transportation (NCDOT) borrow site in 2015, which allowed it to operate sans a permit, a workaround of the state’s Mining Act of 1971 that exempts state suppliers. An NCDOT spokesperson confirmed it does not currently contract with the company.
The mining act also exempts single-source providers from obtaining a mining permit, so long as they obtain erosion sedimentation control plan approval. Dixon indicated she understood the site was operating as a single-source supplier for Duke Energy; however, immediately available state records do not reveal an erosion sedimentation control plan on file for the site.
The property falls within the county’s 2012 Wellhead Protection Plan area. Drafting these plans originated from a requirement imposed by 1986 amendments to the federal Safe Drinking Water Act, tasking states to craft a program to protect wellhead areas from contaminants that could adversely affect public health. Sand mines are listed in the plan as a “higher risk potential contamination source” for groundwater public water supply systems.
According to Dixon, the planning department does not review or consider the wellhead protection plan when approving land-use changes. It also does not oversee the permitting of sand mines; the N.C. Department of Environmental Quality’s Division of Energy, Mineral, and Land Resources (DEMLR) does.
The Mirasol Family Mine submitted its first application to operate a sand mine on May 4, vying for a 10-year permit (the rezoning application was submitted to the county April 28). In the application, Jones’ consultants, Norris and Tunstall Engineering, report the mine would excavate as low as 35 feet. The application reports it’s requesting a “new” permit, meaning previous mining activities would have occurred without state approval. Jones did not return a request to comment.
A spokesperson for DEMLR said the division is aware of the county’s concerns and is requesting more information from the applicant before making a decision on the pending permit.
To begin assessing the extent of the potential problem, the county will pay its on-call engineering firm ECS for consultant services to review Jones’ request and provide recommendations for a modeling plan for the developer to follow, should the analysis indicate further fieldwork is necessary.
At the commissioners’ meeting Tuesday, Commissioner Mike Forte summed up a financial frustration.
“So because they wanna do a project, we gotta lay out $10,350? Somehow their business plan cost us money?” he asked Nichols.
“That’s correct,” Nichols responded. He went on to explain the analysis would also provide the county with protections: If the wells are contaminated, the state could impose new water quality restrictions on the 211 treatment plant, which would necessitate expensive system upgrades to meet the heightened rules; it could also lead the county to abandon wells, another costly task.
Last year, the county spent about $1.2 million to replace the plant’s aging groundwater filters, capable of only treating turbidity and sediment.
Forte wanted some assurance from the consultant in the event the county is told the coast is clear but the wells get contaminated anyway. “What’s our liability?” he asked. “It’s just on us?”
“There’s no hydrogeologist who’s going to provide that type of assurance,” Nichols said.
Send tips and comments to Johanna Ferebee Still at firstname.lastname@example.org