Georgia pays close attention to Trail Ridge in review of Okefenokee mine application

By David Pendered

Editor’s Note: This story has been updated with a new map from the Georgia River Network.

When Georgia’s state geologist wasn’t satisfied with calculations submitted about how Trail Ridge may be affected by a proposed sand mine along the Okefenokee Swamp, he went to the source of numbers used in the calculations.

Georgia scientists who are reviewing an application for a sand mine west of Trail Ridge, near the Okefenokee Swamp, appear to be focused on how the mine could affect the sandy ridgeline. Credit: Georgia River Network

Then he presented this source material to the applicant and asked the applicant to explain the figures it had provided in an application to dig the strip mine.

This exercise speaks to the scrutiny the four applications from Twin Pines Minerals, LLC are receiving from state environmental scientists. The state Department of Natural Resources has final say on whether Twin Pines will be allowed to develop a mine that intends to strip off topsoil, extract valuable sands, and fill in holes in a proposed 577.4-acre site near the southeastern border of the Okefenokee Swamp.

Once the state’s review is complete, a public meeting will be scheduled and public comments will be accepted, the Georgia Department of Natural Resources stated in an email Tuesday. For the time being, the state continues to review the four applications and, likely, responses Twin Pines has submitted since the state sent its initial review on April 14. The state has posted the materials here. The example of the review of Trail Ridge is one of several examples of the state’s attention to detail.

James Kennedy is the state’s geologist. His task was to review the impact the mine could have on Trail Ridge, the long, sandy formation that environmental advocates portray as essential to prevent the freshwater swamp from mingling with the brackish estuaries of the Atlantic Ocean.

State Geologist James Kennedy tracked down this original source material and used it to pose a question to Twin Pines regarding its application for a mining permit near the Okefenokee Swamp. Credit: Georgia

Kennedy indicated in his comments about the application that he wasn’t satisfied with the mathematical calculations provided by the Twin Pines application. The math deals with the recharge rate for a shallow aquifer near the mine and Trail Ridge. Kennedy tracked down the author of the federal report cited by Twin Pines and then issued this directive in his response to Twin Pines:

• “The author of OFR 2003-311 was contacted about specific data for Charlton County, Georgia, and [Georgia] received a map done by a colleague of the author of the recharge rate in Charlton County in millimeters per year (mm/yr): …
• “Please identify the part of the model construction (layering, hydraulic properties of layers, boundary conditions) that led to a USGS [U.S. Geological Survey] steady state recharge rate resulting in unreasonably high modeled head values.”

Another example of the state’s effort involves close reading of footnotes on maps.

In one instance, the state requested that Note 3 on Figure 10 of the Surface Mining Application be changed to ensure vegetation is fully restored to the site:

• “Please change Note 3 to ‘all disturbed areas will be permanently vegetated.’”

Twin Pines had written Note 3 to state:

• “Final restoration of the mining pit shall be permanent vegetation.”

Twin Pines proposes to pump water from the Floridan Aquifer, which is said to provide water to 10 million humans in five states. Credit: usgs.gov

Georgia scientists appear to be paying close attention to Twin Pines’ requests to pump water from the Floridan Aquifer. This vast underground vault of water has been mapped from Mississippi into Alabama, across the plains of Georgia and South Carolina, and the entire peninsula of Florida. It is said to supply drinking water for 10 million humans.

Twin Pines has requested to pump 1.44 million gallons a day from the aquifer. The company’s application puts 1.44 million gallons a day in the context of the 11.1 million gallons a day pumped by four counties in the area – Brantley, Charlton, Clinch and Ware – according to estimates it attributes to the U.S. Geological Survey.

Another perspective is the 1.5 million gallons a day that Jasper wants to pump, according to the city’s water withdrawal permit application pending before DNR. Jasper’s population is about 4,000, according to a Census estimate.

Georgia has requested additional information on how the withdrawal of an additional 1.44 million gallons a day from the Floridan Aquifer could affect the shallow aquifer that exists along with the Floridan Aquifer:

• “Please provide further analysis / detailed modeling to quantify the surficial [shallow] aquifer drawdown at the edge of the ONWR, based on the Floridan aquifer drawdown numbers provided in the application. This may require a more detailed modeling of the drawdown in the Floridan aquifer, and its associated impact to the Surficial aquifer.”

Regarding the timing of the public meeting and public comment period, this is the full statement provided by the Environmental Protection Division, which is handling the Twin Pines’ application for DNR:

• “Georgia EPD is in the process of conducting a thorough review of the environmental applications submitted by Twin Pines for a surface mine in the vicinity of the Okefenokee Swamp.
• “EPD will hold a public meeting and an official public comment period before permitting decisions are made. There is no timeline for a permitting decision. More information is available at [this website].”

Paddling trails meander through the Okefenokee Swamp, the largest black water swamp in North America. Credit: Photo courtesy of Joe Cook