With a decision forthcoming from the U.S. Army Corps of Engineers on a proposed mining project in South Georgia, an August 25 InsiderAdvantage article by Baker Owens discussing concerns of conservation groups requires some context. With apologies to the late, great Paul Harvey, I offer the “rest of the story.”

As noted by Owens, opponents of the proposed project speculate that the Okefenokee Swamp will be threatened by the mining operation. To the contrary, sound scientific evidence documents the mining project will cause no adverse impacts to the Okefenokee Swamp. The proposed mine site is not in, or adjacent to, the swamp. The mine site has been a commercial, planted pine plantation for decades– and was further degraded by the spring 2017 West Mims Fire.

I am part of an extensive team of environmental engineers, geologists, hydrologists and other experienced professionals that have worked with Twin Pines Minerals from the beginning of this project. We completed the initial permit application and then a significantly scaled down, revised application that the Corps of Engineers is currently reviewing as a demonstration project.

Science and the permit application

The revised application addresses opponent concerns and points raised by the Corps relative to the first filing. Twin Pines seeks a permit for a smaller mining area, reduced from 1,268 to 898 acres.  The proposed project will demonstrate, definitively, in this much smaller footprint, that Twin Pines’ advanced methods of mining will not harm the swamp or surrounding areas.

Top scientific experts have completed comprehensive studies to confirm the viability of Twin Pines’ plans for mining. One such expert is Dr. Robert Holt, nationally recognized hydrogeologist and professor of geology and geological engineering at the University of Mississippi. His groundwater models show that the proposed mining area along Trail Ridge is conducive to Twin Pines’ innovative dragline mining and will not disrupt the current hydrologic divide that is present along Trail Ridge.

Holt’s study shows:

  • Twin Pines’ mining operations will not dewater the Okefenokee Swamp.


  • Impacts on groundwater and stream flow to the Okefenokee Swamp and creeks, and to the groundwater system east of Trail Ridge, will be insignificant.


  • Changes in the water table will be insignificant.


Trail Ridge is a classic example of topographically-driven groundwater flow. The ridge acts as a hydrologic barrier that separates the Okefenokee Swamp to the west from the Saint Mary’s River to the east. Rainfall on Trail Ridge provides water in the form of recharge from rainfall to the Surficial Aquifer. This groundwater recharge causes the water table to be maintained within a few feet of the ground surface along Trail Ridge, forming a hydrologic divide that mimics the topography. Because groundwater flow is driven by topography, groundwater flows in both directions from the crest of Trail Ridge – to the west, supplying water to the Okefenokee Swamp, and to the east, supplying water to springs and creeks and ultimately contributing water to the St. Mary’s River located further to the east.

In layman’s term, this all means the proposed mining footprint is a sufficient distance (2.7 miles) from, and at a higher elevation than, the swamp, and will have such a minimal impact to the groundwater system, that the proposed mining will not have a significant impact on the refuge.

“I haven’t seen any technical claims against the mine that are fact-based,” Holt stated. “If there is a valid technical argument that reveals real problems, it is my duty to inform the company and recommend they find solutions or halt the project.”

In fact, authoritative sources have supported the validity of Holt’s modeling. Results were reviewed and confirmed by hydrologists and geologists at the University of Alabama and reinforced by the U.S. Environmental Protection Agency in April 2020 comments to the Corps of Engineers.

Advanced mining

“I’ve seen the emotional responses and arguments that Twin Pines is planning to use technology and mining approaches that are 25 years old, which is simply not the case, Holt added.

Twin Pines dragline mining method uses a large, crane-like, earthmoving machine with a bucket to excavate material. The proposed method allows for progressive backfilling of the mine pit as mining advances. This state-of-the-art approach allows for a small open mine pit footprint ranging from one to 1.5 acres that is continuously filled as mining progresses.

The land excavated is backfilled, graded and covered with topsoil and seeds/seedlings (depending on the time of year) within days of excavation. In fact, the post-mining activities will leave the property better than we found it when we started conducting studies of the site over two years ago.


Thus far, arguments against the mine have been opinion-based and speculative. Twin Pines on the other hand is offering science-based facts that tell a different story and leave no room for conjecture. Details of the mining proposal have been discussed in open public forums and are available in Twin Pines’ application on the Corps of Engineers’ website for all to see. I encourage anyone interested to read the application, study the evidence and decide for themselves.

Speaking for the project’s engineering, hydrogeologic and environmental consulting team, we look forward to continued cooperation with the Corps of Engineers and helping Twin Pines bring their mining proposal to fruition.

Mark Tanner is a Georgia-licensed senior principal geologist with TTL, Inc. a national, industry-leading environmental engineering firm. He has been an integral part of the team that is evaluating the mining site in Charlton County, Ga. and reporting results to the U.S. Army Corps of Engineers, which oversees the project and is considering the Twin Pines permit application as well as reporting to the Georgia Environmental Protection Division.


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