2004-2017 Snapshot:
Where Opportunity Runs Deep
Beneath the hills of Valmeyer, IL, there’s a business park unlike most others. One that’s not carved from steel and glass. Instead, more than a million square feet of commercial and warehouse space sits deep inside a former limestone mine.
Rock City Underground Business Park is a one-of-a-kind development that transformed an existing network of former limestone mines into a thriving center of commerce. And from the very beginning, TWM has been part of that vision, helping turn an unusual piece of geology into an opportunity for growth.
In 2004, when Phase I was completed, it brought approximately 1 million sq. ft. of usable space underground. But developing beneath the surface came with a very different set of challenges not found on a typical site. Instead of traditional property lines and building footprints, the team was working within a maze of existing mine spaces. This required a precise understanding of the underground environment that was essential to future development.
That become especially important as Rock City prepared to support one of its most notable tenants, the National Archives’ National Personnel Records Center. To help plan the facility, TWM deployed advanced 3D laser scanning technology to map and capture the intricate interior of the mine and create a precise digital model of the underground space.
The resulting data helped lay the groundwork for Annex II, a 75,000 sq. ft. expansion completed in 2010. By bringing the underground environment into a detailed digital model, TWM helped give the project the accuracy and confidence needed to expand in a setting where traditional surveying methods simply weren’t enough.
The innovative use of surveying and mapping technology earned TWM the ACEC-IL Engineering Excellence Award in Surveying & Mapping Technology, a recognition that underscored just how unique the project was.
But Rock City’s story didn’t stop there.
Over the past two decades, TWM has contributed to 26 projects throughout the Rock City Complex, working alongside Admiral Parkway and the Village of Valmeyer as the development continued to evolve. That work has included infrastructure planning and improvements, a storage area in 2016, and a freezer expansion in 2017. TWM has also helped secure and administer EDA and other grant funding in coordination with SIMAPC, supporting the infrastructure and investment needed to keep the complex moving forward.
What began as a limestone mine has become much more. Rock City stands today as a rare example of adaptive reuse at scale – a hub of economic activity where businesses operate, products are stored, and opportunity continues to grow. Proof that sometimes the next innovative development means looking below the surface.
