New Melle Mine Seeks Major Expansion to Support I-70 Widening Between Wentzville and Warrenton
Date Posted: December 16, 2025
Posted In: Organizations, Projects,
by Tom Finan, Executive Director, Construction Forum
A long-operating limestone mine near New Melle is poised to grow significantly if St. Charles County leaders approve a planned 174-acre expansion. The expansion is tied directly to the urgent need for construction materials for the widening of Interstate 70 between Wentzville and Warrenton.
The mine, owned by Maryland Heights-based New Frontier Materials, has been in operation since the 1980s and has been conducted entirely underground since the mid-2000s. The company says the proposed expansion would not increase the mine’s current production rate, but would extend the life of operations on the property it already owns. Truck traffic volumes are expected to remain unchanged.
I-70 Expansion Demands Material Capacity
The expansion request is closely linked with the ongoing Improve I-70: Warrenton to Wentzville project, a major Missouri Department of Transportation effort to modernize and widen this segment of the interstate. That project is adding a third travel lane in each direction and updating pavement, bridges, and interchanges as part of a broader statewide initiative to expand I-70 capacity. Construction began in 2025 and is on track to run through late 2028.
According to MoDOT, materials such as crushed limestone and base aggregates from the New Melle mine will be used specifically for the I-70 expansion work in this corridor — particularly the stretch between Warrenton and Wentzville.
Local Review Underway
St. Charles County’s zoning commission is scheduled to discuss the special permit request, a necessary step before final approval by county leaders. While the proposed expansion covers about 174 acres — roughly the size of 132 football fields — company officials characterize it as a repositioning of mining within land they already own rather than an increase in major activity.
The area around the mine is largely rural and forested, with the nearest residential properties located more than 2,500 feet from the proposed expanded zone, according to county planning officials.
New Frontier Materials was formed in 2020 with a mission to partner, acquire, and grow companies in the construction materials sector, including aggregates and asphalt operations across the St. Louis region. Its operations include more than 20 sites supplying crushed limestone, asphalt, and related products for infrastructure and building projects.