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Excavation and Disposal

Texarkana, TX: Soil Remediation by In-Situ Soil Mixing


The Texarkana Wood Preserving Site was used for various lumber-related activities since the early 1900's. Creosoting operations began at the site prior to 1954. In 1961 it began using a combination of creosote and pentachlorophenol (PCP) to treat wood in large pressure cylinders. Numerous environmental discharges occurred from the facility and were documented by regulatory agency investigations continuing through 1984 when the company went bankrupt.

Site characterization showed that subgrade contaminants were present in 12 areas of the 24-acre site. Seven of the areas were designated as Risk Areas, the other five as Source Areas. Risk Area soils were excavated, collected and placed in controlled lifts in the consolidation cell. These soils were then covered with an engineered cap. Source area soils were stabilized and required to pass both Synthetic Precipitation Leaching Procedures and strength testing before being left in place. Geo-Con's expertise in the field of soil stabilization was key to remediating the environmental impacts present at the site.

Soil mixing was completed utilizing Geo-Con's custom Calweld drill deck mated to a lattice boom crawler crane. The unit was easily able to complete over 700 cubic yards of soil stabilization in a ten-hour shift resulting in completion ahead of schedule. Over 40,000 CY of contaminated soils were stabilized on this project.


Field personnel utilized a proprietary grout blend consisting of impacted storm water, Portland cement and powered activated carbon to treat site soils. The cement acted to bind and strengthen the mixed soils while the carbon acted as a chemical adsorber. This method rendered the contaminants much less harmful so they could remain on site without requiring costly disposal.

Geo-Con enacted a fully documented quality assurance program for this project including both chemical and geotechnical analysis. Field tests of the mixed soil materials were performed according to specifications and documented utilizing Geo-Con's in-house Quality Control Standard Operating Procedures.

This project was successfully completed having met all our client's parameters, meeting schedule and remaining in budget.


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