Geologic and Environmental Probe System (GEOPS)

Abstract

This paper describes the engineering design and development of a novel 2004 R&D 100 award winning probe system that is used to monitor and collect samples from within waste areas safely — without negative exposure to the environment or people. The Idaho National Laboratory (INL) has developed a multiple-use, low-cost subsurface probing system to safely sample and monitor targeted subsurface areas, from within and below abandoned or active landfills, mining areas, farms, airports, or from any of the more than 77,000 identified potentially hazardous waste sites across the U.S. The probe system uses a unique probe casing and tip system that—once placed in a zone of interest—accepts instrument inserts to provide invaluable potential contaminate transport or other data from saturated or unsaturated waste zones, or from groundwater zones. The Geologic and Environmental Probe System (GEOPS) is the newest generation of INL-developed subsurface probes. The system’s robust probe casing platform is installed into or below a waste zone using direct push or sonic drill rigs, using a technique similar to pushing a needle into an apple. Subsurface conditions are not disturbed as in rotary drilling operations, cuttings are not brought to surface during installation, and workers and the surface environment are isolated from contaminants. One key to the capture of samples from the extremes of the subsurface using the GEOPS is the probe tip system. The specially designed tip utilizes a cylindrical section of sintered steel that has small pore openings and are used to filter liquid and gas samples from surrounding soil (i.e., area of interest) into the probe system. The sintered steel filter has reduced material properties, as compared to the probe casing platform and is vulnerable to high loadings, as would be experienced during probe installation. The probe tip system was specially designed to shield the filter component from large compressive and tensile loading and deliver it safely to a target depth. Once the casing is at the desired sampling depth, the instruments are placed into the platform, a vacuum is imposed on the system, and vapor and liquid subsurface samples are brought safely to surface though the sintered steel filter.