TECHNOLOGY DESCRIPTION:
Morrison Knudsen Corporation (MK) is working under a joint venture agreement with Spetstamponazhgeologia Enterprises (STG) of Ukraine to demonstrate the effectiveness of a clay-based grouting technology. This technology uses clay slurries as a base for grout solutions, which are injected into bedrock fracture systems to inhibit or eliminate groundwater flow in these pathways. The clay slurries may also be used as a base for slurry wall construction.
The MK/STG clay-based grouting technology is an integrated method involving three primary phases: obtaining detailed site characteristics; developing a site-specific grout formulation; and grout mixing and injection. The first phase, site characterization, includes obtaining geophysical, geochemical, mineralogical, and hydrogeological information about the target area.
The second phase, a site-specific grout formulation, is developed in the laboratory. The overall properties of clay-based grout depend on the physical and mechanical properties of the clay, cement, and other additives. Formulated clay-based grouts are viscoplastic systems composed primarily of clay mineral mortar and structure-forming cement. The clay is normally a kaolin/illite obtained from a local source; other additives may be required. The formulation is laboratory-tested to determine suitability for the desired application.
The third phase is grout mixing and placement. The process for preparing and injecting the clay-based grout is shown in the diagram below. Boreholes drilled during the site characterization phase may be used for grout placement. Additional boreholes may be drilled to complete the injection program. A quality assurance program ensures that placement and project objectives are met. After injection, the clay-based grout retains its plasticity and does not crystallize, providing permanent underground protection.
This technology is suitable for providing a flow barrier to groundwater contaminated with both heavy metals and organics. The clay-based grout can be formulated to withstand detrimental conditions such as low pH. The technology can be used at inactive mine sites that produce acid mine drainage. Other potential applications include liquid effluent control from landfills, containment of groundwater contaminated with chemicals or radionuclides, and reduction of brine inflows.
This technology was accepted into the SITE Demonstration Program in winter 1993. It was partially installed in fall 1994 at the abandoned Mike Horse Mine site in Montana; operations were suspended due to winter weather conditions. The second phase, to complete installation of the grout, was canceled due to EPA budget constraints. The demonstration was completed in 1996, but the technology was not fully evaluated due to loss of accessibility to the site.
Over 200 projects using this technology have been completed during the last 20 years in the former Soviet Union and Eastern block countries, as well as in China and Australia. The technology has not been applied in the United States or western hemisphere other than at the Mike Horse Mine site.
EPA PROJECT MANAGER:
Jack Hubbard
U.S. EPA
National Risk Management Research Laboratory
26 West Martin Luther King Drive
Cincinnati, OH 45268
513-569-7507
Fax: 513-569-7620
TECHNOLOGY DEVELOPER CONTACTS:
Kathryn Levihn
Rick Raymondi
Morrison Knudsen Corporation/STG
P.O. Box 73
Boise, ID 83729
208-386-6115
Fax: 208-386-6669