Product
An example of superb microfracture grouting in rocksalt at the WIPP site
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Cracks as small a 6 microns in size were filled at the Lake Mead Project
US Grout is also effective in filling larger cracks as demonstrated here.
The process at the Lake Mead Project
A typical Permeation Grouting procedure
The Waste Isolation Pilot Plant (WIPP) is a Department of Energy pilot repository for radioactive and hazardous waste disposal. Sandia National Laboratories is the scientific advisor for the WIPP, responsible for designing and conducting tests that prove the repository is safe. This was done to the satisfaction of the Environmental Protection Agency and the site was opened in 1999.
The repository horizon is 2,154 feet below surface in a salt bed approximately 2,000 feet thick. All underground openings are subject to a closure force, which is simply the weight of the overlying rock. This force, equal in all directions, is roughly one pound per square inch per foot of depth. Stress redistribution around the openings results in microfracturing of the salt, which ultimately extends into the enclosing salt as much as a meter and a half. This microfractured rocksalt, called the "Disturbed Rock Zone", (DRZ) would allow brine and radionuclides to bypass any seal placed in the tunnels.
A microfine cement based grout was required to effectively seal these extremely small fractures (often as small as 6 microns). To enter such tiny fractures, the grout particles had to be even smaller than the fracture width. Commercially available microfine grouts were analyzed in the laboratory and found to be unsuitable for one reason or another. Sandia National Laboratories then proceeded to develop a new grout which, after extensive laboratory development and testing, was successfully tested underground in salt at the WIPP. The permeability of the DRZ was lowered as much as 1,000 times, and the grout has been approved for use at the WIPP.
Sandia National Laboratories obtained two patents on this grout and transferred the process, under license, to U.S.Grout, LLC. A state-of-the-art, computer controlled, manufacturing plant is located in Malad, Idaho approximately 100 miles north of Salt Lake City, Utah.
Other Users
Arrowrock Dam (BC): US Grout Standard Ultrafine Grout was chosen to decrease the permeability of the rock below the concrete dam (this is called a grout curtain and is required to prevent water from passing beneath the dam through fractures in the rock).
Hollywood Metro Tunnel (downtown Hollywood, CA): Hayward Baker (a major Geotechnical firm) selected US Grout Standard Ultrafine grout as the material of choice to seal the tunnel against water inflow and to prevent settlement of the surface (the tunnel passes under very expensive real estate). They were pleased with its performance. The tunnel is now part of an expanded subway system.
United States Strategic Petroleum Reserve: (SPR) US Standard Ultrafine Grout was used to successfully seal water inflow at Weeks Island, Louisiana (a salt dome housing a large part of the SPR).
Cargil Salt: U.S. Standard Ultrafine Grout is currently being injected into salt at a commercial salt mine, located in a salt dome at Avery Island, Louisiana. The grout is used to seal microfractured salt and stop water inflow. This commercial enterprise is very pleased with the grout performance.
Lake Mead Intake #2 A large pump forebay and a 1,600 foot tunnel (16 feet high x 14 feet wide) 340 feet below the surface of Lake Mead, was recently successfully completed by the firm of Peter Kiewit and Sons. This project, part of a multi-billion dollar water project for the Southern Nevada Water Authority is situated about 20 miles south of Las Vegas Nevada. The on-schedule completion of Intake #2 was critical to other segments of the project. Lake Mead Intake #1 is parallel to, and a short distance south of #2 but at a higher elevation and therefore a lower hydrostatic head. Driven in the late 1970's, it was delayed for nine months due to water inflow. 1,500,000 pounds of U.S. Standard Ultrafine Grout was used in Intake #2, successfully controlling the water and allowing an on-time completion. The contractor was totally pleased with the product.