Successful Piloting of Discrete ISS at a CCR Impoundment.pdf

George Little, Forgen
Paul Lear, Lear Environmental Consulting
Tim Silar, Silar Services
Richard Chapman, Forgen

Description

Successful Piloting of Discrete ISS at a CCR Impoundment Authors Mr. George Little - United States - Forgen Dr. Paul Lear - United States - Lear Environmental Consulting Mr. Tim Silar - United States - Silar Services Mr. Richard Chapman - United States - Forgen Mr. John Magee - United States - Silar Services Mr. Ambaresh Tijare - United States - Forgen Mr. David Miller - United States - Forgen Abstract Discrete ISS involves targeted stabilization treatment in a discrete treatment zone. Rather than treating overburden, the mixing auger injects water and/or air as a drilling fluid until the top of the treatment zone is reached. Reagent grout is then injected as the mixing auger moves through the treatment zone. For CCR impoundments, Discrete ISS offers the ability to produce a low permeability treated zone underneath the CCR material, hydraulically isolating it from groundwater. Forgen conducted pilot testing at a CCR impoundment in the Summer of 2022 under the direction of Silar Services Incorporated (SSi), the discrete ISS technology patent holder. In three areas of the impoundment, Forgen successfully drilled through 25 to 45 feet of CCR material and stabilized a 4 to 5-foot thick layer of ash and underlying native soil. A rosette of 7 columns was installed in each of the 3 areas. Logs were generated for each column by the drill rig monitoring system, including the inclination of the Kelly bar/drill shaft (via x and y inclinometers) and the horizontal location (northing and easting) of the mixing head tip logged continuously throughout the advancement of the auger at each column location. The logs allowed Forgen to demonstrate that complete overlap was achieved between adjacent columns. Combined with the QC results for collected wet grab samples and post-treatment core samples, Forgen was able to demonstrate that the treatment zone was emplaced at the planned top and bottom elevations and that the hydraulic conductivity of the treated material was less than 1x10-6 cm/s. The pilot study results indicate that a low permeability layer can be installed underneath the CCR material in the impoundment.

 
May 14th, 1:30 PM May 14th, 2:00 PM

Successful Piloting of Discrete ISS at a CCR Impoundment.pdf

Grand Rapids, Michigan

Successful Piloting of Discrete ISS at a CCR Impoundment Authors Mr. George Little - United States - Forgen Dr. Paul Lear - United States - Lear Environmental Consulting Mr. Tim Silar - United States - Silar Services Mr. Richard Chapman - United States - Forgen Mr. John Magee - United States - Silar Services Mr. Ambaresh Tijare - United States - Forgen Mr. David Miller - United States - Forgen Abstract Discrete ISS involves targeted stabilization treatment in a discrete treatment zone. Rather than treating overburden, the mixing auger injects water and/or air as a drilling fluid until the top of the treatment zone is reached. Reagent grout is then injected as the mixing auger moves through the treatment zone. For CCR impoundments, Discrete ISS offers the ability to produce a low permeability treated zone underneath the CCR material, hydraulically isolating it from groundwater. Forgen conducted pilot testing at a CCR impoundment in the Summer of 2022 under the direction of Silar Services Incorporated (SSi), the discrete ISS technology patent holder. In three areas of the impoundment, Forgen successfully drilled through 25 to 45 feet of CCR material and stabilized a 4 to 5-foot thick layer of ash and underlying native soil. A rosette of 7 columns was installed in each of the 3 areas. Logs were generated for each column by the drill rig monitoring system, including the inclination of the Kelly bar/drill shaft (via x and y inclinometers) and the horizontal location (northing and easting) of the mixing head tip logged continuously throughout the advancement of the auger at each column location. The logs allowed Forgen to demonstrate that complete overlap was achieved between adjacent columns. Combined with the QC results for collected wet grab samples and post-treatment core samples, Forgen was able to demonstrate that the treatment zone was emplaced at the planned top and bottom elevations and that the hydraulic conductivity of the treated material was less than 1x10-6 cm/s. The pilot study results indicate that a low permeability layer can be installed underneath the CCR material in the impoundment.