Borehole Geophysics Supports Landfill Closing Effort
At the request of Dan Drommerhausen, professional geologist at Shaw Environmental (The Shaw Group), the ISGS Geophysics Section is providing borehole geophysical logging support for Shaw. Shaw is one of the contractors providing environmental and engineering expertise for Allied Waste and Congress Development Company during the closing and monitoring of the Hillside Landfill, Hillside, Illinois, in Cook County. The 300-foot Hillside Landfill was established during the 1970s at the site of a previous limestone/dolomite quarry. Shaw and Raimonde Drilling are core drilling and sampling the bedrock at 11 points surrounding the quarry landfill, and continuous cores are being collected to 200 feet in depth in order to help Shaw Environmental better understand the hydrogeologic complexity of the bedrock surrounding and enveloping the landfill. Many of the boreholes are within ~20 to 30 feet of the old quarry wall. A major reason for requesting technical assistance from the ISGS Geophysics Section was its borehole acoustic imaging capabilities, both operationally and in post-processing the data. This particular logging method helps in detecting bedding planes, fractures, vugs, and voids as well as lithologic boundaries and other changes at very high resolution compared with other, more common logging methods. Since the probe is also equipped with a magnetometer and inclinometers, ISGS scientists are able to also determine the orientation and dip of fractures and bedding planes within vertical or angled coreholes. In addition to acoustic imaging, the ISGS is recording fluid temperature, resistivity, and several other physical properties. The landfill was scheduled for closure in 2008 and is required to meet certain parameters and timelines set by the Illinois Environmental Protection Agency and Attorney General's office.
The ISGS Geophysics Section is committed to providing technical expertise and actively promotes the use of borehole and surface geophysical methods for projects throughout the state that involve the safety and well-being of its citizens, and where borehole and other geophysical methods are not readily available, or when such methods are cost-prohibitive, or when such methods are only considered after a project is under way and timeliness and availability of these methods are critical.