Information Last Revised:
TTP Reference Number: AL911201-G2
1. Technical Name of Technology: Site Characterization using Broadband Electromagnetics (EM)
2. Common Name of Technology: Broadband EM
3. PI and Telephone No: H. D. Mac Lean, 303-248-6101
4. Affiliation: Chem-Nuclear Geotech, Inc.
5. Technology Category: Characterization and Monitoring technologies
6. Developers: Buried Waste Integrated Demonstration (BWID)
7. Application
7.1. Where (in-situ/ex-situ): In-situ
7.2. Media: Soil, Rock
7.3. Targeted Contaminants: Electrically conductive objects or media (such as metals, saline solutions).
8. Scope of project (feasibility study, treatability, bench, pilot, field):
Evaluation of instrument capability and of interpretation methods for buried waste.
9. Integrated Demonstration (ID) Need/Requirements:
The Technology Needs Assessment Final Report (GJPO, 1991) identifies three high-priority characterization needs for environmental restoration. These needs were identified by site personnel responsible for restoration, and include: (1) "non-intrusive methods of locating and identifying buried waste areas, waste forms, and utilities"; (2) "non-intrusive methods of locating and identifying buried contaminants"; and (3) "better methods of characterizing the subsurface geology." A geophysical approach can play an important role in meeting these needs for all DOE sites that require remediation. The BBEM or TDEM, method has the potential to meet all of these needs to some extent.
10. Objective
10.1. Objective of technology:
The objective of this subtask is to evaluate available BBEM systems for their applicability in characterizing waste sites (Mac Lean, 1992). This will require selection of the best instrument available, adaptation of hardware and/or software for shallow, high resolution problems, and then demonstrating its performance capabilities.
10.2. Baseline (baseline technology to which it is compared):
Conventional Electromagnetic (EM) System (EM System)
11. Process Description:
BBEM is an asymmetric two-coil induction system utilizing a large 5 meter diameter transmitting loop used to generate the equivalent of a three-decade frequency spectrum. When current flow is interrupted a transient magnetic field may be briefly observed. This transient decay is analyzed to determine the magnitude of the induced field at systematic intervals. This information provides one with conductivity information at various delay intervals which may be equated to different depths of penetration. The system may be employed in either a traverse/profile configuration or as a vertical electric expander, or "sounding" device. For this reason it is easily adapted to use in describing three dimensional bodies.
11.1. Input:
As BBEM represents a non-intrusive technique, the only input will involve the momentary introduction of a transient electromagnetic field beneath the property surveyed.
11.2. Output:
No physical product will be produced by the BBEM technique; the only output will be in the form of data describing electrical properties of the earth.
12. Summary of Technology Advantages (relative to the baseline: faster, better, cheaper, safer):
BBEM is a superior method to measure earth conductivity due to its utilization and analysis of the full transient decay curve. This provides, in effect, the equivalent of three frequency decades of information and, through a single station, scans a section of ground into the third dimension. This approach provides one with an expander, or vertical electric "sounding" at each station, revealing the changes in conductivity distribution with depth. An interpretation curve is firmly founded on 20-30 data points rather than the usual single point for each combination of frequency and coil separation. In addition, the depth of investigation is not dependent on the coil separation so that the survey may be designed to avoid dilution from adjacent ground and/or cultural obstacles.
13. Limitations of Technology (relative to the baseline: faster, better, cheaper, safer):
Although broadband induction provides a more sophisticated alternative, it also requires more data manipulation to transfer the transient decay information into conductivity values. This, in turn, requires more operator knowledge and a reduction in survey speed when compared to a frequency domain system. BBEM also requires a greater investment in instrumentation, with the going price at least triple that of a conventional system.
14. Major Technical Challenges:
a) Select the best commercially available hardware and software system for waste characterization. (Snyder, 1990)
b) Develop field procedures for the candidate system which will be most effective in providing desired target definition. (Dickerson, 1990)
c) Develop methods of analysis which optimize interpretation capabilities. (Hohmann, 1987)
15. Technical Effectiveness:
15.1. Performance
15.1.1. Remaining Contamination: (contamination mobility reduction, volume reduction, toxicity reduction)
Summary (20 words or less): Not applicable
Further Description (unlimited length):
15.1.2. Process Waste
15.1.2.1. Status of waste (mobility, volume, hazard, recyclability)
Summary (20 words or less): Not applicable
Further Description (unlimited length):
15.1.2.2. Treatment (needed, available)
Summary (20 words or less): Not applicable
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15.1.2.3. Decontamination / Decommissioning
Summary (20 words or less): Not applicable
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15.1.2.4. Disposal (needed, available)
Summary (20 words or less): Not applicable
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15.1.3. Practicality
15.1.3.1. Foreclose Future Options
Summary (20 words or less): No effect on future options.
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15.1.3.2. Reliability
Summary (20 words or less): The recommended BBEM technique should perform routinely in the field with less than 10% production down-time.
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15.1.3.3. Failure Control
Summary (20 words or less): No immediate consequences due to failure.
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15.1.3.4. Ease of Use
Summary (20 words or less): The system is designed for use only by a fully-trained operator and interpreter.
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15.1.3.5. Infrastructure
Summary (20 words or less): None required.
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15.1.3.6. Versatility
Summary (20 words or less): BBEM will be useful to describe any waste environment where conductive targets are sought.
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15.1.3.7. System Compatibility
Summary (20 words or less): BBEM will be compatible with any other non-intrusive sensing technology and may be advantageously integrated for analysis purposes.
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15.1.3.8. Off-the-Shelf (procurement ease)
Summary (20 words or less): This instrument is currently available from commercial sources.
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15.1.3.9. Maintainability
Summary (20 words or less): BBEM will require no modification and can be readily maintained with the help of the manufacturers warranty service.
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15.1.3.10. Safety Measures
Summary (20 words or less): No hazards whatsoever.
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15.1.4. "Works" (functions as intended)
Summary (20 words or less): Field demonstrations performed during 1992 indicate the utility of this technique. (Mac Lean, 1993)
Further Description (unlimited length): BBEM has located vertical pit boundaries with 1 meter precision and pit depth extent within 2 meters.
15.2. Cost
15.2.1. Start-Up Cost
Summary (20 words or less): Projected cost of this evaluation program is $450K.
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15.2.2. Operations and Maintenance Cost
Summary (20 words or less): A rough estimate to operate BBEM 50 hours/week would require, perhaps 5 hours of maintenance.
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15.2.3. Life-cycle cost
Summary (20 words or less): The presently available candidate system may be purchased for $75K from Geonics, Ltd. of Mississauga, Ontario, Canada.
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15.3. Time
15.3.1. Years Until Available
Summary (20 words or less): This evaluation procedure will be completed by 09/30/93.
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15.3.2. Speed/Rate
Summary (20 words or less): A survey requiring detail coverage over 1/2 acre can be performed in one working day.
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15.3.3. Years to Finish
Summary (20 words or less): Two years are required to complete evaluation of the candidate hardware and software system.
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16. Environmental Safety and Health
16.1. Worker Safety
16.1.1. Exposure to Hazardous Materials/Hazards
Summary (20 words or less): Not applicable
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16.1.2. Physical Requirements
Summary (20 words or less): Movement of 50 pound instrument packages and antennae units will be required.
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16.1.3. Number of People Required
Summary (20 words or less): Two persons will be required to move coils, take readings, and perform initial quality control in the field.
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16.2. Public Health and Safety
16.2.1. Accidents
Summary (20 words or less): Not applicable
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16.2.2. Routine Releases
Summary (20 words or less): Not applicable
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16.2.3. Transportation
Summary (20 words or less): Not applicable
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16.3. Environmental Impacts
16.3.1. Ecological Impacts
Summary (20 words or less): Not applicable
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16.3.2. Aesthetics
Summary (20 words or less): Not applicable
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16.3.3. Natural Resources
Summary (20 words or less): Not applicable
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16.3.4. Energy Demands
Summary (20 words or less): Energy usage is minimal (<100 watts).
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17. Socio-Political Interests
17.1. Public Perception
17.1.1. Proponent Reputation
Summary (20 words or less): Non-intrusive BBEM surveys are totally benign and should be completely acceptable to the public.
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17.1.2. Familiarity / Understandability
Summary (20 words or less): Non-technical persons are unlikely to be familiar with this technology.
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17.2. Tribal Rights / Future Land Use
17.2.1. Capacity for Unrestricted Use (terrestrial, aquatic)
Summary (20 words or less): No restriction should be placed on applications of this non-intrusive technology.
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17.3. Socio-Economic Interests
17.3.1. Economic Impacts
Summary (20 words or less): Not applicable
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17.3.2. Labor Force Demands
Summary (20 words or less): Not applicable
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18. Regulatory Objectives
18.1. Compatibility with Cleanup Milestones
Summary (20 words or less): Not applicable
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18.2. Regulatory Infrastructure / Track Record
Summary (20 words or less): Not applicable
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18.3. Regulatory Compliance
Summary (20 words or less): Not applicable
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19. Industrial Partnerships
19.1. Company Names:
19.2. Rationale:
19.3. Contract Mechanism:
19.4. Other Potential Companies:
19.5. International:
20. Intellectual Property
20.1. Patent Ownership:
20.2. Other Owners:
20.3. Patent Number:
21. Cost Sharing:
22. Background on this technology (Where did the idea come from? Who else is doing similar work? What have the results been to date? What is the most significant competitor to this technology?):
The theory for induction EM techniques is based on the analysis of the response of models to a transmitter signal consisting of a single harmonic frequency. For this reason, early EM instruments and most contemporary EM instruments are narrow band. That is, they measure steady-state parameters (e.g., amplitude and phase) of a magnetic field created by a transmitter driven by a steady-state harmonic current. It has been recognized that the transmitter frequency of such systems affected their depth of exploration and, to some extent, their resolution. In general, higher frequency offers better spatial resolution at the expense of a smaller depth of investigation. Consequently, so-called frequency domain EM systems are optimized for a particular exploration problem by properly choosing a transmitter frequency and a transmitter-receiver separation.
The principle of BBEM is to transmit a signal that covers a broad frequency spectrum (i.e., perhaps 3 decades). The received signal resulting from a broadband transmission contains more information, not only about the depth of buried conductors and geologic features but also about their conductivity. Modern instruments for acquiring BBEM data are based on the time-domain technique. In TDEM, the transient decay of the magnetic field is measured following the interruption of current flow in the transmitter coil.
Development of the TDEM method for applications in mineral exploration was started 15 years ago by Newmont Mining and by CSIRO in Australia (Spies 1980). In the decade or so since its introduction, a wealth of technical papers covering TDEM have appeared in the literature.
The TDEM method has not been widely applied to geotechnical problems because of the relatively high cost of the instrumentation and the lack of methods for the analysis of small conductors contained in a conductive host. Contemporary literature on the TDEM method suggests that the technique can reveal quantitative information on the nature of DOE sites identified in Technology Needs Assessment Final Report (GJPO, 1991).
23. Reference Documents:
Dickerson, J. W., 1990. Electromagnetic Geophysical Response Characteristics of Common Objects, U.S. Department of Energy Grand Junction Projects Office, Chem-Nuclear Geotech, Inc., Grand Junction, CO, ERDP Report, September 1990.
Grand Junction Projects Office, 1991. Technology Needs Assessment Final Report (Predecisional Draft), DOE/ID/12584-92, Vols. 1 and 2, U.S. Department of Energy, August 1991.
Hasbrouck, J. C., 1989. Geophysical Surveys at INEL/RWMC Cold Pit, Acid Pit, and Pit 9, Report UNC/GJ-103, U.S. Department of Energy Grand Junction Projects Office, UNC Geotech, Grand Junction, CO
Hohmann, Gerald W., 1987. "Numerical Modeling for Electromagnetic Methods of Geophysics," in Electromagnetic Methods in Applied Geophysics, Nabighian, Misac N. (ed.), Tulsa, OK, Soc. Expl. Geophys.
Mac Lean, H. David, 1992. Commercially Available Broadband Electromagnetic Systems for U.S. Department of Energy Waste Site Characterization, Report GJPO-GP-2, U.S. Department of Energy Grand Junction Projects Office, Chem-Nuclear Geotech, Inc., Grand Junction, CO.
Mac Lean, H. David, 1993. Time Domain Electromagnetic Survey of Three Waste Burial Pits at INEL Radioactive Waste Management Complex, Vols. 1 and 2, U.S. Department of Energy Grand Junction Projects Office, Chem-Nuclear Geotech, Inc., Grand Junction, CO
Snyder, D. D., 1990. Optimal Application of Induction EM to DOE Site Investigations, U.S. Department of Energy Waste Site Characterization, U.S. Department of Energy Grand Junction Projects Office, Chem-Nuclear Geotech, Inc., ERDP Report, September 1990.
Spies, B. R., 1980. "TEM in Australian Conditions--Examples and Model Studies," Ph.D. Thesis, Macquarie University, Sydney, Australia, March 1980.