Application Of Magnetic And Multi-Frequency Em Techniques For Landfill Investigations: Case Histories

Magnetic and electromagnetic techniques were used in the investigation of three landfill sites.<br>Historical records of the content and location of buried waste in all three landfills were poor.<br>The geophysical surveys were conducted to map the trenched areas or locate buried drums and<br>other metal objects within the landfill. Waste filled trenches exhibit a higher conductivity than<br>the surrounding undisturbed materials. Drum burial areas have a higher apparent conductivity<br>and also produce significant magnetic anomalies.<br>These geophysical surveys provided accurate locations of the trenches and drum caches in all<br>three cases. When used together, the magnetic and electromagnetic data could be used to<br>differentiate between ferrous and non-ferrous metallic waste. Modern equipment measures and<br>logs EM and magnetic data efficiently, allowing surveys to have high spatial density. This<br>increase in data density provides more precise delineation of trenched areas and more accurate<br>location of buried objects such as drums. The increased efficiency of the modern instruments,<br>computers, and techniques enables the user to complete high quality surveys in hours or days and<br>present the environmental investigator with understandable maps in the field.