Skip to contentUnited States Department of Transportation - Federal Highway AdministrationSearch FHWAFeedback

Geotechnical Engineering


Geophysical Technologies for Detecting Underground Coal Mine Voids:
An Interactive Forum

Using Helicopter Electromagnetic Surveys to Identify Flooded Workings in Underground Coal Mines

Presenter: Richard Hammarck
University/Organization: USDOE-NET
Phone: 412-386-6585
Fax: 412-386-4459
Mailing Address: P.O. Box 10940
Pittsburgh, Pennsylvania 15236-0940


The U.S. Department of Energy's National Energy Technology Laboratory (NETL) has used helicopter-mounted electromagnetic (HEM) surveys to identify mine pools within active and abandoned underground coal mines in the eastern United States. Currently, two types of HEM surveys have been tested: frequency domain electromagnetic surveys (FDEM) and time domain electromagnetic surveys (TDEM). Preliminary results of this evaluation indicate that FDEM surveys can identify flooded mine workings in areas where overburden is less than 50-m thick. In areas of thicker overburden, TDEM may be preferable. A demonstration of TDEM for the detection of deeper mine pools is currently underway.

Forum Home

Updated: 04/15/2015

United States Department of Transportation - Federal Highway Administration