Electromagnetic Geonics EM-31 Ground Conductivity Meter

Included Accessories: The EM-31 can be used without a data logger.  However, data logging devices such as the Juniper Archer are available as an optional rental item.

Suggested Optional Accessories: For automatic integration with GPS, we suggest the Trackmaker 31 software operating with the Juniper Systems Geode GPS unit.

The EM31 maps geological variations, groundwater contaminants or any subsurface feature associated with changes in the ground conductivity using a patented electromagnetic inductive technique that makes the measurements without electrodes or ground contact. With this inductive method, surveys can be carried out under most geological conditions including those of high surface resistivity such as sand, gravel and asphalt. The effective depth of exploration is about six meters, making it ideal for many geotechnical and groundwater contaminant surveys.

Ground conductivity (quad-phase) and magnetic susceptibility (in-phase) measurements are read directly from an integrated DL600 data logger (which can be easily removed from the console for data transfer). Real Time (RT) graphical presentation of the data during collection is possible by connecting a computer directly to the RS232 output port on the front panel with an optional RS232 interconnect cable.  Important advantages of the EM31 over conventional resistivity methods are the speed with which surveys can be performed, the precision with which small changes in conductivity can be measured and the continuous readout and data collection while traversing the survey area. Additionally, the in-phase component is particularly useful for the detection of buried metallic structure and waste mater

Specifications     MEASURED QUANTITIES 1: Apparent conductivity in millisiemens per metre (mS/m) 2: In-phase ratio of the secondary to primary magnetic field in parts per thousand (ppt)     INTERCOIL SPACING   3.66 metres     OPERATING FREQUENCY   9.8 kHz     POWER SUPPLY   8 disposable alkaline "C" cells (approx. 20 h continuous)     MEASURING RANGES   Conduct.:10,100,1K mS/m; In-phase: +/- 20 ppt     MEASUREMENT RESOLUTION   +/- 0.1% of full scale     MEASUREMENT ACCURACY   +/- 5% at 20 mS/m     NOISE LEVELS   Conductivity: 0.1 mS/m In-phase: 0.03 ppt     DATA STORAGE   10,000 records (2 components); 16,500 records (1 component); ext. memory available     DIMENSIONS   Boom: 4m ext.; 1.4m stored Case: 145x38x23 cm     WEIGHTS   Instrument: 12.4 kg; Shipping: 28 kg