Description
The length between receiver and transmitter loops range between 20 m and 400 m for standard applications. This system allows to work with 10 frequency ranging from 110 Hz to 56 kHz. The depth of penetration depends on the spacing and on the frequency. It is usually considered as of the order of half the spacing. A profiling can be performed by moving both the transmitter and the receiver to the next station.
Traditional HLEM slingram systems only measure the vertical component of the magnetic field (Hz). The Secondary/Primary magnetic field ratio being linked to the soil conductivity, they allow to locate conductive structures intersecting a profile. The 3 components measured by the PROMIS system permits to give an information on the direction (strike) of the structure (because the magnetic field remains perpendicular to the eddy current directions).
With the Promis system, the productivity is increased by an automatic processing (measurement automatically carried out for the set of frequencies, without required communication between the two operators). Two leds indicate when the transmitter has to move to the next station. Two inclinometers correct for deviations from horizontal position and a GPS unit can be connected. The selection of the frequencies and the stacking parameters is made at the beginning of the survey for optimizing the field work.
The data can be transferred, edited, filtered, plotted and exported with the EMSYS software provided with the instrument.
Applications
Water resources
- Locate conductive fault in fractured aquifer
- Assess water table characteristics
- Characterize salt water wedge extension in groundwater
Environment
- Monitor pollution
- Detect leaks and monitor degradation in waste disposal
- Locate and image buried structures
Natural hazard
- Detect and characterize cavities
- Assess landslide extension and volume
- Detect and locate clayey layers for geotechnical application
Mineral exploration
- Detect dike type orebody
- Deep orebody or detection
- Detect lens type orebody
