Gap GeoPhysics Australia (GapGeo) has a long history of delivering quality and efficient EM surveys. GapGeo’s EM surveys include the industry standard SMARTem24 Receivers manufactured by Electromagnetic Imaging Technology Pty Ltd (EMIT) and GapGeo’s own proprietary TM-7 SAM Receivers. These instruments are coupled with high-powered GeoPak Geophysical Transmitters to produce data with unprecedented signal / noise ratios.
The receiver, type of sensor and acquisition mode used for EM surveys will depend on the target type and survey objectives. GapGeo uses three main survey techniques.
SAM EM This technique uses a caesium-vapour sensor and the TM-7 SAM Receiver to collect both total magnetic field and transient EM responses from a moving survey. It is designed for very rapidly acquired high resolution surveys – can be foot, vehicle or helicopter acquired.
SAMSON is the most sensitive mode of operation for acquiring very high precision, low noise TEM data. It is typically used for deep penetration surveys. Data is acquired using the TM-7 SAM Receiver at a sequence of stations (typically for 3 – 5 minutes) along each survey line. Depending on the terrain 8 – 12 stations can be acquired per hour.
SMARTem24 developed and manufactured by ElectroMagnetic Imaging Technology (EMIT), the SmartTEM24 system can acquire multiple parameters including TEM and Magnetics. The SMARTem24 is used for predominately Fixed-Loop EM (FLEM) and Moving-Loop EM (MLEM) in conjunction with either an EMIT SMART Fluxgate sensor and / or a GeoPak RVR coil.