Transient Electromagnetics (TEM)

Transient Electromagnetics equipment sends a strong electrical current through a ground loop, then cuts it off abruptly and measures the resulting decaying magnetic field to detect conductive material below the surface. The sudden current shutoff induces eddy currents in any conductive body underground, such as an ore deposit or a metal object, and these eddy currents produce a secondary field that a receiver coil picks up as it decays over a few milliseconds. This decay pattern reveals both the depth and conductivity of the target, giving more detailed subsurface information than simple metal detection alone.

Transmitter loop size varies by survey scale, ranging from small handheld loops around 1 metre square for shallow, localized surveys up to large ground loops covering hundreds of metres for deep mineral exploration work. Current output through the transmitter typically reaches several amps, with higher current improving signal strength but also increasing power demands on the field generator or battery bank running the system. Receiver coils measure the decaying field at multiple time intervals after shutoff, called time gates, building a profile of how quickly the signal fades at different depths.

Depth penetration depends on loop size, current strength, and ground conductivity, with systems capable of reaching several hundred metres in favorable geological conditions. Data recording units log readings alongside GPS position, letting survey teams build a subsurface map covering an entire exploration grid rather than isolated point readings.

Mining and mineral exploration companies use TEM systems to locate ore bodies before committing to expensive drilling programs. Groundwater survey teams use TEM to map aquifer boundaries and salinity layers underground. Geotechnical firms also use TEM for site investigation ahead of major construction projects needing subsurface conductivity data.

Tactical Supply Pakistan supplies Transient Electromagnetics equipment to mining companies, groundwater survey teams, and geotechnical firms across Pakistan. Loop size and power configuration are matched to expected survey depth and area coverage.