Time-Domain Electromagnetics (TDEM) Surveys – Ground & Borehole

In mineral exploration, knowing where and how to drill can make all the difference. Ground and Borehole TDEM surveys help you identify and prioritize conductive targets, even those buried beneath conductive cover or located beyond the reach of your drillhole.

Abitibi Geophysics offers a suite of advanced TDEM solutions tailored to different deposit styles, environments, and stages of exploration. Whether you're chasing deep VMS conductors, mapping graphite-rich zones for uranium, or refining drill targets around a known deposit, our methods improve confidence in your models.

Where TDEM helps most

Ground and Borehole TDEM are particularly useful for:

Detecting sulphide lenses and shear zones
Mapping conductive structures hidden under overburden
Following up airborne EM targets with higher resolution
Extending known deposits or targeting new ones at depth
Clarifying conductor geometry (dip, width, continuity)
Identifying graphite-rich zones and alteration patterns

These methods help you see what drilling can’t and choose drill targets with more confidence. Smarter drill planning starts here.

Ground TDEM Surveys

We tailor every TDEM survey to your geology, terrain, and objectives. Our ground-based configurations include:

Conventional Single Loop EM: often used as an initial survey when limited information is available, or to confirm depth extensions of known targets. Commonly applied in exploration for massive sulfides and other base metals, the loop can be positioned more effectively when target geometry is better understood to optimize coupling with the expected conductor.
Moving Loop TDEM: flexible for lateral tracking and anomaly refinement, widely used in uranium exploration to follow graphitic conductors beneath glacial or sedimentary cover.
InfiniTEM: duel lobed, single- or double-loop configuration for deeper, better-resolved imaging, commonly applied in VMS exploration with steeply dipping targets under conductive overburden.
OmniVision: three-loop design detects conductors of any dip, ideal when target geometry is unclear or in folded/complex settings with uncertain orientation.

All systems use our portable 18kW TerraScope® transmitter and ARMIT-3 sensor, which captures both B-field and dB/dt on all three axes in a single pass, even in rough terrain.

Borehole TDEM Surveys

Borehole EM expands your investigation volume by detecting conductors near or beyond your drillholes. Using downhole probes and optimized surface loops, we help you:

Detect off-hole conductors not intersected by drilling
Map geometry and dip to improve 3D targeting
Extend your detection radius and depth
Follow up known intercepts or model ambiguous results

We tailor every TDEM survey to your geology, terrain, and objectives. Our borehole configurations include:

InfiniTEM duel lobed, single- or double-loop configuration for increased penetration
Conventional Square Loop: detects conductors when loop placement and target orientation are reasonably constrained.
Duel Square Loop position: boreholes can be read with two loops at different positions to optimize coupling with targets of varying or unknown geometry.

What Is TDEM?

Time-Domain Electromagnetics (TDEM) works by generating a primary magnetic field with a transmitter loop, which induces eddy currents in the ground. As the transmitter current shuts off, these eddy currents decay, producing a secondary magnetic field that is recorded by a receiver. This data reveals underground conductive features, distinguishing weaker conductors like nickel from stronger ones like copper.

We measure both dB/dt and B-field using the ARMIT-3 sensor. dB/dt enhances detection of weak conductors, while B-field better defines strong ones, providing a complete picture in less time.

Why Choose Abitibi’s TDEM?

Up to 30A current with the 18kW TerraScope® transmitter
Proprietary InfiniTEM and OmniVision loop designs
ARMIT-3 3-axis sensor for complete data in a single pass
Multiplexing and smart switching, more data, fewer passes
Fully portable setups for remote or rugged terrain

Talk to Our Geophysicists

We’ll help you match the right TDEM configuration to your geology and exploration goals. Whether you're planning a first-pass survey or refining advanced targets, we're here to support better decision-making.