Magnetic Susceptibility


The QL40-HM borehole magnetic susceptibility tool is typically used in mining, geotechnical, and lithology applications. All electronic circuitry resides in a high strength non-magnetic enclosure. The operating frequency is chosen to be sufficiently low to avoid interference from rock conductivities and the circuitry is temperature compensated to minimize thermally induced drift. The QL40-HM is offered with one or two measuring ranges and will resolve strata down to 25 mm. Probe response is practically instantaneous (<0.5s).

The extended range is designed for measurements in complex igneous or metamorphic rocks up to high magnetite rocks. This extended range has been chosen so as to identify layers containing magnetite (0.005 – 100%). The main use of the probe is for prospection on deposits of Fe minerals – magnetite, pyrite and hematite. These data are to be used for quantitative interpretation of the magnetic components in the rocks and estimation of the thickness of layers. In this way, the QL40-HM can directly be used for economic evaluation of the deposit.

The QL40-HM tool is offered in standard range, extended range, dual range magnetic susceptibility, and as a combination tool with induction. All of these options are stackable within the Quick Link (QL) product line or can be run as a standalone tools.

QL Stack Possibilities

  • QL40HM + QL40GR (Gamma): Lithology tool, Glacial till characterization
  • QL40HM + QL40IP (Induced Polarization) : Clay Typing, Geotech
  • QL40HM + QL40IP (Induced Polarization) + QL40GR (Gamma): Mining Exploration tool
  • QL40HM+ QL40IP (Induced Polarization) + QL40IND (Induction): Mineral and Ore body Identification


Two coil system

Temperature – Pressure

0-70°C (32-158°F)
200 bar (2900 psi)

Diameter – Length

45 mm (1.77”) – 1.5 m (59”)


7 kg (15 lbs)


Two depths of investigation for detailed formation characterization

Less temperature drift than other tools on the market

Easy to calibrate for specific borehole magnetic susceptibility ranges

Operates on any standard wireline (Mono, 4, 7 conductor, or Coax)

Slim, 45 mm diameter. One-person operation

Can be combined with other logging tools of the QL product line or operated as a standalone tool


Manufactured by Geotomographie GmbH

Technical Details

Generated wave types: SV
Signal frequencies: Up to 500 Hz (depending on geology and borehole distance)
Operational depth: Up to 100 m
Source length: 1015 mm
Source weight: 6 kg
Cable weight per metre: 377 g
Borehole diameter: 75-100 mm (or larger if spacers are used)
Clamping system: Infatable bladder
Depth indicator: Cable marking every 2 m
Connector: To impulse generator IPG800 or IPG5000
Storage: On drum
Switch box: Switch between two vertical shot directions

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