MEGATEM

MEGATEM is the most powerful time-domain airborne electromagnetic system available in the world. MEGATEM has a high level of client acceptance, attributable to its depth of penetration, large exploration footprint and capability to fly remote survey areas. The MEGATEM multi-sensor configuration offers the lowest exploration cost per volume of rock explored.

The MEGATEM system is installed on a Dash 7 aircraft which has the capacity to carry a large transmitter loop plus a multi-sensor geophysical payload. The Dash 7 has significant operational efficiencies due to its reliability, long range endurance and good performance at high altitudes and temperatures.  The Dash 7 with its long endurance is most cost effective on large regional surveys with few airports.

MEGATEM is used to advance the geological understanding of geographically remote areas by measuring multiple physical rock characteristics simultaneously with a one-pass, non-intrusive flight. In addition to providing superior direct target detection, the multi-parameter geophysical data is acquired to assist with the interpretation of the geology. Routinely MEGATEM surveys include a high resolution magnetometer as well as a multichannel gamma-ray spectrometer. The Dash 7 has the capability to also include an airborne gravity gradiometer system.

Fugro Airborne Surveys, in cooperation with the Government of Canada, the Government of Quebec and Xstrata (formerly Noranda/Falconbridge) sponsored the UQAT research project on mineral exploration applications of the MEGATEM system in the Abitibi Region of Quebec. For details on this project and to view the MEGATEM data over the Iso New Insco VMS deposits in Hebecourt Township, Quebec, please click here.

Fugro is continually enhancing the MEGATEM system by incorporating new advances in electronics, signal processing technologies and evolving software processing methods.  The significant advantages of the MEGATEM system are:

2,000,000 Am² dipole moment

Power translates into depth of penetration. MEGATEM has been used extensively in the Athabasca Basin, Saskatchewan, Canada, to map conductors occurring in the basement unconformity which may be at depths in excess of 1,000 meters.

Multiple receiver coils to measure X, Y & Z axis response

The additional data from the 3-axis receiver coils improves the interpretation of conductor location and orientation yielding more definitive information about conductor depth, shape, strike, dip, and lateral offset from the flight line.

12.5 / 15 /25 / 30 / 75 / 90 Hz Transmitter frequency

The low frequency options are used to increase the depth of penetration in low resistivity environments. The higher frequencies provide better signal-to-noise ratios which improve depth penetration in high resistivity environments.

B-field, dB/dt, on-time, and off-time measurements

Expand the sensitivity range to weak conductors and very good conductors; e.g. nickel sulphides.

Early time measurements (broadband)

Broadband receivers allow collection of early time windows, improving sensitivity to weak conductors with rapid decay, such as alteration halos and zinc sulphides and increasing depth of penetration in resistive environments.

Large separation between transmitter and receiver coils

The combined effect of the MEGATEM geometry and dipole moment result in the largest exploration footprint of any airborne EM system. As a result, the line spacing can be widened on exploration surveys with little risk of missing a conductor.

Dash 7 aircraft is an efficient workhorse

The Dash 7 safely carries a 29 meter diameter, 6-turn loop plus it has capacity for other sensors. It has proven to be remarkably efficient at high altitudes in Chile and Peru; on remote projects far from any airport and in a wide range of temperatures.

MEGATEM System Specifications