Snowmobile-mode, ATV-mode, Vertical-mode, Tunnel-mode, Basin-mode, Water-mode
Snowmobile-mode data are superior in quality and usefulness for inversion modeling compared to those acquired by drones or other aircraft because the sensor is much closer to the target mineralization.
Snowmobile-mode cesium magnetomter surveys are the most common. Other methods carried out in snowmobile-mode include GPR, EM34 and IMAGEM.
Snowmobile-mode Cesium Magnetometer Surveys:
Navigation track-lines pre-programmed, no existing grid is needed.
Readings positionally or time triggered, typically 3-metre stations or 10 times per second.
‘Ruggedized’ navigation computer also records GPS and geophysical data – seamless.
Survey speeds 2 m to 5 m per second in rough terrain – faster over fields and flat areas.
GPS antenna located at front of sleigh or cart, magnetometer located at back of sled/cart.
Post-processing includes Layback and Latency corrections.
Operational in exceptionally rough terrain, boulder fields, etc. and in severe cold.
Capable of collecting gradient magnetics data by adding sensors.
Base Station Magnetometer System:
Magnetometer readings at 0.5s or 1s intervals.
At least 2 base stations running for quality control and duplication in case one fails.
Base stations are ‘leap-frogged’ along the survey area to keep as close to survey area as possible – important for best precision in the arctic.
Magnetometer readings linked to GPS time.
Snowmobile-mode GPR Surveys
GPR setup is mounted in a standard plastic snowmobile sleigh.
A large counter wheel extends from behind to trigger readings.
Snowmobile-mode IMAGEM Surveys
The IMAGEM system is a state-of-the-art high resolution time-domain system that is capable of recording 200 channels of on- and off-time EM measurements.
Approximately 700 amps are transmitted through a single-turn and highly portable platform. This system, which is based on airborne survey designs, replaces 50-m and less inter-coil MaxMin/Promis readings. The fixed receiver and transmitter configuration provides data that are easier to interpet particularly in variable/rough topography. Readings are collected at less than 1-second intervals for much higher resolution than MaxMin or Promis surveys.
Time constants can be calculated and the data can be imported to modeling software such as Maxwell.
The IMAGEM system is in high demand for gold exploration where high precision is required. ClearView continues to apply it for walking-mode surveys and dual cesium-magnetics & electromagnetic snowmobile-mode surveys in the arctic.
All data are processed and plotted in the field using Geosoft and proprietary in-house software.