Paris, June 20 : A space radar originally developed to investigate the soil structure on the Moon and other planets on ESA (European Space Agency) planetary missions, is now being used in Canadian mines to spot hidden cracks and weaknesses in mine roofs, which may revolutionize mine safety on Earth.
The special ground penetration radar GINGER, developed by ESA, will be mounted on a Moon or Mars rover to investigate the soil structure of planets on future space missions.
Ground penetration radar is a geophysical, non-destructive technique, which employs radio waves to determine structures and objects buried in the ground.
Now, the German-Swiss company RST has used this space technology to develop two radars to detect invisible separations in the roofs and walls of mines.
The two radars are the Crack Identification System (CRIS) for hard rock mines and the Potash Roof Inspection System (PRIS) for potash mines.
"CRIS and PRIS are based directly on the GINGER radar technology which we started to develop with ESA in 1994. We have changed the operating frequencies to target what we search for in mine drifts, that is cracks and structural weakness," explained Yvonne Krellmann, RST Project Manager.
"During test campaigns with our two radars CRIS and PRIS in Canada, we have verified that this technology is very successful in spotting horizontal cracks in the roofs of mine drifts; cracks which are difficult to identify with the human eye and which, in time, could cause a roof to fall down," he added.
In principle, a ground-penetration radar works in the same way as a radar to detect aircraft; it sends out an impulse of radio waves and receives the reflected energy.
The radio waves are reflected on any boundary where the dielectric properties of the materials change. While in the case of aircraft radar, this is when the waves hit a plane; for ground-penetration radar used in mineshafts, it is when the waves meet a separation in material or a clay seam in a wall or roof, thus reducing its strength.
To calculate the exact distance or depth to the detected boundary, the travel time of the waves is measured.
According to Hans Martin Braun, RST Manager and shareholder, "Efforts to improve mine safety could, in the near future, include equipping mining machines with ground penetration radars, which are faster and more efficient at detecting weakness in mineshaft walls than visual inspection."