A de-mining team in Lipovac, Croatia, locates an undestroyed mine.

Photo courtesy United Nations/J. Isaac

Locating Mines

Landmines can remain active more than 50 years after they are planted in the ground. For this reason, there is a growing worldwide effort to rid the world of landmines. To do this, we must first locate the millions of landmines that are still buried in dozens of countries around the world. Finding these landmines is extremely difficult, as most minefields are unmarked. And those that are marked can take years to de-mine.

Landmine detection is a slow, methodical process due to the danger involved in locating landmines. While location technology is improving, the following conventional techniques are still relied on heavily:

  • Probing the ground - For many years, the most sophisticated technology used for locating landmines was probing the ground with a stick or bayonet. Soldiers are trained to poke the ground lightly with a bayonet, knowing that just one mistake may cost them their lives.
  • Trained dogs - Dogs can be trained to sniff out vapors coming from the explosive ingredients inside the landmine.
  • Metal detectors - Metal detectors are limited in their ability to find mines, because many mines are made of plastic with only a tiny bit of metal.

Scientists at Ohio State University are developing a new ground-penetrating radar (GPR) device that may be more effective in locating and disarming landmines. This new device would be helpful in locating mines that have little or no metal content. All landmines, including plastic ones, are filled with explosive agents that have electrical properties that make them detectable to the right technology, such as GPR.

A GPR device focuses radar energy just below the ground and just a few feet in front of the user, according to researchers. The device ignores signals that bounce back from the surface and uses specially designed software to make buried objects shine brighter in the radar image. The GPR has been successful in detecting two common landmine casings filled with a waxy substance that is similar to TNT.

Once a landmine is detected, the GPR device shoots two chemical agents into the ground to deactivate it. One agent solidifies the triggering mechanism along with surrounding soil, allowing soldiers to cross the ground. The second chemical agent then solidifies the mine and soil permanently. The mine can then be shoveled out and destroyed.