Detection Methods

Detection Strategies

Land mine detection methods are normally based upon two different strategies:

When a land mine is buried beneath the surface of the ground, the surrounding and covering soil is disturbed from its original state. The change in the soil properties can then be used as a means of identification.
A buried land mine will possess different properties (such as density, strength, thermal capacities, etc.) compared to the surrounding soil. These property changes can be detected by various means.

There are three categories into which present mine detection methods fall. These are high-tech, brute-force, and handprodding. Note that metal detection is no longer a reliable method of detection since a majority of mines made today contain very little, if any metal.

High-tech Methods

High-tech methods of mine detection include passive infra- red, microwave, electrical conductivity, and ground penetrating radar. These methods, in addition to being very expensive, have low accuracy, and a high false alarm rate. A false alarm is when a benign object, such as a rock or tree root, is identified as a mine. This wastes time, as an explosive ordnance disposal (EOD) team must uncover it. This process takes about fifteen minutes, during which time no other activity can take place in the area.

Brute-force Methods

Brute-force methods include ploughs, rakes, heavy rollers and flails mounted on tanks, and explosive breaching methods. These methods are generally effective in clearing a path for soldiers and vehicles through a minefield in time of war, but are of little use in a peace-keeping role. The ploughs and rakes destroy the ground, or only push the mines out of the way, leaving them armed.

The flails, heavy rollers and explosives are effective at destroying simple mines, but smart mines can avoid them, and detonate only the second or third time they are run over. Additionally, for Canadian and other UN peacekeepers, who are in a neutral zone between two opposing forces, it is required that mines be detected and removed without detonating them as explosions in these situations could be unsettling.

Hand-Prodding

Hand-prodding is the most reliable method of mine clearing. A probe is manually inserted into the soil at a 30° angle, approximately every five centimeters. When a solid object is detected, several more probings are conducted to get a feel for the shape and size of the object. If the object is determined to be a potential mine, a mine clearing team comes in to uncover the object. Needless to say, this is a very slow, and extremely dangerous method of mine clearing. A person performing this type of clearing can normally only perform this task for twenty minutes before requiring a rest. This method clears one square meter of land in approximately 4 minutes.