Technologies for detecting antipersonnel mines

Antipersonnel mines are explosive devices designed either to injure or kill humans. They are indiscriminate weapons that injure and kill civilians in every corner of the globe, every day. Moreover, antipersonnel mines do not recognize ceasefires and claim victims long after the end of conflicts. 
The 1997 Mine Ban Treaty, a.k.a. the Ottawa treaty, was signed in the Canadian city of Ottawa. Such treaty aims at eliminating antipersonnel landmines around the world. Nevertheless, there are doubts about its effectiveness, since countries like USA or Russia have not joined the treaty.

Since today is the UN day against mines, this article will  give a brief introduction of how technology contributes for detecting and removing personnel mines.
Image 1. Landmine field
Source: GenevaLunch

The technologies used for detecting landmines may divided into 5 categories: Metal detector technologies, Electromagnetic technologies, Acoustic / seismic technologies, biological technologies and mechanical technologies.

The technologies

Metal detector 
They are cheap and easy to use. They are magnetic sensors that send  current through a wire wrapped around a metal rod or loop, producing a magnetic field that penetrates the ground. Nevertheless, one disadvantage is that all metalic objects are detected. Although more sophisticated metal detectors may detect and see parts of less than 1cm, they cannot be detect new mines made of plastic material.

This technology is based on the emission of different radio waves signal into the ground and allow to construct an image of the detected object. Some of the most used electromagnetic technologies are: ground penetrating radar, nuclear quadropole resonance, impedance tomography, microwaves, infrared and ultrasound.

Acoustic / Seismic
This technology vibrates mines by introducing sound or seismic waves into the ground. If there is a material with different properties it will vibrate at different amplitude. The main disadvantage of this technology is that ground depth attenuates the resonant response. Besides, vegetation may interfere with the vibrometers.

The most common biological method is based on tranined animals that detect the smell of landmines buried into the ground. Although the most common animals are dogs and rats, new researchers have demonstrated that bees could search a large mined area in relatively short time.

A new biological methods consist of engineered bacterias that have certain characteristics when grown near a mine. The method would involve spraying bacteria on a mine affected area, and allow them to grow for several hours.

This method may be divided into probes and clearing machines. Probes are devices with a rigid metal stick that slowly penetrates the ground. When it detects an unusual object, it assesses the contour of the object in order to define whether it is a mine or not. The main disadvantage, is that it is an expensive method.  Mine clearing machines are used to clear a safe path over a mine field. It is basically a machine that detonates the mines. This is a quick and effective method, and the most important, it is riskless  Nevertheless, it basically destroys the field.

In 1996 the german humanitarian foundation "Menschen Gegen Minen" (MGM) (People against mines) was created. This organization not only removes mines, but also develops new and innovative mine detection machines. One of such machines is the MGM rotar.

The MGM ROTAR is based on idea of a relative lightly armoured system that could easily and safely remove the top soil, followed by a subsequent inspection.

The MGM ROTAR (Image 2) picks up mine infested soil with its rotating sieving drum. While sieving out the soil, objects with a diameter greater than the grid-size get left behind. The grid can be sized so that these objects including all known mine types. Should the mines detonate during the sieving process there is no danger to  the driver or the vehicle. Extremely strong steel and armoured glass protect the operator from the explosion and any fragments. The mines and pieces of unexploited ammunition that do not detonate as the ROTAR spins are dealt with safely later in a specially developed disposal system.

Image 2. MGM ROTAR

Thechnology and science provided us with several alternative to detect and remove antipersonnel mines. Howerver, removing aintipersonnel mines is just the first step. It is up to us, to have the will and the compromise, so that this threaten to life will never happen again.

References and Further Reading:
Menschen Gegen  Minen (People Against Mines)
The MGM ROTAR system, a new path for humanitarian demining
International Campaign to Ban Mines
UN Office for Dissarmament Affairs
A Review of Sensing Technologies for Landmine Detection: Unmanned Vehicle Based Approach 

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