11 April, 2011

On Landmines

Blasts That Matter, Geopolitics, special feature, pp 18-20, April 2011


The Chattisgarh police is planning to arrange a conference focusing on the role of technology in counter-insurgency warfare. The Special Task Force (STF) dealing with anti-Maoist operations in the state has been entrusted to examine the modalities of this conference. Among other things, the STF and the state police seek knowledge in detecting landmines, which pose grave threat to the security forces not only in the state, but in almost all the Maoist dominated areas of India.

This article focuses, inter alia, on the several existing technologies of land-mine detection. Furthermore, it discusses some novel techniques of unraveling these dormant, yet deadly weapons.

(the link provides an edited version, for full version: see below)

Blasts that Matter

It is not without reason the Chattisgarh police is planning to arrange a conference focusing on the role of technology in anti-insurgency warfare. The Special Task Force (STF) dealing with anti-Maoist operations in the state has been entrusted to examine the modalities of this conference. Among other things, the STF and the state police seek knowledge in detecting landmines, which pose grave threat to the security forces not only in the state, but in almost all the Maoist dominated areas of India.

Undoubtedly, landmines pose a formidable challenge to the world community. It is both a theoretical as well as a practical problem to determine the location of each and every landmine in a geographical area. To defuse them thereafter is an additional difficulty. 

In fact, one of the last century's unsolved problems is the landmines left behind from wars and insurgencies. It is estimated that 15,000–20,000 victims are claimed per year due to landmines. The U.S. State Department reports that a total of 45–50 million mines still remain to be cleared worldwide. Research also tells us that around 100,000 mines are detected and destroyed per year around the globe. 

Thus, going by the present rate of clearance and assuming no new mines are laid; simple calculation shows that it will take another 450 – 500 years to get rid of all the existing landmines. However, according to some estimates, roughly 1.9 million new mines are being placed annually !

Interestingly, mines are inexpensive—costing as little as US $3 each and hence of late, have turned out to be the poor rebel’s potent weapon. But on the other hand, they impose devastating consequences on the affected populace. In 1995, a survey conducted in Afghanistan, Bosnia, Cambodia, and Mozambique found that one in three victims of mine-blasts die. And as would be explained later, many of the victims are children. 

For example, in Afghanistan, the survey found that, on an average, 17 in 1,000 children had been injured or killed by landmines. For those who survived the blasts, the most common injury reported was loss of a leg. Loss of arms, blindness, and shrapnel wounds were also found to be frequent. 

In a January 2011 Issue Brief published by the Centre for Land Warfare Studies (New Delhi), Rahul Misra asserts that there are as many as 10 million mines in Cambodia and one in every 236 Cambodians is an amputee. Laos, according to Misra, is the most heavily troubled country. It had two million tonnes of ordnance dropped on its territory between 1964 and 1973. Also, as per the brief, one of the most problematic issues facing Vietnam is that it continues to view the landmine as a necessary and legitimate weapon for self defence.

Furthermore, the medical bills for survivors of such blasts can bankrupt families. Many victims have to undergo multiple surgeries. Children who lose limbs require multiple prosthetic devices over their lifetimes. Even the rumours associated with landmines may halt all normal activity in an affected area. For example, a 1999 study claims that in Mozambique, a town of 10,000 was deserted for four years because of a rumour that mines were present. Later, a three-month clearance operation found only four mines. Incidentally, the extensive mine contamination of Afghanistan’s fertile valleys has reduced agricultural production in those areas. A 1995 study by Andersson and his group estimated that without mines, agricultural land use in Afghanistan could increase by 88–200 per cent.

Types of Mines

Generally, mines are of two types: anti-personnel and anti-tank. It is the former which is a major cause of concern in the long-term. Ironically enough, anti-personnel mines were first used in World War II to prevent opposing soldiers from clearing anti-tank mines. The original anti-personnel mines were improvised from hand grenades and simple electric fuses. Since then, mine design has changed substantially. Modern-day mines can deliver blasts of lethal pellets extending in a radius of up to 100 m. Some are designed to resemble toys or other everyday objects, such as pens and watches. Presently, at least 350 mine types exist, manufactured by some 50 countries. 

Anti-tank mines are larger and more powerful than anti-personnel mines. However, anti-personnel mines are the most common type of mines, yet the most difficult to find because they are small and often made of plastic. Anti-tank mines generally contain more metal than do anti-personnel mines and are thus more easily detectable by simple metal detectors. Both types are buried as close to the surface as possible and are found in a variety of soils and terrain -- rocky or sandy soil, open fields, forested areas, steep terrain, and jungles. 

For both types of mines, detonation is typically caused by pressure, although some are activated by a trip-wire or other mechanisms. Thus, the major challenge for a land-mine detector is to do its job without having direct contact with a mine. It also must be able to locate all types of mines individually in a variety of environments. 

Although hundreds of varieties exist, anti-personnel mines generally can be classified as either “blast” or “fragmentation” types. Blast mines are buried at shallow depths. They are triggered by pressure, such as from a person stepping on the mine. The weight needed to activate a blast mine typically ranges from 2 to 10 kg. This indicates that these mines are easily triggered by a small child’s weight. They cause the affected object (e.g., foot) to blast into fragments, which blast upward.

Blast mines typically are cylindrical in shape, 2–4 inches (5-10 cm) in diameter, and 1.5–3.0 inches (4-8 cm) in height. Generally, they contain 30–200 gm of explosives. The casing may be made of plastic, wood, or sheet metal. Plastic-encased blast mines are sometimes referred to as “nonmetallic mines,” but nearly all of them contain some metal parts which are usually the firing pin and a spring-washer mechanism, weighing about a gram.

Detection Methodology

The major obstacle in detecting mines is that close to 100 per cent of the mines in any area must be found with few false alarms, i.e., mistaking a rock for a mine. The United Nations, for example, has set the detection goal at 99.6 per cent, and the U.S. Army's allowable false-alarm rate is one false alarm in every 1.25 square meters. However, no existing detection system meets these criteria. Nonetheless, there are a number of general techniques of detecting landmines, which may be enunciated in a nutshell.

Magnetometers: It is marginally effective in its de-mining operations and good only for close-in (point) detection. The approach is effective for ferrous metal while has problems with plastic and non-ferrous metal.

Radar: This technique has the potential for wide-area applications. However, it has problems with detecting plastic mines in some category of soils.

Infrared Sensors: This again has potential for wide-area detection but may be affected by soil disturbance and thermal effects.

Millimeter Wave Sensors: It has the potential for wide-area detection, albeit at a slow scanning rate. Moreover, it can fail to discriminate mines from surroundings.

Visible Light Sensors: The major problem with such devices is that they cannot detect buried items, though they might detect mines planted at the surface.

Light Detection and Ranging (LIDAR): Its potential use is against recently emplaced mines and surface-laid objects.

Electromagnetic Induction: They are only good for point detection of metal mines. By its very nature, it has problems in detecting plastic landmines.

Apart from the detection technologies mentioned above, dogs and other ‘sniffers’ are the most viable. Nevertheless, they have high ongoing expenses, are subject to fatigue and can be fooled by masked scents. As has been pointed above, metal detectors are sensitive to metal mines and firing pins but cannot reliably find plastic mines. Infrared detectors effectively detect recently placed mines, but they are expensive and limited to certain temperature conditions. Also, thermal neutron activation detectors are accurate but are large for field use; slow and expensive.

Ground-penetrating radar (GPR) is sensitive to large mines, has good coverage rate at a distance and with signal processing, can discriminate anti-tank mines from clutter such as rocks beneath the ground surface. This type of radar, however, remains expensive, cannot detect anti-personnel mines because its resolution is too low, and frequently records false alarms.

In 2005, Frigui, Ho and Gader proposed a real-time software system for landmine detection using GPR. The system includes an efficient and adaptive preprocessing component; a hidden Markov model (HMM) based detector; a corrective training component and an incremental update of the background model. The proposed software system was applied to data acquired from three outdoor test sites at different geographic locations, using a state-of-the-art array GPR prototype. The results indicated that, on an average, the corrective training component improved the performance of the GPR by about 10 per cent.

Way back in 1993, researchers at Livermore invented a Micropower Impulse Radar (MIR). The invention led directly to battery-operated pulsed radar that is remarkably small and inexpensive, had a wide frequency band, and worked well at short ranges -- all necessary attributes of landmine detection systems.

MIR's small size, light weight, and low power requirements made it superior to any previous attempts to use GPR to detect landmines. MIR's ultrawide bandwidth was the source of high-resolution imaging capabilities that differentiated it from similar landmine detection technologies. Furthermore, the ability to group individual MIR units in arrays increased the speed and coverage area of the detection work.

In laboratory tests, the prototype MIR clearly distinguished plastic antipersonnel mines from surrounding soils. In field tests at Fort Carson in Colorado and Fort A. P. Hill in Virginia, funded by the U.S. Defense Advanced Research Projects Agency (DARPA), the system performed well, though at a slow pace. Naturally, more research in this direction would bear real fruits in proper detection of landmines, especially the plastic ones.

Way Forward?

The 1997 Convention on the Prohibition of the Use, Stockpiling, Production and Transfer of anti-personnel mines and on their destruction remains the principal international instrument prohibiting the use of anti-personnel landmines. This convention makes it obligatory for signatory countries to clear landmines planted in their territory. The convention recognises that mine action is not just about removing landmines from the ground; it is also about understanding how people interact with a landmine-affected milieu.

Thus more international cooperation in this regard is an imperative. Also, the concern of the security personnel in insurgency and war affected areas is genuine. Hence, when the state police forces in India exhibit urgency in implementing landmine detection technology to combat the Maoist conundrum, they should not be viewed as mere visionaries, rather be hailed as realists.


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