Killers in the soil
Daily Telegraph Connected 11 February 1997
Thanks mainly to Princess Diana and her recent visit to Angola, it is now common knowledge that over 100 million land mines dot the soil of 68 of the world’s poorest countries. Truly dedicated Di followers will also now know that mines kill or maim more than 2,000 people – mainly civilians – every month, and that industry is still churning out between five and ten million new ones every year.
Less well appreciated is the way many organisations – in some cases the same companies that once made the mines – are now setting about developing the technology to locate and neutralise them. This is hardly altruistic behaviour: since the Berlin Wall fell, many arms manufacturers have been looking at anorexic order books, and in the USA at least, the army – and Congress – has recently made it clear that serious money is now available for serious solutions.
The scale of the problem is however awesome. Over 350 different types of anti-personnel mines exist and they are far more prevalent and difficult to detect than the larger and more expensive anti-tank mines. The simplest – blast mines – are often nothing more than 30 grams of high-explosive, a fibreglass spring, and a detonator cap in a plastic case the size of a small yo-yo.
Designed to wound and maim rather than kill, they are quickly covered by vegetation and can last almost indefinitely. Heavy rain can move them far from their first location and five kilograms is often enough to detonate them.
More sophisticated, more deadly, and generally easier to detect, are shrapnel-packed fragmentation mines, and bounding mines, where a perverse jack-in-the-box sequence uses one explosion to lift the device to chest height, and another to scatter shrapnel over a radius of up to 200 metres.
First used in World War I, the original aim of anti-personnel mines was to prevent the removal of larger anti-tank mines. The Germans perfected hard to detect metal-free mines in World War II (bakelite was the key), and US forces are generally credited with the first random use of anti-personnel mines, scattering them from the air in a vain attempt to close the Ho Chi Minh Trail through Laos in the 1960s.
Opposing factions in the Cambodian civil war then perfected their use as a terror weapon, and by the time Soviet forces invaded Afghanistan in 1979, randomly targeted mines had become accepted as normal. Since then, their use has increased and they are causing civilians and military alike great problems in Bosnia-Herzegovina in particular.
Today, the UN considers Afghanistan, Angola, Cambodia, Iraq and Laos worst affected, and recognises a serious problem in 57 other countries. Costing as little as £2 to produce, anti-personnel mines cut off access to farmland and wells, and the cost of removing them can be as high as £600 each.
“Mine detection and clearance technology has always lagged behind mine development and distribution technology, and hand-prodding is still the reality of most mine clearance operations,” says Chris Moon, an ex-Army officer who has worked for the Halo Trust, a British registered charity specialising in mine and unexploded ordnance clearance, in Cambodia and Mozambique.
“This involves lying on your chest and inserting a probe – more often than not a bayonet – into the soil every five centimetres or so at about 30 degrees from the horizontal. When you feel something solid, you can estimate the shape and size of it with more prodding, and if it feels like a mine, a team then comes in to uncover it and destroy it, if needs be with explosives. Needless to say, this is slow and dangerous work.”
Although Chris Moon can tell the difference between an AK47 bullet and a PMN2 mine solely by the ‘signature tune’ emitted by a metal detector, such tools are no longer reliable as many modern mines contain very little, if any, metal. Laterite soils also cause problems, and any conflict zone is likely to be scattered with all manner of metal debris. One grenade for example, can give over 3,000 detectable fragments.
Brute-force methods favoured by the army include ploughs, rakes, rollers and flails mounted on tanks, and explosive breaching methods. All are generally so effective in clearing a path for soldiers and vehicles that some argue that mines now have little tactical use except to terrorise civilians. Allied forces in the Gulf War, for example, breached the extensive minefields around Kuwait City in less than three hours.
Brute-force methods are however generally of little use in what is now referred to as ‘humanitarian’ demining – clearing up after conflict. Ploughs and rakes often only push the mines out of the ground, leaving them armed, and some smart mines only detonate the second or third time they are run over.
An exception is a giant new demining vehicle developed by Bofers, the Swedish armaments manufacturer, which is based on a tank chassis and uses a rapidly rotating four-metre wide roller, made up of hundreds of tungsten carbide teeth, to dig half a metre into the ground and either detonate the mines in its path, or chew them into small, harmless pieces.
The vehicle is armoured and has been designed and tested to withstand detonation of the largest anti-tank mine produced (12 kg) but it can also be driven remotely. “Nothing could withstand hitting something like a warhead from a Scud,” says Allan Carlsson, product group manager for Bofors, “and traps made up of 15 anti-tank mines buried all in one spot are not unknown”.
With one vehicle now working in Bosnia at close to the 99.6 per cent clearance rate required by the UN, Bofers can claim to have begun some sort of rehabilitation of their image, but weighing in at 55 tonnes, and with the whole kit of transport vehicle, fuel tankers, spare roller and a mobile workshop adding up to around £1.5 million, it is not technology everyone can afford.
More novel, and a mite cheaper, is Bofers’ new bio-sensor which sniffs out specific explosives using specially designed antibodies. Effectively an artificial nose, about as sensitive as a dog’s, the device currently exists only as a stationary prototype, but should be available in a field-hardened backpack version by late 1998.
“The big issue was to attach the antibodies, ie. the biological components, to the electrical and mechanical components, and to get them to work together,” says Sten-Anders Brink, president of Bofor’s Celsius group. “Microelectronics, micromechanics and artificial neuron networks based on computer technology were also used. What we have now is a self-learning, self-programming device that can responds to the tiniest trace of explosive within 1 – 2 seconds.”
In association with the Swedish Defence Research Establishment and three other organisations, Bofers is also involved in a long term project to develop a multi-sensor system combining ground penetrating radar, infra-red imaging and an advanced metal detector.
“You have to accept that no single technology is going to solve this problem,” says Douglas A. Perkins of Oilton Inc., a small Minnesota-based company specialising in the remote detection and mapping of underground pipelines as well as unexploded ordnance and land mines. “Any combination sensor system is almost certainly going to be better than a single sensor system.”
“Consequently our AIRDS system, which runs off a helicopter platform, fuses real-time video frame-for-frame with infra-red images, and uses proprietary image processing enhancement software to make best sense of it all. A magnetometer to verify specific mines is also a part of the system, and a specially-developed differential GPS means that navigation and mapping are not dependent on ground-based repeaters.”
In tests conducted under stringent supervision on a military range in Arizona in June 1994, the system located both metallic and non-metallic landmines buried beneath the surface, and even precisely located a scattered handful of two-inch nails.
Chris Moon is not overly impressed. “If you have the helicopters and the people and money to fly and maintain them, such sophisticated systems might be useful,” he says. “But generally we have to ask questions like: will it work eight hours a day, six days a week in the Third World? Will it work both on a frozen mountainside and in a paddy field in the monsoon. And if it breaks down, can it be fixed locally, or does it need an engineer and spares from the other side of the world?”
It must not be forgotten either that once a mine has been located, it still has to be neutralised. And as mines fitted with anti-tamper mechanisms of ever increasing sophistication – some now microchip based – find their way into the field, injuries and deaths amongst deminers are increasing. Currently accidents occur at a rate of about one for every 2,000 mines destroyed.
Armoured visors and flak-jackets have helped to a degree, but according to Chris Moon, the most practical application of new technology has been the development of an armoured hedge-cutter attached to an armoured tractor. “It allows the demining teams at least to see the ground they are prodding,” he says. “It has been very, very successful”.