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Big brothers keep their eyes on missing... Breaking through depth barrier could sh... What makes a smart - and priceless - w... Battling with the land-mine scourge... How to be rejected as a titbit for a sha... |
Battling with the land-mine scourge
SAFETY
IT WOULD take 1 000 years using existing methods to clear the 100 million antipersonnel and antitank mines which have been laid worldwide. This is edging more countries towards banning Detection technologies are struggling to keep pace with those of increasingly sophisticated land mines. For instance, mines made almost entirely of plastics are cheaper to produce, and difficult to find with a metal detector - and newer types of mines include one which can be triggered by some detectors. Where there is a clear military reason for clearing mines, such as moving troops through a battle zone, all sorts of ground-pounding devices and explosive ropes have been developed. However, progress has been slow where the military role is less clear. Systems for clearing former battle areas have not changed significantly since 1945. Local information and dogs trained to detect the smell of explosives may help to establish the limits of a mined area. Then a team of two people goes in, one with a metal detector, to scan a metre-wide path. The other has a probe to check whether signals are from a mine or some harmless piece of metal.
There are still plenty of metallic mines to keep clearing teams busy - including in Angola and Cambodia. But even after the Falklands and the Gulf wars, where plastic mines were used extensively, the demand for a plastic mine detector cannot be met.
Alistair Craib, an independent consultant on land-mine clearance, says there is a hardening consensus that a new mine detector should comprise sensors of two or three types in a hand-held device, or more where they are mounted in a vehicle. Ground-probing radar and infra-red imaging are gathering support as a hand-held sensor duo. Also being researched is a biosensor that can match the sensitivity of a dog's nose, but without the need for a long period of training and loss of sensitivity after about 20 minutes. Several versions of ground-probing radar are in development. The project leader for a research programme in the Falklands - which was later scrapped by the British government because there was no military requirement - was Richard Chignell, who later set up his own company, Emrad, to continue work on the technology. Emrad is marketing its first product, Pipe Hawk, to locate plastic and other pipes underground for utility industries. Its success has also been recognised in other areas, notably for leading police to the remains of the victims of Frederick West in Gloucester.
Mick Gillman of the UK's Defence Evaluation and Research Agency says there has been significant progress over the past two years in a number of technologies. "We are now field-testing approaches that could once operate only under laboratory conditions," he says. "But the 'silver bullet' that reliably finds all mines in all circumstances is still a long way off." For hand-held sensors, the agency is focusing on ground-probing radar and infra-red systems to check the size and shape of objects, and nuclear quadruple resonance to determine whether they contain explosives. This technology, which has been employed at airports to scan luggage, operates from radio frequency signals from nuclei in the explosives.
"The approach depends very largely on soil type and conditions, hence there is not one single technological solution," says Gillman. Until such technologies are perfected, it seems the best strategy the world wants to afford is still two people and a dog, with technology half a century out of date. - Financial Times
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