Search for a Land Mine Solution

Ron Woodfin keeps a small plastic gadget on his desk to remind him of the challenge that lies ahead. It is small enough to fit in his palm. It is a land mine, capable of blowing off a foot or a hand.

“It’s called a butterfly mine, and the Soviets distributed them by the thousands across Afghanistan,” said Woodfin, a systems engineer at Sandia National Laboratory in Albuquerque.

What troubles him most is its appearance.

“It looks literally like a child’s toy,” he said. “It’s a tiny plastic thing with a little metal insert that has the explosive in it. And it looks like a toy.”

Woodfin worries about kids around the world who might pick up the harmless-looking devices left over from the insane activities of their elders. He heads an interdisciplinary team at Sandia that is trying to develop technologies that could reduce the threat.

There are an estimated 100 million land mines scattered throughout 68 countries, according to “de-mining” experts. An average of 2,000 people are killed or maimed by land mines each month, many of them children.

“Even if everyone stopped laying mines today, it still would take 1,000 years to clear those now in the ground throughout the world,” Woodfin said. “In my mind, it’s the worst form of pollution mankind has ever come up with.”

Yet the most effective means of finding mines to disable them is the same today as it was decades ago: probing the ground with a stick. It is also the most dangerous.

Woodfin’s team is working on several methods that could speed up the process and make it safer. Some could be available within a few months.

The most promising is a chemical sensor that “sniffs out” explosives in much the same way bomb detectors do at airports. Molecules from explosives “leak out” of the mines, Woodfin said, and can be detected by small sensors that are already available.

The Sandia researchers are relying primarily on off-the-shelf technology rather than trying to develop new types of sensors. One tool they find promising is a mobile X-ray machine that can create images of objects buried just below the ground. It is a relatively old technology that is being asked to do new things.

A team from the lab tested the concept in September, using a conventional “backscatter X-ray” machine developed by Imatron Inc. of South San Francisco under a contract with the Army. The device sends a beam of X-rays into the soil, then receives a reflected signal similar to that produced by a radar system.

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The signal is converted into an image that allows technicians to judge whether the buried object is most likely a mine, a piece of unexploded ordnance or a beer bottle.

While Woodfin believes these are the two most promising technologies being investigated at Sandia, he feels they are not enough.

“There’s just nothing that’s going to solve this problem all by itself,” he said. What it will take, he believes, is several types of sensors working together and seeking different types of information.

An infrared sensor, for example, could indicate that the ground has been disturbed; a chemical sensor could detect molecules from explosives; an X-ray machine could reveal something that at least looks like a mine.

These devices would work in concert with the most common technology in use around the world: a metal detector similar to the device purchased by consumers to search for objects on the beach, Woodfin said.

He tested a metal detector during a training exercise last summer.

“The first thing I found was an old piece of barbed wire,” he said. “It gave just as good a signal as an antitank mine.”

The device did lead him to an unarmed mine that was buried in a New Mexico field as part of the exercise. But it didn’t alert him to the presence of a nearby antipersonnel mine. In a real-life situation, he said, if he had tried to remove the mine he’d found, he could have been killed by the mine he didn’t see.

“False-positive” results are another big obstacle. Woodfin, who has traveled much of the world studying de-mining, said that in Afghanistan, 116 objects are dug up for every mine found. That can lead to a lack of vigilance on the part of searchers who grow weary of the false alarms.

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A wide range of sensors, packaged in a compact unit that can be easily carried into the field, could reduce false alarms considerably, Woodfin said.

But finding and removing the mines is only part of the solution. The land needs to be cleansed so it can be returned to the people.

“You have to feed those people, and you can’t do that if they can’t use the land,” he said.

But how can you be absolutely certain no mines are left?

Sandia, an Energy Department laboratory, is working with the University of Montana on an intriguing possibility. Research at the lab shows that molecules leaking from explosive devices diffuse widely, even reaching the surrounding vegetation.

Woodfin believes the explosive molecules reach the pollen in some plants. Sandia and Montana researchers are trying to find out if bees are likely to collect the molecules as they dash from plant to plant.

If so, it might be possible to determine if an area is free of explosives just by analyzing honey.

“That’s kind of a wild idea, and I don’t know if it’s going to work, but we’re exploring it,” Woodfin said.

The research at Sandia is more aggressive now than in the past, due partly to the global scale of the problem, but Woodfin says this country has shown little interest in developing adequate technologies to address the issue. Research in Europe, he said, is far more aggressive.

“Proximity creates the interest,” he said. “If you live in Austria and the problem is only 100 miles away, it gets your attention better.”

The absence of land mines in North America, he suggested, has cooled our passion for finding solutions.

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Lee Dye can be reached via e-mail at leedye@compuserve.com