October 23, 1997
Contact: Dick Hatfield Phone: (573) 341-4328; [email protected]
UNIVERSITY OF MISSOURI-ROLLA TAKING A "WATERGUN" APPROACH TO CLEARING LAND MINES
Researchers at the University of Missouri-Rolla are taking a watergun, rather than shotgun, approach to ridding the world of land mines.
As part of a five-year, $5 million Department of Defense project, researchers are using high-pressure waterjets to develop a device that detects, clears and neutralizes land mines. UMR researchers have used the same waterjet technology to clean explosives from warheads, cut slabs of granite into a replica of Stonehenge on campus and construct an amphitheater beneath the Gateway Arch in St. Louis.
Methods of detecting and clearing live land mines have changed little since World War II. "The military has used the same method for years," says Dr. David A. Summers, a UMR Curators' Professor of mining engineering. That method consists of using a hand-held mine detector to clear a path one yard wide and 50 yards long. And the work is slow going; it takes about an hour to move along that 50-yard path, Summers says.
Summers is leading a team of UMR researchers to develop methods to not only detect mines, but also to clear those mines from an area more quickly and to neutralize them -- all in one process, with one instrument.
"First, we have to find the mines," says Summers, the director of UMR's Rock Mechanics and Explosives Research Center and the center's High-Pressure Waterjet Laboratory. "Some of those mines are only two inches in length and are located about six inches below the surface of the ground."
So far, the UMR team has constructed a device about the size of a large lawn mower. It is a prototype for a system which will be put into the field which will use 12 waterjet nozzles, located about three inches apart on the front of the device, to scan a three-foot path. The nozzles fire a short pulse of water into the ground at pressures of 1,000 to 3,000 pounds per square inch -- not enough to detonate the deadly booby traps. When the water from one of the nozzles hits an unusual surface, it makes a different noise. "What we are working toward is a system which can then identify where the noise indicates that a mine is located," Summers says.
Once an object is located under the machine, the operator can stop it and slowly move it over the suspicious ground. The device then uses waterjets to wash away and suck up the soil surrounding the object and expose it to the operator. "Within 10 seconds the suspicious object can be identified," Summers says.
The final part of the operation involves disarming the land mine. The military's method is to blow up detected mines, but "that method can be a problem in some areas," Summers says. "We propose to neutralize the mine."
To neutralize the live mine, the detector, using a small amount of sand mixed with the water, cuts the live mine in half. "The relatively low water pressure from the waterjet's nozzle will not explode the live mine," Summers says.
While still in the early phases of testing, the device holds promise.
"The waterjet device works much faster than the older methods of detecting mines," Summers says. "Waterjets can go forward several feet per minute. We are talking about mine detecting at a walking speed instead of only several feet an hour."
The waterjet mine detector device also is maneuverable enough so that the operator can follow the natural terrain of the Earth. The waterjets can shoot five gallons of water per minute and 300 gallons an hour, Summers says.
Summers makes an important distinction between UMR's mine-detection and - neutralization research and the U.S. military's methods during combat.
"During a combat situation, troops have to get through a mine field in a hurry," he says. "As a result, only about 75 percent of the mines in that field are located."
But the UMR researchers are more involved with the humanitarian aspect of de- mining. "The role that we as researchers are taking means that even though we are not under fire when looking for mines, it also means that we have to find all of the mines that were left undetected," Summers says. "And this is significant because there are more mines in the ground than have been found."
Other research efforts under way at UMR include development of a method in which an infrared camera takes pictures of an area as the temperature of the soil changes. "A mine can change the temperature of the soil that surrounds it," he says.
Another method under development uses ground-penetrating radar to detect mines that have been placed in the ground.
"Those methods are usually fine," Summers says. "But the only problem is, that there are over 2,300 types of mines in different shapes and sizes and many of the new mines are made of plastic. And plastic mines don't always show up using those methods."
The goal of Summers' research team is to find out how fast the waterjet machine can distinguish one object from another and to make the device easy to operate.
More information about UMR's High Pressure Waterjet Laboratory can be found at http://www.umr.edu/~waterjet/
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