(Eliminating Land mines by Aqueous Detection Identification and Neutralization)

The problems of worldwide land mine use are well documented and many organizations, including governmental , academic, and private are working to find and get rid of mines. 

In most cases the techniques which are used in clearing land for humanitarian reasons are similar to those developed during the Second World War, and while there is considerable money being invested in new ideas, few have become widely accepted and used. 

Who are we? 
The project is being run out of the High Pressure Waterjet Laboratory of the Rock Mechanics and Explosive Research Center at the Missouri University of Science and Technology. The project was started by Dave Summers working with Greg Galecki, Bob Fossey, Jim Blaine and Scott Parker on the waterjet parts and with Tom Herrick on the electronic detection. Robert Denier has been the graduate student most active in the development of the electronic equipment.

In the more recent parts of the program, as we have been asked to detect specific mine types rather than just locating the mine itself the signal processing has been under the collective direction of Sanjeev Agarwal, Daryl Beetner, Bob Mitchell, and Joe Stanley.

Graduate students who have worked on this program include Samir Dorle.

What does it do?

There are three parts to the tool.

Finding the mine

In the first part the mine must be detected. The concept goes back to two roots. In most humanitarian demining the deminer probes the ground with a metal rod feeling for mines. The rod is inserted into the ground in a closely spaced pattern and the ground is thus being physically searched, and this takes a long time. If we used a high pressure jet to replace the metal rod then the ground could be probed much more rapidly since the jet of water can penetrate to depths over 8 inches (20 cm) in less than 0.014 seconds. But then how are we to know if it found anything?

Small children often play with water pistols. If they listen they will hear that the sound that the jet makes when it hits different things changes. We have found that we can tell, from the different sounds that we hear as the jet goes into the ground, what it is hitting. (We have also noticed that if you do this for a short while the operator can tell, from the way the ground moves whether he has hit anything or not). So by feeding the sound heard by a microphone into a computer program developed by the signal processing team, we can tell what sort of object the waterjet hit.

Uncovering the mine

Once a suspected mine has been found (and with metal detectors only about 1 object in 300 or so that the detector identifies might turn out to be a dangerous mine) then the object has to be uncovered and inspected so that we can see what it is. Normally this is done by hand and may take about 20 minutes since it must be done very carefully.

With the waterjet system we use a second tool that can be located over the mine area. Three small waterjets spin around with a simple vacuum tube. (In an early model we used a common wet-dry shop vacuum for this). As the jets wash into the soil they break the soil into small particles that are pushed into the tube and sucked away. We can adjust the pressure so that there is very little force on the tool as this is done. (In one case we did not move a pebble that was sitting on a mine and which was only partially uncovered as we moved the soil). By doing this we uncover the object without moving or disturbing it so that it can be examined. It takes about a minute to uncover the mine, depending on how deep it is and how big. Usually we only want to uncover part of the mine and make a gap alongside it so that we can lower our cutting tool into place

We think this is a fairly safe procedure but because others might not we have made the tools so that this can be done from a distance so that everyone is well clear in case the mine goes off.

Disarming the mine

The most common way of getting rid of mines is to blow them up where they are. However some times this is not the best answer. (They might be near something that might be badly damaged - such as a bridge). So we have designed a third tool. This is also fed from the same high pressure water pump as the other two tools, but in this case a small amount of sand is mixed in with the water (about 1lb of sand per gallon of water).

The resulting abrasive slurry jet will cut through just about anything it is likely to find. (At a speed of about an inch and a half a minute it will cut through more than an inch of steel and most mines are not that solid). Because of the way the jet cuts it will cut through the explosive and can cut through the fuse without setting it off (we have done this). If done properly it can be done without disturbing the mine, and the best way to do that is to automate this part of the process. So the third tool has some remotely controlled motors that move the jet so that it cuts through the mine, destroying the fuse and, if needed, washing all the explosive out of the mine. The disabled mine can then be removed.