A new mine detector technology has been tested in Brisbane, Australia, that puts a new spin on hunting things that go boom. The MineReader RDX uses a new principle for mine detection that emphasises seeking the explosive instead of the mine.
Mines have been around ever since engineers figured out that the way to defeat an impregnable fortress was to drive a shaft under the wall foundations so they collapse. However, the modern versions that are packed with high explosives and sit lurking under the dirt to blow up unwary vehicles or pedestrians are much nastier affairs.
There are concerted efforts to ban such devices, but they are still used with depressing frequency. And though modern mines can be made to automatically neutralize themselves after a preset time, some minefields remain deadly hazards almost a century after they were laid.
It's no wonder that mine detection is such a high priority in both military and civilian circles.
MRead
The thing is, mines aren't often easy to detect.
Anyone who has seen enough war movies is probably familiar with mine detectors, which are basically a military variant of a hobbyist's metal detector. These work by electromagnetic induction. A paddle-like thing at the end of the pole sweeps back and forth across the ground, generating an electromagnetic field. The field is monitored by a superheterodyne circuit that isolates different frequencies in the field and looks for changes in intensity that indicate the presence of, among other things, metal objects.
Short version: wave the paddle over a buried coin, and it squeals.
MRead
Since mines are usually made of metal, such a device can detect them. However, the operative word is "usually." Some mines today are made of plastic, and even during the Second World War the Germans would make land mines out of wood, which caused, in one case, British Commandos to abandon their detector in favor of crawling along a beach poking at the sand with their FairBairn-Sykes fighting knives.
The other problem is that there are many other things made of metal and there are other factors that can cause the detector to give false positives. So what to do?
That's where a bit of lateral thinking comes in. The conventional mine detector doesn't detect the workings of the mine, just the metal casing and spring mechanism it comes in. Without the explosives, a land mine is just so much tin, so why not forget about the casing and go straight for the explosive?
MRead
Developed by Australian deep-tech company MRead and based on research by Australia's national science agency, the Commonwealth Scientific and Industrial Research Organisation (CSIRO), MineReader RDX forgoes electromagnetic induction for Magnetic Resonance (MR), which is a kind of spectroscopy that operates in the radio band of the spectrum.
Specifically, MineReader looks for the distinct signature of the explosive RDX (cyclotrimethylenetrinitramine (C₃H₆N₆O₆)). As you can see from the formula, RDX, which is a common explosive, has six nitrogen atoms. Using MR, it's possible to detect RDX because of the way the nitrogen atoms behave in the solid crystalline matrix of the explosive, which generates a unique reaction to radio-frequency pulses that can be recorded and analyzed.
According to the developers, MineReader can detect 50 g (1.76 oz) of RDX at depths of up to 13 cm (5 in) and operates in wet, highly mineralized ground that is littered with metal debris and organic residue. Though there are other techniques for directly locating explosives, these tend to be cumbersome and can only detect explosives in bulk, while MineReader is as portable as a conventional detector rig.
MRead
Though the system is currently configured for RDX, the ultimate goal is to make it detect TNT as well, which will allow it to deal with over 905 of land mines.
"The capability we are ultimately developing is to take the soldier out of the threat area," said MRead CEO John Shanahan. "Combining direct explosives detection with unmanned ground systems will allow a suspected threat to be interrogated remotely, giving commanders greater confidence about what is ahead before personnel or vehicles move through an area."
Source: MRead