Demining
Anti-tank mines are designed to damage tanks or other vehicles; they are usually larger and require at least 100 kilograms (220 lb) of force to trigger, so infantry will not set them off.
[9] Common explosives used in land mines include TNT (C7H5N3O6), RDX (C3H6N6O6), pentaerythritol tetranitrate (PETN, O12N8C4H8), HMX (O8N8C4H8) and ammonium nitrate (NH4NO3).
The most heavily contaminated (with more than 100 square kilometres of minefield each) are Afghanistan, Angola, Azerbaijan, Bosnia and Herzegovina, Cambodia, Chad, Iraq, Thailand, Turkey, and Ukraine.
The cost of clearance can vary considerably since it depends on the terrain, the ground cover (dense foliage makes it more difficult) and the method; and some areas that are checked for mines turn out to have none.
The Cambodian Mine Action Centre found that, over a six-year period, 99.6 percent of the time (a total of 23 million hours) was spent digging up scrap.
[47] Well-trained mine-detection dogs (MDDs) can sniff out explosive chemicals like TNT, monofilament lines used in tripwires, and metallic wire used in booby traps and mines.
The detection rate is also variable, so the International Mine Action Standards require an area to be covered by two dogs before it can be declared safe.
This involves collecting air samples from stretches of land about 100 meters long and having dogs or rats sniff them to determine whether the area needs clearing.
[53][52] Tiller systems consist of a heavy drum fitted with teeth or bits that are intended to destroy or detonate mines to a given depth.
[56] First used in World War I with tanks, rollers are designed to detonate mines; blast-resistant vehicles with steel wheels, such as the Casspir, serve a similar purpose.
Hyperspectral imaging, which senses dozens of frequency bands ranging from visible light to long-wave infrared, can detect this effect.
In principle, the short wavelength would allow high-resolution images, but it may take too long because the intensity must be kept low to limit exposure of humans to the radiation.
Methods such as solid phase microextraction, sorbent sol-gels, gas chromatography and mass spectrometry can be used to identify explosive chemicals in the hive.
[87] Engineer Thrishantha Nanayakkara and colleagues at the University of Moratuwa in Sri Lanka have been developing a method where a mongoose is guided by a remote-controlled robot.
But using a combination of natural mutations and genetic manipulation, scientists from Danish biotechnology company Aresa Biodetection created a strain that only changes color in response to nitrate and nitrite, chemicals that are released when TNT breaks down.
[106] The frequencies at which resonances occur are primarily determined by the quadrupole moment of the nuclear charge density and the gradient of the electric field due to valence electrons in the compound.
[108] For neutron detectors to be portable, they must be able to detect landmines efficiently with low-intensity beams so that little shielding is needed to protect human operators.
[108] The Canadian Army has deployed a multi-detector vehicle, the Improved Landmine Detection System, with a TNA detector to confirm the presence of anti-tank mines that were spotted by other instruments.
A "Timed Neutron Detector" based on this method has been created by the Pacific Northwest National Laboratory and has won design awards.
Usually the sound is generated by off-the-shelf loudspeakers or electrodynamic shakers,[113] but some work has also been done with specialized ultrasound speakers that send tight beams into the ground.
[116][117][118] As well as having a low false positive rate, acoustic/seismic methods respond to different physical properties than other detectors, so they could be used in tandem for a richer source of information.
Drones equipped with cameras have been used to map areas during non-technical survey, to monitor changes in land use resulting from demining, to identify patterns of mine placement and predict new locations, and to plan access routes to minefields.
[121] Geophysicists at Binghamton University are testing the use of thermal imaging to locate "butterfly mines", which were dropped from airplanes in Afghanistan and mostly sit on the surface.
[123][124] At DTU Space, an institute in the Technical University of Denmark, researchers are designing a drone with magnetometer suspended underneath it, with the initial goal of clearing mines from World War II so power cables can be connected to offshore wind turbines.
[126][127][128] Drone programs must overcome challenges such as getting permission to fly, finding safe takeoff and landing spots, and getting access to electricity for charging the batteries.
One delivery system involves a bottle of DETA placed over a mine; a bullet shot through both brings them in contact and the TNT is consumed within minutes.
[134] Thermal destruction methods generate enough heat to burn TNT, such as using leftover rocket propellant from the NASA Space Shuttle missions.
Placed next to a mine and activated remotely, it reaches temperatures exceeding 1,927 °C (3,501 °F), burning a hole through the landmine casing and consuming the explosive.
[52] The mine-clearing line charge, successor to the Bangalore torpedo, clears a path through a minefield by triggering the mines with a blast wave.
[139] In the 2000s Fuel-air explosive (FAE) technology has been increasingly utilized for demining operations, offering an effective method for clearing minefields and neutralizing IEDs.
