In a typical manual mine clearance operation, deminers often spend nearly all of their time finding metal fragments in the search for anti-personnel mines. Often there is too much metal to be able to use metal detectors: then the deminers have to probe an entire minefield by hand, every 25 - 50 mm apart, or even dig through thousands of square metres of ground by hand.
"Magnetic Fragment Collection,"
Journal of Conventional Weapons Destruction: Vol. 3
, Article 21.
Available at: http://commons.lib.jmu.edu/cisr-journal/vol3/iss2/21