Once the mines have been activated they become extremely dangerous. Mines are often buried or hidden so as not to be detected and may be laid in regular patterns around a village, along a road, on bridges, near single trees or along river banks. They may also be laid at random, without a map or plan of any sort. Many mines float so that after heavy rains they are found in unexpected locations.
Mines continue to be dangerous even if they have been in the ground a long time.
As time goes by, they may explode more easily as they become corroded or fragile. Currently, it is estimated that there are 110 million anti-personnel mines laid in about 68 countries, most of them in the developing world. Another 100 million remain in national stockpiles. Mine clearance operations account for the removal of no more than approximately 100,000 mines a year. In other words, for every mine cleared, twenty new mines are laid.