How do land mines work?

Answer 1

In general, land mines consist of two parts: the trigger (or detonator) mechanism, and the warhead.

Trigger mechanism can be one of three forms:

1. Command detonators - some form of external control sends a signal to landmine telling it to detonate. Examples are the trigger grip of the US Claymore mine, cellphone triggers of many IEDs in Iraq, or mines tied to centralize sophisticated sensor packages. Simple tripwire mines are also "command detonated" mines.
2. Contact fuses - pressure on or near the mine causes the fuse to be driven into the ignition mechanism, detonating the mine. Tilt sensors (those that detect a change in the level of the mine) are a form of contact fuse. All of these fuses drive small spike into a pyrotechnic trigger to start the explosion. The amount of pressure (or tilt) required to set off the mine varies according to the exact trigger mechanism used.
3. Magnetic influence - the mine trigger detects a disturbance in the magnetic field in the area caused by a large metallic object.

The vast majority of mines use the second form of trigger.

The warhead of the mine varies considerably, according to the type of target the mine was designed to attack.

• Anti-personnel mines generally consist of a small amount of explosive coupled with some sort of fragmentation material (small metal spheres, sharp metal or ceramic shards, junk metal, nails, etc.). The idea is to fill the "kill zone" with a large amount of small fragments, which can kill or wound a much larger number of people than the same amount of explosive material could.
• Anti-vehicle mines contain a much larger explosive charge, to produce a large shock wave which can damage vehicles.
• Anti-tank mines usually contain an Explosively Shaped Penetrator - this consists of a specially-shaped explosive charge, with a metal sheet covering the end towards the target. The explosion forces this sheet into a dagger-like form, which will penetrate heavy armor much better than a normal explosion.