An Anti-handling device is an attachment to or integral part of a landmine, designed to prevent tampering. However, anti-handling devices may also be encountered as an integral part of the fuzing mechanisms used in other types of munition e.g. some fuze types found in air-dropped bombs (e.g. Mk 83), cluster bombs and sea mines etc. In every case, when the protected device is disturbed in some way it detonates, killing or severely injuring anyone within the immediate blast area.
Technology to incorporate sophisticated anti-handling mechanisms in fuzes has existed since at least 1940 e.g. the Luftwaffe's ZUS40 anti-removal bomb fuze used in the London Blitz. ZUS40s were usually fitted underneath a type 17 clockwork long delay fuze which gave up to 72 hours delayed detonation. Other German anti-handling bomb fuzes of the Second World War included the type 50 and 50BY fuzes, normally fitted to 250/500 kg bombs, which contained mercury tilt switches. All these fuzes were specifically designed to kill bomb disposal personnel.
Regardless of the type of munition or way in which it is emplaced, anti-handling devices serve two military purposes:
- To prevent the capture and reuse of the munition by enemy forces
- To hinder bomb disposal or demining operations, thereby creating a much more effective hazard or barrier
However, these devices also increase the impact of mines on the civilian population, as anti-tank mines equipped with this technology can easily be triggered by humans. Additionally, they add to the difficulty and cost of post-conflict clearing operations due to the inherent dangers of tampering with them.
Classes of anti-handling devices
US Army field manual FM 20-32 classifies four classes of anti-handling devices:
- Anti-lifting devices. A device which initiates an explosion when a protected mine is lifted or pulled out of its hole.
- Anti-disturbance device. A device which initiates an explosion when a protected mine is lifted, tilted or disturbed in any way e.g. a notable variant of the VS-50 mine featuring an integral mercury switch.
- Anti-defuzing device. A device which initiates an explosion when an attempt is made to remove a fuze from a protected mine.
- Anti-disarming device. A device which initiates an explosion when an attempt is made to set the arming mechanism of a mine to safe.
Types of anti-handling fuzes
The different classes of anti-handling devices are normally created using a variety of fuzes. This is a list of the types of fuzes used as anti-handling devices:
- Pull fuzes — these are typically installed in secondary fuze wells located on the side or bottom of landmines. The fuze is normally connected to a thin wire attached to the ground, so the wire is automatically pulled if the mine is lifted, shifted or disturbed in any way. Simple pull-fuzes release a spring-loaded striker. More sophisticated versions are electronic i.e. feature a break-wire sensor which detects a drop in voltage. Either way, pulling on the hidden wire triggers detonation.
- Anti-lifting fuzes — these are typically installed on the bottom of landmines, and trigger the mine when the mine is lifted and the pressure on the fuze is reduced.
- Tilt/Vibration switches — this is a fuze installed inside the device which triggers detonation if the sensor is tilted beyond a certain angle or is subject to any vibration. Typically, some form of pendulum arrangement, spring-loaded "trembler" or mercury switch is used to detect this.
- Anti-mine detector fuzes — developed during the Second World War to detect the characteristic signals used by electronic mine detectors.
- Electronic fuzes — modern electronic fuzes may incorporate anti-handling features. Typically, these fuzes incorporate one or more of the following sensors: seismic, magnetic, light sensitive, thermal or acoustic sensitive. Potentially, such fuzes can discriminate between various types of mine clearance operations i.e. resist activation by devices such as mine flails, plows, or explosives, whilst still detonating when handled by demining personnel. Additionally, electronic fuzes may have an inbuilt self-destruct capability i.e. some form of timer countdown designed to trigger detonation hours, days or even months after deployment, possibly whilst people are attempting to render the device safe. Although fuzes with a self-destruct capability are not anti-handling devices per se, they do add an extra complicating factor to the EOD process.
- FM 20-32, Landmine Warfare, August 1966