Anti-personnel mine

When a person steps on a blast mine and activates it, the mine's main charge detonates, creating a blast shock wave consisting of hot gases travelling at extremely high velocity. The shock wave sends a huge compressive force upwards, ejecting the mine casing and any soil covering the mine along with it. When the blast wave hits the surface, it quickly transfers the force into the subject's footwear and foot. This results in a massive compression force being applied. In most cases, the victim's foot is blown off by the blast wave.

The resulting injuries to a human body depend on the size of the mine's main charge, the depth, type of soil it was laid in and how the victim contacted it, e.g. stepping on the mine, using all or part of the foot. Different types of soil will result in different amounts of energy being transferred upward into the subject's foot, with saturated "clay-like" soil transferring the most. Larger main charges result in a release of significantly more energy, driving the blast wave further up a target's foot and leg and causing greater injury, in some cases even described as severe as traumatic amputation of the leg up to the knee.[1]

Secondary injuries from a blast mine are often caused by the material that has been torn loose by the mine's explosion. This consists of the soil and stones that were on top of the mine, parts of the victim's footwear and the small bones in the victim's foot. This debris creates wounds typical of similar secondary blast effects or fragmentation. Special footwear, including combat boots or so-called "blast boots", is only moderately protective against the destructive effects of blast mines, and the loss of a foot is a typical outcome.

Blast mines have little effect on armoured vehicles, but can damage a wheeled vehicle if it runs directly over the mine. Small blast mines will severely damage a tire, rendering it irreparable while some types could also damage adjacent running gear.

The mine casing houses the components of the mine and protects it from its environment. Early mines, such as the ones used in the World War II era, had casings made of steel or aluminium. However, by the middle of the conflict, the British Army was using the first, practical, portable metal detector—the Polish mine detector. The Germans responded with mines that had a wooden or glass casing to make detection harder.

Wooden mines had been used by the Russians in 1939, before the appearance of metal detectors, in order to save steel. Some, like the PP Mi-D mine, continued to be used into the 1980s as they were easy to make and hard to detect. Wood has the disadvantage of rotting and splitting, rendering the mine non-functional after a comparatively short time in the ground (or the advantage, in that the mine can be considered self-disabling, and will be less likely to cause unintended injuries years later).

Mines manufactured after the 1950s generally use plastic casings to hinder detection by electronic mine detectors. Some, referred to as minimum metal mines, are constructed with as little metal as possible – often around 1 gram (0.035 oz) – to make them difficult to detect. Mines containing absolutely no metal have been produced, but are uncommon. By its nature, a mine without any metal components in it cannot be found using a metal detector.

The fuze mechanism is designed to set off the detonator, either by striking it with a spring-loaded firing pin, compressing a friction sensitive pyrotechnic composition, or by passing an electric charge through it. Most mines employ a spring-loaded striker that hits a stab detonator when activated by the victim. Typically, the detonator contains a tiny pellet of lead azide. The fuze is the most complicated component in any mine, although the amount of effort required to design and manufacture a simple fuze mechanism is quite low, similar to the retraction mechanism in a ballpoint pen. More sophisticated examples, such as the Italian SB-33 mine have a fuze mechanism that detonates the mine if subject to gradual, steady pressure, but locks the fuze if subject to a sudden shock. This defeats one of the main methods of clearing a path through a minefield — detonating the mines with explosive devices, such as mine-clearing line charges.

The booster charge is a highly sensitive explosive that will activate easily when subjected to the shock of the detonator. Typically, a pea-sized pellet of RDX is used. The purpose of the booster is to amplify the shock of the detonator and initiate the main explosive charge.

The main charge consists of a stable explosive that is detonated by the booster charge. This is necessary, because making a mine entirely out of a highly sensitive detonator or booster explosive would be more expensive, and make the device more sensitive and thereby susceptible to accidental detonation. In most AP blast mines TNT, Composition B or phlegmatized RDX are used. On a US M14 mine, 29 grams of tetryl is used, while 240 grams of TNT is used in a Russian PMN mine.

Anti-personnel blast mines are the most common type and are typically deployed on the surface (hidden by leaves or rocks) or buried under soil at a depth of 10 – 20 mm. They are activated by pressure, i.e. when the victim steps on them, but it could also be a vehicle driving over them.

They were designed for use as area denial weapons. Weapons of this type are supposed to deny opposing military forces access to a specific area.

These mines are deemed to be more efficient than purely "blast effect" mines, because the shrapnel covers a greater area, potentially injuring more combatants.

The shrapnel from these mines can even disable some armoured vehicles, by puncturing their tires and—in the case of soft-skinned vehicles—also penetrating the skin and damaging internal components or injuring personnel. Because fragmentation mines generally contain a much larger charge than blast mines, they can cause severe damage to an unarmoured vehicle which runs directly over one.

These mines (such as the Russian POMZ) are entirely above ground, having a fragmenting warhead mounted on a stake at a suitable height, concealed by vegetation or rubbish and triggered by one or more tripwires.

Bounding mines have a small lifting charge that, when activated, launches the main body of the mine out of the ground before it detonates at around chest height. This produces a more lethal spray of shrapnel over a larger area. One such—the US M16 mine—can cause injuries up to 200 metres (660 ft) away. The steel shrapnel makes bounding mines easy to detect, so they may be surrounded by minimum metal mines to make mine clearance harder.

Directional fragmentation weapons (such as the M18 Claymore) differ from other types in that they are designed to direct their fragments only in a limited arc. They are placed so that the blast will be directed at the target area and away from friendly forces. This design also allows forces to protect themselves by placing these types of mines near their own positions, but facing the enemy. They are triggered in a conventional manner with either tripwire or command detonation. They are generally referred to as claymore mines from the US mine of this type.