OZM

The OZM-3, OZM-4 and OZM-72 are Soviet manufactured bounding type anti-personnel mines. They are fragmentation-barrier mines, which in the Russian and other post-Soviet armies as informally called "frog mine" or "witch".

They are normally painted olive green, and issued with a spool of tripwires and two green painted wooden or metal stakes for affixing the tripwires. Both OZM-3 and OZM-4 have cast iron fragmenting bodies while the OZM-72 also contains preformed steel fragments, and all three are issued with empty fuze wells, so a variety of fuzing options are possible.

Operation The mines can be activated by a variety of fuzes, including electronic fuzes or command initiation, although they are most commonly fitted with an MUV booby trap switch which is activated by a tripwire.

On firing, a metal base plate remains in the ground, while the mine body is thrown up by a small lifting charge, but remains attached to a strong wire tether. When the end of the tether is reached at a height of approximately 0.5 m, the main charge explodes and scatters fragments of the casing across a wide area.

OZM mine may sometimes be laid directly on top of an MS-3 mine. The MS-3 is an anti-handling device which closely resembles a PMN mine, except that it has a "blister" on top and operates purely as a pressure-release boobytrap. Lifting an OZM mine (without rendering safe the MS-3 placed underneath) will trigger detonation.

Variants

OZM-3 Casing materialcast ironWeight3.2 kg (7 lbs)Fragmentation charge (TNT)0.75 kgCasing diameter75 mmCasing height130 mm (5.1 inches)Length of the sensor target (one-way)5 or 10 mSensor sensitivity0.5–1 kg (MUV, MUV-2); 1.5–6 kg (MUV-3, MUV-4)Radius of guaranteed lethal destruction9 meters (29.5 ft) Temperature usage range-40 to +50*C (-40 to +138*F)Mine burst height0.4–1.4 mSources

OZM-4 Casing materialcast ironWeight5.4 kg (12 lb)Fragmentation charge (TNT)0.75 kgCasing diameter90 mm (3.5 inches)Casing height170 mm (6.7 inches)Length of the sensor target (one-way)10 or 20 mSensor sensitivity0.5–1 kg (MUV, MUV-2); 1.5–6 kg (MUV-3, MUV-4)Radius of guaranteed lethal destruction13 meters (42 ft)Temperature usage range-40 to +50*C (-40 to +138*F)Mine burst height0.6–0.8 mSources

OZM-72 Casing materialsteelWeight5 kg (11 lbs)Fragmentation charge (TNT)660 gr (1.49 lb)Casing diameter108 mm (4.1 inches)Casing height172 mm (6.7 inches)Sensor sensitivity0.5–1 kg (MUV, MUV-2); 1.5–6 kg (MUV-3, MUV-4)Radius of guaranteed lethal destruction25–30 mRadius of fragments50 meters (164 ft) Temperature usage range-40 to +50*C (-40 to +138*F)Number of preformed steel fragments2400 pcs.Mine burst height0.6–0.9 mArea of effects2124 m²Sources

Ottawa Treaty Since the Ottawa Treaty, a number of countries have decided to retain their OZM mines, but convert them to command detonation only by destroying all fuzes which can be indiscriminately activated – potentially by non-combatants or animals. Belarus in particular has decided to keep 200,000 OZM-72.

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