Andy Smith
Mine action specialist

Detecting what?



Humanitarian Demining

Detecting what?

In demining, metal-detectors are used to detect the metallic content of explosive hazards remaining after conflict. When items have gone deep into the ground, special detectors may be required. Some of these deep-search detectors are ferrous locators and will not detect metals that do not have an iron content so should not normally be used to search for plastic cased mines with aluminium parts. For the most part, the most difficult target for the deminer to find is a plastic cased mine (which may be anti-personnel or anti-vehicle) that has a small metal content in the fuzing system. The metal may be stainless steel and the detonator casing is usually aluminium. These are called 'minimum metal mines'.

The metal signatures of mines vary widely, and it is not only the smallest signatures that can be hard to locate with a detector.



But this is what detectors find most of the time. Defensive mined areas around villages often get used as rubbish dumps.

Then there are fragments associated with conflict.

This is a typical scrap-pit from one deminer's lane in the hills of Afghanistan.

This is a scrap-pit for a group clearing a mined area in Mozambique where the mines included fragmentation mines.

Moving onto the real targets - the PMA-2 is a notoriously hard mine to detect. It is common throughout the Balkans, but is rarely found anywhere else.

This is a section through the PMA-2 with the only metal part being the aluminium detonator shell. The detonator size is 6mm x approximately 7mm.

This is the R2M2, which shares its fuze with the R2M1, the RAP "carrot" mine and the SA No8 AT blast mine - so sharing the same metal signature. It is common throughout Southern Africa.

This is the R2M2 spring, pin and ball bearings. The steel used for the spring and ball bearings is often surgical quality stainless. This means that it is often only the detonators that can be reliably detected.

The R2M2 detonator size is shown above.

This a Type 72a - the minimum metal mine that is most widespread in use - although not necessarily the most common in any one country. It has been recorded in Afghanistan, Cambodia, throughout Southern Africa, Iraq, etc - but not in the Balkans.

Here are the metal parts from a Type72a. There is a two-part detonator, a pin, and a thin 'arming' spring.

It is not only minimum metal content that causes problem. Mines with plenty of metal that are deep or heavily corroded can be really difficult to detect.

This is the GYATA-64 - a Hungarian mine that is common in Southern Mozambique Yemen and Lebanon.

There is a lot of metal in this mine - but when rusty, it can be very hard to detect.

This is probably the most common mine in the world, the PMN.

Like the Type 72a, it has been used in most theatres except the Balkans. The metal content of a PMN is less than that in a Gyata-64 - but the large ring holding the rubber top in place makes it easy to detect - as long as the ring is intact.

It is not just the metal bulk that makes detection easy - its is also its shape and orientation in the ground.

If a detector can find that range of mines at a depth of 13cm (to the top of the mine) in electromagnetic and reactive soils, it is doing very well. If it could find them at 30cm - it would lead the field.

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