Thursday, December 10, 2009

Demining

Demining is the process of removing land mines or naval mines from an area. Minesweeping is the detection of such mines. There are two distinct types of mine detection and removal: military and humanitarian.

Mine clearance
In the combat zone, the process is referred to as mine clearance. The priority is to breach the minefield quickly to create a safe path for troops or ships. Speed is vital, both for tactical reasons and because units attempting to breach the minefield may be under enemy fire. In this situation, it is accepted that mine clearance will be imperfect and there may be casualties from undiscovered mines. Correspondingly, in these mine clearance operations, the methods that are applied for detection and removal are quicker, but not exact. These methods include those that detect and remove in a single action, such as mechanical demining, carpet bombing, burning of the land or the use of Bangalore torpedoes or mine-clearing line charges. According to the doctrine of the U.S. and other armies, mine clearance and demining is carried out by combat engineers.

Humanitarian demining
In times of relative peace, the process of mine removal is referred to as demining. This is a thorough, time-intensive process that seeks to locate all mines so that the land or sea area may be safely returned to normal use. It is vital that this process be exhaustive. Even if only a small handful of mines remain undiscovered, then demining can actually lead to an increase in civilian mine casualties as local people re-occupy an area they previously avoided in the belief that it has been made safe. In this context demining is one of the tools of mine action. Coordinated by Mine Action Coordination Centers run by the United Nations or a host government, civilian mine clearance agencies are tasked with the demining. In post-conflict areas, minefields are often contaminated with a mixture of explosive remnants of war (ERW) that includes unexploded ordnance as well as landmines. In that context, the humanitarian clearance effort is often referred to as battle area clearance.
In some situations, clearing landmines is a necessary condition before other humanitarian programs can be implemented. A large-scale international effort has been made to test and evaluate existing and new technologies for humanitarian demining, notably by the EU, US, Canadian and Japanese governments and by the Mine Action Centres of affected countries.

Current humanitarian demining methods
The main methods used for humanitarian demining on land are: manual detection using metal detectors and prodders, detection by specially trained mine detection dogs, and mechanical clearance using armored vehicles fitted with flails, tiller or similar devices. There is an organization, APOPO, that is training African rats to detect landmines much as dogs do, offering a local solution to countries in Africa. In many circumstances, the only method that meets the United Nations' requirements for effective humanitarian demining, the International Mine Action Standards (IMAS), is manual detection and disarmament. The process is typically slow, expensive and dangerous, although demining can be safer than construction work if procedures are followed rigorously. New technologies may provide effective alternatives.

Manual detection with a metal detector
Metal detectors were first used, after their invention by the Polish officer Józef Kosacki. His invention known as Polish mine detector Allies used to clear the German mine fields during the Second Battle of El Alamein when 500 units were shipped to Field Marshal Montgomery.
The first step in manual demining is to scan the area with metal detectors, which are sensitive enough to pick up most mines but which also yield about one thousand false positives for every mine. Some mines, referred to as minimum metal mines, are constructed with as little metal as possible - as little as 1 gram (0.035 oz) - to make them difficult to detect. Mines with no metal at all have been produced, but are rare. Areas where metal is detected are carefully probed to determine if a mine is present; the probing must continue until the object that set off the metal detector is found.

Dogs
Well-trained dogs can sniff out explosive chemicals like TNT in landmines, and are used in several countries.

Rats
Like dogs, Giant pouched rats are being trained to sniff out chemicals like TNT in landmines. These rats are currently working in minefields in Mozambique and are trained in Tanzania by APOPO. The rats are called HeroRATS.
These animals also have the advantage of being far lower mass than the typical human. They are less likely to set off small mines intended to injure or kill people, if the bomb-sniffing animal crosses directly over the top of a buried mine.

Mechanical clearance
Special machines effectively combine mine detection and removal into one operation. In the past, these machines were applied in both mine clearance and demining but are now generally used only for demining. They can be used to verify land that is not expected to be contaminated or as an extra layer of security after an area has been cleared by another method, such as dogs.
The machines consist of a special vehicle that is driven through the minefield, deliberately detonating the mines it drives over. These vehicles are designed to withstand the explosions with little damage. Some are operated directly with armour to protect the driver; some are operated under remote control.

a) Mine rollers and mine flails. The roller method originated during World War I and the flail method during World War II but both are still used. Neither system is completely reliable and both will leave undetonated mines, requiring the minefield to be rechecked by another method. Mine flail effectiveness can approach 100% in ideal conditions, but clearance rates as low as 50%-60% have been reported. This is well below the 99.6% standard set by the United Nations for humanitarian demining.

b) Mine plow - a device in front of a tank that excavates the ground, exposing any mines or turning them upside down, which significantly lessens their effects if they explode.

c) Modified long-armed demining bulldozers are being used in a number of countries. It has the capability to remove vegetation before demining and can withstand antipersonnel and antitank landmines. Its long arms give it the benefit of reducing damage to the main body, especially to the operator's cab. Three inch (9 cm) thick bulletproof glass protects the operator from directional mines.
 
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