Andy Smith 2007 [See also Chapter 3: Releasing Land (Tech Survey and Task Risk Assessment).pdf written in 2009]

All Mine Action decisions in a particular country or district should be "context based". It is not always possible for the decision making process to be made entirely by national personnel, but it should always be possible to prioritise decisions in a way that is approved by nationals as being appropriate in their country. Because norms about what is an “acceptable risk”  vary geographically and also change over time, any system will vary from country to country and will require revision as time passes.

There is currently no approved global method of reducing areas recorded as hazardous. The process is sometimes called "Resurvey", "Retrofit survey" or simply "Area Reduction". This paper attempts to give simple guidelines that I find useful. By definition, areas that are currently recorded as hazardous must have been recorded in an earlier survey of some kind so identifying errors in the earlier survey will require some kind of “resurvey”. When the mines were placed by disciplined fighting forces, a lot can be done to avoid wasting time clearing ground without mines. When the mines were placed using “nuisance” or ambush strategies, the clearance of a lot of land that is not mined may be unavoidable.

The art of survey

The "art" of survey is rarely discussed openly. This may because it is one aspect of demining that many people believe is a mysterious "black art" which relies so heavily on experience that it cannot be taught. This is not true. Good surveyors do tend to have wide experience, and the basis of their decisions may appear to have as much to do with subjective "gut-feeling" as any conscious rational decision-making process. But there are methods in play even when surveyors are unwilling to explain how they have made a decision. In my experience this is often because they cannot express the process clearly and are afraid that they will lay themselves open to criticism if their decisions do not seem rational - or if a decision turns out to have been inappropriate. Some survey decisions will be wrong, if only because new information is later collected and that changes the evidence on which a decision is based. As long as the survey system makes provision to update and change past decisions, making an incorrect decision is always better than making no decision at all.

When the Survey Action Centre was established to carry out "impact surveys" I spoke out against their apparent neglect of those survey skills that could be taught. I argued that they should use existing demining surveyors to make impact surveys, so combining existing knowledge with the new information about the impact that a risk area was having on people. I was right because impact surveys alone have proven to be very misleading when conducted by staff appointed for their language skills rather than any knowledge of how mines are used, what a mined-area looks like and how they may be cleared.

A rapid impact survey is as inaccurate as the rapid mined-area surveys that preceded them, and may be of less use. When impact surveyors visit an area and discuss the threat with local people, they can easily be misled. Sometimes their own desire to be successful at finding threat areas may contribute to inaccuracies. At other times, the local people may overstate the problem for reasons varying from a desire to please to the desire for a mine-clearance group to come and spend money in their district. Whatever the reason may be, it is widely acknowledged that impact survey generally does not give a true indication of the extent of hazardous areas. I believe that it was always intended that impact survey should be followed up with a Technical Survey before prioritisation for clearance and tasking. This would rarely be cost effective, and what Technical Survey occurs is usually conducted by clearance groups directly preceding and during the clearance of a reduced area. Part of the reason for this may be that donors do not always recognise the value of Technical Survey and so do not want to pay for it. In fact Technical Survey is as important as (often more important than) area clearance when the desired end result is the rapid release of land that is safe to use.

When an initial rapid or impact survey was conducted some time previously, perhaps carried out by personnel who are no longer employed by the programme, perhaps under pressure for speed and with severe spending constraints, and perhaps while security concerns prevented freedom of movement, its findings should not be presumed to be correct. If resurvey consistently confirms the accuracy of the first survey, the National Authority may decide that there is no need for resurvey. But when tasking based on the initial survey leads to resources being wasted on areas where nothing is found, it will almost certainly save a programme time and money to conduct some kind of resurvey.

My recent experience in this area is of impact survey leading to risk areas being misreported in terms of place and scale. Sometimes the surveyors combined several discrete risk areas into one large area. This was probably done because they did not visit the sites and confirm the threats, so they were uncertain where one might end and another start. If they had looked at the landscape and the areas being defended, this might have been obvious. But it was quicker to take a GPS reading from a known safe point and crudely estimate the area to be cleared. For example, a minefield at the top of a mountain pass was reported to measure 15 square kilometres when in fact the total mined area is much less than half of one square kilometre. A demining group started work in the area and did not carry out "area reduction" by Technical Survey because the Mine Action Centre had given them the entire reported area as a single “clearance task". Local people laughed at the deminers because they were clearing places where the locals regularly harvested hay and ignoring those areas where accidents with people and livestock had occurred.

In this example, expatriate advisors had no experience of Technical Survey and no apparent desire to avoid wasting donor money by clearing areas with no threat. The national staff listened to the local people, but lacked the confidence (or the authority) to make any decision to reduce the area themselves. With no one wishing to take responsibility for a decision that could be wrong, a country with a small mine problem was set to take seventy years to achieve a mine-safe environment.

What they needed was a method of re-assessing recorded risk areas with a view to reducing the over-estimate whenever possible without missing genuinely hazardous land. The method had to be such that it could be applied and subjected to Quality Assurance checks with a level of objectivity that meant that no individual could be blamed if it was later discovered that the land had been released in error. At its simplest, the method uses a checkbox resurvey that can release some land and confirm other land very quickly and with a very high level of confidence. The process becomes more difficult where there is some evidence of a risk from mines and ERW, but not enough evidence to convince everyone. The method of assessing uncertainties has to be agreed in order to avoid having to treat all uncertain land as hazardous. This agreement should be between the Surveyors, the National Mine Action Authority and the donors paying for the work, and so will vary from country to country.

What is “risk” in Mine Action?

For the civilian, the simple risk is of being injured as a result of a device detonating. This is compounded by the risks of not entering a risky area to gather wood, water or gain access to fields, etc. Restricted access may affect the health and well-being for the people in many ways. In demining activities there are two principle risks:

1. That of leaving behind an explosive item.
2. That of being injured during the demining process.

You may add to that:

3. The risk of doing more than was needed, and so of taking more time to conduct a task (and of paying more for the work) than was necessary.

If a demining team spends more time than necessary at a task, they will be unable to be in the next place where the risks to civilians will continue. The desire to be 100% thorough has to be balanced against the need to be working in the next task area.

If a demining team habitually spends more time and money than necessary, the donors will eventually notice that they are not cost-efficient and put their money elsewhere.

The risks must be balanced, or “managed”.

Risk management - and NKR

Deciding where to work is always a risk management activity. In any post-conflict mined country, there is always a risk that items of ordnance or mines might be almost anywhere. When the threats include aerially dispersed mines and submunitions this is even more likely. Payloads may have been dispersed in the wrong place at night, when the weather is bad or when aircraft are under fire. If this may have happened, must you check the whole country? 

Of course that is not possible, but a series of decisions can be made about where to clear and when to decide that there is "No Known Risk" in an area. I have found the term "No-Known-Risk" (NKR) especially useful. For example, there is probably NKR in your own garden, so you will not ask anyone to spend a lot of money clearing it. However, if your child comes into the house holding a piece of UXO she has found in the garden you may decide that there is now a reason to believe that there is a risk, and set out to minimise it. Minimising the perceived risk may mean clearing the whole garden with a professional demining team, but perhaps not. If your child found the item in an old rubbish pit, you may decide that only the rubbish pit needs to be investigated. The context matters greatly. So does the discovered item. An unfuzed relic from fifty years ago should cause a lot less concern than a touch-sensitive submunition discovered after a recent conflict.

The "impact" of clearance is important. Limited resources mean that areas where there is known to be a risk to the local population should be cleared before minefields where no one goes, and so no one is at any immediate risk. For this reason, even a known mined area could present "No Immediate Risk" if no one used the land, and so be given a low tasking priority by the National Mine Action Authority.

Impact is the effect that the presence of a threat from munitions (or the believed presence of that threat) has on the users of the land. There may have been accidents with people or livestock. The people may be unable to use the land and so suffer food and resource shortages that impact on health. The people may be unable to cross the land to reach water, woodland, fields, markets, health centres or schools.

The impact of the perceived threat may be higher than any real risk. For example, a small minebelt of sixty mines in good condition might reasonably be thought of as presenting a higher risk than a minefield of ten thousand mines that have atrophied to such an extent that their detonators are no longer capable of functioning. However, if no one will use the large mined area because of the fear of these "dead" mines, it may be a higher humanitarian priority to clear them than to deal with the smaller minefield of “live” mines. The National Mine Action Authority might reasonably make clearance of an area with "No Immediate Risk" a higher priority that areas with a "Known Risk".

And in many areas there will be a "perceived risk" that is not proven to exist. A perceived risk may need to be processed as a high priority if it impacts heavily on the users of the land, but that process need not involve full clearance until the reason to believe that there is a Known Risk becomes compelling. Area reduction processes and/or confidence building processes should be used in these areas. For example, there is a site where people believe that a protective minebelt of anti-personnel blast mines was placed in front of an old military position. There have been no accidents, no loss of livestock, and the military have no record of having used mines at the place. It might be decided to drive over the area with a light flail followed with a close visual inspection for evidence of broken mines. If nothing is found, Explosive Detecting Dogs might be run over the area after the flail to increase confidence that the land is safe. Alternatively, deminers might cut exploratory breaches across the area using manual clearance methods. Depending on what is discovered, parts of the area may be redefined as having a "Known Risk" or as having "No Known risk". Any area with a "Known Risk" should reward the application of full clearance processes with mines/ERW being discovered. Areas with "No Known Risk" can be released for use because there is no reason to believe that they are hazardous. "No Known Risk" areas should not be released as having been "cleared", merely as having no known reason why they should be cleared. They will be "reduced".

Definitions of area-reduction concepts

No Known Risk (NKR) - no compelling reason to believe there is a risk from mines and ERW to people in an area. This means than an area previously recorded as presenting a risk can be released without being subjected to clearance processes. The release of areas previously recorded as hazardous without having processed the land with any full clearance techniques is usually referred to as "Area-reduction".

Known Risk (KR) - compelling reason to believe there is a risk to people in an area. This means that the area must be subjected to appropriate clearance processes before being released for public use.

No Immediate Risk (NIR) - no compelling reason to believe that any risk there may be in an area adversely effects people at this time. A Known Risk area may also be an NIR area. This means that the area can be given a low priority in a list of clearance tasks that is prioritised according to their impact on people.

Perceived Risk (PR) - people believe that there is a risk but there is no compelling evidence to support their belief. In this case, area-reduction and/or confidence building processes will be appropriate. The priority given to this kind of task will be dictated entirely by the "impact" that the demining work will have on people wanting to use the land.

Threat – the actual item(s) that present an explosive risk. These may be mines or other Explosive Remnants of War (ERW).

The terms NKR, KR and PR are all defined using the word "compelling", which means that the user must take the risk presented by the threat should be taken seriously. So what makes the decision of a surveyor conducting area-reduction "compelling"?

What one person finds "compelling" may differ from the opinion of another because one person may not interpret the significance of a piece of information in the same way as someone else. To keep consistency across the area-reduction process, a method has to be put in place so that the interpretations of individual surveyors are minimised. This protects individual surveyors by spreading the responsibility for each decision throughout those responsible for Mine Action.

So the point at which information about an area compels it to be listed as having a Known Risk must be decided by those in authority. In the example that follows, I give a suggestion that I think will fit a lot of places. If it does not fit yours, I hope it will give you a starting point to develop your own. Some of this is very basic but it is necessary to include it to avoid confusion.

Reducing suspect areas

The application of a series of questions should start the process - and the answers may mean that the area recorded as presenting a risk need not even be visited.

1) Is there evidence of a threat?                 Yes/No
2) Is that threat visible?                               Yes/No
3) Have there been accidents/incidents with livestock?         Yes/No
4) Have there been accidents/incidents with people?            Yes/No
5) Are there any records from those who placed mines or witnessed their placement?       Yes/No
6) Are inhabitants unwilling to use the land because they believe that the area is dangerous due to ERW?     Yes/No

If the answer to any of the above is “Yes”, the area should be visited and subjected to a "Confidence check" or "Technical Survey". If the answers to the above clearly indicate that there is a risk, and the information comes from one or more credible source, the area can be recorded as having a KR. If the information about the above is unclear and there may have been accidents of evidence of risk, the area should be defined as having a PR.

If none of the above are answered “Yes”, the area has NKR and should not be subjected to any demining activity. It can be "reduced" without a visit and recorded as having NKR at this time.

Usually, the local inhabitants will believe that some of the area originally recorded as a mined area does present a risk. A resurvey team will have to visit them to gather more information before reassessing the extent of the risk area. The resurvey team must write down each decision they make and include the reasons for making that decision. This will protect them if it is later discovered that they made an error.

Visiting the nearest settlement(s)

When assessing a PR or KR area, go to the district and speak to as many of the local people who believe there is a risk as possible (starting with the local representatives, but do not speak only with them). To avoid confusion, try to talk about one risk area at a time. Interview each person on their own and without others overhearing. Write down the answers and the names of those giving information. Children may roam more widely than others so may provide good general information, although they are often inaccurate about detail. Marginalised adults tending livestock may also know more than most. Never presume that reported distances, times and numbers are accurate. Also, never presume that people use the same names for things that you do. This applies to places, features and explosive devices. Question gently but persistently in order to be clear about how much each informant knows.

Take with you a printed collection of real photographs of all the mine and ERW threats that could be in the area and see whether anyone can identify them. The photograph collection should include clear pictures of all common devices in real situations (photographed in previous working areas with a similar context whenever possible). If the same items are identified by more than one informant (interviewed separately), there is a high chance that those items are present. Other, perhaps concealed, items may also be present. The photograph collection should cover all mines and ERW believed to have been used in that part of the country, with generic examples for munition types such as rifle grenades, rockets and mortar bombs.

If people have collected devices or parts of devices, ask to see them. The collection of devices and fragments happens frequently. Be cautious and never accept that an item is “safe” just because the informant thinks it is.

If there have been accidents to people or livestock, question people closely about the injuries received. The extent of injury can make it clear whether the threat was a fragmentation or a blast device, a large item of ordnance or a small mine. Question victims or witnesses closely about the circumstances surrounding each accident. Local shepherds huddled around a fire at night and putting on an item of broken ordnance because they know that the explosive will burn is a rather different accident than the same shepherds tripping an OZM-72 fragmentation mine, but the injuries can be similar.

1) What devices are reported to be present in previous survey or minefield records?....................................................................................................

2) What devices are reported to be present by locals?.......................................................................................................

3) Are any of the reported threats anti-personnel mines? ……………        Yes/No

4) Are they blast or fragmentation mines? ……………………   Blast/Fragmentation/Both

5) Are any mines tripwire operated?..................................................     Yes/No

6) Are the tripwires intact? …………………………………….. Yes/No/Uncertain

7) Is there any suggestion of anti-lift or booby-trap devices?............          Yes/No

8) Are any of the reported threats anti-vehicle or anti-tank mines?....          Yes/No

If none of the reported threats are mines, may any of the ordnance be movement sensitive?...   Yes/No

If ordnance is identified that the surveyor does not have details about, that detail should be sourced through the International community so that informed decisions can be made.  

From the answers to the above, you can decide whether the task includes a minefield or is a Battle Area (has explosive ordnance, but no mines). If it is a Battle Area, knowing which devices or generic type of device can help when determining what assets to deploy when the area is processed using BAC.

It is possible that there will be no information about the devices present and that the Surveyors will have to deduce the likely threat with help from accident details.

Write down the perceived threat - and the Surveyors' confidence that it is correct and complete. If they have experience in similar situations, the surveyors may suspect the presence of unreported devices.

What is the threat?...............................................................................................................

What condition is it in? ........................................................................................................

Is there any reason to believe that other devices are present? …………..              Yes/No

If "Yes", what  reason(s)? .......................................................................................... ……….

Is the threat likely to be above ground?.......................................................           Yes/No

When the surveyors have as much information as possible from all sources, and there is reason to think that there are threats in that area, their job is to go to the area, confirm the presence of threats that pose a risk, and reduce the recorded hazardous area to accurately reflect the known risk limits. This does not mean defining particular minebelts (although they may sometimes be visible) but does mean excluding land that is definitely not part of the risk area. As a general rule in areas mined by disciplined forces, the area may be reduced up to ten metres from the closest mine. When the position of the mines is uncertain, that distance may be extended to twenty metres. In areas where the mines were dispersed in the air, the distance should be extended to reflect the known spread and the known movement of the devices.  For example, mines dropped on steep hillsides may have moved into gullies and down the slope by a considerable distance.

Going to the reported hazardous area

The accident record shows that surveying is not an especially hazardous Mine Action activity. Even so, surveyors should take all the precautions common in demining. A survey team should comprise a minimum of five people  including a medic. All should have the widest possible experience of demining, with everyone trained in first-aid, basic demining and device recognition skills. The team should speak local languages and have respect for local people and customs.

The survey team should take PPE and the widest range of demining tools possible. For example, a mini-flail would often be an invaluable surveying asset. In many cases it could give easy access and allow a confidence check to be carried out on reduced areas during the survey.

The minimum medical backup required by the NMAA for demining should accompany the surveyors whenever they intend to enter a PR or KR risk area. When the requirement includes an ambulance vehicle within a short distance and access makes this impossible, an amendment to the minimum NMAA requirement should be requested.

The surveying team should be able to communicate with their base. This may be by satellite telephone when necessary. They should notify their base before any visit to a KR or PR area is made.

Surveyors should be taken to the area by the local people who report the presence of a threat. The only time when this need not be done is when the only reason to expect a threat is because a minefield is recorded on minefield maps received from combatants or from reliable informants. If local people will not accompany the surveyors to the perimeter of the area believed hazardous, attempts should be made to persuade them. In some cases, a gift or a small payment may be appropriate. It should be stressed to the guides that they should not lead the team into the mined area, only into its vicinity. Surveyors should use paths, roads or tracks and be led by the local guide(s). In some remote areas it can be advisable to approach the area on mules or horseback to ensure that the surveyors arrive fresh and able to think clearly, carrying the appropriate equipment.

The reported area should, whenever possible, be viewed from all sides. It may be appropriate to climb nearby hills to gain an overview of the area. Surveyors should take photographs of the area, including any landmarks used by the local guides. If undergrowth is too dense to get an overview, they should use the most detailed maps available and regularly check exactly where they are as they progress. Surveyors must not try to complete this in a hurry. An extra day spent at this stage may have thousands of deminer working days later.

The purpose of the visit is to conduct area-reduction and to identify/confirm the threats that are present, so the Surveyors should already have at least one map. That map may be entirely inaccurate, but it should be consulted and reference made to it when recording their access route and any new GPS co-ordinates.

If local people regularly use any part of the area for access, grazing, crop-gathering, wood-collection, or anything else, the places that are used should be recorded (GPS) and reduced UNLESS there have been accidents or devices discovered inside that area. Surveyors should stay inside the area believed to be safe when recording co-ordinates. A “safe” area can include an area containing Explosive Remnants of War that are not touch sensitive. When no accidents or devices have been found inside the used area, the area believed to be safe will include the places that are used by local people. Outside these areas, surveyors must use paths and tracks that are used by locals. This includes paths and tracks that pass through areas that may be hazardous.

When devices have been found within a used area, the device type and condition is important. Some ordnance is generally considered to present a very low threat. Many mortar bombs and some grenades fall into this category. Perhaps surprisingly, the same can be true of some mines. For example, POMZ-2 mines on wooden stakes that have all fallen over and without intact tripwires may represent a low-threat. Both the fuze and the explosive have often reliably separated from the mine bodies. When people use the land around them and there have been no accidents, it may be appropriate to move through the area guided by locals who regularly do so. In cases like this, the area should be accurately recorded with GPS so that the residual threat can be cleared later using appropriate assets (in this case it might be appropriate to use visual BAC methods after random metal detector checks confirmed an absence of AP blast mines from the mine pattern).

It is possible that surveyors will have to cross an uncertain area in order to reach another used area or path that is presumed to be safe. Depending on the assessed threat, surveyors may use confidence building or Technical Survey techniques to move across an uncertain area as long as they have appropriate medical backup. These techniques cannot be used without the approved medical support being present. To do this appropriately, a preliminary assessment of the threat must be made. This should be recorded in writing.

Assessing the threat

To assess the threat the survey team must have a list of identified mines and ordnance, and should have detailed knowledge of these devices, how they function, and how they were deployed. They must also have an idea of the condition of the devices and details of the accidents to people and livestock that have been reported.

The accident/incident record can provide a lot of evidence about the devices that may be found. Detailed knowledge of the anticipated devices is also very important. If the surveyors know how the devices work, it can sometimes be possible to judge whether they have “armed”. For example, it is often possible to see whether touch-sensitive submunitions (such as the BLU-97 and the KB-1/M42) have armed. If they have not armed, moving them can be considered. It is also good to know that not all submunitions present the same degree of risk as the BLU-97 and KB-1. Some can be safely moved for destruction even if they have armed. For example, the ShOAB 0.5 and AO 2.5 are impact fuzed and can be moved carefully by hand. 

If a conflict has been over for some time, some devices will have reliably decayed. Unfortunately, no in-depth study of the deterioration of mines and ERW has been conducted. This means that (at this time) the NMAA and demining staff in each country must make their own assessment and share the responsibility for the decisions that are made.

Mines that can no longer function as designed are not necessarily safer. However, atrophy often works in favour of the deminers as tripwires decay, fuze systems corrode and explosives crumble.

These pictures show a wooden “shoe-box” PMD-6 blast mine and a POMZ-2 fragmentation mine. The TNT has crumbled and fallen apart in the PMD-6 and has fallen out of the POMZ-2, so the detonator could not set it off. They cannot function as designed but the parts include detonators which present a small risk if the remains of the device were tampered with.

Plastic bodied MUV fuzes like the green one shown above may have been used in OZM and POMZ mines. Many have been softened by bushfire. This can prevent movement of the firing-pin or lead to the firing pin firing upward so that it is no longer present. The mines would then still contain a detonator, but no means of readily initiating it.

It is necessary to know the threat devices well before deciding that their decay is a reduced risk.

As an example of atrophy reducing risk, PFM mines that were air scattered will have been attacked by weather and sunlight. After some years, the cases will probably have split and the liquid explosive evaporated. What is left contains a small detonator but it is not easy to set off and presents a very small risk of injury unless deliberately tampered with.

PFMs in this condition can be handled with caution.

A PFM minefield is often extensive because the mines were air dropped and designed to spread widely. It can take many man-years to clear an area strewn with PFMs using conventional demining methods. When they have decayed as shown, the devices themselves cannot operate as designed, but they may still present some risk.

In this case, it may be appropriate to conduct a rapid visual BAC – except in areas where the mines may have been buried by earth movement. Alternatively, driving a demining machine over the threat area will not reliably initiate the detonators, but may give confidence that any small hazard that remains is an “acceptable risk”. This partly depends on what other tasks are waiting to be performed, but also on the accident record. When no person or animal is recorded as having been injured in recent years, the NMAA may consider it safe to presume that their PFM minefields represent a very low threat and allow BAC or Mechanical ground processing (not recorded as full “clearance”) or simply move these areas to the bottom of any priority list. 

Age and decay can also work against the deminer. The pictures below show an R2M2 and a GYATA-64. The plastic case of the R2M2 has become brittle and begun to break up. These mines have been recorded as detonating “spontaneously” as deminers approach them. The GYATA-64 firing pin is held up by the leaf-spring illustrated. Over time, if the mine fills with water, the spring decays and the firing-pin is then not held up by anything beyond a small amount of friction. Very minor pressure could then set it off.

Knowledge of the devices should be augmented by knowledge of the context. For example, the land may be flat or steep, rocky or heavily overgrown. There may be so much undergrowth that the ground cannot be seen. During the resurvey, the context should be photographed so that any demining team that follows will know what it will have to deal with.

The context can affect a decision over what to do next. If the survey team has secure funding and are able to schedule its resurvey tasks well in advance, they may decide to return at another time of year when some of the problems have been resolved by seasonal change. Very wet ground may have dried out, or winter may have killed off undergrowth, for example. When the threat is believed to be on the surface and may be visible at another time of year, a decision to return later can be appropriate and cost-efficient.

Approved confidence building methods

When there is no compelling reason to believe that an area is mined or contains touch-sensitive munitions but local people still believe it may be hazardous, the use of mechanical assets to build confidence is allowed. This includes areas that are believed to lead up to a genuine risk area. Machines do not reliably clear mines, but they do give confidence to those watching and many expose evidence of mines even if they do not destroy them. When a machine that engages the ground is used to raise confidence, whether a flail, roller or even a bulldozer, the area must be checked using BAC or BACS detection methods afterwards. Any manned machine that is used should be armoured against the threats in the region. Mechanically processed ground may also be checked using Mine Detection Dogs (MDDs) after a suitable soak time (as detailed in the MDD SOPs). Generally, MDDs should not be used following a ground engaging machine when broken devices have been found during the visual BAC because the number of pieces of broken device can confuse the dogs. If a machine has broken or detonated mines in a densely mined area, it can be impossible to count the number of mines that have been disrupted or estimate their original positions. When the number or pattern of mines is known (as when reliable minefield records are available), the use of a machine can make it impossible for manual deminers to know when all mines have been found. It can be far more efficient to manually follow the minelines and, when all expected mines are found in the patterns recorded, deploy the machine to conduct a confidence building process over the surrounding areas.

MDD may need to be preceded by a machine that cuts undergrowth so that they can keep their noses close to the ground. Undergrowth cutting before dogs is not usually done manually – but may be done using manually held petrol-engine strimmers when a lateral MDD SOP is used and the deminers with strimmers do not stand on any land until after the dogs have checked it. When vegetation is cut to ground level, brush rakes (grass rakes) may be used to remove cuttings after strimming when the cuttings include thorns or thistles. Any area that the MDD cannot fully access (such as around bushes or vehicle wrecks) should be searched with standard manual methods, but the deminers may approach these discrete areas over land searched by the dogs and only use lane marking on the land they actually clear. Remember, the purpose of marking is to leave no confusion between land that has believed to be NKR and land that may present a risk.

Dedicated undergrowth removal machines may be used but should be armoured against the threats in the region unless they are remotely controlled. A remotely controlled flail (not hitting the ground) may be used to remove the undergrowth over a wide area. When the undergrowth is removed but the ground surface itself has not been processed, reliable MDD should be used to confirm that the area is safe. In these circumstances BAC teams should not be used before dogs have raised confidence. If any mine or other ERW is found, the task must be reassessed. Discovering solitary items of ordnance that are not touch-sensitive may be thought a minimal risk and so will often mean that the confidence building process can continue. Discovering a mine or part of a broken mine will usually mean that the survey team withdraws and marks the perimeter of the hazardous area at least ten metres back from the discovered item. 

The land reduced by survey should be recorded as Area Cancelled by Resurvey.

Approved Technical Survey methods

Technical survey should only be conducted on areas with a KR. The areas leading up the risk area should be processed using confidence building methods.

To avoid the cost of multiple deployments, Technical Survey should be conducted by a demining team prepared to continue and clear the risk area. All SOPs applying to clearance tasks will apply. Starting from a marked safe lane in the area with NKR, manual demining teams may cut lanes (breaches) into the risk area in an attempt to find any minebelts that may be present. The distance between the breaches will depend on the threat assessment but will not normally be less than ten metres. The method used in the breach will constitute full clearance to a recorded depth.

When no mines are found, the area between the breaches should be subjected to one or more confidence building methods before being released as having NKR. The area between the breaches should be recorded as reduced, not as having been cleared.

When mines are found, the demining team must adjust the breaching work appropriately in order to identify likely minebelts. The minebelts must then be cleared, including at least five metres on both sides of the mines. When mines are missing from the pattern and there is no evidence of them having detonated, the possibility of mine movement should be considered. In some cases, mines may have been moved by soldiers or locals and used for other purposes, and in others they may have been moved downhill by rainfall, etc. When necessary, the area around a missing mine that is cleared should be extended until the deminers are confident that they would have located any mine that has moved. The places searched should be determined by intelligent assessment. There is no reason to clear uphill from a mine that may have been moved by rain, for example.

Land that has been subjected to Technical Survey followed by clearance of some parts will be recorded in terms of those square metres subjected to full clearance methods (cleared) and those square metres subjected to confidence building methods and so having NKR (reduced). The total of the square metres is the Area Released by Demining.  The total Area removed from the database may be greater because it may include area cancelled without any field activity.

See also:

Are tripwire operated mines the greatest danger to deminers?

FFE/FFI - or blow in-situ? (pros and cons)

HSTAMIDS - metal-detector and GPR combination

Monitoring success in MRE (Mine risk education)

NVESD and the publicity machine

Risk from ERW (Explosive Remnants of War - other than mines)

The truth about "red plants" or the "purple weed system"
(2003 trial report)

Utility of mines, and of the ICBL

What goes through a deminer's head.... at the time of an accident

Working prone? (safer or stupid?)

ARESA "red plants" and the con goes on