Clearing Areas Right; Clearing the Right Areas

by Håvard Bach [ GICHD ]

Although land release is a widely used term, its definition is not universally understood. There are various approaches to mine clearance with different survey steps taken before conditions of safe land release are met, and some techniques are more efficient than others. This article examines ways of improving land-release methodology to more effectively define and ultimately resolve the landmine problem.

(Click the image to enlarge)
This figure illustrates how land can be released by Non-technical Survey (NTS), if it provides sufficient confidence that land is mine-free.
All graphics courtesy of the author

Is land-release methodology useful? The answer to this question requires insight into what land release is as a concept and how it can be applied in the field. The term land release is not entirely new, and it has gradually found its way into mine action, as well as the lexicon of most governments and organizations. It is now widely used, and while a few criticize the term, most embrace it. Rather than being an indication of a problem with the term itself, this criticism is perhaps related to the differences in understanding what it implies. Misuse of the term to support specific agendas may also have added to the backlash.

In the past, the practice of releasing land was based on a subconscious and subjective decision-making process by demining organizations in the field. There is, in principle, nothing wrong with informal decision-making, but when it causes excessive clearance, and subsequently a waste of resources, there is a need to reflect on whether current practices are efficient and if they should be challenged. A comparison between cleared areas and the numbers of mines and pieces of unexploded ordnance found in 15 countries showed that less than 3 percent of the land cleared contained mines or UXO. While it is not always the case that demining organizations waste resources clearing mine-free land, it unfortunately is a problem that occurs far too often to be ignored.

The Problem

Often in the field of mine action, we know there are mines but do not know their exact locations—nor even how many there are, or the actual size of the mined area. In the absence of a more detailed framework for completing the task, it is left to operators and contractors—guided by rigid criteria to leave no mines behind—to assess the task at hand and decide where to use scarce demining resources. The absence of a proper framework for defining and guiding mine clearance has inflated the perceived landmine problem, while allowing inefficient mine-removal practices. Clearing mines is actually the least difficult aspect of mine action. The real challenge lies in defining the task and determining the location of the mines, but there has been reluctance to find effective solutions. Relevant factors that promote inappropriate and conservative decision-making include:

  • Flawed use of success indicator
  • Pressure by local authorities
  • Faulty survey concepts
  • Fear of making wrong decisions
  • Unclear use of terminology
  • A lack of an evidence-based survey approach
  • Poorly understood role of clearance assets in Technical Survey
  • Failure to combine Non-technical and Technical Survey results
  • Poor documentation procedures

Definition of Land Release

No clear consensus on the meaning of land release exists, and this lack of understanding has led to numerous misguided discussions. Using basic definitions in the context of mine action, land release should be understood as an evidence-based process of defining, and subsequently removing, suspicion of landmines or other explosive remnants of war.

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Overall confidence in survey can be a product of confidence provided by the Non-technical and Technical Survey. It can lead to a clearance requirement or to the release of land.

Cleanup of Databases

Land release is often confused with the process of cleaning up incorrect entries in databases after a previous Landmine Impact Survey. The polygons from a Landmine Impact Survey or other non-evidence-based survey are, however, incorrectly perceived as the boundaries of mined areas. Governments should not use impact-based data (such as from a LIS) to define the geographical extension of a mine problem, but should rather use data from an appropriate Non-technical Survey process. Non-evidence-based data may be a useful indicator of where further investigation is required, but it does not remove the need for a Non-technical Survey process.

Political Framework

The majority of mine-affected countries—and most international donor countries—have signed the Ottawa Convention (ban on anti-personnel landmines). The Convention has had a positive impact on all mine-action stakeholders, despite some countries’ refusal to sign it. At the Ninth Meeting of States Parties in November 2008, a policy paper on land release offered these important recommendations:

  • Land can be released by Non-technical means, Technical Survey and clearance.
  • States Parties should develop national policies and standards that detail the shift of liability from operators to the state after land is released.
  • The new International Mine Action Standards series on land release will assist in providing a global set of terminology. Terms interpreted differently by stakeholders should be clarified or not used at all.
  • States Parties that are required to prepare extension requests should explain how clearance and other forms of land release will be applied during the period of the extension.
  • States Parties are encouraged to release more land by survey processes.
  • The release of land by Non-technical and Technical Survey is not a shortcut to implementing Article 5.1, but rather a more appropriate way to fulfill obligations, provided that the survey can confidently conclude that land is mine-free.

The Ottawa Convention requires the removal of all known mines in a specified timeframe while acknowledging the need to prioritize different areas in this process. The Convention is a political instrument that does not directly interfere with the operational aspects of mine action, but the focus on Ottawa timeframes has drawn discussion on whether current operational practices are adequate.

Purpose of Land-release Methodology

Any land-release concept should provide an appropriate framework for decision-making, a method of addressing legal and policy aspects, a way of defining appropriate technical solutions, and the promotion of sector-wide use of land-release principles. It should also prevent future inflation of the landmine problem by offering methods that more accurately define the real boundaries of mined areas before clearance assets are employed.

A good land-release concept does not always need to be detailed and formalized. A balance is required between the need for simplicity, the validity of the concept and increased efficiency. The simplest form of land-release methodology is already in use, but it has repeatedly failed to be efficient. For example, Non-technical Surveys have typically failed to collect and assess information in order to justify the release of land or define the minimum Technical Survey requirements.

International Mine Action Standards

Three IMAS drafts on land release have been developed in response to growing concerns about excessive clearance of mine-free land. The IMAS Review Board has reviewed and accepted the drafts, and they are currently awaiting final endorsement from the Inter-Agency Coordinating Group for Mine Action. According to the IMAS Web site, where the drafts are currently posted, “The content has effectively already been accepted by the mine action community and as such they can be used with immediate effect.”1 Minor changes may still occur, but the bulk is likely to remain unchanged.

  • IMAS 08.20 explains the principles of land release and details the responsibilities of donors, governments and operators in the context of land release. It further explains how the different components of survey and clearance should be viewed and how they can be combined to ensure efficient land release.
  • IMAS 08.21 explains the principles of a Non-technical Survey and how and when land can be released by it.
  • IMAS 08.22 explains the principles of Technical Survey and how the requirement for it can be defined by building on evidence already gained through the Non-technical Survey process.

Once endorsed, the three IMAS standards will form a useful framework for a wider use of land-release methodology.


Attempts have been made in the draft IMAS to resolve issues relating to terminology by introducing new terms, providing definitions of the most commonly used terms and discouraging the use of redundant ones. The proposed terminology aims to promote a broader understanding of land-release principles. The most important terms are discussed below:

  • Non-technical Survey is the new IMAS term for what was previously called General Survey, Polygon Survey, Level One Survey or Baseline Survey. It is a non-intrusive investigation into whether an area is mined or not.
  • Technical Survey is a technical investigation using demining assets to collect information for further assessment. The purpose of Technical Survey is to more accurately define the mined areas while also building sufficient confidence that the remaining areas are mine-free.
  • Clearance should be the method of last resort in the land-release process. An effort should be made to release as much land as possible by survey processes in order to limit clearance to well-defined mined areas.
  • Suspected Hazardous Area is an area with some indication of mines/explosive remnants of war but that has not been appropriately surveyed to provide an evidence-based survey conclusion.
  • Confirmed Hazardous Area is the product of an evidence-based Non-technical Survey and a polygon that defines the boundaries of the suspected area.
  • Defined Hazardous Area is the product of a Technical Survey. A DHA is the area that will end up cleared regardless of whether it was initially defined by Technical Survey.

Basics of Evidence-based Survey Components

The crucial question in both Non-technical and Technical Survey is how to define when there is enough information or evidence to confidently consider an area mine-free or mined. In the absence of appropriate decision-making criteria, the estimated size of a SHA is easily exaggerated because there is no incentive to do the opposite, but there is apprehension that the area is too narrowly defined.

A sufficiently high confidence that no mines/ERW exist in an area is a pre-condition for land release, and the meaning of the term thus needs to be clearly defined and consistently used. Terms like mine proofing, mine verification and risk reduction typically describe processes that lead to increased confidence in an area or a road being mine-free, but they are seldom quantified and would not lead to formal release of land or roads.

There are inherent inaccuracies in any Non-technical Survey and it may not capture sufficient information to justify many defined levels of confidence. Moreover, if it is impractical to use more than a few Technical Survey levels, a Non-technical Survey defining more levels of confidence is redundant. Overall survey confidence can be defined by assessing the value of information provided by the informants, weighting each and adding them to determine an overall rating of confidence. The scoring and the value of the information rely on two factors:

  1. Quantitative indicator: The amount of information (basis value of informant)
  2. Qualitative indicator: The accuracy of information (degree of trust in individual informant)

Confidence-scoring tables can be used to capture all possible informants and assets while giving each of them a unique score and at the same time allowing an adjustment of the scores based on the perceived accuracy of the information. The principles of defining confidence in Technical Survey are the same as for Non-technical Survey. Confidence in Technical Survey can be found by defining the value of information provided by each asset.

The simplest form of confidence rating has two values: high and low. Considering the survey always endeavors to prove whether an area is mined or not, the outcome from such a survey will potentially give four options:

  • No mines and high confidence could be defined as the main criteria for land release because a sufficient amount of reliable information suggest that there are no mines.
  • No mines and low confidence requires some degree of Technical Survey to boost the confidence to high and allow land release, if no mines are found (which is the likely outcome).
  • Mines and low confidence requires a higher degree of Technical Survey to accurately define the location of mined areas and possibly allow the remaining parts of the area to be treated as “no mines” with high or low confidence.
  • Mines and high confidence could be defined as the areas where full clearance is required because the boundaries have been defined.

High and low confidence will allow for two Technical Survey levels:

  1. A limited Technical Survey if the Non-technical Survey concludes there are likely no mines
  2. A more in-depth Technical Survey if the Non-technical Survey concludes there are likely mines, but at the same time fails to define the exact boundaries

Increasing the number of confidence levels to three would allow four levels of Technical Survey instead of two. Further increasing the number of confidence levels to four would allow six levels of Technical Survey, probably exceeding the accuracy of the Non-technical Survey. The Geneva International Centre for Humanitarian Demining has therefore developed models using three levels of confidence. In these models, the output from the Non-technical Survey is defined as mined or not mined, combined with three levels of confidence defined as low, medium and high.

If the Non-technical Survey suggests there are mines but the boundaries are not properly defined, the main purpose of the Technical Survey is to assist in defining these boundaries. If the boundaries can be defined, clearance is required to gain full confidence that there are no mines in that area. After clearance, the final classification could theoretically be “no mines, high confidence,” justifying the release of that land. Clearance is, however, often undertaken before the boundaries are defined, and the result of the clearance process is the main instrument in defining these boundaries. The clearance process is thus part of the evidence-based survey process. The three processes of Non-technical Survey, Technical Survey and clearance are in fact often concurrent activities, each of which increases confidence that an area is mine-free. The overall output from a broader survey is the product of evidence, or of confidence levels, provided by the Non-technical and Technical Survey, and even clearance. Convincing evidence provided by Non-technical Survey will require much less supplementary evidence from Technical Survey before land can be released.

Non-technical Survey

The purpose of a Non-technical Survey is to collect information that will determine any Confirmed Hazardous Area, and assist priority setting and the planning of subsequent Technical Survey, clearance, marking and mine-risk education. The output from a Non-technical Survey is purely based on a nonintrusive information-collection process. The survey has the potential to define the minimum requirements for Technical Survey.

Land is not always released by a Non-technical Survey, since it is often the first step in the chain of the evidence-based assessment of the problem. Land can, however, be released if the survey replaces a previous, less accurate Non-technical Survey and the new Confirmed Hazardous Area is smaller. If not, the survey will simply define reasonably accurate boundaries of hazardous areas and provide information that will assist further mine-action activities.

A way to define confidence in a Non-technical Survey is to develop a scoring table in which each source of information is given a confidence score and the sum of all scores provides the overall confidence rating. Information provided by those who laid mines, mine victims or others who physically observed where mines were laid could, for example, be grouped as firsthand information. Information with decreasing levels of confidence will be classified in the remaining three categories, depending on circumstance.

If three levels of confidence are used to define the accuracy of the Non-technical Survey, six potential outcomes exist:

  • No mines, high confidence: Land may be released.
  • No mines, medium confidence: A need for limited Technical Survey before land can be released if the Technical Survey provides further evidence of no mines.
  • No mines, low confidence: A need for normal Technical Survey before land can be released if the Technical Survey provides no evidence of mines.
  • Mines, low confidence: A need for increased Technical Survey before land can be released if the Technical Survey provides no evidence of mines.
  • Mines, medium confidence: A need for extensive Technical Survey before land can be released if the survey provides no evidence of mines.
  • Mines, high confidence: Land needs full clearance. The boundaries have been defined.

A Confirmed Hazardous Area may be classified as one of the above, but there may be additional gain by subdividing a CHA into several sectors and giving them a unique classification based on the amount of evidence for each. There is thus an opportunity to reduce the requirement for Technical Survey in some sectors based on what the survey reveals in the previous sectors.

A CHA could in theory be divided into an unlimited number of sectors, and several sectors may be given the same classification. It may, however, be useful to limit subdividing. Each of the subsectors should be treated as unique and will require a separate analysis and quantification of information in the survey report.

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If manual mine clearance and two mine-detecting dogs are defined as default accuracy levels, the challenge lies in defining how much additional ground other assets need to cover to provide the same confidence.

Technical Survey

Clearance and verification assets are used during Technical Survey, but the intention is to collect information that can be assessed for planning purposes. There are few, if any, universally accepted principles of Technical Survey, and there is scope for significant streamlining of most Technical Survey concepts.

Technical Survey, like Non-technical Survey, can provide measurable evidence about whether mines are present in an area. The amount and quality of evidence can be used to define levels of confidence in the effectiveness of the survey. Information provided by Technical Survey should be viewed in conjunction with information provided by the Non-technical Survey or by clearance (if some has occurred in the area). The type and amount of Technical Survey will then depend on how much additional evidence is required after Non-technical Survey to gain sufficiently high confidence that an area is mine-free.

It can be difficult to agree on generic scoring values of informants in Non-technical Survey, and this process is no easier in Technical Survey. A combination of test results and empirical evidence can form the basis for developing credible Technical Survey solutions. Governments and organizations should consider establishing “expert groups” to analyze and define the accuracy of assets in survey. Once agreed upon, a more streamlined Technical Survey concept can be developed, preferably in conjunction with a Non-technical Survey concept.

Accuracy of Assets: Qualitative Indicator

Manual mine clearance is the most accurate survey tool. All mines are normally found when manual demining is applied. Using two accredited animals to detect mines is also considered clearance by IMAS. Confidence in the survey, however, is due to the accuracy and the quantity of information.

IMAS defines the use of two accredited animals as clearance, but how much information will one accredited animal provide? The quality and accuracy of animals differs considerably between organizations, impeding the process of defining a generic scoring value for the use of one animal. The fact that less reliable mine-detecting dogs are currently used in survey assessments is a concern, but it is more a management problem than a generic problem with dogs. If we assume only well-trained, tested and accredited dogs are allowed for use, we can define confidence in the use of one animal in Technical Survey as fairly high. Evidence suggests that well-trained animals will find most mines, if not all.

A similar algorithm can be used for machines. A crushed mine, while acceptable in clearance, may not provide any recordable information in survey. Thrown-out mines, while unacceptable in clearance, can normally be spotted on the ground and recorded during survey. Testing of flails shows that most of them will crush or detonate between 94 and 98 percent of all anti-personnel mines and a high number of anti-tank mines. They typically fail to detonate unexploded ordnance, but they often slash off the fuze. Experience in the field, however, suggests fewer mines are crushed or detonated than during trials. There may be a discrepancy because flails are sometimes used on rugged or rocky terrain, or the fuzes are broken and no longer detonate on impact.

More important in survey is how much information flailing will provide. It is necessary to balance the difference in accuracy with an increased ground-coverage requirement during the survey.

The accuracy of other assets like tillers, rollers and low-sensitivity metal detectors (large loops, etc.), can be similarly defined by using a mix of tests and empirical evidence and, as in Non-technical Survey, a scoring table can be developed. The figure on the previous page is an example of how assets can be analyzed and grouped in accordance with the relative level of confidence (accuracy).

If there is a requirement for 50-percent ground coverage by manual mine clearance, the required ground coverage when using one dog is higher (approximately 60 percent), and the required ground coverage when using a flail is even higher (approximately 70 percent).

If the requirement for Technical Survey varies (which will depend on the type and amount of information already provided by the Non-technical Survey or clearance activities), the proportional increase of ground-coverage requirement by other assets can be defined. For example, if there is only a need to cover 30 percent of an area by manual mine clearance, it may be necessary to cover 40 percent of the same area with one dog to gain the same confidence.

While initially it may be a challenge to develop a concept as discussed above, using it can be fairly simple and straightforward in the field. One advantage is that decisions about how much ground to cover are given by the concept and do not need to be defined by field managers for each new task.

Documentation and Handover of Released Land

In the possible event that landmines are found in areas that have been released, the quality of documentation acquired during the decision to release the land may well determine whether an organization should assume liability. Appropriate documentation is important when areas have been released and “handed over” to the local population or authority after the completion of a survey and/or clearance task. Since land may be released by a combination of concurrent activities, the decisions may change as work on a task progresses, and there is a need to document every step in the decision-making process.

Released land may be removed from the layer in the database that defines the mine/ERW problem, but information about how land has been released should be maintained in different database layers for the purposes of quality control, potential investigation, and operational management and assessment. Just as land is reported released by clearance, land should be reported released by Non-technical and Technical Survey, showing the detailed methods of survey and a documented decision-making process. Many current databases are not configured to capture land released by survey, an issue that needs to be addressed.

Potential Gray Areas

While land release is typically illustrated as a straightforward progression from Non-technical Survey to Technical Survey to clearance, the field process is more composite, and the potential exists for inconsistent reporting and documentation. Some of the gray areas are discussed below:

  • Land may be released by the activity that provided the last piece of evidence (confidence) that an area is mine-free. If it was Technical Survey, land may be released by Technical Survey while it may, in fact, have been the Non-technical Survey that provided most information and made up for most of the confidence.
  • If clearance leads to the removal of suspicion of adjacent land, clearance arguably justifies the release of adjacent land, since it provided the last piece of evidence. It is better to view the information provided by the clearance activity as Technical Survey and thus report adjacent land as released by Technical Survey.
  • If buffer zones around a cleared area are verified by anything less than clearance and this confirmation is deemed appropriate and sufficient, these buffer zones should be reported released by Technical Survey if no mines are found.
  • If exploration lanes are made by manual demining teams in Technical Survey, the size of these lanes could be recorded as clearance. Reporting exploration lanes as cleared could discredit the survey process because questions may be legitimately asked about why clearance was applied in one lane while not on both sides. Thus, it is more appropriate to report the whole area as released by Technical Survey.
  • It is essential that the local population trust released land, regardless of whether it has been released by survey or clearance. The methods of releasing land should therefore be discussed with the local authority or population, and a proper hand-over process should be adopted.
  • If the local population still suspects mines after land has been released by survey, this skepticism should not prevent release; rather it compels a need for more confidence-building, preferably through better explanation of why the land can confidently be released or, at worst, by applying some degree of physical confidence-building (roller, large loop, etc.).


Land release systematically captures several current but isolated activities and clarifies how each of them is related. A structured assessment of these relationships can lead to improved efficiency. Consistent use of the term and all its facets has the potential to improve the quality of the individual components. It will inevitably take some time before land release is universally understood, as there is no one uniform method for its application. Land-release methodology is, however, a useful instrument to better define and subsequently resolve the landmine problem. Ottawa Convention States Parties may find this tool particularly useful when assessing their own compliance with the Convention or when there is a need to prepare extension requests.


Håvard Bach heads the Operational Support Unit for the GICHD. Projects under his responsibility currently include studies on mine-detection dogs, mechanical mine clearance, manual mine clearance and risk management. He also gives consultancy advice, often related to operational demining activities and demining technology. Prior to employment at the GICHD, Håvard worked as a Norwegian military engineering officer before being employed by Norwegian People’s Aid, managing several mine-action programs worldwide.


  1. “IMAS: What’s New” (June 2009). International Mine Action Standards.
    Accessed 21 July 2009.

Contact Information

Håvard Bach
Head, Operational Methods Section
7 bis, avenue de la Paix
P.O. Box 1300
1211 Geneva / Switzerland
Tel: +41 22 906 1670
Web site: