Over the past decades much has been written about the threat posed by landmines and in particular anti-personnel landmines. While there has been a great deal of debate about the veracity of the quantitative aspects of the threat there is no doubting the major impact the presence or suspected presence of landmines has on individuals and communities. What is often overlooked, a consequence of the focus on landmines and the associated terminology humanitarian demining, is the threat posed by the millions of non landmine munitions. A simple definition of a munition is any item containing explosive, nuclear, biological, chemical, radiological or other hazardous material, whether manufactured or improvised, the primary aim of which is to cause harm. It therefore follows that munition clearance is the application and management of all appropriate skills, procedures and equipment to mitigate the impact of munitions on life, property, the economy and the environment. Most munition casualties outside those caused during the contact battle are a consequence of either not knowing that munitions are present or the mishandling of munitions. To achieve the end state of clearance or indeed to confirm that an area is clear of munition contamination an operation may pass through several phases although not all phases will be necessary in every case.
Munition Clearance Phases
Survey will be essential, when potentially large areas are contaminated with munitions or their residue, to define the area to be isolated and subjected to detailed search. When the threat constitutes single or few munitions and is therefore localised survey will not usually be required.
Search and Detection
Search is the application and management of systematic procedures and appropriate detection equipment to locate specified target items. Whether the munitions being sought are manufactured or improvised, abandoned, discarded or deliberately placed adherence to the principles of systematic procedures and appropriate equipment will significantly enhance the probability of safely locating the target munition. Search is the capability, detection the equipment used and location or proof of absence the outcome. There is a tendency to judge the success of munition clearance by the number of munitions recovered or destroyed. In fact the suspicion of the presence of munitions whether or not they are actually there will often prevent or modify usual activity therefore demonstration of their absence can be as important to the restoration of normality as their clearance.
In the case of those munitions that are on or just below the surface access will not usually be a major problem although vegetation may pose a significant barrier. It will on occasions however be necessary to overcome substantial obstacles to subsequent phases be such barriers physical, environmental or technological. Examples of barriers that may require to be overcome are collapsed buildings, geological strata and in the case of terrorist devices and booby traps trip wire or motion detectors. Contaminated environments, including those where depleted uranium particles are present, and non-life supporting atmospheres are likely to require specialist equipment and techniques to achieve access to the target munition.
The presence of key facilities and in the case of chemical weapons the need to prevent atmospheric release will dictate the requirement for the implementation of effect mitigation to to address the impact of high order detonation or other means of functioning. Such measures include containment structures, suppression equipment and engineering works such as trenching to minimise ground shock, shoring to stabilise vulnerable buildings and blast effect reduction measures.
Identification and Evaluation
Once clearly visible the munition may be identified and evaluated. The latter involving a process of assessment to establish the physical condition, content and state of a munition thereby determining the most appropriate subsequent action.
Making safe involves the stabilising of a munition to prevent it functioning during subsequent activity. This may include actions such as the insertion of safety pins, fuse removal and in the case of chemical weapons, leak sealing and packaging before transportation.
Disposal is the final phase that directly involves the munition and encompasses the complete breakdown, demilitarisation or destruction of the munition so as to render it incapable of causing any further hazard. Subsequent to the munition disposal in-situ or removal it may be necessary to undertake site remediation to remove any residual contamination, such as explosives, missile fuels, DU particles, chemical warfare agents and other hazards.
Having considered the phases of munition clearance it is apparent that location of munitions is key to successful completion and one of the principles of search, the location enabling capability, is the use of appropriate detection technology. While detection equipment may involve highly complex leading-edge technology, under certain conditions basic tools and techniques may prove the most suitable. Detectors may be configured to detect form, anomaly, component, material and the payload or by-product released as a consequence of functioning or damage such as chemical warfare agents and depleted uranium particles. The large number of detection technologies in use or under development include the following.
The human eye is able to import a vast range of visual information and when an individual knows what the target or associated sign looks like, provides a potent location capability. Sight may be enhanced by viewing aids such as binoculars and, in low light conditions, image intensifiers. Fibre optics facilitate the location of munitions concealed in the fabric of a building or other structure. Aerial photography, including infra red and false colour, and its interpretation by experts is also an effective tool in identifying either likely munition locations or the munitions themselves.
Mine Prodders, Bomb Probes and Trip Wire Feelers
These low tech equipments are usually used in conjunction with other detection technologies, most often metal detectors, and are often key to the accurate location of munitions or in the case of trip wires their triggering mechanism.
Dogs and rats have been used with considerable success against a range of munition components for many years. They may be trained to detect a variety of signatures and currently have greater sensitivity than most man-made technologies although work is being undertaken to duplicate canine olfaction. Dogs do not provide a 100% detection capability but nor does any other system although dog failures seem to be a far more emotive subject than those that result from other equipments. Dogs may be used free running, on leads or vapour samples may be collected and taken to them. Detection research using other animals including pigs and cockroaches has been undertaken but has not been developed into a credible field capability.
Metal detectors work on the basis of changing magnetic fields inducing the flow of an electric current in a conductor. The current in turn produces a magnetic field that is then detected. In munition clearance the most commonly used metal detectors are hand-held although walk-through archway detectors are an effective means of preventing the movement of concealed munitions. Arrays of metal detectors used in conjunction with positioning equipment are also useful for plotting the presence of metal contamination on ranges and military training areas. Development in minimum metal mine detectors incorporates the automatic rejection of signals from mineralised ground.
Gamma Backscatter Detectors
Gamma backscatter detectors utilise gamma radiation to detect material with low atomic numbers including explosives. It is particularly effective when searching vehicles or buildings for hidden explosives although an understanding of what other low atomic material, such as water and fuel, is likely to be present is necessary to maximise effectiveness.
Electronic Circuit Detection
Improvised munitions and manufactured booby-traps may employ electronic circuitry. Both oscillators and non- linear junctions, when irradiated with RF signals, emit radio signals significant enough to be detected. Again, the knowledge of what might be expected to be present in a structure will minimise responses to false alarms.
Ground Probing Radar
Minimum metal mine detection has been a particular problem over the years. Ground probing radar produce an image when an electromagnetic energy pulse is reflected from a target with an electromagnetic signature that differs from the surrounding soil and is displayed on a screen via the receiving antenna.
Vapour and Particle Detection
Vapour in the air and particles on surfaces are detected by collecting and analysing samples and processing the resultant data. Vapour collection usually involves drawing air through a collecting medium and particulate collection by wiping surfaces. The samples are then heated and vapours separated before passing to a detector. Data processing then indicates the type of explosive present. Vapour and particle detectors indicate that explosives have been or are present but will not pinpoint the location as other munition detection systems do.
Many countries continue to work on the refinement of existing technologies, the development of new systems and multi sensor fusion. The latter offers the particularly exciting prospect of the safe detection and accurate location of a range of munitions under most environmental conditions.
No matter how good the detection technology, to maximise success and safety, munition clearance must involve detailed planning and the management and application of systematic procedures. While the equipment and drills used will be determined by the environment, target munition, urgency and acceptability of risk the need for thorough, systematic procedures will remain a constant. This is particularly evident when searching for victim operated munitions whether anti personnel landmines, sub munitions, terrorist devices or military booby-traps.
An indeterminate number of munitions contaminate a vast area of the earth’s land surface. They are responsible for thousands of post conflict injuries and fatalities as well as environmental contamination and denying the restoration of normality. The origin of many is illegal manufacture or indiscriminate use, others are a by-product of war. Whatever their origin as long as there are causes of human conflict there will be a residual munition threat. Effective and safe munition clearance undertaken by trained, equipped and organised teams will facilitate threat mitigation to the benefit of all.
By Garth Whitty