LANDMINES CHARACTERISATION BASED ON
Miroslav Omelic , Josip Stepanic
(Faculty of Mechanical Engineering and Naval
Architecture – University of Zagreb),
Paper presented at the 8th
ECNDT, Barcelona, June 2002
Prevalently, the only metal content in antipersonnel landmines are some parts of trigger
mechanism. We radiographed these parts for types of blasting antipersonnel landmines, which
are buried in the Southeastern Europe, and used them for possible landmines characterisation
in the appropriate data base thereby formed. The data base serves as a basis for future
investigation and characterisation of range of conditions in which landmines were found.
Efficient humanitarian demining is technically demandable problem . Significant
contribution to this is brought about through landmines detection process. Generally, this is a
high risk and large duration process. The discrepancy between required and possible rates of
humanitarian demining, in regions where war activities ceased, motivated efforts of scientific
community to work toward development of more efficient humanitarian demining, in
particular toward realisation of improved landmines detection technique . Despite efforts,
such a technique still does not exist . Partially, inefficiency of present detection techniques
is caused by complex character of landmine-soil systems, which are to be treated
simultaneously. On average, these systems have been left untouched typically for several
years, because of what their present states represent a variety of different configurations.
Efficient detection technique should optimise between sensitivity and robustness. Sensitivity
is required in order to exploit slight differences between landmines and their particular
environment, while robustness is required in order to have rather small number of widely
applicable types of detection equipment. Typically, R&D toward detection technique
improvement includes several mutually interacting phases, e.g. testing of prototype equipment
in controlled conditions, in which usually landmines are simulated with other samples .
Underlying principles of these phases are (i) maximisation of the resolution of the equipment,
so that landmines and other buried objects are more distinct structures, and (ii) maximisation
of the demining process automation, thereby lessening the accompanied risk for the deminers.
One of the consequences of automation is that landmine-soil system is transformed into
particular type of signals which have to be analysed, regularly using advance signal
For both principles it is useful to have knowledge about realistic landmines, their structure and
composition , what is more important for landmine triggers. Triggers are the rather non-homogeneous
parts of landmines, hence rather complicated for characterisation. However,
because of their seemingly artificial shape and existing metal parts triggers are parts that usually
represent part of a mine which is actually detected, and extracted from noisy environment in.analysed signals. For example, if metal detectors are used than low metal content mines are
detected only on the basis of metal blasting cup, metal trigger pin or its metal spring.
Owing to variety of producers, produced types and different series of landmines, it is not
known in advance whether landmines in a given area resemble completely dimensions and
composition of other landmines, or there exist some differences. Additionally, there is a
possibility of different types of damages in trigger components, the probability of which may
be inferred on the basis of existing radiograms. Beside contribution to R&D process,
radiograms of triggers are useful in education of pyrotechnicians and other personnel of a
humanitarian demining process .
Somewhat similar problem exist in the context of unexploded ordnance disposal. A typical
situation is to have grenade with steel casing, in which there may be a chemical agent. The
procedures for its disposal differ significantly in case when there is a chemical agent,
compared to a case when there is no such agent.
In order to formulate a data base of trigger characteristics which is to be used in testing
processing algorithms, work was started toward formulation of data bases of landmine
triggers, and development capabilities to represent triggers in a form appropriate in testing of
a particular technique. In this paper the phase of database forming, in which radiograms of
triggers are obtained and evaluated, is described.
The paper is organised as follows: in the second section characterisation of triggers is
presented from various points of view, yet radiography excluded. In the third section the set-up
of equipment and other relevant parameters for radiography of triggers is described.
Radiograms obtained are discussed in the fourth section. Summary of important conclusions
is given in the fifth section.
Antipersonnel landmine triggers description
Landmine triggers are water resistant, non-magnetic parts which transform mechanical
stimulus, through blasting composition, into high-pressure and high-temperature particle flow
capable of activating high explosives like TNT or RDX which are put in landmines. Duration
of that process is of the order of 10 milliseconds. Several types of triggers are shown in figure
1. Composition of these triggers is given in table 1. Triggers UPROM 1, UPMR 2A S and
UPM 2A are made for antipersonnel metal mines. In particular, UPROM 1 is made for
jumping mine PROM 1, while other two triggers are for mine PMR 2A. Trigger UPMAH 3 is
made for low metal content mine PMA 3.
Fig 1: Triggers of several types of antipersonnel landmines. From left to right:|
UPROM 1, UPM 2A S, UPM 2A, UPMAH 3.
*these are cabs for main explosive activation. There is also detonation train for activation of explosive for jumping.
||UPM 2A S
push or pull
activated by pulling
| E 67,|
M 17 P2
|Metal content ||high ||high ||high ||low
||115/22|| 77/37|| 62/21 ||37/13
|Table 1: Some characteristics of triggers shown on figure 1.|
Radiograms of triggers were obtained following standards [7, 8], using Balteau 200/5 X-ray
apparatus. Parameters set constant in all cases shown here were: focal distance of 700 mm,
exposition of 1 min, and current of 4 mA. Voltage range taken was from 80 kV to 120 kV.
Pictures shown are digitalised versions of radiograms recorded on AGFA Structurix D-5 films.
According to CEN the film class is C3. Chemical treatment of films included 7 min of
developing time at 20°C, with developer G 128. Fixer was G 328, used during 15 min.
Washing time was 30 min.
Owing to almost axisymmetric shape, and relatively small dimensions, a trigger can be
sufficiently covered using a single radiogram.
Results of trigger radiographying
Examples of radiograms are given in the figures 3 - 5. They are obtained in two steps; initial
radiogram digitalisation followed with obtained grey scale picture grey level inversion. Because
of that, darker regions on pictures of radiograms refer to materials with larger X-ray absorption
coefficients. In order to confirm that the resolution of a sample in the process described is to a
sufficient degree a constant, the radiogram of etalon wires is shown in figure 6.
Fig 3: Trigger UPM 2A. Voltage during exposition was 80 kV.
Fig 4: Trigger UPROM 1. Voltage during exposition was 120 kV.
Fig 5: Trigger UPM 2A S. Voltages during expositions were 90 kV and 100 kV for left
and right radiogram, respectivelly.
In radiogram of figure 3, large difference between representations of trigger parts point to
essentially different materials, e.g. steel parts in polymer casing. Such a difference does not
exist on radiogram of figure 4, because there all the parts are metal. Radiograms of figure 5
show how changes in some parameters, in this case voltage, infer resolution obtained. From
radiogram obtained with 100 kV, it is seen how the initial cab is connected through metal
needle with a trigger head, which is made of relatively thick polymer layer. Absorption
coefficients for materials similar to those used in triggers are given in Table 2.
||Material Voltage, kV
||µ /r , cm2
||µ en/r , cm2
||80 ||0,2018 ||0,05511
|100 ||0,1704|| 0,03794
||80 ||0,1707 ||0,02200
|100 ||0,1602 ||0,02292
|Table 2: Relevant absorption coefficients .|
Fig 6: Picture of radiogram of etalon wires, obtained after the same
transformations as were applied to radiograms of triggers.
Profiled humanitarian demining includes data base of different mine components. Here the
data base of triggers is proposed. It is obtainable using radiography in a particular range of
parameters. Results of radiograms obtained should be considered as one part of more complex
data bases. Such a data base enables researchers, experts and producers to have a detailed scan
of existing trigger, and in broader sense also of landmine, varieties; make reliable trigger
simulants; or extract some piece of information about its structure. The particular realisation
exploited here was a laboratory one. However, presence of portable X-ray devices makes
possible closer-to-field inspection of triggers. The approach considered is not appropriate for
mine detection as it operates in transmission mode, whereas the reflection mode is needed for
applications in mine detection.
This work is financed through the project CRO MoST 120098.
various authors – International Workshop State-of-the-art in Landmines Detection,
National Park Plitvicka Jezera, Croatia, 5-6 April 2001,
- “EFNDT WG5 – APMD Programme”, Doc1, 1999,
- N.Kingsbury, “Land Mine Detection DOD’s Research Program Needs a
Comprehensive Evaluation Strategy”, US GAO Report, GAO-01 239, 2001,
- V.Krstelj, J.Stepanic Jr., I.Leljak, “Quality Assurance in Evaluation and Certification of
Humanitarian Demining detection Equipment”, Journal of Mine Action, Vol.4, No.2, 2001,
- V.Krstelj, J.Stepanic Jr., “Humanitarian de-mining detection equipment and working
group for antipersonnel landmines detection”, Insight, Vol.42, No.3, 2000, pp.187-190,
- D.Zvizdic , L.G.Bermanec, V.Krstelj, “Modular Education Programme for setting up
mine detection 'field' laboratories”, this conference,
- HRN EN 444:1997 hr - “Non-destructive testing - General principles for radiographic
examinatins of metallic materials by X- and gamma-rays” (EN 444:1994),.(8) HRN EN 4:1997 hr - “Non-destructive testing - Image quality of radiographs - Part 1:
Image quality indicators (wire type) – Determination of image quality value” (EN 462-