Metal Detector Handbook for Humanitarian Demining

Abstract

This handbook instructs the reader o how to confidently assess their detector's ability in the place where they must work. The problem of electro-magnetic ground properties is addressed in detail, including advice how to predict the clearance-depth in other areas. There is detailed advice how to conduct comparative trials of metal detectors, and the technical background how detectors work.

Full text

A book about
metal detectors,
covering detection procedures
in the field, and the
testing and evaluation
of metal detectors
for humanitarian demining
Authors: Dieter Guelle, Andy Smith, Adam Lewis, Thomas Bloodworth
EUROPEAN
COMMISSION

Metal detector handbook
for humanitarian demining
A book about metal detectors, covering detection procedures
in the field, and the testing and evaluation of metal detectors
for humanitarian demining
Authors
Dieter Guelle, Andy Smith, Adam Lewis, Thomas Bloodworth

Acknowledgements
We acknowledge help, advice and invaluable input from the following individuals. While they share in any merit this
book may deserve, any errors and failings remain the authors’ alone.
For advice and assistance with technical aspects, special thanks to Yogadhish Das. For help and advice on a wide variety
of other aspects, our thanks to Jacky D’Almeda, Roger Hess, Tim Lardner, Russell Gasser, Ken O’ Connell, Franciska Borry,
Marta Garotta, Gian Luigi Ruzzante, J. T. (Theo) van Dyk, Edgardo Maffia, Pete Hindy, and Chris Leach.
Many other people have helped in small ways — too many to mention by name. Our thanks to you all.
© All photographs and diagrams are copyright of the authors unless otherwise acknowledged.
Europe Direct is a service to help you find answers to your questions about the European Union
New freephone number:
00 800 6 7 8 9 10 11
A great deal of additional information on the European Union is available on the Internet.
It can be accessed through the Europa server (http://europa.eu.int).
Cataloguing data can be found at the end of this publication.
Luxembourg: Office for Official Publications of the European Communities, 2003
ISBN 92-894-6236-1
© European Communities, 2003
Reproduction is authorised provided the source is acknowledged. All photographs and diagrams are copyright of the
authors unless otherwise achnowledged.
Printed in Italy

Working in a research environment, it is always of con-
cern when I am confronted with statements, like ‘To date,
technology has had only a marginal impact on mine
action equipment.’ Therefore, it was a very rewarding
moment when, earlier this year, I was able to communi-
cate the results of the European Committee for Standard-
isation (CEN) working group on an agreement by an
international community of experts on how to test and
evaluate metal detectors to be used in humanitarian mine
clearance.
During the work on the establishment of this workshop
agreement, it became obvious that there are at least two
areas related to metal detectors that need further
research. The first one is the electromagnetic characterisa-
tion of soils and terrain in general terms, in order to pre-
dict the performance of metal detectors in different
mined areas. The second one is the assessment of the per-
formance of mine detection on the basis of reliable statis-
tical testing. Work in both demanding areas of research is
now in progress.
In order to ensure that our research efforts will make an
impact in humanitarian mine clearance, it is vital that the
results can be implemented by those working in the field.
To achieve this, it is important to communicate the results
achieved, through training sessions and presentations in a
digestible way. It is therefore important to have hand-
books available, which present the actual state of knowl-
edge and which are written by experts in both mine clear-
ance and technical development in easily understandable
language. The handbook in front of you is such an
example combining these vital ingredients.
An interesting point that arises from the handbook is that
deminers working in the field can provide useful informa-
tion to researchers and developers by making simple
measurements to record the conditions that they meet,
for example, by measuring the soil properties.
I am pleased that the Joint Research Centre (JRC) has been
able to contribute to the production of this handbook
and I hope that it will soon become a reference for those
who are confronted with the challenging task of mine
clearance.
Dr Alois J. Sieber
Head of Unit,‘Humanitarian Security’
Institute for the Protection and Security
of the Citizen (IPSC)
Joint Research Centre, European Commission,
Ispra (VA), Italy
Foreword
3

Dear readers,
I have been using metal detectors of one kind or another
for over 20 years. First with the US Army, and for the last
five years while establishing and managing humanitarian
clearance programmes in the Balkans, Asia and Africa.
Part of my role has been to train local deminers in how to
use a range of different detectors in both shallow and
deep-level searches.
Over the last 10 years, detector designs have changed and
the features available have become more sophisticated.
With this, I have had to learn constantly about the
strengths and weaknesses of the new equipment. Manu-
facturers have usually done their best to assist, but they
rarely understand exactly what we need in the field or the
conditions we will be using it in. So I have usually had to
find my own ways of getting the answers I was looking for.
Over the past 10 years, accidents have occurred because
deminers and their supervisors have not understood the
limitations of the detector they were using. It is essential
for the user to know the real detection depth that can be
achieved at the task site and what is a safe rate of for-
ward advance. Both of these depend on what the de-
miner is searching for, but fortunately the smallest target
that may be present in a particular area can usually be
predicted.
This handbook instructs the reader on how to confidently
assess their detector’s ability in the place where they must
work. The problem of electro-magnetic ground is ad-
dressed in detail, including advice on how to predict the
clearance-depth that will be possible in other areas. The
book also includes detailed advice on how to conduct com-
parative trials of metal detectors.
None of this is theoretical. It is all based on genuine hands-on
experience and the solutions are practical to use in the field.
The book includes a quick field-user index and is even printed
on tough, washable paper so that it will survive field-use.
For those who want to understand how detectors work in
more detail, there is a technical chapter. Even this is writ-
ten in simple language so that most people will be able to
understand it.
I recommend all trainers to read this book and all site
managers to carry a copy into the field. If the rules out-
lined in this book are followed and adapted when neces-
sary, deminers/operators will be safer and we will all be
able to have greater confidence in the depth and
thoroughness of clearance that has been achieved.
Cheers, Roger Hess
Demining and Explosive Ordnance Disposal Technical
Consultant
Introduction
5

Throughout this book, the following abbreviations and
acronyms are used.
ADP Accelerated Demining Programme
AG anti-group (mine)
AP anti-personnel (mine)
AT anti-tank (anti-vehicle) (mine)
CCW United Nations Convention on Conventional
Weapons
CEN European Committee for Standardisation
CWA European Committee for Standardisation
workshop agreement
DDAS Database of Demining Accidents
DNT dinitroluene
EDD explosive detecting dog
EDR explosive detecting rat
EIT electrical impedance tomography
EM electromagnetic
EMI electromagnetic interference
EOD explosive ordnance disposal
ERW explosive remnants of war
FFE free from explosive
FNA fast neutron analysis
GC ground compensating (of metal detectors)
GICHD Geneva International Centre for Humanitarian
Demining
GPR ground-penetrating radar
GPS Global Positioning System
GRH ground reference height
HD humanitarian demining
HE high explosive
ICBL International Campaign to Ban Landmines
IMAS International Mine Action Standards
IPPTC International Pilot Project for Technical
Cooperation
Abbreviations and acronyms
7

8
IR infrared
ITEP International Test and Evaluation Programme
ITOP International Test Operational Procedures
standards
NATO North Atlantic Treaty Organisation
NGO non-governmental organisation
NQR nuclear quadrupole resonance
PE plastic explosive
QA quality assurance
RDX Research Department Explosive (cyclonite)
SD self-destruct
SDA self-deactivate
TNA thermal neutron analysis
TNT trinitrotoluene (explosive)
UN United Nations
UNADP United Nations Accelerated Demining
Programme
UNMAS United Nations Mine Action Service
UXO unexploded ordnance
WWI World War One
WWII World War Two

To prevent constant repetition, the authors have adopted
some simple definitions that the reader should under-
stand before reading the book. Each follows what we
believe is the ‘normal’ field-use of terminology.
Contaminated ground: The expression ‘contaminated
ground’ is used to refer to ground with pieces of manu-
factured metallic material in it. The metallic material may
be fragments from explosive devices, bullets, casings or
discarded material with a metallic content.
Detector sensitivity: The expression ‘detector sensitiv-
ity’ is used to refer to the metal detector’s ability to locate
a target at varying depths, so is directly related to the dis-
tance from the search-head at which a target can be
detected. The greater the distance between the search-
head and the target at which a detector signals, the
greater its ‘sensitivity’.
Magnetic ground: The expression ‘magnetic ground’ is
used throughout this book to indicate ground that has
electro-magnetic properties that make a metal detector
signal. The cause may be spread throughout the ground
over a wide area, or may be erratic such as when some
rocks, stones or building blocks make the detector signal.
Search-heads or coils: Metal detector search-heads are
sometimes called the ‘coil’ or ‘coils’. Throughout this book
the terms are used to refer to the same part of the metal
detector.
Definitions
9

2.3.3. Batteries 34
2.3.4. Locating metal/mines 35
2.4. Using metal detectors 38
appropriate for the threat
2.4.1. Tripwires 38
2.4.2. Minimum metal mines 40
2.4.3. Fragmentation mines 40
2.4.4. Anti-vehicle mines 41
2.4.5. Detecting deep-level 41
explosive remnants of war
2.5. Targets for routine 44
metal detector checks
2.6. Real mined areas 45
2.6.1. Grassland 46
2.6.2. Woodland 47
2.6.3. Open hillside 48
2.6.4. Unsurfaced roads and tracks 49
2.6.5. Surfaced roads, railway tracks 50
2.6.6. Urban (town or city) 51
2.6.7. Village 52
2.6.8. Mountain (high altitude, 53
steep gradient)
2.6.9. Desert 54
2.6.10. Paddy field 55
Contents
11
Chapter 1: Background to humanitarian 15
demining
1.1. The development of mines 18
1.2. Detecting mines 20
1.2.1. Manual detection 21
using metal detectors
1.2.2. Manual detection 22
using area excavation
1.2.3. Explosive detecting 22
dogs and manual methods
1.2.4. Mechanical and manual 23
methods
1.3. Treaties controlling mine use 23
Chapter 2: The role of metal detectors 27
in humanitarian demining
2.1. Types of mined areas 28
2.2. Using metal detectors 29
during surveys
2.3. Using metal detectors 30
in area demining
2.3.1. Daily routines 30
2.3.2. Test-pieces 32

12
2.6.11. Semi-arid savannah 56
2.6.12. Bush 57
Chapter 3: Detector standards and detector 59
test standards
3.1. International standards 59
for metal detectors
3.2. International standards 60
for metal detectors
in humanitarian demining
3.3. European Committee 61
for Standardisation workshop
agreement (CWA 14747:2003)
3.3.1. What is covered by the 61
detector test agreement?
3.4. Previous metal detector tests 62
in humanitarian demining
3.4.1. Why so many field trials? 64
3.5. The output of humanitarian 64
demining detector trials
3.6. Output of the international 66
pilot project for technical
cooperation trials
3.6.1. Tests in air 66
3.6.2. Tests in the ground 67
3.6.3. Tests in the field 67
3.6.4. Miscellaneous tests 68
3.7. Output of other tests/trials 68
3.8. Do current detectors match 72
the needs in humanitarian
demining?
3.9. Lessons for future tests/trials 73
3.9.1. Data collection/analysis 74
during field tests/trials
Chapter 4: Metal detector technology 77
4.1. How metal detectors work 77
4.2. Electromagnetic properties 79
of materials
4.3. Metal detector working 80
principles
4.3.1. Pulsed induction versus 80
continuous wave
4.3.2. Frequency-domain versus 83
time-domain
4.3.3. Single coil versus separate 83
excite/receive coils
4.3.4. Static and dynamic modes 83
4.3.5. Single receive coil versus 84
double-D (differential)
receive coils
4.3.6. Bipolar pulse versus 85
unipolar pulse

13
4.3.7. How are metal detectors 86
designed for demining
different from other types
4.3.8. What is important from 86
the user’s point of view?
4.4. Suppression of electromagnetic 87
interference
4.5. Ground compensation 88
4.6. How the electromagnetic 91
properties of materials
are quantified
4.6.1. Conductivity and resistivity 91
4.6.2. Magnetic susceptibility 92
and permeability
4.7. Factors that affect detection 92
4.7.1. The metal object or ‘target’ 93
4.7.2. Distance between 93
the detector’s search-head
and the metal object
4.7.3. Ground properties 95
4.8. Metal detectors, radar 96
and radio waves
Chapter 5: Training 97
5.1. Deminers and their basic 97
training requirements
5.2. Training in the use 99
of metal detectors
5.3. Recommendations for trainers 100
5.3.1. Self preparation 100
5.3.2. Trainee assessment 100
5.3.3. Structuring your training 102
5.4. The training content 104
5.4.1. Assuring trainee competency 105
5.4.2. Search-head sensitivity 105
profile (footprint)
5.4.3. Determining a field-accurate 108
sensitivity profile (footprint)
5.4.4. Discriminating adjacent targets 109
5.4.5. Stacked signals 109
5.4.6. Linear metal targets 109
5.4.7. Electromagnetic disturbance 110
5.4.8. Pinpointing targets 110
5.5. Work in ‘prepared’ 111
and ‘unprepared’ areas
5.6. Rescue/evacuation 112
using metal detectors
Chapter 6: The use of metal detectors 115
in mined areas
6.1. The detector ‘set-up’ 116
6.2. Adjusting for different ground 118

14
6.3. Adjusting to specific targets 120
6.4. Discrimination 121
of ‘innocent’ metal
6.5. Action on getting 122
a detector signal
Chapter 7: The way forward 127
7.1. Lies, damned lies and statistics 127
7.2. Reducing false alarms 128
7.3. Incremental improvements 129
7.3.1. Incremental advances 129
in metal detection
7.3.2. Incremental advances 130
in other technologies
Annex A: Explosive detecting dogs (EDDs) 131
Annex B: Other explosive remnants 135
of war detection methods
Annex C: Explosive content of mines 151
Annex D: CWA 14747:2003 test overview 157
Annex E: Calibration of the Schiebel AN19/2 M7 159
Annex F: Suggested further reading 161
INDEX
Quick reference index for field users 163
Main index 165

While aspects of mine clearance have been a part of mili-
tary procedures for more than 80 years, the specialised
clearance of all explosive remnants of war (ERW) only
began in the late 1980s when civilian organisations start-
ed humanitarian demining (HD) in Afghanistan and Cam-
bodia. HD involves clearing ground that has no military
significance and where all explosive items must be
removed or destroyed to a recorded depth. This is done in
order to support peacetime activities and protect civilians
from ERW injury. By contrast, military demining is usually
carried out for strategic purposes and under pressure to
work quickly. Often, only a route through a mined area is
cleared. In return for speed, the military may find it
acceptable to use armoured vehicles or take losses among
their soldiers. Well-equipped forces will usually clear
routes mechanically, avoiding putting personnel on the
ground. Land ‘cleared’ in this way is not safe for civilians
to use. In humanitarian demining, the deployment of
people to clear the ground is routine — and it is not
acceptable to take losses among deminers or among the
civilians who will use the land at a later time.
Still in its adolescence, HD was started by charity-funded
non-governmental organisations (NGOs). Their lead was
quickly followed by United Nations (UN) supported pro-
grammes largely staffed by seconded military personnel.
Before long, commercial demining companies had sprung
up, offering more cost-effective clearance to the donors.
Huge variations in working speed and methods raised ques-
tions over the quality of the work and opinion over safety
varied widely. The need for the industry to adopt agreed
minimum standards became obvious at the UN-sponsored
International Conference on Mine Clearance Technology (
1
)
held in July 1996, in Copenhagen. The process of defining
and implementing international standards began. In 1997,
the first international standards for humanitarian demi-
ning were published. The move towards adopting interna-
tional standards continued with the United Nations Mine
Action Service (UNMAS) publication of greatly revised
International Mine Action Standards (IMAS) in 2001 (
2
).
The IMAS defines ‘demining’ in the HD context as: ‘the
clearance of contaminated land by the detection, removal
(
1
)http://www.un.org/Depts/dha/mct/
(
2
)http://www.mineactionstandards.org/imas.htm
Chapter 1: Background to humanitarian
demining
15

16
or destruction of all mine and unexploded ordnance
(UXO) hazards’ (
3
).
With the ink still wet on the international standards there
is some way to go before they are universally adopted. In
such a young ‘industry’, it is not surprising that there are
very few specialist publications dealing with particular
aspects of HD. What is published is often of more interest
to scientists and researchers than to the men and women
actually clearing the ground. This book is primarily writ-
ten for those training deminers but may also be of use to
scientists and researchers.
In Cambodia and Afghanistan, where formal HD began, the
ERW problem was the result of protracted conflicts resul-
ting from the East–West divide and the cold war. Similarly,
communist–capitalist ideologies fuelled the long-term con-
flicts in Angola and Mozambique and led to the wide-
spread contamination of ground. In the Balkans, it was the
politics surrounding the end of the cold war that fuelled
conflicts in what had been a weapons-producing area.
Again, mines and other ordnance were often used without
concern for the long-term threat. From Lebanon to
Namibia, Bosnia and Herzegovina to Vietnam, and
Guatemala to Peru, the ERW left over after conflicts takes a
steady toll on lives and limbs, and prevents safe reconstruc-
tion. Actual numbers of dangerous items on the ground are
not known, but it is known that huge areas of land are
abandoned and that this inhibits the transition to peace in
many ways, crippling the lives of many in the process.
The ERW that has received most publicity are mines and
booby traps that are designed to be victim activated and
so pose a great threat to post-conflict civilians. But many
civilians are also injured by unexploded ordnance and by
munitions that may have been poorly stored and have
become unstable. Sometimes the civilians are injured
when trying to recycle the explosive and metal content of
ERW in order to earn a little money.
Humanitarian deminers do not only clear mines. They
must also clear all ERW and leave the area safe for its
intended use. Sometimes this means that an area must be
searched to a considerable depth to find all unexploded
ordnance. This is usually necessary when there are plans
to carry out construction on the site of a former battle or
bombing site.
To date, the manual deminer has usually relied on a metal
detector to help locate concealed ERW. Until recently, the
detectors used had all been designed for military use
because the HD market did not warrant the investment
required to develop new models. This meant that the
detectors often had features that were not necessary or
desirable in HD, but those features sometimes increased
the price. For example, some detectors are supplied with
(
3
)Annex A of the International Mine Action Standards (IMAS), Section 01.10, Paragraph A1.2.
http://www.mineclearancestandards.org, the text in bold is the authors’.

17
a case that is infrared (IR) invisible allowing it to be back-
packed in a conflict without showing up on the enemy’s
IR night-sights. This expensive feature is entirely irrelevant
in HD. Most of the detectors were primarily designed to
be used for short periods while standing. In HD, it is
increasingly common for short detectors to be used while
kneeling, squatting or bending — and to be switched on
for six hours or longer every working day.
Manufacturers of many of the latest generation of metal
detectors have listened to the needs of HD and tried to
design for its needs as well as the military. Many newer
designs are intended to be used while kneeling, squatting
or bending and most now have the option of a speaker
instead of headphones. The best are simple and robust
enough for fairly constant use in difficult conditions.
Perhaps of most importance, detector designers have
increasingly listened to the HD need for a detector capa-
ble of locating small metal pieces in ground that has elec-
tromagnetic properties that can make detectors signal as
if metal were present (
4
). This feature is also of occasional
benefit to military purchasers, although the higher sensi-
tivity may slow down the process of crossing a mined
area. When the military have to use metal detectors, it
can be a high priority to minimise the number of detector
signals that would slow down the process of crossing the
mined area. When operating under fire or with a tight
time constraint, tiny scraps of rusted metal are often seen
as ‘false alarms’. While minimising false alarms is also a
concern in HD, any piece of metal is generally not seen as
a ‘false alarm’ at all. In areas cleared by metal detectors, it
is common for the quality assurance (QA) check to require
that the area be metal-free, so every scrap of metal must
be removed. In HD, it is always better to spend time dig-
ging up a nail than to suffer an injury.
In some cases, demining groups may choose to tune
down a sensitive detector so that it does not signal on
very small metal pieces. This is done when the devices in
the area are known to include relatively large amounts of
metal, and when other hazards can be confidently exclud-
ed. If this is done, any QA checks carried out with detec-
tors on that ground must be carried out with the same
detector tuned to the same level of sensitivity. In these
circumstances, some groups prefer to use explosive
detecting dogs (EDDs) for QA.
Despite the desire of many detector manufacturers to
supply what is needed in HD, the commercial reality
requires that they also try to sell for military use. As with
other equipment used in HD, the potential market is just
not big enough to warrant the development of models
designed solely to meet humanitarian demining needs.
(
4
)Very few detectors had ground-compensating features between WW II and the beginning of the 1990s.

18
1.1. The development of mines
Victim-initiated explosive devices, placed under, on, or
near the ground, have been used in war for centuries (
5
).
The earliest ‘mines’ were probably underground tunnels
packed with explosive and detonated beneath the enemy.
This is how they got their name. Today we understand
‘mines’ to mean containers filled with explosive that are
initiated by the victims or their vehicles. Developed during
World War One (WWI), these began to be widely used
during World War Two (WWII). Seen as a ‘force-
multiplier’, they allowed the users to:
(a) provide a defensive barrier around vulnerable sites
and utilities. The initiation of the mines would pro-
vide early warning of attack and, if dense enough,
the mined area might stop an attack in its tracks;
(b) channel enemy troops and vehicles into an unmined
area where they themselves would be vulnerable to
attack;
(c) deny the enemy safe access to utilities they might need,
even after those placing the mines had withdrawn;
(d) assist in surprise attacks and ambushes.
Some of these uses required that the enemy knew the
mines were there, others relied on surprise. The nature of
the conflict and the professionalism of those engaged
have affected the way in which mines are used. In con-
flicts where the opponents have large differences in mili-
tary equipment and capability, such as insurgency wars,
the less well-equipped groups have tended to make max-
imum use of unmarked ‘surprise’ mines. In conflicts where
one side has no desire permanently to occupy the
territory, the use of unmarked minefields is common.
With the increased use of mines, methods of detecting
them began to emerge. Early mines were usually cased in
metal, so the development of metal detectors as mine-
detectors began.
The early detectors were relatively crude devices requiring
a lot of power. To minimise their metal content, the
detector heads were first made using wood, then hard
plastic (Bakelite). Often heavy and awkward to use, they
allowed paths to be cleared through areas sown with
metal-cased mines.
Anxious to maximise their military effectiveness, mine
designers responded to the use of metal detectors by
reducing the mines’ metal content. They used wood and
Bakelite to make the mine bodies and they began to
reduce the metal content in the firing mechanism. This
coincided with the rapid development of a wide range of
small mass-produced mines designed to be initiated by a
person’s weight — anti-personnel (AP) blast mines — and
(
5
)Those interested in the history might like to read the accounts by Schneck, Grant, McGrath, and McCracken (see Annex F).

19
anti-personnel fragmentation mines, sometimes called
anti-group (AG) mines, that were often tripwire initiated.
Since WWI, early versions of these mines had been
deployed to inhibit infantry movements in the same way
as anti-tank (AT) mines were used to restrict the use of
vehicles. During WWII, AP mines were increasingly used to
protect AT mines so that a person attempting to clear
them with an insensitive metal detector would step on an
AP mine laid nearby.
Some old designs of AP blast mine were still in wide-
spread use recently, notably the PMN and GYATA-64.
These will usually remain functional for at least 25 years
after being placed. Many other early designs are no
longer used and so are rarely found, but they may remain
in military stores and so remain a threat. The earlier mines
usually contained significant metal in the parts of their
firing mechanism and also between 100 and 300 g of high
explosive. Later AP blast mines (such as the M14, PMA-3
and Type 72 AP) contained much less explosive, which
allowed them to be smaller, cheaper to produce and
easier to conceal. The increased reluctance to risk foot-
soldiers in conflict led to the development of ‘scatterable’
AP blast mines that were dispersed from vehicles, helicop-
ters or as submunitions dispersed from a canister in the
air. These were used in such numbers that enemy soldiers
were denied use of the target area. Ignoring earlier con-
ventions, these mined areas could not be easily mapped
or marked and are almost always poorly defined.
Some of the simplest early fragmentation mines are still
found widely, notably the POMZ-2 and POMZ-2M which are
easily reproduced locally. A more complex and (in military
terms) more effective fragmentation mine is the bounding
type. These mines are propelled above the ground before
exploding and sending lethal fragments in all directions.
While many of the early designs of bounding fragmenta-
tion mines have been abandoned, the OZM range is still
found in many areas and the later generation PROM-1 and
Valmara-69 are infamous for having claimed the lives of
more humanitarian deminers than any other mines.
Figure 1.1:
An early mine detector
with a wooden search-head.
The extra pole is a handle
extension and lead
counterweight. This is the Polish
Mk3 as used by the British army
during WWII.The full length
of the handle is over 2.5 m.

20
Another category of fragmentation mine is the ‘directional
fragmentation’ or ‘off-route’ mine. On detonation, these
spread pre-cut metal fragments in a limited arc from one
side. Designed to be used by people who remain behind the
mine, they are often detonated by a soldier at the appro-
priate time (as in an ambush). When fitted with a
command-detonation fuze, these devices are not techni-
cally ‘mines’ according to the definition agreed in the con-
vention to limit use of AP mines (see Section 1.3).
Scatterable fragmentation mines have also been devel-
oped, sometimes deployed with remotely placed AT mines
as submunitions dispensed from cluster bombs. As with
scatterable blast mines, the method of remote deploy-
ment means that the mined area is usually unmarked and
poorly defined.
1.2. Detecting mines
In humanitarian demining, the common methods of
detection in current use are:
• manual, using metal detectors;
• manual, using area excavation;
• dogs and manual;
• mechanical and manual.
Notice that all include the use of manual deminers. This is
because, to date, the industry has not accepted that any
fully mechanised method of ground processing can find
and remove all ERW. The machines have not yet matched
the mental and physical attributes of the deminers.
Figure 1.2
:
The photograph shows two
metal detectors used in
humanitarian demining
and illustrates the way that
metal detectors have developed.
On the left is the Schiebel AN19
introduced in the 1980s,
for years the workhorse
of the industry. More modern
instruments are now available
from several manufacturers
(including Schiebel themselves).
On the right is an example,
the Foerster Minex 2FD 4.500,
which features an extendable
one-piece design and ground
compensation (GC).

21
1.2.1. Manual detection using metal detectors
All deminers know that their most reliable detection tools
are their eyes and brains. It is often evident where mines
are placed, and in many cases parts of the device are visi-
ble after the undergrowth has been removed. This is
often true with recently placed AP mines of all types, and
sometimes true of AT mines. But when mines were placed
a decade or more ago, they have often become more
deeply concealed. Even when partly exposed, their cases
have weathered and may be impossible to see. Where
land erosion or the deposit of alluvial sediment occurs,
mines can move from their original place or become
buried deeply beneath ‘new’ soil. New alluvial soil is very
fertile and can be thick with roots that the mine is tan-
gled inside. Apart from those areas, deeply buried AP
pressure mines are usually only found in areas that were
mined many years ago. In a few cases, AP mines were
deeply buried on placement, despite the fact that this
made it less likely that they would explode as designed.
The presence of deeply buried mines, or the belief that
they may be present, can slow demining down a great
deal and so increase the cost.
As long as the ground is not too naturally magnetic or
contaminated by scrap metal, manual deminers rely on
metal detectors to locate the metallic parts of mines and
UXO that cannot be seen.
The metal content of fragmentation mines is so high that
they do not normally present a detection problem. Also,
most of them are designed to be laid with their fuze
mechanism above ground, and many are placed with half
their body exposed, so they are often easy to see after the
undergrowth has been removed.
The reduction of metal content in AP blast mines over the
years has led to a few modern mine designs having no metal
content. Thankfully, very few of these mines have found
their way into use and their manufacture and sale is now re-
stricted by the terms of the 1997 Mine Ban Treaty (see Sec-
tion 1.3). Some have been found during HD using dogs or
excavation. Of those known to the authors (notably the M1
APD 59 found in Lebanon and Angola) the detonators ap-
pear to have deteriorated and become non-functional after
a decade in the ground. It is to be hoped that similar prob-
lems occur with other non-metallic fuze systems.
The detection and fairly accurate location of metal in the
ground is essential for deminer safety. It is not only neces-
sary to get a signal, the deminer must also be able to cen-
tre the reading and place a marker almost exactly where
the metal is. This allows the deminer to start probing or
excavating a safe distance away from the reading. The
deminer probes or digs sideways towards the reading so
as to approach the device from the side and avoid press-
ing directly onto the pressure plate of a mine. But mines
are not always lying flat in the ground. If they have tilted,
a cautious deminer can still set the mine off. Detonating a
mine while exposing it is the most common accident in
HD. When adequately protected, most deminers survive
this without disabling injury.

22
1.2.2. Manual detection using area excavation
In areas where magnetic ground or scrap metal contami-
nation is so high that a detector signals constantly, the
deminers may have to put the detectors aside and
excavate the entire top-surface of the ground to an
appropriate clearance depth. This ‘difficult’ ground may be
a naturally occurring high level of magnetic ground inter-
ference or may be caused by mankind. In many areas, no
natural magnetic ground occurs, but in all areas that have
been occupied by people, some scrap metal contamina-
tion occurs. In the experience of the authors, and as a
crude ‘rule of thumb’, if more than three pieces of metal
are found per square metre, it can be faster to excavate
the entire area than safely to excavate the metal pieces
separately. The excavation process is so slow that it is usu-
ally only done in very limited areas where there are
known to be mines, although it has been done over long
stretches of road. Explosive detecting dogs may be used
to reduce the suspect area to a minimum before starting
to excavate.
If a mine has been deliberately buried deeply, as with an
AT mine on an unsurfaced road, the removal of the top of
the road may reveal where a deeper hole has been previ-
ously dug and so allow the mine to be unearthed. How-
ever, this is not always the case and the use of dogs to
locate the well-spaced mines on roads is usually preferred.
1.2.3. Explosive detecting dogs and manual
methods
Explosive detecting dogs may be used to reduce an area
prior to manual clearance, and occasionally for precise mine
detection. To increase confidence, it is normal for at least
two dogs to be run over the same piece of suspect ground.
It is generally accepted that dogs cannot reliably pinpoint
the source of the explosive in a densely mined area where
the scent from more than one source may combine. Dogs
can only be used to pinpoint mines when the mines are
widely scattered. Where dogs are used to pinpoint explo-
sives, one common method is to ‘box’ the area into 8–10
metre squares. The dogs are then run inside each boxed
area from which any dense undergrowth must have already
been cleared (usually using an armoured machine). When
the dogs signal, a manual deminer then clears (using a metal
detector and/or excavation techniques) an area extending
several metres around the spot where the dog indicated.
Sometimes the deminer must clear the entire marked ‘box’
in which the dog indicated the presence of explosives. This is
because it is recognised that the dog’s ability to pinpoint the
position of the explosive (and to discriminate two readings
within a few metres of each other) may not be reliable.
Dogs are also used as a quality control check on land that
has been cleared, especially if the devices found have not
been detonated where they were found. Destroying the
devices in situ can spread the explosive scent over a wide
area, which means that there must be a time interval
before dogs can be reliably used to check the ground.

23
In all cases, the dog acts as a ‘detector’ and anything it
detects is investigated by manual deminers (
6
). For more
about the use of dogs, see ‘Annex A: Explosive detecting
dogs (EDDs)’. For an indication of the variety of types of
high explosive (HE) that a dog may have to locate, see
‘Annex C: Explosive content of mines’.
1.2.4. Mechanical and manual methods
Machines are increasingly being used to assist in the man-
ual demining process. The most common use is to cut the
undergrowth before the deminers start work. Other uses
include the use of back-hoes to remove and spread out
building rubble or the collapsed sides of trenches. On
roads and in open areas, they are increasingly being used
to carry one or another means of detection. This usually
allows an array of detectors to be used, so potentially
increasing speed (
7
). More controversially, ground milling
machines, flails and rollers are sometimes used to deto-
nate or destroy mines where they lie.
In all cases, to have confidence that all ERW has been re-
moved, manual deminers must follow the machines. Some-
times they may use dogs as detectors, often metal detectors.
1.3. Treaties controlling mine use
Two major international treaties control the use of land-
mines: Protocol II to the Convention on Conventional
Weapons (CCW) of 3 May 1996 and the Ottawa
(
6
)At the time of writing, the GICHD does not have a dedicated website recording the research it is organising into the use of dogs.
There are several relevant papers on the GICHD site, for example, http://www.gichd.ch/docs/studies/dogs.htm
(
7
)Currently, there are several vehicle-based metal detector arrays in existence and several prototype multi-sensor systems combining
other detection techniques such as GPR and NQR with metal detection (see ‘Annex B: Other explosive remnants of war detection
technologies’).
Figure 1.3
:
A mechanically prepared area being marked out for searching by dogs.

24
Convention or Mine Ban Treaty of 3 December 1997. The
full names of these treaties are respectively:
Protocol on Prohibitions or Restrictions on the Use of
Mines, Booby-Traps and Other Devices as Amended
on 3 May 1996 (Protocol II as amended on 3 May
1996) annexed to the Convention on Prohibitions or
Restrictions on the Use of Certain Conventional
Weapons Which May Be Deemed to Be Excessively
Injurious or to Have Indiscriminate Effects (
8
); and
Convention on the Prohibition of the use, stockpiling,
production and transfer of anti-personnel mines and
on their destruction (
9
).
Under the CCW, the manufacture of completely non-
metallic anti-personnel mines is banned and other restric-
tions are placed on anti-tank mines and booby traps as
well as anti-personnel mines. Mines designed to be acti-
vated by metal detectors are banned. It is forbidden to
use mines against other than military objectives. Almost
all countries with a significant arms production capability
are State parties to the CCW or have signed it.
Under the Ottawa Convention, anti-personnel mines are
essentially banned completely. Its provisions do not apply
to anti-tank mines. Many arms-producing countries have
signed it but those who have not include such major arms
producers as the United States, Russia and China. At the
time of writing, the existing, new and applicant Member
States of the EU have signed and ratified it with the
exception of Greece and Poland (signed but not ratified),
and Finland, Latvia, Estonia and Turkey (not signed).
AP mines are often seen as the greatest threat to civilians
after conflicts have ended, and the Ottawa Convention
was built around them. The Ottawa Convention (and the
public campaigning that surrounded it) has had an obvi-
ous effect on AP mine production and deployment. The
development of metal-free mines has virtually ceased.
Although there is continued disagreement about the mil-
itary utility of AP mines, some of those who have not
signed the Ottawa Convention have agreed to increase
the metal content of their stocks of minimum metal mines
so that they can be more readily detected. Others are
seeking to perfect mines that self-deactivate (SDA) or self-
destruct (SD) after a set period of time, so theoretically
removing the persistence of their threat to non-
combatants. Currently, there is mixed opinion over whether
SD and SDA mines will perform as designed. There are
also concerns about clearing up SDA mines that have
deactivated, but still contain a detonator and high explo-
sive and so remain a threat to civilians.
One unintentional effect of the Mine Ban Treaty may be
the increased use of other munitions that have an
(
8
)The text of CCW Protocol II can be found at http://www.unog.ch/frames/disarm/distreat/mines.htm
(
9
)The text of the Ottawa Convention can be found at http://www.icbl.org/treaty/text.php3

25
area-denial effect similar to mines, but that are not
designed as mines. An example of this is the BLU-97 sub-
munition that has a high failure rate on impact and an
inertia fuze system that can be sensitive to any later
movement. Where these have been used (most recently in
Iraq, Afghanistan, Kosovo and Kuwait), both deminers
and civilians have been killed by them in relatively large
numbers. The BLU-97 is not the only submunition that
causes these problems. The BL-755, M118 ‘Rockeye’, BLU-
61, BLU-62 and KB1 are others. Some campaigners are cur-
rently seeking to limit their use or change their design so
that they pose less of a threat when the conflict has
ceased. At the time of writing, new protocols restricting
or banning these devices are being prepared for consider-
ation as additions to amended Protocol II of the CCW. The
change in the public attitude to the use of indiscriminate
and persistent weapons coincided loosely with the end of
the cold war and the consequent reduction in ideological
wars that were fought by proxy on foreign soils. In those
wars, mines were often seen as cheap and effective force-
multipliers, and were provided in huge numbers to the
combatants by outside agencies. The scale of the mine
problem in Mozambique, Angola, Afghanistan and
Cambodia dates from this time.
While the use of AP mines has declined, their continued
acceptance and use in non-signatory States such as Azer-
baijan, Myanmar (Burma), Chechnya, China, India, Korea,
Nepal, Pakistan, Russia, Sri Lanka and Uzbekistan indicate
that the ‘ban’ is far from complete.

The process of demining can be crudely divided into five
general stages. Metal detectors may be used during
stages 1, 2, 3, and 5.
1. Locate the mined areas.
2. Determine where the mines are within the suspect area.
3. Locate each individual mine/UXO.
4. Destroy each individual item.
5. Check that the area is really clear before release to
the public.
Until recently, these were often referred to as:
1. Survey Level 1 — Country survey including impact survey
2. Survey Level 2 — Technical survey, area reduction
3. Mine detection/Demining
4. Demolition
5. Survey Level 3 — Quality control/Sampling
A further survey level (Survey Level 4), is sometimes used
to describe the subsequent searching of the area for
deep-level ordnance that would not be found without a
specialist deep-level detector (see Section 2.4.5, ‘Detecting
deep-level explosive remnants of war’).
The first version of the UN’s International Mine Action Stan-
dards (IMAS) recognised the distinctions in survey levels
listed above. The 2002 revision of the IMAS uses the term
‘General mine action assessment’ to cover what was re-
ferred to in the earlier IMAS as ‘Survey Levels 1 to 3’, along
with ‘Impact studies’, ‘Post clearance inspection’ and ‘Sam-
pling’. The activities are combined under one heading be-
cause this allows the survey and mine clearance process to
be seen as integrated and continuous, rather than as a se-
ries of tasks that should be completed sequentially (
10
). For
example, information that may be part of a general Survey
Level 1 may only be discovered during a Level 2 technical
survey or actual demining, but provision should still be
made for it to be recorded and used during future planning
and prioritisation tasks. No survey task should be thought
of as being ‘finished’ until the clearance is completed and
the land returned to the users.
(
10
)See http://www.mineclearancestandards.org/links.htm
Chapter 2: The role of metal detectors
in humanitarian demining
27

28
The term ‘Survey Levels 1 to 3’ is still widely used, but what
it actually involves varies in different parts of the world and
may be surprisingly limited. In most areas, a Level 1 survey
does not involve placing perimeter signs around a suspect
area — so does not include any means of warning the pop-
ulation that a danger exists. It is only during a Level 2 tech-
nical survey that perimeter markings are placed. In many
areas a technical survey is not carried out separately, but as
part of ‘area reduction’ immediately prior to clearance, so
the area may be left unmarked for years.
The elements of ‘General mine action assessment’
(described in IMAS 08.10) can be crudely expressed as:
1. emergency threat assessment/survey;
2. technical survey and clearance (including impact
survey) — IMAS 08.20;
3. post-clearance documentation (including QA inspec-
tions) — IMAS 08.30.
2.1. Types of mined areas
The use of a metal detector can be influenced by the
place where the mines are situated.
While every mined area is unique, common characteristics are
sometimes identified in order to reach generalised conclu-
sions. The following generic mined area ‘scenarios’ are taken
from the Geneva International Centre for Humanitarian
Demining’s (GICHD) study of global operational needs (
11
).
Grassland Open (flat or rolling) land
Woodland Heavily wooded land
Hillside Open hillside
Routes Unsurfaced roads and tracks,
including 10 m on either side
Infrastructure Surfaced roads, railway tracks
(to 10 m on both sides)
Urban Large town or city
Village Rural population centre
Mountain Steep and high altitude
Desert Very dry, sandy environment
Paddy field Land allocated for the growing
of rice
Semi-arid savannah Dry, open and flat, little
vegetation
Bush Significant vegetation
and possible rock formations
A scenario is assigned to each mined area. The scenario is
then refined by assigning defining characteristics, such as
a description of the ground type, the level of magnetic
interference and/or scrap metal contamination,
(
11
)Geneva International Centre for Humanitarian Demining, Mine action equipment: Study of global operational needs, Geneva,
2002, ISBN 2-88487-004-0.

29
vegetation, slope, the presence of trenches and ditches,
fences and walls, buildings and building debris, water-
courses, ease of site access and the mine/UXO hazard. This
was done as part of an exercise to find out which HD
activities could most effectively be improved (see also Sec-
tion 2.6, ‘Real mined areas’.)
Of special relevance to the use of metal detectors is the level
of naturally occurring magnetic interference and of scrap
metal that may be present. The level of metal detector ‘dis-
turbance’ that results can be recorded using the GICHD
method as ‘none’, ‘low’, ‘medium’ or ‘high’. The definition
of ‘medium’ includes a reduction in the ability to detect
minimum metal mines and ‘an impact on safety and the
rate of clearance’. The definition of ‘high’ is that the distur-
bance prevents ‘the use of conventional mine-detectors’.
These conditions can occur in any of the listed scenarios.
The GICHD study allows a variety of conditions to be
assessed as part of the HD planning process. The antici-
pated threat is an integral part of this. For example, it
may be that the area has a medium level of ground ‘dis-
turbance’ but that minimum metal mines were not used
there, so reliance on appropriately tuned/adjusted metal
detectors may still be safe. However, there is not current-
ly an industry-wide agreement about how the level of
‘disturbance’ should be measured.
It may not be quite so obvious that the practicalities of
demining with metal detectors can also be influenced by
other factors. Examples are listed below.
(a) The terrain — steep and irregular land can make it im-
possible or unsafe to use a detector in the way described in
a group’s operating procedures. For example, the deminers
may need to change their normal safety distances, or
change the normal working position of deminers.
(b) Rocky ground — which can make it impossible to use
the group’s ‘normal’ marking procedures during detection
and clearance.
(c) Wet ground — which can inhibit the operation of
some detectors and change the apparent level of what
the GICHD study called ground ‘disturbance’.
2.2. Using metal detectors during
surveys
The way in which mined areas are surveyed varies widely
around the world. At some stage during the planning of
clearance, there should be a detailed survey in order for
the planning authority to decide which demining meth-
ods and resources are appropriate to use in the suspect
area. During this, a metal detector can be used to gain
some indication of its ability to locate the target mines
under local conditions.
In some areas, a sloping cutting in the side of a trench can
be used to get a reasonable indication of a particular

30
detector’s ability to locate particular mines at various
depths. This can be important when a clearance contract
specifies the depth to which the deminers must work. The
cavity around the mine may affect performance, so the
result should be checked by burying a target mine at the
maximum detection depth.
2.3. Using metal detectors in area
demining
Area demining is the clearance of ERW from land under
given conditions. Some indication of how varied those con-
ditions can be has already been given. To begin to under-
stand how that variability can affect the use of a metal de-
tector, the reader may like to look around the vicinity of
their own homes assuming that everywhere is mined. If
they were to take a detector onto the nearest patch of
grass, it is likely that they would get very many signals from
buried metal that has accumulated over the years. In real
mined areas, the vegetation, moisture, magnetic ground,
ground incline and many other features affect detector use.
Metal detectors cannot be used as mine-detectors every-
where, but the latest GC models can be used in most
mined areas. Where they are used, some rules should be
followed to make their use as safe as possible.
2.3.1. Daily routines
The group’s operating procedures are approved routines
for the deminer to follow. The daily detector routines are
standing (or standard) operating procedures (SOPs) like
any other and should be documented. As a general rule,
it is very important to follow the instructions provided in
the manufacturer’s manual when setting any detector up
for optimal use.
Figure 2.1:
The picture on the left shows
Fredrik Pålsson using a cutting
in the side of a trench during
detector selection trials
in Afghanistan during 1999.

31
While the manual may specify further checks, the follow-
ing routines are the minimum checks that should be made
before using any metal detector in a mined area.
(a) Checking the detector’s general condition. Check
that the battery connections are tight and reliable,
and (when possible) that the batteries retain a suit-
able charge level. Check the detector for visible dam-
age, loose screws or connections, and any other parts
known to fail or identified in the detector manual.
Only after a detector has passed these checks should
its functions be checked.
(b) Checking the detector’s functions. After assem-
bling the detector, it must be checked to ensure that
it is working properly. This process has various names,
but it is often called the ‘set-up’ or the ‘warm-up’.
Detector manufacturers usually provide a sample tar-
get for the detector to signal on. This is often called a
‘test-piece’. Most test-pieces are not only designed to
show that the detector signals on metal. They are also
designed to indicate whether the detector signals on
the target at a set distance from the detector-head
(usually in air). This is usually referred to as measuring
the detector’s ‘sensitivity’. After this test, the deminer
knows whether the detector is functional. The time
needed to conduct a ‘set-up’ test varies by detector
type, but is generally not more than a few minutes.
(c) Adjusting the detector to the ground condi-
tions. Checks (a) and (b) are usually carried out in
strict accordance with the instructions found in the
detector’s manual. Adjustment to the ground condi-
tions may also be adequately explained in the
manual, but is often extended with the experience of
the users.
A detector without a GC facility may simply be ‘tuned
down’ by reducing its sensitivity until it no longer sig-
nals on the patch of pre-cleared ground used as a test
area. Detectors with a GC facility may be adjusted
automatically, or manually. In both cases, the
detector’s ability to detect at depth is frequent-
ly reduced by the adjustment.
(d) Adjusting the detector to the target. This is the
most important check because it can make the work
both safer and easier but it is not carried out by all
demining groups. It involves reducing the danger to
one that is known. This is achieved by checking that
the detector can find what the deminers are looking
for. The most difficult target to find is selected. This
will often be a minimum metal mine but may be a
bigger metal target buried at a greater depth. Some
demining groups use real mines that have been ren-
dered safe. Some demining groups use test-pieces
that simulate the detectability of the target mine. The
target is buried at the maximum clearance depth
required and the detector is used to locate it.
This check is not only of the detector’s ability to do
the job required. It can also be used to check the

32
deminer’s ability to use the detector in the way
required. By carrying it out, the deminers are given
confidence in the equipment and in their ability to
use it. When it includes measuring the ‘sensitivity
area’ of the detector beneath the ground, it can also
provide vital information about how far to advance
the detector-head on each sweep (see Section 5.4.2,
‘Search-head sensitivity profile (footprint)’). By inclu-
ding this routine before work, the deminers are
shown that those in charge care about their safety.
The authors recommend that this check always be suc-
cessfully completed before deminers are allowed to
work in the mined area.
Routines while working in the mined area are listed
below.
(e) Maintaining confidence. After check (d) above, the
deminers start to use the detectors to search for metal
in the mined area. Many models of detector make a
sound to show that they are working normally. This is
often called a ‘confidence click’. Although the sound
should be enough to give confidence, deminers usual-
ly feel a need to make their own regular check that
the detector is working. This is done by routinely pre-
senting the detector to a visible metallic target, such
as tools or the eyelets on the user’s boots.
(f) Repeating ‘set-up’ for changed conditions. Work-
ing hours vary, but on average a metal detector is
used for about six hours a day in HD. If the detector is
turned off during that time, checks (a) to (d) should
be repeated when it is turned back on. The ambient
conditions in the work area will also change over a
six-hour period. For example, the temperature and
the level of humidity may rise a great deal. Also, the
condition of the detector and its batteries can
change. As a result, all detectors should be ‘set up’
again after a predetermined time. At the very least,
set-up checks (a) to (d) should be repeated if there is
a temperature change of 10°C.
(g) End-of-day check. The last routine at the end of the
working day is to clean and disassemble the detector,
repeating check (a) in the process. The detector can
then be packed away ready for use the next day.
2.3.2. Test-pieces
Two kinds of detector test-piece are recommended: the
‘manufacturer’s test-piece’ and a ‘confidence test-piece’.
The manufacturer’s test-piece is usually supplied with a
specific detector. These test-pieces are small pieces of
metal, often encased in plastic. They are used with a dis-
tance scale to check that the detector is working properly
and achieving its design ‘sensitivity’.
The ‘confidence test-piece’ is either an original mine (free
from explosive) or a surrogate designed to be a substitute
for the metal content of a mine. Some surrogates attempt
to simulate a generic mine type rather than a particular

33
mine model. Some attempt to simulate a specific mine,
and may be called ‘simulants’. The distinction between
the use of the terms ‘surrogate’ and ‘simulant’ is not uni-
versal and the words are often used to mean the same
thing. Both surrogates and simulants may be designed to
have detection characteristics similar to those of real
mines and so be used as substitutes for them when testing
detectors.
While we follow field-use and make no strict distinction
between ‘simulant’ and ‘surrogate’ in this book, a stan-
dardised naming convention for mine targets exists as one
of the four-nation international test operational proce-
dures standards (ITOP 4-2-521) and has been recognised
by the North Atlantic Treaty Organisation (NATO) (Stanag
4587) (
12
). This convention defines ‘types’ in the following
way.
Type 1: Production mine — a fully ‘live’ mine.
Type 1a: Production mine — a mine with an active fuze
but the main HE charge removed.
Type 2: Surrogate mine — a production mine with a dis-
abled fuze.
Type 3a: Surrogate mine — a production mine that is
free from explosive (FFE), air-filled.
Type 3b: Surrogate mine — a production mine that is FFE
and filled with an inert material.
Type 4a: Reproduction mine — a model of a specific type
of real mine (air-filled).
Type 4a: Reproduction mine — a model of a specific type
of real mine (inert-material-filled).
Type 4c: Reproduction mine — a model of a specific type
of real mine (explosive-filled).
Type 5a: Simulant mine — a generic model of a class of
mine, with significant explosive fill.
Type 5b: Simulant mine — as 5a with an active fuze but
without a main charge.
Type 5c: Simulant mine — as 5a but with no fuze and
only trace amounts of explosive.
Type 6: Simulant mine — a generic model of a class of
mine that is FFE.
Type 7: Instrumented mine — as may be used for test-
ing mechanical clearance equipment.
Type 8: Calibration target — for example, a metal test-
piece.
(
12
)For more details, see Target standardisation for demining testing, 20 December 1999,
http://www.itep.ws/standards/pdf/TSFDTnon4.2.521.pdf

34
A range of ITOP surrogates (
13
) that can be used for test-
ing radar, metal detectors and mechanical equipment are
available commercially with restrictions. However, they
are expensive and the authors know of no NGO or com-
mercial demining clearance organisation that uses them
in the field.
It is usually accepted that the best ‘confidence test-piece’ is
an original mine taken from the area to be cleared, or from
a mined area of a similar age nearby. After removal, the
mine is rendered free from explosive (FFE) and clearly
marked so that no one can confuse it with a live mine. The
FFE process usually involves removing the detonator, which
is sometimes replaced by a similar-sized piece of metal but
is often left absent. This ‘confidence test-piece’ now con-
tains metal of the same type and in the same condition as
the metal in the mines that must be found. Some groups
prefer to remove the metal from a mine and use that metal
to make a test-piece that does not look like a mine at all. Ef-
fective ‘confidence test-pieces’ can also be made using any
piece of metal that the detector reacts to at the same depth
and with the same strength as the target mine. However,
one advantage of using FFE targets that still look like mines
is psychological. When the deminer uses a test-piece that
looks exactly like what he (
14
) wants to find, his confidence
in the detector and his own abilities is enhanced.
Caution: Some demining groups prohibit rendering any
device FFE in their SOPs. Others only allow some kinds of
mine to be rendered FFE. Dismantling and removing the
high explosive from some designs of mine is always
unsafe. Mines that have been in the ground for long peri-
ods can become unstable. In the authors’ opinion, a suit-
ably experienced person should always carry out the FFE
process and no attempt should ever be made to FFE any
obviously damaged device.
2.3.3. Batteries
Every metal detector used in HD requires batteries. (Re-
search into clockwork and inertia-charged batteries has not
resulted in a fieldable product at the time of writing.) Most
manufacturers recommend a battery type to use. For exam-
ple, some of the European and Australasian manufacturers
recommend alkaline batteries. Unfortunately, when demi-
ning for long periods in remote areas, specific batteries
may not be easily available. If the right voltage batteries of
the wrong type are used, the metal detector will still work.
However, it will be unlikely to work for the number of op-
erational hours claimed by the manufacturer. Some de-
mining groups routinely use the cheapest batteries, others
go to great lengths to maintain supply of the recom-
(
13
)For more details, see ‘Scientific and technical report — Simulant mines (SIMs)’, 21 October 1998
http://www.uxocoe.brtrc.com/TechnicalReps/misc1.htm
(
14
)We use ‘he’ rather than ‘he/she’ not as a value judgement, but to reflect the fact that most deminers are male, and so that the
text flows more easily.

35
mended type and brand. Still others use rechargeable bat-
teries. As long as the performance of the detector is
checked regularly and the batteries are replaced as soon as
performance falls-off, the decision over which batteries to
use is a matter of opinion. In the authors’ experience, the
option that looks cheapest may not really save money.
Detector manufacturers tend to design their equipment
to use batteries of a readily available physical size and
voltage. This is convenient, of course, but also means that
the batteries can be used to power other equipment. To
prevent batteries being ‘secretly’ discharged by powering
radios, music systems, flashlights, etc., a strict control over
the use of batteries is advisable.
Most modern detectors include a battery-check circuit to
warn the user when the power state is low. Some de-
mining groups routinely change their detector batteries
before the detector warns of a low-battery state. This may
be done to simplify logistics by replacing all batteries at
the same time. Some groups believe that it enhances safe-
ty to replace batteries before the need is indicated, but
the manufacturers of modern detector models deny this.
The authors questioned many manufacturers about this
and all claimed that their detectors lost no sensitivity
before the point when they began to warn of severely
depleted power in the batteries. At the time of writing,
no independent test of the battery check-circuit against
the battery-state of leading detectors has been published.
The authors recommend instigating the battery replace-
ment regime that feels safest.
Rechargeable batteries are used by some groups but
should not be used with standard chargers and power
from generators. Some specialist charging systems are
available. Ideally these have a charging time of not more
than four hours and can use a wide range of power inputs
so that an unstable mains power supply, generator or a
vehicle may be reliably used as a power source.
In one prototype detector tried in Mozambique, a photo-
voltaic solar collector was connected to the detector pole.
The solar-panel charged an accumulator in the detector.
This worked in field trials but was not developed and mar-
keted commercially. While such a power source would be
undesirable in a detector developed for military use, it
could have potential in HD. Anyone with experience of pur-
chasing detector batteries in HD is aware of the cost savings
that could result from a ‘battery-free’ solar-power source.
2.3.4. Locating metal/mines
When a detector signals the presence of metal, the de-
miner must always assume that the signal is from a mine.
Although signal strength may vary, this cannot be used
reliably to discriminate the signals from a crushed beer
can and a grenade, or a ring-pull and a minimum metal
mine. If the signal occurs in a place that is consistent with
the pattern of mines already located, or where mines
have been specifically reported, the deminer may have
extra reason to believe it is the signal from a mine. In
other cases, the deminer has to believe that every detec-

36
tor signal could be. It is not always easy to maintain a
suitable level of deminer caution because deminers spend
most of their time locating metal that is not part of a dan-
gerous item.
To illustrate this point, a recent report about Afghan
deminers stated that they expect to investigate 1 000
detector readings for each mine found. In 1999, the de-
miners at the United Nations accelerated demining pro-
gramme (UNADP) in Mozambique, had an average of 550
detector readings for each mine. During 2000, that num-
ber was reduced to 330 by increasing the use of explosive
detecting dogs to reduce the search area. Even the
reduced average number of 330 to 1 means that deminers
commonly investigate hundreds of innocent objects for
each metal piece connected with ERW.
To maintain concentration and adherence to SOPs at a
level that prevents accidents, a combination of self-
discipline and strict supervision is required.
As a crude average, in around 50 % of cases the source of
the signal is visible. When the metal is not visible, the
deminer must start an excavation procedure. This proce-
dure varies according to the demining group’s SOPs.
What follows is a generic example that may not cover all
possible excavation procedures.
(a) The deminer uses the detector to find the signal again,
approaching from different directions. This gives more
information about the size of the reading and its precise
position (for a description of ‘pinpointing’ a detector
reading, see Section 5.4.8, ‘Pinpointing targets’). With
some detectors, the detector-head can be turned onto its
side and the edge of the head used to find the ‘centre’ of
a shallow reading (the authors do not recommend this).
Some groups place a marker in the centre of the reading.
(b) Most important is that the detector should then be
used to determine precisely where the signal starts and
a marker should be placed at the closest point of the
signal to the deminer.
(c) In a two-man drill, the deminer with the detector then
withdraws and the excavating deminer comes forward.
In a one-man drill, the deminer puts down his detector
and starts to prod/excavate at least 20 cm back from the
closest marker. Some groups measure the distance back
from the reading by using the width of the detector’s
search-head. Other demining groups use a stick or a
purpose-made measure. The deminer then uses his
tools to excavate a hole at least 10 cm wide approach-
ing the signal. If the area over which the detector sig-
nalled was wider than 10 cm, the excavation should be
at least 5 cm wider than the area. The depth of the ex-
cavation varies according to the mined area, but is usu-
ally at least 10 cm and may be much deeper. Generally,
when making a deeper excavation the deminer must
start further away from the signal.
For all prodding and excavation, the authors recom-
mend using tools that are designed so that they will

37
not break up in a detonation and that will keep the
user’s hands 30 cm from any blast.
(d) When no closer than 5 cm to the nearest marker, the
deminer should start to probe forward with a prod, try-
ing to feel the side of any obstruction. The probe
should be inserted at intervals spaced to reflect the size
of the target and at a low angle to the ground (usually
30° or less). The low angle reduces the risk of pressing
onto a mine’s pressure plate but also reduces the risk of
injury if a mine is initiated. If the ground is severely
compacted or contains a lot of roots or stones, it may
be necessary to vary the prodding angle in order to de-
fine the outline of any concealed object. In very hard
ground, it may be impossible to prod forward without
applying extreme pressure. In this case the hole must
be cautiously extended towards the signal by scraping
away the face of the excavation. Alternatively, water
may be used to soften the ground. (Those using water
should be aware that water can alter the ground’s
properties and affect the sensitivity of some detectors.)
If the prodder locates no obstruction that could be a
mine, the hole is extended towards the signal and the
metal located. If the prodding indicates an obstruction
that could be a mine, the ground is further loosened
with the probe and carefully removed until a part of
the device is visible.
Deminers using a one-man drill usually have the
detector close to them as they excavate. This allows
the deminer to use his detector to pause and re-check
the position of the detector reading as he works.
When no obstruction is found with the prodder, hav-
ing the detector close by can also make it far easier to
locate the metal piece that caused the signal. In a typ-
ical example, the deminer may prod and loosen the
ground where the detector made a reading. He then
checks that the reading is still in the same place, and
starts gently to remove the loose ground, checking
the detector reading constantly. When the detector
reading moves, the deminer knows that the fragment
was in the last bit of ground he moved. If all the loos-
ened ground is put aside and the detector continues
to signal in the original place, the deminer must move
back to the start of his excavation and work forward
again at greater depth. This usually means that the
deminer must make the first excavation wider to
allow him to use his tools properly.
(e) When a deminer has exposed enough of the device to
be sure that it is a mine or UXO, the information is
usually passed to a supervisor. If the demining group
routinely moves the type of device located for remote
demolition, the deminer may have to expose the
entire device before calling the supervisor.
(f) When the supervisor arrives, he either decides how
much of the device needs to be exposed in order to
guarantee a safe and effective demolition, or disarms
the device and it is removed for remote demolition.
Disarming usually involves removing the fuze, deton-
ator and/or booster charge. Decisions over whether to

38
destroy devices in situ or move them for bulk demoli-
tion may be influenced by the desire to use explosive
detecting dogs in the area, or by a desire not to have
to close working lanes pending an in situ demolition.
Some fragmentation mines may be disarmed and
moved to prevent the risk of spreading metal frag-
ments over the working area when they are
destroyed. Most groups recognise that there are a
few especially sensitive mines that should never be
disarmed, and that damaged devices should always be
destroyed in situ. Although all disarming procedures
involve some risk, there is also a small risk involved in
laying charges for in situ demolition. The authors of
this book recommend destroying mines in situ unless
there is a compelling reason to do otherwise.
Some demining groups use a shaped hook to lift and
turn a mine prior to disarming. This is done using a
long rope from a safe distance. Many mines can be
fitted with anti-handling devices and all can be
booby-trapped to hinder clearance. This can be rela-
tively common in areas where rapid clearance was
anticipated, such as parts of the Balkans. By moving
the mine remotely, any functional anti-disturbance
device will be initiated and the mine will detonate at
a safe distance from the deminers.
In general, UN-controlled demining groups carry out
in situ demolitions of mines at the end of the working
day. Some NGOs and commercial groups withdraw
their deminers and destroy devices in situ as soon as
they are found. From their observations, the authors
believe that most demining groups (including those
under UN control) routinely move common UXO such
as mortar bombs and remove fuzes from common
fragmentation mines to allow remote demolition.
2.4. Using metal detectors
appropriate for the threat
Many of the older metal detectors with no ground-
compensating (GC) characteristics are still in use in HD at
the time this book is being written. Depending on the
conditions where they are being used, these older designs
may be able to locate the threat reliably. For this reason,
some of the commercial companies and NGOs retain some
old models and use newer GC detectors only when
ground conditions make this necessary.
2.4.1. Tripwires
Tripwires are commonly used with fragmentation mines.
A tripwire may activate the mine when the wire is pulled
(pull-mode) or when the wire is cut (tension-release
mode). Pull-mode is far more common. Mines could be
placed at both ends of a tripwire, so the deminers must
check both ends. Tripwire-activated fragmentation mines
are also often laid with AP pressure mines around them or

39
beside the wire. When placed, the fragmentation mine
and its tripwire is visible, so the AP pressure mines are
placed to prevent the enemy moving into the area and
cautiously disarming them.
With the passage of time, tripwires may rust, break or be
burned off during vegetation fires. A broken tripwire is
not safe. Parts of the tripwire may litter the ground, con-
fusing the deminer as he searches for buried AP pressure
mines. The end of the wire attached to the mine may be
caught among undergrowth and so may still initiate the
mine if walked into. Some of the fuzes used with tripwire
mines are also pressure and tilt-sensitive, so must be
approached with great caution even when the tripwire
itself has gone.
Using a metal detector in a fragmentation mine area is
further complicated by the fact that some mines will
probably have detonated. The wires can be pulled by ani-
mals passing through the area, and sometimes by becom-
ing caught in growing vegetation. Any detonation will
have spread metal fragments over a wide area. Immedi-
ately after detonation the fragments are almost all on (or
very near) the ground surface but after the passage of
time they can become buried.
Tripwire detection drills usually start by using a ‘feeler’
(usually a stiff wire or thin stick) to reach into the uncut
overgrowth ahead of the deminer to a depth of about
30 cm at ground level. The stick is then gently lifted and
any obstruction investigated. This works well in sparse
vegetation but in heavily overgrown areas the stick is con-
stantly snagged by undergrowth and the process takes a
very long time.
In long grass, some groups run the metal detector over
the top of the grass before carrying out a ‘feeler’ drill.
Other groups report that their detectors do not reliably
signal on tripwires.
When the deminer is confident that there are no tripwires in
the area immediately ahead, he can cautiously cut and re-
move the undergrowth. While doing this, the deminer must
constantly look out for the fuzes of tripwire mines that may
be above ground. He should pass his detector over each
layer of vegetation before cutting. Striking the fuze with a
vegetation cutting tool can initiate it, and several deminers
have died as a result of accidentally striking such a fuze.
With the undergrowth removed, a metal detector can then
be used to check whether any metal is buried in the area.
In recent years, many groups have developed armoured
machines to cut the undergrowth ahead of the deminers
so that tripwire risks are reduced. Increasingly, demining
groups are issuing deminers with light magnets with
which to sweep the ground surface when fragment con-
tamination is high. The magnet is used between cutting
the vegetation and using the detector, so removing sur-
face fragments and reducing detector signals.
There is a need for further research into why some metal
detectors have apparent difficulty locating tripwires. The
cause may be a basic technology limitation, the type of

40
metal in the tripwire, a feature of the detector design, a
mistake in the way the user makes adjustments, a result
of the way in which the detector is actually moved, or a
combination of one or more of these. It is reported that
even purpose-designed tripwire detectors do not
work well.
2.4.2. Minimum metal mines
The term ‘minimum metal’ is used to describe a mine in
which the metal content is so small that it is difficult to
detect with a metal detector. In some, the PMA-2 for
example, the only metal is a small aluminium tube around
the detonator. Others, such as the M14, also include a
firing pin. Still others also include a spring (Type 72 AP),
and tiny ball bearings (R2M2) (see Figure 2.3).
The type of metal is significant. For example, some detec-
tors fail to signal on high-chrome stainless steel or high-
carbon spring metal. Some also have difficulty finding the
heavily rusted steel in older mines.
The depth of the metal is also significant. All metal detec-
tors have a sensitivity range, and the maximum detection
depth of a target can be significantly reduced when a
detector is used in GC mode. Fortunately, most minimum
metal AP mines were not designed to be deeply buried.
Some have become deeply buried over time, but most are
very close to the surface.
This is not true of minimum metal AT mines. The
detonator in an AT mine is bigger than in an AP mine.
Sometimes the pin and spring are also bigger, but not
much. AT mines may be buried far deeper that AP mines.
They have been found at a metre below the surface.
Some metal detectors can locate a metal-cased AT mine at
that depth in easy ground. No metal detector known to
the authors can reliably detect a minimum metal AT mine
at that depth. Mine detecting dogs have done so, but it is
not known how reliably. A working group at the GICHD is
currently engaged in a study of explosive detecting dogs
that is intended to clarify their abilities, effective training
methods and the context in which they can be reliably
used (
15
).
2.4.3. Fragmentation mines
The presence of metal fragments (usually cast-iron or mild
steel) in a fragmentation mine is generally easy to locate
with a metal detector. The common POMZ and PMR frag-
mentation mines are stake mounted. If mounted on
wooden stakes, they will often fall over. On metal stakes,
this is less likely except in soft ground. When still on their
stakes, they can be located by eye. If they have fallen over,
(
15
)At the time of writing, the GICHD working group does not have a dedicated website recording its research into the use of dogs.
There are several relevant papers on the GICHD site, for example, at http://www.gichd.ch/docs/studies/dogs.htm

41
they present a large metal signature to the metal detector.
Bounding fragmentation mines either contain pre-cut
metal fragments inside a metal jacket that may have a plas-
tic outer (as with the Valmara-69), or have thick walls that
shatter into fragments on initiation (as with the OZM-4).
These mines are frequently placed with half of the body
above ground. Their fuze is always exposed. If ground
movement, falling vegetation or floodwater sediment bury
them later, they have a large metal signature that is usually
simple to find with a metal detector.
See Section 2.4.1, ‘Tripwires’, where the use of AP
pressure-initiated mines alongside fragmentation mines is
discussed.
2.4.4. Anti-vehicle mines
Many of the anti-vehicle or anti-tank mines found around
the world are old designs encased in metal (such as the
TM-46 and TM-57). The large steel case and metal fuzes
are generally easy to detect at a reasonable depth even in
magnetic ground. Often, AP pressure mines are used to
protect the outer edge (or every mine) in an AT minefield.
This is intended to discourage the enemy from trying to
breach the minefield by removing or defusing the AT
mines. Conventionally, three AP pressure mines are placed
close to three sides of the AT mine. The fourth side is the
side closest to the defenders and it is left without a mine
so that they can approach the AT mine to maintain the
integrity of the minefield when necessary.
When an AP blast mine is placed close to a large metal-
cased AT mine, a metal detector should be able to dis-
criminate between the two signals and allow both to be
precisely located. If the AP pressure mine is of a minimum
metal type, some detectors are unable to distinguish or
pinpoint the smaller signal (see Section 2.4.2, ‘Minimum
metal mines’).
2.4.5. Detecting deep-level explosive remnants
of war
Explosive remnants of war can frequently become buried
at depths beyond the range of conventional metal detec-
tors. This may be due to natural events that deposit spoil
on top of the devices. More frequently, ERW that have a
‘delivery method’ which involves ground impact can be
deeply buried on arrival. Examples range from mortars
and artillery to air-delivered bombs. Opinion varies over
the average percentage of munitions that fail to detonate
as designed but the authors accept that 15 % is probably
a low estimate.
Most conventional detectors used in demining have a nor-
mal working depth of not more than 20 cm. Optimised to
find small metal objects that are near the surface, they
may find large devices at a deeper level but few can reli-
ably locate a large metal-cased AT mine at depths over
40 cm. When an area is cleared using ordinary metal
detectors, deeply buried ERW will be missed. Those
issuing demining clearance contracts recognise this and

42
specify a depth to which clearance must be carried out. In
magnetic ground, this depth may be as little as 10 cm.
Deeply buried ERW does not normally present a threat to
pedestrians, but does present a threat to heavy vehicles
and to anyone seeking to build on the affected land. It
can also present a threat to farmers who plan to level and
plough the land. As a result, responsible mine action cen-
tres are beginning to deploy ‘deep-search’ teams in areas
where deeply buried ERW presents a high risk. Deep-
search methods are usually only used after conventional
demining methods have declared the area clear. This is
because a detector optimised to search deeply may miss
small metal signatures on or close to the ground surface.
Two categories of technology are commonly used in deep-
search: ‘active’ and ‘passive’ instruments. The distinction
between active and passive instruments is that an active
instrument applies energy in some form to the region of
investigation while a passive sensor makes do with what-
ever energy happens to be naturally present.
Active instruments work on the same principles as those
used in the metal detectors used in conventional de-
mining but have a much larger search-head (coil). The
search-heads can be a metre in diameter. The sensitivity of
a metal detector falls the further away from the search-
head the target is. This ‘range’ is generally about two or
three search-head diameters. Making the search-head
larger increases the maximum detection depth so that a
1 m diameter coil may have an effective range of up to
3 m. But increasing the search-head size also reduces the
sensitivity to small targets because the large coil spreads
the magnetic field over a wide area, which reduces its
local intensity and allows small targets to be missed. So an
active instrument is a conventional metal detector opti-
mised to search deeply for larger metal targets.
Passive instruments are ‘magnetometers’, which measure
the natural magnetic field of the earth. The presence of a
large magnetic object, such as a steel-cased bomb, disturbs
the pattern of this field. Because they rely on magnetism,
they cannot locate non-magnetic metals. The user makes
Figure 2.2:
A fluxgate magnetometer.
The two sensors
of the gradiometer are mounted
at opposite ends of the vertical
black tube.

43
detailed measurements with the magnetometer and infers
the location and depth of any magnetic objects from the
shape of the disturbance, which is referred to as an ‘anom-
aly’. Magnetometers cannot detect plastic mines with only
minimal magnetic content but can detect steel-cased mines
and mines containing steel fragmentation. A magnetometer
may be able to detect large targets at depths of up to 5 m.
The conventional instrument for passive UXO detection is
called the fluxgate magnetometer (
16
). A fluxgate is a spe-
cial material whose magnetisation is very sensitive to the
magnetic field in its vicinity. A small piece is contained
inside the instrument, surrounded by a measuring coil
connected to an electronic circuit.
The magnetometer read-out is usually in the form of a
meter showing positive and negative values in nanotesla
units (nT). The earth’s natural field varies between 25 000
and 50 000 nT, depending on where you are. A good UXO
detector has a sensitivity of about 1 nT, so the anomalies
that it is capable of detecting are extremely subtle.
UXO magnetometers are usually constructed with two
fluxgate sensors connected in opposite directions at either
end of a tube about half a metre or so long. Uniform
fields which affect both sensors equally do not give a sig-
nal. Only fields which are stronger at one end of the tube
than another cause a signal. This arrangement is referred
to as a ‘gradiometer’. Its advantage is that the strong uni-
form background field of the earth is removed, which
makes it easier to show the anomalies.
Also available commercially for UXO detection are alkali-
metal vapour magnetometers (
17
). These instruments
make use of the light spectra of potassium or caesium
vapours, which are very sensitive to magnetic fields. The
authors do not have experience in their use and cannot
comment on their merits with respect to the established
fluxgate technology.
When the magnetic ground disturbance allows a free
choice on which instrument to use, active systems are usu-
ally preferred when searching for ERW that is not very
deep. This is likely to include projectiles from shoulder-
fired weapons, mortars, small- to mid-range artillery, and
cluster-bombs. Passive instruments are the best choice if
the area has been subjected to aerial bombardment or
large calibre artillery (above 200 mm) because of their
(
16
)The fluxgate magnetometer was invented by H. Aschenbrenner and G. Goubau in 1936, and developed by V. Vacquier and, inde-
pendently, F. Foerster. For its history, see http://www-ssc.igpp.ucla.edu/personnel/russell/ESS265/History.html
For more information you may like to contact companies selling fluxgate magnetometers, such as at http://www.foerstergroup.com
http://www.vallon.de http://www.ebingergmbh.de http://www.bartington.com
(
17
)For more information, you may like to contact companies selling alkali metal vapour magnetometers, such as those at
http://www.scintrexltd.com http://www.gemsys.ca

44
increased detection depth. When the required depth of
clearance exceeds 5 m, boreholes can be used to increase
the detection depth.
The most effective method of detecting deeply buried
items is by using geo-mapping and data-logging equip-
ment along with the search instrument(s). This method
can help to eliminate human error caused by an operator
walking erratically and swinging a detector to the right
and left while searching. It can also provide an accurate
record for later analysis and verification. Because the pre-
viously cleared land is safe to walk on during the search,
there is not a need for ‘real-time’ detection.
Geo-mapping involves using a simple assembly to hold the
detector in a level, straight position while it is moved
across the search area. This usually means that it is mount-
ed on a vehicle. The data-logger records the signals. The
search swathes can be either manually recorded or plot-
ted by differential GPS systems for greater accuracy.
Maintaining the detector-head(s) in steady and parallel
lines during the search provides signals that the computer
can readily analyse to construct an image of them that is
very easy to read. Expressed simply, when analysed by com-
puter, the user can often reliably estimate the size and
depth of the object detected (some hand-held operators
claim they can do this accurately, but the claim is not veri-
fied). When looking for large, air-dropped munitions this
information is essential in order to decide how large an area
should be evacuated (for safety) during the excavation task.
2.5. Targets for routine metal
detector checks
The targets used by deminers who want to check that
their detector can find the threat in their area should
match that threat. They may be actual examples of the
mines (that have been rendered safe), substitutes made
using the metal content from the target mines, or simu-
lants that have a similar effect on a metal detector. These
simulants may not have a metal content that copies the
metal in the targets as long as a metal detector reacts
similarly to it.
Figure 2.3 shows the metal content of some common anti-
personnel blast mines. The presence of a number of metal
Figure 2.3:
The metal content of some commonly found mines

45
parts does not necessarily mean that a mine will be easy
to locate even if it is not deeply buried.
The GYATA 64 contains a large firing pin, coil- and leaf-
springs, a circlip, a small piece of chopped lead and a det-
onator. The metal tends to rust and can be far more diffi-
cult to detect after it has corroded than it is when ‘new’.
The R2M2 contains a stainless steel spring and ball bear-
ings than can be very hard to detect. The pin is cut from a
steel sewing needle and is very thin. So it is often only the
aluminium-alloy of the small detonator shell that makes a
metal detector signal.
The Type 72a has two small aluminium-alloy detonator
shells one on top of the other, a steel-alloy pin and small
spring that is part of the arming mechanism. The spring is
made of a metal that may not signal even when held
against a search-head. The pin is above the stacked deto-
nators, so it is that tiny stack that a metal detector must
find.
The only metal in the PMA-2 is the small aluminium-alloy
detonator shell. Fortunately it is usually laid with its pres-
sure ‘spider’ above ground and so the detonator is very
close to the surface.
The PMN has a large firing pin, springs, a piece of
chopped lead and a circlip. It is usually located by detect-
ing the large aluminium-alloy band that clamps the rub-
ber top in place. Metal detectors locate ‘rings’ of metal
more easily than other shapes.
2.6. Real mined areas
The scenarios described in the GICHD ‘Study of global oper-
ational needs’ (see Section 2.1, ‘Types of mined areas’) were
simplified in order to limit the variables to a manageable
number and reach generalised conclusions. They serve the
purpose of the study well, but should not be thought of as
comprehensive. In fact, all mined areas are unique and
present unique challenges and few fall neatly into any one
of the categories the study has adopted. The photographs
in this section are intended to provide readers with an idea
of how varied the demining context can be.

46
2.6.1. Grassland
The three pictures below show deminers working on what
might be defined as ‘grassland’ but each scenario is very
different.
Mined area ‘A’ shows the
clearance of a border minefield
in Africa.The long grass is a
small patch in dense bush.
The mined area stretches
hundreds of kilometres and
passes through terrain from
mountains to jungle.
Mined area ‘B’ shows clearance
in the garden of houses inside a
city in the Balkans.
The clearance was complicated
by burned out vehicles, possible
booby traps and the discovery
of corpses.
Mined area ‘C’ shows glassland around a pylon
in Afghanistan. Unusually for Afghanistan, the
ground was saturated and unstable.

47
2.6.2. Woodland
The nature of ‘woodland’ varies significantly according to
your geographic location. The density of plant growth is
perhaps the most obvious variation but some plants are
also very fibrous and difficult to cut — and some wood-
land is the habitat of snakes and other dangerous
wildlife.
As the GICHD study recognised, demining in these two
environments are very different activities for many
reasons other than the variation in vegetation but the
vegetation variation is also significant.
Mined area ‘A’ shows woodland in the Balkans.The undergrowth
between the trees is relatively low.
Mined area ‘B’ shows woodland in southern Africa. The undergrowth
is dense and matted.

48
2.6.3. Open hillside
An ‘open hillside’ may imply the absence of an under-
growth problem but this may depend on the time of year,
and also on what is thought of as ‘open’. In some areas,
the term ‘hillside’ may also imply a need for the deminers
to have climbing skills.
Any description of a landscape is to some extent subjec-
tive. Our description of the road bridge in ‘D’ as ‘heavily
overgrown’ might be challenged by someone working in
a jungle area.
Mined area ‘A’ shows a hillside in the Balkans.The mined area crossed
the hills but additional mines were placed in the gully where attackers
might take cover.
Mined areas ‘B’ and ‘C’
show deminers working on
open hillsides in
Afghanistan.
Picture ‘D’ shows an open hillside in Africa. The heavily overgrown
road bridge has been mined and the suspect area extends among the
baobab trees where goats are allowed to graze.

49
2.6.4. Unsurfaced roads and tracks
If a route is defined as including 10 m on both sides of the
road (as it was for the GICHD study) the variation in what
this can actually involve is as varied as mine-clearance itself.
(
18
)Photograph reproduced courtesy of Menschen gegen Minen (MgM), a German demining NGO.
(
19
)Photograph reproduced courtesy of Menschen gegen Minen (MgM), a German demining NGO.
Mined area ‘A’ shows a rough
dirt road running through dense
bush. Clearing the sides took
far longer than clearing the
road.
Mined area ‘B’ shows a
dirt road near the coast
where the ground is
sandier and the
undergrowth less dense.
A mine is just visible in
the picture (lower right).
Mined area ‘C’ (
18
) shows a dirt road that is mined and has been
abandoned but is still used as a path. The belief that a person could not
set off an anti-vehicle mine is very common but not always true.Anti-
personnel mines are sometimes placed on top of an anti-vehicle mine.
Mined area ‘D’ (
19
) shows a dirt road that is being reclaimed by
undergrowth. This is common and dirt road clearance can be
complicated by difficulties locating the original route of the road.
In extreme cases, the route is located by aerial survey.

50
2.6.5. Surfaced roads, railway tracks
Surfaced roads and railway tracks are part of a country’s
infrastructure that can be high demining priorities, along
with power lines, bridges, dams, airports, etc. The varia-
tion in condition of the roads or railway lines can make it
impossible to make general assumptions about the clear-
ance that work worldwide.
(
20
)Photograph reproduced courtesy of Menschen gegen Minen (MgM), a German demining NGO.
Picture ‘A’ shows a broken
road surface. Mines are
often concealed in the
potholes. They may also be
concealed under the thin
tar by melting areas and
putting the soft tar back on
top of mines.
Picture ‘B’ (
20
)
shows a surfaced
road that has
become so
damaged that it
cannot be
traversed in an
ordinary vehicle.
Picture ‘C’ shows a railway line.
Clearance is complicated by the
presence of wrecked carriages
and by the fact that the line has
been turned upside down, then
booby-trapped.

51
2.6.6. Urban (town or city)
Urban mined areas vary dramatically from town to town
and country to country.
Mined area ‘A’
shows a suburb of
a Balkan city.
The building has
been booby-
trapped to prevent
the return of the
people who lived
there.
Mined area ‘B’ shows a building in an abandoned part of an African
city. Undergrowth is now a real problem for the deminers.The building
is not booby-trapped but there are unexploded munitions around and
the area around the building has been mined.
Picture ‘C’ shows a suburb in the
same city where unexploded
munitions are lying within metres
of houses among rat-infested
refuse. The difficulties deminers
face are very different from those
in the Balkans.
Picture ‘D’ shows a pile of
ordnance in the foreground. The
munitions have been moved by
people anxious to rebuild after a
conflict has ended. On this site,
some people have built alongside
the mined area and over the top
of munitions.

52
2.6.7. Village
In different countries, a ‘village’ may mean anything from
a group of stone houses with street lights and tarred
roads to a cluster of reed huts.
Mined area ‘A’ shows the edge of a rural village in Africa.The
suddenly dense undergrowth marks where a defensive minefield was
placed. This village is still occupied and the mined area is used as a
rubbish dump.
Mined area ‘B’ shows a village of brick and concrete that has been
abandoned and so has become heavily overgrown.
Mined area ‘C’ shows mine
clearance in a village in Cambodia.
The village is occupied and the
deminers have to work around the
children and the chickens.

53
2.6.8. Mountain (high altitude, steep gradient)
Terms such as ‘steep’ and ‘high altitude’ allow a good deal
of latitude depending on which country you are in.
Mined area ‘A’ shows a
mountain gorge in Afghanistan
where the road was defensively
mined. The area around the road
was actually quite readily
accessible, but deminers did
have to change the way that
they worked in order to clear
safely in a confined space.
Mined area ‘B’ shows a
mountainous area in the
Balkans. The mountains are not
quite on the scale of those in
Afghanistan. The area being
cleared is not on the steep
slopes, but it was still called
‘mountain clearance’ locally.
Mined area ‘C’ shows demining
on what the Afghans call a ‘hill’
but would probably be called a
‘mountain’ in most other
countries.

54
2.6.9. Desert
Deserts are not only rolling sand dunes sculpted by the
wind — although these do pose special problems in de-
mining because the depth of devices can vary overnight.
Most areas of desert that are prioritised for clearance are
used by people, so they are not entirely inhospitable.
Mined area ‘A’ is high in the mountains and the ground is not sand,
but baked clay. The site is hard to get to and the ground is too hard to
safely excavate.
Picture ‘B’ shows a
common post-war
problem, whether in the
desert or the jungle. The
abandoned tank contains
a variety of ammunition
and may be booby-
trapped. Deminers have to
clear around and inside it
before it can be removed.
Sometimes abandoned
military assets also
contain corpses that must
be removed and disposed
of with dignity.
Mined area ‘C’
shows another
problem that
deminers may find
in remote areas of
deserts. A nomad
family has camped
in the suspect area
and the deminers
must try to
encourage the
family to move
before starting
work.

55
2.6.10. Paddy field
A paddy field is usually part of a water management sys-
tem that allows fields to be flooded in sequence. Because
the land is regularly and deliberately immersed, mines
inside the paddies can be especially difficult to clear.
When the paddy is underwater, demining cannot be con-
ducted. When the paddy is drained, it often dries to hard
clay very quickly, so complicating the safe excavation of
any metal detector signals.
Mined area ‘A’ shows paddies that are in use, but some of the walls
between them are believed to have been mined. The walls are used as
paths.
Mined area ‘B’ shows a road flanked by paddy fields. Mines were
placed close to the trees to prevent sneak attacks on the village
beyond. Notice the crude bridge made using rough timber. No heavy
vehicle could cross that without it breaking.
Mined area ‘C’ is among the
terraces on the right of this
picture. The terraces are all
paddy fields and the picture
illustrates the way that paddy
fields are not all on low ground
or close to rivers.

56
2.6.11. Semi-arid savannah
Defined as having little vegetation, the circumstances that
deminers face in arid grassland can also be very varied.
Mined area ‘A’ is an area of
sparse grassland that was
mined to prevent the movement
of tanks across it. The ground is
very hard and stony, and the
grass never grows more than
20 cm high. The small bush that
can be seen to the right of the
deminer’s head is very tough
and can only be easily cut using
wire-cutters.
Mined area ‘B’ is an area of arid grassland around the base of power
lines which were mined to prevent attack. The deminer is checking
how the sensitivity of his detector is affected close to the
electromagnetic lines.
Mined area ‘C’ shows the same
power line. Each pylon was mined,
and some areas between them
were also mined.
Picture ‘D’ shows a termite mound
close to the pylon shown in ‘C’.
These are common obstacles in
some countries. In many places,
deminers have to cope with biting
insects and venomous snakes.

57
2.6.12. Bush
‘Bush’ is the term used throughout Africa for the light for-
est that covers a significant proportion of the continent. It
usually comprises well-spaced trees without dense under-
growth beneath. The height of the trees depends on the
rainfall and the soil quality.
Mined area ‘A’
shows bush on the
approaches to a
reservoir. The area
was mined to
prevent attacks on
the water supply.
Mined area ‘B’ is part of a border
minefield. It shows how conditions in
the bush vary according to the season
— and also the way that wildlife may
find sanctuary in mined areas. The
presence of a healthy giraffe does not
prove the area is safe, the bones of
less lucky animals are further inside
the minebelt.
Mined area ‘C’
shows an area
where bush has
been reclaiming
farmed land for 20
years. The deminer
has just cut the
small tree he is
carrying out of the
way. When bush is
growing up, the
area between the
trees tends to be
densely overgrown.
Mined area ‘D’ was taken further along the border in the same
minefield as picture ‘B’. The land in these areas is often very irregular,
including ravines and massive obstructions like these boulders.

The first metal detectors to be used as mine-detectors were
developed for the military. Following military custom, a
written instruction was produced for their use and this pro-
vided a ‘standard’ for the users. Since then, other ‘standards’
for metal detector use have been developed by organisa-
tions that use detectors in their work (such as police, cus-
toms and security organisations). The most comprehensive
of these ‘standards’ cover design and manufacturing fea-
tures as well as performance specifications/expectations.
3.1. International standards for metal
detectors
In recent years, a need for a metal detector standard that is
relevant to humanitarian demining has been recognised.
This need became urgent as detector manufacturers began
to offer products with widely varying capabilities. Today’s
purchasers need independently derived and universally ap-
plied ‘benchmarks’ to help them select which metal detec-
tors to buy.
Because military forces can be directly involved in breach-
ing through minefields, some of their needs are shared
with HD, so the existing standards of most immediate rele-
vance to HD are those used by military forces. The standard
documents in this area are the National Institute of Justice
(NIJ) Standard 0602.02 (September 2000), and Performance
Specification MIL-PRF-23359H (November 1997). The latter
has been widely adopted/adapted for use by the armed
forces in countries other than the United States. The ‘Inter-
national test operational procedures standards’ (ITOP) was
another document adopted in 1999 by France, Germany,
the United Kingdom and the United States. The Perfor-
mance Specification MIL-PRF-23359H and its variations all
include a detailed specification of military needs that in-
cludes many elements that are of no relevance in humani-
tarian demining. For example, there are general require-
ments that the detectors have a ‘camouflage’ colour, that
they be hardened against nuclear, biological, chemical
(NBC) agents, and that they operate without visible or au-
dible emissions. Some performance specifications are not
only unnecessary, but are inadequate for HD. For example,
the MIL standard states that a detector should ‘have a
greater than 92 % probability of detecting standard metal-
lic military mines … and mines containing small metallic
content’. This level of detector performance is inadequate
for HD. Also, the scope of the MIL standard does not cover
the many variables that affect detector performance so
Chapter 3: Detector standards and detector
test standards
59

60
does not lend itself to adaptation for HD purposes. Simi-
larly, the ITOP (which has been adopted by NATO) defines
detection standards and testing requirements from a mili-
tary perspective that is only partially applicable to HD and
cannot be readily adapted.
The UN’s International Mine Action Standards include a
standard for the ‘Test and evaluation of mine action
equipment’ (IMAS 03.40), which outlines basic principles
for test and evaluation techniques. Being a document
with wide applicability, it does not provide specific con-
tent of relevance to testing and evaluating metal detec-
tors, but it does provide a basic template that could be
used to build a standard.
3.2. International standards
for metal detectors
in humanitarian demining
When this book was in preparation, the first agreement
over standards for metal detectors in HD was reached.
The process began when the European Commission man-
dated the European Committee for Standardisation (CEN)
(
21
) to make progress in standardisation within humani-
tarian demining. In response, CEN BT/WG 126 was estab-
lished. WG 126 recommended that CEN workshops should
be established to work on the test and evaluation of both
metal detectors and mechanical equipment for use in HD.
The international test and evaluation programme (ITEP)
(
22
) also requested a CEN workshop on metal detector
testing and evaluation.
Before European standards are formally adopted, they
must go through a ratification process that can take sev-
eral years. However, a CEN workshop agreement is similar
to a ‘draft’ standard and can be used pending achieve-
ment of a formal European standard. Any European stan-
dard on metal detectors that is produced may or may not
be based on the CEN workshop agreement.
The UNMAS has agreed to reference the CEN workshop
agreement in its IMAS.
Adoption of the CEN workshop agreement will allow test
and evaluation of metal detectors in HD to be made in an
internationally standardised way. Like IMAS documents,
the agreement will be subject to revision over time. The
early adoption of this agreement allows purchasers to
understand better what they are buying and this should
increase safety by ensuring that deminers are using the
(
21
)The CEN is the European standardisation organisation that establishes common standards for industry and science and of which
almost all European countries are members.
(
22
)The ITEP develops standards for testing and evaluating all kind of humanitarian demining equipment.

61
best tools for the job. The CEN agreement also provides
manufacturers with procedures that make it easier for
them to evaluate their own products. CWA 14747:2003
(the agreement from CEN workshop 07), was formally
published on 18 June 2003 (
23
).