Mine Clearing Technology

Introduction to

ABSTRACT

This paper presents the technologies and methods developed

for mine clearing operations currently used by the military and

humanitarian demining organisations. In any mine clearing

operation, the operating environment and the type of threats

are never the same. Thus, a single method or type of equipment

rarely constitutes the most successful means of resolving the

problem in terms of time, cost and effectiveness; a combination

of tools is more commonly employed to ensure a successful

mine clearing mission. This paper aims to give an introduction

to and appreciation of the key mine clearing methods and

equipment, and the key differences and considerations for

military and humanitarian operations. The common methods

of demining such as manual demining, explosive mine breaching

and mechanical demining will be discussed. The design

considerations for mine flails on mine clearing vehicles will

also be presented.

Tan Chun

Gary Wong Hock Lye

Bryan Soh Chee Weng

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INTRODUCTION

History of Mines

Mines, derived from the Latin word ‘Mina’meaning ‘vein of ore’ was originally used todescribe the digging of minerals from theearth. Over time, it has become a term usedby military engineers to denote the explosivesthey lay in the ground during battles.

Mines were first used in third B.C. in the formof non-explosive metal spikes laid in the earthas a form of defensive tactics. In the 14thcentury, the world ushered in the arrival ofexplosive mines which are commonly foundeven in modern times. The basic design of themines was usually simple explosive matterburied with debris or metallic pieces that wereto be used as fragments during an explosion.

Mines became a regular feature of warfareonly in the 19th century. It was in 1918 thatmines first became used on a large scale as aneffective means against the assault tanksintroduced then.

Since then, mines have become a new threatin war, which also meant that a solution hadto be developed against them. Thus, thissparked the development of various mineclearing techniques.

NEED FOR MINECLEARING

By World War Two (WWII), mines had evolvedto perform two major functions: to kill andmaim personnel, or to destroy and disabletanks and vehicles. The US Army recorded that2.5% of fatalities and approximately 21% oftank losses of WWII were mine-related.

In addition to WWII mines, an estimated 400million mines have been laid in various conflictareas since then.

Despite the initial development of mineclearing concepts as a form of countermeasureagainst mines during wartime, the real needfor mine clearing usually begins after the endof hostilities. This is attributed to the verynature of why mines were laid in the first place– to deter access to and use of land. Mines laidduring conflicts are rarely removed at the endof the conflicts due to the lack of proper minemaps, markings, loss of such maps and markingsor changes in mine location due to soil shifts.Unlike soldiers, mines do not recogniseceasefires and treaties or differentiate betweenfriends, foes or civilians. Mines continue to dotheir job even years after the end of a conflict.

To this day, there are up to 65 countries stillafflicted by mine threats from past conflicts,with the worst regions being Angola, Namibia,Mozambique, Somalia, Ethiopia, Eritea, Sudan,Croatia, Iraq, Afghanistan, Russia, Cambodiaand Vietnam. On average, there areapproximately 70 injuries and death from minesevery day. It is this threat posed by mines thatplaces extreme risks on the civilian populationwho return to the land after a conflict.

The problems caused by active minefields donot end here. There are also socioeconomiceffects as fertile lands are not available foragriculture, roads are not accessible and landcannot be cleared for industries. Theseeventually lead to continued poverty andfamine in the affected areas. Thus, despite thehigh cost of humanitarian demining efforts,Mine Action Co-ordination Centres supportedeither by the United Nations (UN) or hostcountries have been set up in differentcountries to drive the demining efforts.

TYPES OF MINECLEARING METHODSAND EQUIPMENT

The estimated cost of clearing a mined areaof one square kilometre is about US$1 million,whereas it takes only a few dollars to acquire

Mine Clearing Technology

Introduction to

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a mine. Thus, the search has always beenongoing to find a more effective solution formine clearing. In this section, the types of mineclearing methods and equipment will bediscussed.

Manual Demining

Manual demining is the most commonly usedmeans in humanitarian demining. It is also theonly recognised method of demining that isable to achieve the 99.6% clearance raterequired by UN standards. Its main function isto detect and locate mine locations fordeactivation or destruction in the later stages.It consists of the use of manual proddingmethods, use of detectors such as metallicdetectors and even animals.

As the name suggests, this is also the mostlabour-intensive and costly method whichrequires a large amount of human effort andspecialised training. In the case of manualprodding and metal detection, large numbersof people from the local population areemployed to work through a selected piece ofland with personnel protection kits and selectedtools (see Figure 1). Although the method iseffective, it is one of the slowest ways ofclearing a piece of land. The progress ofdemining is either hampered by high falsealarm rates due to instances of metallic objectsin the ground or by deeply placed metal mineswhich are hard to detect. Recent developments

include the introduction of Ground PenetratingRadars. Although more effective, thetechnology has its fair share of drawbacks interms of high false alarm rates.

Manual demining also creates a socioeconomicbenefit for the population of the area as itcreates a large number of jobs for people whoare usually living below the poverty line. Thesejobs eventually enable the local population toslowly rebuild their lives.

In the case of mine detection using animalssuch as dogs and rats (see Figure 2), the animalsare carefully trained to detect the explosive

Figure 1. Manual deminer with body armourusing prodding tool

Figure 2. How a mine dog is deployed to detect mines

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substances from the mines (RDX1 or TNT) andto react in a prescribed manner when theypinpoint the location of the mine. Theeffectiveness of using animals is limited by thetraining they undergo and the duration theycan be deployed in the field. Without sufficienttraining, the effectiveness of the method canbe greatly reduced. Effectiveness is also reducedif the animal is deployed in the field for toolong, as fatigue may also affect its ability todetect.

Use of Explosive Charges inDemining

In essence, the use of explosive charges indemining is usually limited to the destructionof the mines after they have been detectedthrough more traditional means such as manualdemining.

But in the arena of military operations, itprovides a fast and effective way to create apath for vehicles or men through a minefield.This is often referred to as ‘breaching’.

The main underlying concept of this methodis the deliberate triggering or destruction ofmines within the section route or area throughthe introduction of massive blast waves createdby an explosion. The same blast wave will alsoact to trigger any Improvised Explosive Devices(IED) within the selected area.

Although the same concept is employed,different types of equipment have beendeveloped to create this capability. Whatdifferentiates them from one another is usuallythe breadth and length of the cleared paththat is created. Some more common forms ofexplosive charges used are bangaloretorpedoes, man-carried or vehicle-mountedline charges (see Figure 3). The more modernapproach would be the use of vehicle-launchedfuel-air explosive bombs.

Mechanical Demining

Mechanical demining methods deployed sinceWorld War One (WWI) includes the use of tillersystems, mine rollers, mechanical excavation,mineploughs and mine flails. Although themain concepts have not changed much overthe years, the technology behind them has.Recent developments on mechanical demininginclude the use of remote control systems whichallows remote operations of the equipmentfrom as far as 5km away. Additional armourto protect the operator cabin, improved cabindesigns to improve crew survivability andsystem designs to overcome the traditionallimitations of mechanical demining methodshave also been developed.

Although developed initially for militaryoperations, some mechanical deminingmethods have been used in humanitariandemining operations. The advantage of usingmechanica l demining methods forhumanitarian purposes is the ability to clearlarge amounts of land quickly. However, thereare doubts on its effectiveness and ability toachieve the 99.6%2 clearance rate required.Thus, a secondary method is usually employedto validate the cleared land. The followingsection will briefly describe the functions anddesign of each mechanical demining method.

Figure 3. A Cobra Projection Line charge usedby combat engineers

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Tiller Systems

Tiller systems (see Figure 4) are generallypurpose-built systems designed for destroyingmines or Unexploded Ordnance (UXO). Due tothe nature of their operations, they are usuallyheavy and large in size. Substantial power isrequired to operate the heavy tiller drum aswell as the prime mover, which is most likelya tracked vehicle. The tiller system employsthe use of rotation drums fitted withoverlapped teeth or bits that would grind upthe ground in accordance with the depth they

are required to dig. Mines or UXOs wouldeither be destroyed or activated through directcontact with the teeth of the rotating drums.

Key issues with the tiller system are thepossibility of burying the mines deeper belowthe tiller due to the downward force of thedrum and the collection of mines in the ‘bowwave’ (see Figure 5). The bow wave is thecollection of loose soil in front of the drumcaused by the forward movement of the drum.The tiller system has also been reported tohave lower effectiveness in soft and rock-stewed soil.

Anti-Mine Rollers

One of the older mechanical deminingmethods, the anti-mine roller was first deployedin 1914 on the British tanks. It has been adaptedfor humanitarian purposes over the years.

Although a typical anti-mine roller would bemounted on a modified tractor or wheel loaderand made to run over selected areas todeliberately activate mines that are live andin serviceable conditions, most anti-mine rollersused in humanitarian demining are not capableof surviving an anti-tank mine blast. As such,careful surveying of the ground is necessaryprior to their application. A key issue with themine roller is its inability to deal withunserviceable and serviceable mines that mightbe buried too deep.

Figure 4. The tiller drums of the Rhino system

Figure 5. An example of a mine “surfing”on the bow wave

Figure 6. M1AI equipped with mine roller

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Mechanical Excavation

Mechanical demining employs the use ofvarious machines to enable the removal of soilfrom suspected areas for inspection of minesand UXOs. Soil is sent for processing via sifting,manual inspection or crushing to identifyunexploded ordnance, which in turn will besent for disposal by the Explosive OrdnanceDisposal (EOD). This method enables soil to becleared to depths that may not be reachableby tillers, flails and mine rollers.

Equipment used in mechanical excavation istypically construction machines installed withmine blast protection and additional armourin the cabin to protect the operator. Suchequipment includes tractors, front-end loaders,bulldozers, excavators and soil sifters. In orderto further protect the equipment, larger UXOor anti-tank mines are identified by metaldetectors for separate disposal.

To date, there is no known critical drawbackof the method as long as appropriate safetymeasures are taken.

Mineploughs

Similar to anti-mine rollers, mineploughsoriginated from military applications. One ofthe earliest applications of mineploughs wasin WWII where they were mounted on Churchilland Sherman tanks as part of the assault onNormandy. The mineplough was used as a‘softer’ approach to mine clearing as unlikethe flail, it does not create large columns ofdust and craters from destroyed mines. Themineplough works by moving a speciallydesigned shovel just below the surface of thesoil in order to plough up mines and push themto the sides of the path created.

The concept of employing the mineplough infront of an armoured vehicle has not changedover the years. As it is still a quick and effectivesolution for creating a vehicular path across adeep minefield, many variants of modern-daymain battle tanks (MBT) are still fitted withthe mineplough system.

Today, the depth of clearance can be variedthrough hydraulic controls and vehicles can beoperated remotely increasing the safety levelfor the operator. One of the most widely usedmineplough systems today is the Pearson FullWidth Mineplough system which can be easilyadapted to various platforms without extensivemodifications.

Figure 7. The Hydrema M1100 excavator withan armoured cabin which can be attached

with different tools for mechanical demining

Figure 8. A mechanical sifter which can beattached to a commercial mechanical

demining machine

Figure 9. A Bullshorn mineplough mounted ona WWII Sherman Tank

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The key issue with the mineplough is thepossible collection of mines that are pushedto the sides of the path. As the mines are rarelyactivated by the mineplough, secondary meansof ordnance disposal must still be in place andthus, the mineplough has not been adaptedfor humanitarian uses.

Mine Flails

Mine flails were also first developed for militaryapplications and were famously used in WWIIwhere they were fitted on Sherman tanks. TheSherman tank flails are known to be veryeffective and played an integral role in theinitial shore invasion in Normandy.

With the growth of humanitarian deminingin the 1990s, flail systems were developed tomeet the demand for tools against mines andsmall UXOs. In the Singapore Armed Forces(SAF), the Hydrema MCV 910 Series 2 has beenin service since 2005. The SAF, DSTA andSingapore Technologies Kinetics have jointly

developed and built a Tracked Mine Flail whichoffers more protection to the crew andexceptional mobility performance over othercommercial off-the-shelf mine clearing vehicles.The Tracked Mine Flail features a fullyautomatic deployable flail system and theworld’s first hydrostatic tank transmission forboth creep and normal mobility.

Conceptually, most flail systems utilise the sameconcept: a drive system, an extended arm, arotating drum and chains with weights at theends to provide the pounding force. The forceof the swinging hammer is transferred ontothe ground upon impact. It is this same impactforce that either causes the mine to detonateor shatter.

Each flail system is different in terms of clearingspeed, clearing depth, survivability and clearingeffectiveness. The next section will cover anin-depth discussion of the design considerationsfor mine flail systems.

Figure 10. The mine clearing vehicle (Hydrema MCV 910 Series 2)Source: Army news (April/May 2006)

Figure 11. Tracked Mine Flail System

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DESIGN CONSIDERATIONSFOR MINE FLAIL SYSTEMS

The key components in the design of mine flailsystems are as seen below:

Blast Protection

Blast Shield

Modern mine flails operate with the flail infront of a blast plate system. This blast platedeflects the blast wave and also acts as aprotective layer between the mine explosionand the operator. In some cases, the blast shieldcovers the flail circumference to also preventthrow-out of mines that are not destroyed bythe initial impact of the flails.

Blast shield strength and thickness are mainlydetermined by the threat the flail is designedto meet and the blast shield’s angle ofinclination. Finite Element Method studies aremade in accordance with the expected threati.e. amount of explosives in the mines andquantity of mines to defeat before inspectionand repair to determine if blast shield designscan cope with the blast pressure andfragmentation damage. Actual blast trials areconducted to verify and correlate the stresseson the blast shields with the theoretical results.

Protection of the Cabin AgainstAnti-Tank Mine Fragments

Although the blast effect of a mine is supposedto be contained by the blast shield, there isalways a risk of the vehicle going over a missedmine. In order to protect the operator frompossible fragmentations in a mine explosion,the cabin is required to be suitably armouredfor crew protection.

Protection against Loss of StructuralIntegrity and Lift

The impact of the blast overpressure affectsthe platform in two different situations. Oneis during the detonation of mines by the flailand the other during the detonation of missedmines under either one of the wheels or tracks.

Figure 12. A Finite Element Method study made on ablast load case on a blast shield design

Figure 13. Fragmentation damage from ananti-tank mine with 4.45kg TNT

Figure 14. The blast shield from the Hydrema910 Series 2 – the flexible flap at the top of theshield deflects the blast wave over the cab without

sustaining damage from the blast wave.In addition, the tilted angle of the flap helps

to recirculate dust in blast shield duringflailing operations.

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Fringe Levels

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It is extremely important to ensure thestructural integrity of a vehicle against mineattacks. When a mine detonates under thevehicle and should the vehicle belly rupture,the blast energy from the mine explosion wouldcause an overpressure in the cabin. The suddensurge of pressure would injure the unprotectedear and other gas-filled organs e.g. lungs ofthe operator. The physical limits foroverpressure are 200Pa for the ears and 19KPafor the lungs and intestines.

Therefore, to protect the vehicle from mineattacks, forces from the mine blast energyshould either be deflected or absorbed toprotect the vehicle belly from being rupturedespecially at the weld joints. To deflect theforces, a V-shaped hull design can be used suchthat impact forces are deflected off the sides

of the undercarriage of the hull. To absorb theforces, a deflection budget or a sacrificial blastshield can be designed into the hull such thatthe forces are intentionally absorbed withoutcausing damage to the main hull. In thesecases, the deflection budget and the blastshield are usually designed such that they canbe easily replaced.

The usage of V-shaped hull design, deflectionbudget and blast shields are also designfeatures that prevent ‘lift’ i.e. overpressureforces that act on the impact point causing thevehicle to be lifted off the ground. The suddenlifting of the vehicle can lead to acceleration-related injuries on the foot, ankle and spinalcord of the operators. In severe cases, it mayflip the entire vehicle.

Figure 15. An example of adeflection budget

Figure 16. How lift affects a vehicle

Figure 17. The limits of acceleration exposure prior to injury

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Flail System

In our technical evaluation of mine clearingvehicles and the Design Test and Evaluation ofthe Tracked Mine Flail, we conclude that thereare basically four modes by which a mine flailcan neutralise the mines. This was derived fromextensive testing of the mine clearing vehiclesin various terrain and conditions.

In the simplest mode, the chains and strikers(or hammers and weights) of the flail strikethe activating plate of the mine and detonatethe mine. Mine flails have a typical strike forceof more than 1,000kg and it is more thansufficient to set off the mines which typicallyrequire 150kg to 200kg. However, when a minedetonates under the flail, there may be damageto the flail system and immediate repairs arerequired before further operations.

In the second mode, given the strong strikeforce and intensity of newer flail systems, themines can be smashed into pieces. This is thedesirable mode of defeating the mines as theleast damage will be inflicted on the flailsystem. However, the debris which consists ofexplosives and detonators can still be a threatto unprotected personnel.

In the third mode, the mines are partiallydamaged but not smashed in the less drasticcases. The chances of damaging the firingmechanism when the mines are partiallydamaged are very high. Such mines are alsoconsidered neutralised as they cannot deliverthe full impact of the charges.

Lastly, the flailing is essentially a diggingoperation and mines may get thrown up duringflailing. However, only mines thrown off thepath of the flailing are considered neutralised.

The modes of neutralising the mines are alsodependent on the types of mines. For singleimpulse actuated mines which were commonlyused during WWII, the flail is capable ofdetonating them. For newer anti-shock andanti-flail resistant mines, the other three modes

i.e. destruction, neutralisation and throwingoff are more common.

There have been limited studies made on therelation between flail effectiveness and groundconditions. Thus, when an area is set to becleared, it is compulsory for flail operators toperform a test flail to determine the settingsof the system. Through comparison of testresults from local trials, Swedish EOD &Demining Center and Croatia Mine ActionCenter reports, DSTA engineers derived thatthe effectiveness of the flail is a function ofthe power pack output, flail width, groundcondition and creep speed i.e. speed of vehiclemovement during flailing. The powerpackneeds to be suitably sized in accordance withthe flail width required. Generally, theacceptable power output to flail width ratiois between 50HP to 60HP per metre of flailwidth.

In a given test environment, where the groundconditions are unknown, a test flail must beperformed to obtain the creep speed foroptimal flail performance. The depth of theflailing is measured to ensure that there issufficient dig depth to defeat the mines. Inour local trials, extensive testing using the MCVto determine the optimum flailing performanceon different types of terrain was conducted.With this relationship between flailperformance and terrain established from ourtrials, we can calculate and estimate theperformance of other mine clearing equipmentwithout local testing and this saves considerabletime and cost during the evaluation of thisequipment.

Other Enhancements

Additional enhancement systems are availableto improve the operating capability of the flailsystem. They are as follows:

• Lane marking system allows marking out offlail path to demarcate safe zones to travelin. This is more commonly used as a militaryapplication in breaching operations.

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• Slow clearing speed – For militaryapplication, the slow rate of clearance viamost mechan ica l means (exceptmineploughing) means that the system isoften exposed to enemy fire.

• Intelligent mines – In military applications,a mine field may not just be filled byconventional mines that are detonated viapressure or magnetic means. There areintelligent mines such as off-route mineswhich use thermal, seismic, or magneticsensors or a pressure sensitive wire laid acrossthe road to detect vehicle movement. Oncea vehicle is detected, a rocket or otherammunition hidden alongside the road isfired at the vehicles. The more advancedversions can not only differentiate betweena tank or other class of armored vehicle, butcan even decipher friend from foe as wellas between models such as the T-80 andT-72 MBTs. With ranges up to 100m,mechanical demining tools would have littleor no protection against them.

• Remote control system allows the remotecontrol of the entire system from as far asa five-kilometre line of sight. This enablesthe operator to operate in high-risksituations without endangering his life.

• GPS position logging systems log the pathcleared by the flail system. The same datacan be transferred to a digital map forconfirmation of the areas that have beencleared.

Challenges for Mechanical MineClearing Systems

Although a large number of mechanical mineclearing systems has been developed toimprove the process of demining, manyavailable systems are still unable to cope withthe following challenges:

• Steep, undulating terrain – As mechanicaldemining requires ground contact to beeffective, the presence of undulating terraincan cause ‘skip zones’ where eitherinsufficient pressure or impact was appliedonto the ground. These skip zones remainas potential mined spots within a clearedarea unless a secondary means is used tovalidate the land.

• Defective mines/mines with delaycharges – The risk comes when the minedoes not detonate during the initial contactwith the mechanical demining system. Thedetonation may only be activated secondslater or when the wheel/track pressure isexerted on the mines. This places theoperator in danger as the blast detonationmay only come after the passing of the blastshield.

• Shaped charge mines – Unlike normal mineswhich cause damage through the transferof overpressure forces and fragments, shapedcharges mines have the capability of piercingthrough the majority of the armourprotection on mine clearing platforms.

Figure 18. A German Parm 1 off-route mine

REFERENCES

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Axelsson H. 8 January 2003. Mine ClearingVehicles Crew Safety Standard, SwedishDefence Material Administration. Retrievedfrom http://www.itep.ws/

Bishop, C. The Encyclopaedia of Weapons ofWorld War 2, pp 54-59.

Dutch Ministry of Foreign Affairs. MineClearance – Policy Framework for humanitarianmine action. Retrieved on 11 July 2008 fromhttp://www.minbuza.nl/en/developmentcooperation/Themes/HumanitarianAid,mine-clearing

Geneva International Centre for HumanitarianDemining. Which areas are affected bylandmines? Retrieved on 11 July 2008 fromhttp://www.gichd.org/mine-action-and-erw-facts/faq/countries-affected/

Geneva International Centre for HumanitarianDemining, GICHD. (May 2004). A Study ofMechanical Application in Demining, pp 9-41.

CONCLUSION

This paper has discussed the different toolsand concepts employed for demining. Despitethe wide variety of equipment developedagainst mine threats, there is no single methodor tool that is truly a perfect match for allsituations. Careful surveying and situationalassessment are still required to determine themost effective solution for each situation.Further improvement of existing tools mightbe a way forward but the cost of doing so maysimply be beyond the means of those whoneed them. The collaboration of two or moreindependent tools, each operating using itsdistinct detection and clearing method, mightbe a better and cost-effective solution toachieve a more thorough mine clearingperformance in the long run.

Hameed, A. February 2008. Attack of Armourand IEDs. Singapore FVD course presentation,pp 21-34.

History of landmines. (1998-2006). InternationalCampaign to Ban Landmines. Retrieved on 11July 2008 from http:/ /www.icbl.org/problem/history

Paul Hubbard & Joseph Wehland. July 1997.Goliath: Landmines, the Invisible Goliath.Ret r ieved on 31 Ju l y 2008 f romhttp://library.thinkquest.org/11051/history.htm

Schneck, W.C. (July 1998) Origins of militarymines: Part 1, pp 1-7. Retrieved on 11 July 2008f r o m h t t p : / / w w w. f a s . o r g / m a n / d o d -101/sys/land/docs/980700-schneck.htm

Theimer, T. 15 January 2001. MCV MechanicalMine Clearing Report Land Clearance Testfacility WTD 51 Identification Number 235014390. Retrieved from http://www.itep.ws/

1 RDX (Cyclotrimethylenetrinitramine) and TNT(Cyclotrimethylenetrinitramine) are explosivesubstances widely used in military and industrialapplications.

2 All UN-sponsored clearance programmesrequire the contractor to achieve the agreedstandard of mine clearance of 99.6% to a depthof 200mm.

ENDNOTES

Tan Chun is a Principal Engineer and Programme Manager (Land Systems).He has many years of experience in managing projects in the areas of militarybridges, mine clearing vehicles, engineering plants and light sea vessels. Heobtained his Bachelor degree in Mechanical Engineering from the NationalUniversity of Singapore (NUS) in 1993. In 2001, he obtained a Master ofScience in Military Vehicle Technology from the Royal Military College ofScience, United Kingdom.

BIOGRAPHY

Gary Wong Hock Lye is a Senior Engineer (Land Systems). He is currentlyinvolved in the acquisition management of combat engineer systems for theArmy. Gary is also involved in the development of mine clearing vehicles. Hegraduated with a Bachelor degree in Mechanical Engineering in1999 and obtained a Master of Engineering in 2002 from NUS, with the areaof research in characterisation and synthesis of functional materials.

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Bryan Soh Chee Weng is an Engineer (Land Systems). Currently he is involvedin the acquisition management of combat engineer systems for the Army.He graduated with a Bachelor degree in Mechanical Engineering in 2004from NUS under the Singapore Armed Forces Local Study Award. Between2004 to 2007, he served as a Military Engineering Officer in the army as aregular officer.