Andy Smith
Mine action specialist
 
Machines in HD, part 2

 

Humanitarian Demining

Machines in HD, part 2

Ground-engaging machines

See Chapter 8: Mechanical demining in the Global SOPs for details of
how machines can be used.

See also Machines in demining at the Powerpoint downloads page.

 

 

Clearance machines?

A range of machines are designed to expose or initiate mines and other explosive hazards as they work. What these all have in common is that they engage the ground, and that none of them reliably expose or initiate all of the explosive hazards that must be removed for ground to have been 'cleared' to the definition of Clearance given in IMAS 09.10 Clearance requirements.

"Land shall be accepted as 'cleared' when the demining organisation has ensured the removal and/or destruction of all mine and ERW hazards from the specified area to the specified depth."

Usually developed from machines intended to work in military minefield breaching, where complete clearance is not as important as speed, there is a powerful lobby for these machines to be more widely used in Humanitarian Demining. This lobby appears not to understand the essential difference between military and humanitarian demining. In the latter 'all' explosive hazards must be removed to a predetermined depth so that the area is safe for civilian use. Removing only those simple pressure operated hazards that threaten soldiers when they cross is not enough - especially because the land which was previously avoided will be believed safe after the machine has been used, and so will be used. Incomplete search and clearance can INCREASE the risk to civilians and must be avoided by all those who want to call their work 'humanitarian'.

The commercial interests behind the machines often claim that machines that cannot clear an area can be used for Area Reduction. In so far as they can provide increased confidence that an area does not need to be searched - when there is no reason to believe that the area is hazardous anyway - this might be true. However, any land processed for this purpose cannot be recorded as 'cleared' so the method cannot be relied on for Technical Survey unless all of the processed land is aso searched using a reliable method. Machines may initiate or expose some devices but they do not search and clear any ground. Humanitarian Demining is about clearing ground of all hazards, not just detonating some easily initiated devices.

The main types of ground-engaging machines are: Flails, Rollers, Millers and Tillers, Sifters, Dozers, and graders.

Flails

    This picture is taken from the cab of an Aardvark flail in Angola - looking forward through the spinning flail heads.

    This is the same machine standing idle.

     

    And one of its "brothers" in bits, awaiting repair and rebuilding.

    A machine this size costs a lot to purchase and run (purchase cost frequently in excess of 1.5 million US$). Supporting it logistically is often beyond the capacity of a demining group working in a developing country. They are frequently out of use for months - with their support crews standing idle. This may be because they break down (which they do often because they were not designed for constant use) or because they damage themselves by running over explosive hazards that the flail has failed to initiate, which also happens more frequently than the manufacturers admit.

    Here is a Hydrema, a rather more expensive flail than the Aardvark, after just such an 'accident'.

     

    This Hydrema was in Eritrea. It had just run over a shallow AT blast mine that the flails did not initiate. An axle has been lost and the armour of the cab compromised. The driver was injured. The sales blurb for this machine starts by saying that this is a "mine clearance vehicle capable of clearing all mines which have been conventionally buried or non-directional anti-tank mines up to 10 kg without receiving any damage". Er, yes... another honest advertisement. And one wonders how many others the flail missed and the wheels did not run over...?

    More importantly, no one even claims that these machines can detonate or 'clear' the mortars, RPGs, rockets, large bombs and other explosive hazards that may also litter the ground. They also miss mines with pin-pull fuzes. Worse, their passing can completely conceal things that were obvious before the machine passed through.

    None the less, some demining groups like flails because they can allow a large land-area to be processed very quickly and this can improve their performance figures. In some cases, the donors bear the responsibility because they press for better 'numbers' regardless of the quality of the work.

    The large number of ground-engaging flails on the market is an indication of the way that the manufacturers have perceived a potential for profit.

    Here is an ARMTRAK 100 flail

    And here is the dust it raises in use - blocking cooling systems, blinding the driver and causing a wide range of mechanical failure.

    This picture shows the chevron tracks of the flail and the dust-covered broken rocks left behind. On the bottom left is a V69 bounding fragmentation mine lying on its side and crushed into the ground. It would not be safe to step on that - so even the track-paths cannot be considered safe after a flail has passed. This mine was crushed into the ground. There have been other examples where flails have thrown the mines around and some have landed on the surface in the tracks behind the machine. When the flail raises dust, the entire area gets coated and exposed devices can be almost impossible to see.

    A SISU Finnish flail

    The MineCat

    The Patria RA 140 DS

    The RM-KA 02

    The Samson 260

    The Minemill MC 2003

    The Minelifta flail unit

    The Scanjack 3500

    The Viking

    I put that list together a decade ago and there are a dozen new contenders since then. Even then, this was by no means all of the available large flails (mini-flails were covered in Machines in HD: Part 1). When you see how many there are and start to consider how much effort and money has gone into their development instead of into the search and clearance of land, it can make one despair. But commercial self-interest is a reality and governments have always liked to give 'development' money to companies working at home... And this does not really matter as long as no one pretends that they can leave any ground 'cleared'.

    If you have not been there yet, go to the Introduction to HD and look at the typical mined areas shown... These machines could not be used in many areas even if they could destroy all explosive hazards on level ground with friable soils. Independent tests have shown that in real minefields they do not reliably process the ground to an even depth, they do not initiate all pressure mines (even when they are in good condition) and are far more likely to throw damaged UXO around than to initiate it. Detonating a few mines is not always a good thing - see Myths, Mines and Ground Clearance and does not "clear" any ground at all. This is not to say that ground engaging machines have no use - merely that their use must always be followed by a more reliable search and clearance procedures, and so their uses adds to the costs involved. This may be desirable in some circumstances as described in Chapter 8: Mechanical demining in the Global SOPs.

Rollers

Rollers rely on applying pressure to the ground, so detonating pressure-sensitive devices. In practice, mined areas are rarely level and large rollers fail to apply ab even pressure, so missing pressure initiated hazards that would theoretically have been initiated by the roller's weight.

Designers attempted to get around that with segmented disc rollers, supposedly following ground contours more accurately than long rollers.

In order to achieve this, the undergrowth must first be cleared AND removed. Even then, rocks, tree stumps or large irregularities mean that the discs do not always touch the ground.

This shows a Soviet T55 bridge layer tank with KMT5 roller system mounted on the front. Tanks with the KMT5 were once used to 'clear' a defensive belt of AT mines in Angola.

This picture was taken when a T55 tank and KMT5 rollers failed to detonate a pressure initiated AT mine, then drove over it. The tank's armour was breached and an occupant killed. The system missed mines, and was even unsafe for its operators.

The fundamental problem with rollers is that they can never let off anything but a pressure-operated device that is orientated correctly and in good working condition. Mines on their side or damaged, mines that are not pressure fuzed, and all manner of unexploded ordnance will always be left behind - and may be left behind in a more damaged state. If the ground is uneven, anything could be left behind, even by heavy roller systems.

Millers and Tillers

Millers are ground processors - chewing or milling the ground. Tillers are push-or-pull ploughs designed to turn up and expose mines.

Millers are designed so that AP mine detonations do not disrupt operations. A few claim that even AT mine detonations cause only minimal damage. See what happened to the tank in the previous section - AT mines are designed to disrupt armoured vehicles so the claim of AT immunity always relies on the device detonating in a conveniently 'harmless' place.

The FMR-2000 is one of these 'miracle' machines.

As is the optimistically named 'Mineguzzler'...

The Minebreaker

or the Minemill

Tillers use tines or plough blades to break up the soil and expose any shallow buried items that may be there. In areas where there is friable soil without dense tree roots, this can be effective - but the effect may be to simply turn devices over, or to bury them more deeply than they originally were.

To protect the machines, some are designed to push rather than pull the tiller. The machine above is the Mine Clearance Cultivator (MCC). It weighs 32 tonnes (too heavy for the road bridges in many countries) and pushes its tiller through the ground with immense force. Needless to say the tiller blades tend to be broken off by the pressure, especially when there any large stones or roots for them to catch on. The only effective way to use it is with a minimal cutting depth, so ignoring any mines buried below 8cm. Given that its target is AT mines, and it is normal for them to be buried more deeply, this is a fairly significant design limitation.

None-the-less, the machine was backed by huge sums of US taxpayers money and 'found' two AT mines in Angola. It blew itself up with both.

The cost of the repairs alone would have paid for many months of real clearance by a real demining team.

Some millers and tillers are on a smaller scale - usually as attachments to fit on a multi-purpose machine. As usual, multi-purpose machines rarely perform any action as efficiently as a dedicated item, and some...

...even contrive to look absurdly amateur despite vast sums of R&D money being spent.

If these machines could really locate and break up the range of unexploded ordnance common in mined areas, (which includes ordnance with an armour piercing capability) they would blow themselves to bits in the process regularly. What happened with the MCC illustrates what can happen with simple blast devices. If they reliably exposed everything that must be found in HD, commercial demining groups might find them commercially viable to purchase, but they do not.

Processed ground tends to look smooth despite the original irregularities - so items can be missed and buried more deeply than they were before. Bed-rock, fibrous tree roots and soft ground all lead to failures of coverage that means the whole area must be searched again using reliable procedures. If the machine has disrupted mine patterns or left damaged devices behind, this can be slower and more expensive than it would have been without the machine being involved. In any case, the cost of using the machine must be added to the cost of manual search and clearance - so it can never be cheaper than manual clearance would be.

 

Sifters

Sifters range from large machines that mill the ground, then pick it and sift it, to smaller improvised methods.

This is the MineBuster, deployed on the Zimbabwe/Mozambique border minefield.

It had a toothed roller than milled the ground...

A nylon toothed sifting system...

....and a conveyor belt rack to "riddle" the output. Intact mines were meant to be deposited on the surface behind the machine.

Confounded by tree roots and rocky ground, it left smoothly processed ground that was once 'lumpy', so must have concealed some of the mines in the dense minebelt at a depth beyond the reach of a metal-detector. Some of the mines deposited on the surface detonated spontaneously as deminers approached (in several recorded accidents).

It broke regularly and had lengthy downtimes, and could only be used in carefully selected areas of the minebelt. While less critical than I am, those who used it did accept that its purchase and use was not at all cost-effective.

A similar method is used by the Amtrak sifter attachment shown here.

Other sifters use a drum that can be used to pick up suspect soil and sift out the loose content before spreading what is left for manual inspection.

Although this is expensive, its reliance on manual search and clearance of the spoil makes the method a kind of mechanised mine-detection rather than mechanised area search and clearance.

On a smaller scale, the ill-conceived "Berm-sifter" was developed to help clear mounds of earth left by bulldozer 'clearance'". With a very narrow and short wheelbase, the machine was too unstable to be deployed over any unsurfaced area, so was not used.

What was being used was a "bucket" and grid...

The bucket dumped the spoil on the grid, then shook it (spilling some of the content over the sides).

Then unprotected men moved in to sift through the items too big to have fallen through the grid. This illustrates how a commitment to a mechanical method that does not work can lead to dangerous improvisation. The work was hailed as a triumph by the donor, which seems to have been unaware of what was really happening.

There are other methods of collecting and sifting topsoil with manual inspection of the results that may be effective in terms of searching and clearing spoil - but must always be very expensive and destructive of the environment.

Dozers and graders

It may seem strange to think of bulldozers as mine clearance vehicles - but they have often been used as such.

Obviously, all they can do is move the problem from one place to another - but sometimes the client is happy with that. If you want access to power lines, for example, you may not worry about the local people who will climb the spoil heaps when you have gone. This is not Humanitarian Demining.

A road grader is really just a bulldozer - although its use on dirt-roads does make it more likely that the disturbed earth where something is deeply buried may be spotted. Graders have missed mines and blown off their own wheels as a result - so no sane person would call them a 'clearance' machine.

Machines can assist demining in many ways - and I wholeheartedly support their use when it does not reduce the standard of clearance and so put the end users of the land at increased risk. Mine 'clearance' machines invariably do this - because the range of devices and the context in which they are found are never fully addressed in the design aims and probably never will be. There are no mine clearance machines, just machines used in demining, or 'demining machines'.

Manual demining is slow - but it can be really thorough... and, compared to the real costs of most mechanised procedures, rather cheap. Even if manual demining were more expensive, the money spent on manual deminers goes into the local economy and promotes stability and peace in a post-conflict region, which can be a significant incidental benefit in support of HMA goals.

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