For years, NPA in Sri Lanka provided assistance to the Tamil demining groups and authorities, helping them to refine their own systems and so meet the requirements of the International Mine Action Standards. Uniquely, they achieved this without losing the low-cost features that are essential to any locally sustainable method. NPA also supported a similar process in government controlled areas, working with both the army (in co-operation with RONCO) and civil demining groups. Their civil partners were the Melinda Morigoda Institute for People’s Empowerment, HORIZON and Sarvatra – the first of which was a local Sri-Lankan NGO moving into Humanitarian Demining and the two others were demining branches of development NGOs based in India and led by retired Indian army engineers.
clean up after 'Gulf War 1' was a long time ago – but it was the first time I heard about the use
of rakes to find mines. Back in those days Royal Ordnance were active
in Kuwait alongside deminers from many countries. Referred to rather
disparagingly as TCNs (Third Country Nationals) deminers from India
and Pakistan used rakes to expose mines in the desert. I am told that
Royal Ordnance gave the rakes a try but did not take them up. The threats
included V69 bounding fragmentation mines with tripwires and tilt-sensitive
fuzes, so their rejection of rakes made good sense. A lot of TCN accidents during
1991-93 are on record, but the reports did not include enough detail to know whether the rakes were a cause. Nonetheless, the idea of clearing mines with rakes was discredited and the potential
was ignored by mainstream groups in humanitarian demining. I was among
those who dismissed the use of rakes as obviously dangerous. I was wrong.
The SL army raking in 2001
In Kosovo in 2000 and 2001, leaf-rakes were used under Luke Atkinson’s
direction (with the demining group Danish Church Aid) to remove the
forest leaf-litter and expose PMA-2 and PMA-3 mines in well defined
mine-belts. The rakes set off no mines. Detecting minimum-metal AP mines
with metal-detectors in those areas was a hit and miss affair, as the
accident record shows. Exposing them with the rakes was both faster and safer.
At the start of the new millennium in Sri Lanka, demining was being
conducted on both sides of the border between government and Tamil forces.
With limited funds and extensive human resources, both sides used a
low-cost, labour intensive raking procedure. The Tamil’s
Humanitarian Demining Unit (HDU) managed demining in Tamil controlled
areas. They used short-handled rakes without marking the area, without
imposing any safety distance and without wearing any PPE. Across the
border, Government forces wore PPE, but paid similarly scant attention
to the concept of safety distances and area marking. Clearance on both
sides of the border was 'successful', but there were severely
disabling casualties and the random method meant that the ground had
not been thoroughly searched, so not cleared to IMAS standards.
When NPA were invited to advise the HDU in 2002, it would have been
easy for them to dismiss the rakes and impose metal-detector drills.
The cost of importing hundreds of metal-detectors would have been high,
but many saw no alternative. However, Luke Atkinson was made the NPA
programme manager and he saw that the raking was potentially as thorough
as sieving the ground and so found it very attractive - if it could be
controlled within a marking and safety package that would be effective
in preventing missed mines and accidents. NPA looked at ways to refine
the tools and to control rake-use within site marking and supervision
regimes that would create an entire system that would be accepted within
mainstream demining. That system is the Rake Excavation and Detection
System, known as REDS.
The REDS uses two simple raking tools to excavate and sift the ground
to the required depth. Conventional demining site markings are used,
and side of lane depth trenches allow effective QA of depth. A 'Base-trench'
across the front of the lane marks the extent of the processed area.
Loose soil is brushed from the uncleared area into the Base-trench,
and then packed to the rear of the trench. When the use of the Brush-rake
becomes ineffective, the Harrow-rake is used to scarify the ground,
allowing the Brush-rake to be used again. The Base-trench rolls forward
as work progresses, which can be surprisingly fast in ideal ground conditions.
has flexible tines that exert little pressure in any one place on the
ground. Tens of thousands of mines were exposed using it, and none
detonated. The Harrow-rake is heavier and is used to both
scarify the ground and to lift shallow mines to the surface. If used
incautiously, mines can be initiated by hitting the rake-head on the
ground. This happened several times in Sri Lanka, but no serious injuries occurred. The long handle on the Harrow-rakes keeps the deminer at a
distance from the blast, and the PPE that is part of the REDS system
completes the protection against small anti-personnel blast mines very
The Brush-rake in use in 2004
Harrow-rakes in use in 2004
The early design
of Harrow-rake head was very cheap and worked adequately in loose, sandy
soils. It was revised for use in harder soils by me when working for Norwegian
People’s Aid (NPA) and Sarvatra (Sarvatra was a demining NGO from India who
were working in government controlled areas of Sri Lanka). My revision
of the Harrow-rake uses a material with a proven record of maintaining
integrity in AP mine blasts (low-grade Stainless Steel). The tools dig
into and cut the ground without the need to apply any downward pressure
and can be refurbished periodically to have a very long life. Locally
made, they cost rather more than the original rake-design, but do not
cost as much as three sets of batteries for a metal-detector.
The heads of the revised Harrow-rakes
With SARVATRA, I then refined the design
further, to make the REDS applicable on even harder ground and to make
refurbishment a simple field exercise.
Because the REDS
system sieves the ground, it gives the kind of complete confidence of
clearance to the required depth that metal-detectors and other area-excavation
techniques cannot achieve. [This conclusion is among the results of
GICHD comparative trials of manual demining systems which took place
in Mozambique during October/November 2004.]
The main limitation
of the REDS system was the time that it can take to complete when there
is dense undergrowth or the ground is hard with complex root systems.
There was a need to turn
the jungle into loosened ground so that REDS could be used efficiently
in a wider range of conditions.
Typical Sri-Lankan jungle
Ideal ground for REDS
To solve this problem,
mechanical means of preparing the area were devised by SARVATRA in collaboration
The use of machines in Humanitarian Demining is rarely cost-effective,
environmentally friendly, or sustainable. Sarvatra proved that this need not always be the case. They adapted construction-site machines to
provide the platform for vegetation cutters. The 'used' platforms were low-cost
earth moving machines with hydraulic arms designed to carry excavation
buckets for use on building sites. The hydraulic arm reached out into
the minefield while the machine stayed on safe ground.
The first set of teeth cut
undergrowth and roots.
The second set of teeth raked to the
With my assistance (through NPA employing me), those platforms were armoured and
new ground preparation tools made. The platforms were being
used in advance of the manual deminers using the REDS system throughout Sri Lanka. The tools
removed dense undergrowth and scarified the ground, raking it to depths
beyond that needed for confident searh and clearance. The mechanised vegetation
cutters and rakes were not designed to detonate mines, merely
to break up the ground so that manual REDS could be rapidly conducted
behind the machine.
At a unit cost
of less than US$30,000, the machine cost less than a good 4x4. Unlike
large flails, they did not turn the ground into dust, destroy mature
trees or disrupt patterned mine belts. The use of widely used plant
machinery meant that spare parts were widely available, servicing was
simple, operation was straightforward, and the machine could be converted
back to conventional uses by retrofitting its original tools in a matter
of minutes. This versatility was unique and guaranteed that the machines
did not have to be scrapped when their demining role was over.
Of course, the peace process in Sri Lanka failed and its great supporter, Norway and NPA, was thrown out. But Sarvatra kept working and had twenty of their machines before they left. The success of the machine was so obvious that five different NGOs were using it by the end, many hired from Sarvatra.
NPA took the rakes on to Jordan, modifying REDS for that environment with complete success. When they cleared the Jordan/Syria border, they used metal-detectors to find the mines and the REDS rakes to expose them. Meanwhile DDG moved the REDS system into Sudan (where NPA followed) and I last heard of the REDS system being used with great success is Libya in 2011.
So after many years
spinning in a backwater, the simple low-cost rake drifted
into the mainstream of demining technology. Both hand-held and mechanised,
rakes are sustainable, cost-effective and (used in a well designed system)
give total confidence of search and clearance to depth.
Thanks to Sarvatra for showing me something “new”. Individual
thanks to Mr Brar and Mr Petri (Sarvatra); Luke Atkinson and Jan Erik Stoa, (NPA).
The use of REDS rakes to excavate metal detectors readings in Jordan is a REDS (rake) Powerpoint case-study - Click here to start downloading. The case study shows how safe the raking system is when compared with other excavation methods.
Return to COMMENT.