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By Dana Watsham,

Mine clearing with metal detector (photo: Danish Demining Group)

Land mines are a very real menace, and have been used more and more in the last 30 years as warring nations have had less to spend on military hardware. War goes discount, so to speak. Unfortunately for those living with the remains of warfare, mine clearance is expensive and agonisingly slow.

PL Brake came up with an idea for mine clearance in 1996, and developed it along a very stringent set of specifications:

  • Low cost
  • Portability
  • Easy operation by one person
  • Safety first


The inventors' consortium PL Brake works as the idea generator, carrying out the initial R&D and prototype building for a given project. Later in the process, a project company is formed to commercialise the idea

The R&D process for the mine detector has been conducted in close cooperation with Danish Demining Group, Danish Defence Demining Centre (DANDEC/HIAS), and Danish Defence Research Establishment (DDRE), as well as invaluable assistance from Roger Hess, Hendrik Ehlers, the MgM network, and several NGOs such as YADC, BCBL, and HALO.

The basis of the detector is sound waves. Sound bouncing off solid objects is different from sound bouncing off hollow objects, such as mines, as well as UXO. With pattern recognition software to receive the signals, the 'false' hits are sorted out. Combined with radar, the PL Brake detector will both detect and recognise objects. And unlike the old-fashioned metal detector, which will also find every scrap of shrapnel, the PL Brake mine detector will find both plastic-shelled and metal cased mines.
The detector pinpoints depth and position of objects by using a sonar-analogue signal, and an image indicating the depth, position and nature of detected objects is generated on the operator’s display by interfacing a recognition unit and a compact database. The mine detector is operated at levels between 10 and 35 centimetres above ground. This enables the detector to work in terrain with for instance marked ridge-and-furrow features without necessitating vertical movement.

At the test demonstration in August 1999, we proved the ability to detect plastic objects (we used CD jewel cases) buried in humid sand to DDRE.

With the aid of University of Southern Denmark (SDU), Bruel&Kjaer, and Danish Demining Group, a prototype was built and tested in controlled conditions in January 2000. The results were not perfect (the detection rate was estimated at 84%), but were good enough to impress the various experts present.

(Photo: Finn Frandsen)
Prototype demonstration, January 2000
Present at the demonstration: left: Lieutenant Colonel Steven M. Czepiga. U.S.Embassy Denmark, in the background Supervisor Senior Sergeant Jens Block HIAS, right: Arne Vaagen and Bo Bishoff, Danish Demining Group



At a scientific demonstration conducted in May 2002 at the Physics Department, Technical University of Denmark, we documented yet again that we are able to detect M-56 AP mines, made with plastic casings, buried in humid sand. f1 and f2 on the picture are the sound return spikes.


I asked Mr. Arne Vaagen, Head of Danish Refugee Council International, (previously Head of Danish Demining Group). To give his views on mine clearing and the need for innovation:

Where are we now in terms of mine clearing, especially in developing countries?

Humanitarian mine clearance has gone through some major developments the recent years:

The focus on the problem has been significant and maintained, and stronger international networks and standards have been developed.

The UN has been very active in establishing efficient monitoring, training and co-ordination mechanisms. 

National governments have become involved through national agencies responsible for priorities and co-ordination.

How many mines litter the landscapes of the world today?
The oft-quoted number 110 million mines  is more for fundraising and public awareness than operational priorities. Operationally, the focuses have shifted from the actual number of mines dispersed to the removal of such mines as hamper and endanger everyday lives. The mines in and around the well, school, bridge, field, road to neighbouring village, etc. They are a daily menace. The mines littering remote mountains are not.

The fear of mines can ruin lives for many. Removing the fear may result in detection of one mine. Obviously the right mine to remove. The hundred mines in an isolated mountain area have to wait.

How, then, do you select what mines to clear?
Mine clearance organisations use such parameters as sustainability, ownership, sharing of responsibilities, and co-operation with other organisations and authorities to a larger extent in their planning than before. Documentation, SOPs, and security standards have all been improved, and the number of casualties in connection with clearance are impressingly low. In many countries, such as Somalia, Afghanistan, Mozambique, Angola, and Sri Lanka progress has been considerable. The mine problem has been surveyed and numerous mines have been removed.

And the development of new equipment and techniques?

Significant improvements have taken place in operations, organisationally and regarding co-ordination.

However, in spite of an innovative environment with room for improvements and new methods at a practical field level, the development in technical and other solutions has come to an almost total stand-still. New technologies and methods have been tested, and have shown considerable weaknesses. This is one of the main reasons that mine clearance is so agonisingly slow.

Mechanical clearance is extremely expensive, and is not sufficiently efficient. A mechanically cleared mine field has to be verified manually, and thus represents a very small step forward. The logistic requirements are immense, and the cost-effectiveness compared with manual clearance is highly questionable.

Dogs are unreliable. Impressive if conditions are good, but conditions vary and dogs might easily be distracted by heat, smell, noise, etc - and like human beings, they get tired and moody.

The good old metal detector is dependent on sufficient metal in the mines, reacts to any metal fragment - a huge problem in old battlefields, and if the soil contains natural metal it is practically impossible to use efficiently.

Other technical solutions require huge logistic capacity as well as advanced training and experience (mechanical sniffers etc)

What remains as the most secure and accurate method is still the primitive, slow and painstaking prodding technique combined with other manual solutions like brooms etc. It requires manpower, discipline, good management, and patience. All available in a professional mine clearance organisation, but except for some socio-economic effects in the local communities (men at work - receiving salary) it has few advantages except for the reliability. It simply requires too much time, and of course it is expensive as well.


Where does the demining community stand on new technology to get the job done?
I am convinced that the professional and innovative environment characterising demining organisations would welcome such developments.

Requirements to QA and reliability would have to be stringent, and with my knowledge of the working ethos within the system, I know that there is a wide spread scepticism towards new and creative inventions.

A lot of solutions have been tested, such as various forms of instance mechanical cleaning, sniffer dogs, and mechanical sniffers. Other, more spectacular, inventions and projects such as rats, and flowers turning red, are met with disbelief and ridicule.

A new device will have to prove its efficiency in field tests in order to convince experienced and sceptical experts that this is a both cost-effective and reliable tool. But of course the experts have a list of both wishes and requirements for such new technologies, and for a new tool:

The new technology should be able to fit into a one-man portable device which is:

  • Battery powered
  • Not affected by heat
  • Not affected by contaminated soil
  • Does not require long term training


What is your opinion of the PL Brake initiative?

I have followed the development of a new portable detector by PL Brake for the last five years. I am not familiar with the technical details, but I have been involved in the initial definition of requirements and some testing of a prototype.

It is based on a certain sound frequency sent out from a portable tool looking very much like a mine detector. Advanced ultrasound technology enables the device to detect items in different kinds of soil.

One major, and important, principle is the detection of hollow items – which a mine would be - in order to avoid signals from items such as stones, shrapnel, etc. Other possibilities which may be built into the system is the ability to compare the shape of the detected item with shapes of actual mines and unexploded ordnance in a small database, again a failsafe to avoid signals from each and every buried item.

I have participated in a controlled test of the equipment. In humid sand, I was able to detect seven out of ten personnel mines with the prototype. I was very impressed by the equipment, and the fact that detection was based on variations of sounds in earphones. I had received no particular training prior to the test.

I found the experiment very promising, and have encouraged the team to continue the development of this device. I think it deserves a chance.


PL Brake is focused on finding a global partner with the financial clout to help finalise the project, and set up worldwide sales and service for our portable mine detector. For further information, see