INTERNATIONAL CONFERENCE ON MINE CLEARANCE TECHNOLOGY 2-4 July 1996 Copenhagen, DENMARK TECHNOLOGY FOR MINE CLEARANCE OPERATIONS DETECTION OF "HARD TO FIND MINES" Vernon P. Joynt Introduction 1. This paper has been expanded to include clearance because some of the techniques have clearance and enhancement of detection as a single step. In fact it is impractical to separate the various applications in a complete clearance task, and so emphasis is on the practical aspects of applying these and other techniques in the field. Techniques are examined that are already used under real contract conditions with tools that would be useful additions to the mine clearance toolbox. The equipment is mostly already used or under test. 2. With respect to the constraints to development, there are some situations that contribute positively to development, not the least of these being brought about by the current positive changes in South Africa. CURRENT TECHNIQUES 3. The first three slides (slides 1, 2 and 3) show one of the key technologies Mechem uses in most of their contracts, including the current UNAVEM III, 7,000 km road clearance contract in Angola. This technique is known as the Mechem Explosive and Drug Detection System (MEDDS). It was initially used in Mozambique for the UNOMOZ 2,000 km road contract and subsequently in the Cahora Bassa Powerline Survey, and now the clearance contract. The system is an enhancement of sniffer dog capabilities to bring the results up to the magical 99.6 per cent clearance requirement. The technique has been discussed in detail before, notably at the Geneva Conference in 1995. Subsequent development has in essence been that improvements have been brought about by mainly three factors. Firstly, using hand pumps instead of vehicle mounted pumps. Secondly, using the absorptive properties of vegetation in capturing explosive vapours to the maximum. Thirdly, statistics obtained from dogs working in separate environments, that is, in two separate dog centres, are more reliable. 4. The MEDDS system has proved to be a reliable method of detecting buried explosives even if they are deep or have no metallic parts. It also has the big advantage that it can sweep up to 20 metres wide in one pass. The system uses a concentrating device to collect explosive vapours, and specially trained dogs to detect them. The system was originally developed by Mechem for explosive and drug detection at border posts and airports, and was successfully used in the struggle against smuggling of weapons, bombs and mines. 5. It was realized that MEDDS could be adapted to the detection of buried explosives, because all explosives give off vapour, even if they are contained in plastic or metal-cased mines. Concentrator systems were developed for this task, one version being carried in a Casspir mine-protected vehicle and the other on a backpack. The latter may sound a trifle dangerous, but in fact there is little danger to a man on foot as long as he remains on a defined safe footpath or the wheel tracks of a heavy vehicle. The system is so sensitive, however, that a swathe of a width of at least 10 metres is reliably audited in a single pass, indicating the presence of explosives within five, but even up to 15 metres of each side of a path. By spacing more than one concentrator on the front of a vehicle, cross checks can be obtained. The system works best in dense vegetation, as encountered in Angola and Mozambique, because the plants absorb the explosive vapours, and in turn the vapour concentrators pick them up. 6. Routes are divided into sectors, and these are marked as the audit progresses. It has been found in Africa that, owing to wars and other factors, the position of roads and even villages may have changed when compared with the latest available maps. The position of markers of sectors is therefore confirmed with a Global Positioning System (GPS) reading, and this is recorded against the reference numbers of the relevant vapour concentrator tubes. The vapour concentrator tubes are then sent by road or air to a base camp or dog centre, where the specifically trained MEDDS dogs indicate those which are positive. This results in a great saving in the next stage of the operation, because only sectors which are indicated as positive need to be checked for mines. The mine-free areas are indicated at a better than 99 per cent confidence level. 7. Free running dogs are then sent to search along a positive sector, and lie down as soon as they smell explosive vapour. Because of this they never endanger themselves by stepping on a mine. This reduces the final search to an area of about 10 metres diameter, which is then done in the normal way using men with metal detectors and prodders. On occasion these men are augmented with mechanical clearing devices mounted on a special Casspir. With metal detection loose pieces of metal slow down the process with MEDDS cartridges and live rounds are also detected. These non-mine signals, however, are in practice between 500 and 1,000 times less than with metal detection. 8. Auditing large areas with MEDDS will reliably show the explosive-free zones. This saves time and money, which would be wasted looking for mines to clear in those areas. The follow-up mine clearance can therefore be applied more productively. 9. The Cahora Bassa hydro-electric power plant in northern Mozambique, completed in the 1960s, was intended to supply power to Mozambique and South Africa. Owing to the prolonged guerrilla and civil wars, extensive damage was done to the power lines, which were rendered useless. The warring factions laid mines which prevented repair teams from approaching the lines even after hostilities had ceased. 10. As a first step in the rehabilitation process, Mechem was contracted by Hydroelectrica Cahora Bassa to conduct a mine survey of the powerline route and access tracks using the MEDDS system. The length of powerline to be surveyed was 1,800 km, with an estimated 500 km of access tracks. The results of the survey were noted on maps, with reference points being confirmed using the Global Positioning System satellites. Because the pylons were 400 m apart, this was taken as the standard sector. Much of the route was through territory where nature had taken over, and dense bush and uncharted streams caused considerable delays. Where progress by vehicles was impossible, MEDDS samples were taken by men on foot with backpack suction pumps. MEDDS samples do not deteriorate rapidly, and batches of samples were flown weekly to Pretoria, up to 2,000 km away, for checking by the MEDDS trained dogs. This was far more reliable than relocating the dogs, which perform best in familiar surroundings. A total of 12,400 samples were used in the survey. 11. By completion of the contract, in just over two months, 1,303 km of powerline and 194 km of access tracks had been surveyed, of which 37 per cent of the powerline route and 40 per cent of the surveyed access tracks were indicated positive by MEDDS, with a confidence level of 99.6 per cent. This meant that more than half the distance would not need mine clearance, cutting both time and cost in half. A typical test result plotted on a map is shown in slide 3. 12. The experience with free running dogs, supplied and used under subcontract by the company RONCO, is shown in slides 4, 5 and 6, as is the technique of using a radio link to the dog (slides 7, 8 and 9). 13. There are problems and advantages experienced with manual detection, which is used as a key tool. Mechem used personnel of G.S.G. (Gurkhas) and Minetech (former Zimbabwean soldiers), under contract to do this work. In addition local deminers from the Government of Angola and UNITA are being used on the UNAVEM III contract. The slides show some field tasks and conditions. The men all performed admirably and it is quite clear that the man with his metal detector, prodding stick and trowel at present is still a totally essential part of the operation (slides 10, 11 and 12). 14. The mechanical techniques shown on the next series of slides, however, proved to be capable in making the manual operation up to three times more efficient in both time and safety. These techniques include the following: (a) Roller wheels to flatten undergrowth and leave safe track marks on which the man can keep his feet (slide 13); (b) Rippers to loosen the earth, which lowered the magnetic background due to conductive soil so that sensitive settings on the metal detectors could again be used (slide 14); (c) Rippers to loosen the hard earth so that the signals could more easily and therefore safely be opened up by the men using their trowels ("spade men") (slide 15); (d) Steel wheels and disc rollers to detonated mines in anti-personnel minefields (slide 16); (e) Gasbag detonations to open the terrain and detonate most of the mines before the men do their normal search and lifting as a final step (slide 17 + 17a); (f) Dogs used in the normal search mode compliment men usefully. In fact one or two mines in the Angolan contract were found with these dogs, where the men did not find them. In Mozambique there were some French "Inkstand" mines, which have absolutely no metal content. So some dogs have been added to the Minetech-Mechem Cahora Bassa team. 15. In countries which fell victim to the informality of modern warfare, such as Angola and Mozambique, there are very few formal minefields. Exceptions, such as anti-personnel (AP) minefields laid by armies to protect the pylons, are rare. So informal are some of the minefields that, in some cases, they were laid by peasant farmers, who were given a bag of seeds and a box of mines, and were instructed how to protect their crops by laying a minefield around them. The biggest problem facing the rehabilitation of countries which have been ravaged by these wars is the removal or destruction of the numerous unrecorded minefields. The majority of the mines are anti-personnel, because tank warfare was not widely used in these areas. Very often the mines have been overgrown, and lie undiscovered until some unfortunate person has an accident while clearing the bush when trying to restore farmland. 16. Mechem has developed a variety of remotely controlled devices and mechanical techniques for the detection and removal or detonation of mines from within a mine-protected vehicle, eliminating the risk of booby-trapped mines. These include Casspirs fitted with steel wheels and special disc rollers, which are used to clear formal anti-personnel minefields. These may be assisted by gasbags containing an explosive gas, which may be unrolled from a safe position over known minefields, and detonated to cause a fuel-air blast pulse to set-off first generation pressure mines. PROPOSED TECHNIQUES 17. Ground demining tiller system. Mechem has been privileged to be involved in the United Nations supervised field trails of a Krohn Tiller system in Mozambique near Moambo, where it was being used to clear the ring minefield around the town. The slides show the equipment and men (slides 18, 19 and 20). It is proposed that, although the Tiller by itself could not clear all mines or achieve good clearance rates with certain solid metal jumping mines, like the OZM-4, it would indeed be a very successful tool when used to break up bush and rocky ground for a manual demining team. These men would then remove the mines and dangerous debris in more advantageous conditions than when they had to tackle the virgin bush itself - safety and time improvement. The Tiller detonates a large percentage of the mines, lowering the exposure density for the men and also speeding up their work rate. 18. Flails. These would be less useful than when applied in their military mode, but if used to clear surface bush and obstacles so that men and dogs could follow, there would be an advantage. Dogs are quickest to track down stray mine thrown to the sides by the flail action - especially because these mines are not buried anymore and the dog can even use his eyes! 19. Mechanized signal interrogation techniques. These are being investigated under research efforts. 20. Ground penetrating radar (GPR). In the mid-1980's the South African Army tested a locally developed GPR system (slides 22 + 23) in the South West African war theatre. The north of Namibia, as also the south of Angola, is a mix of loose sand and vegetation. None of the secondary roads have the tennis court smoothness that one observes in the slide (slide 23). The Army eventually did not use the system because, although one could detect and signal process at the required 20 km/h, one could not average more than 1 to 2 km/h because of false alarms. Especially the TMA-3 mine (slide 21), which occurred 75 per cent of the time, has its signals lost or merged into that of the uneven surface reflection. A TMA-3 mine must be planted shallow or it will not function. Experience is that signal processing is better for deep buried objects, but severely restricted if mixed into surface clutter. SUMMARY 21. By using existing mechanical demining equipment and other techniques in a "toolbox" system, quite good improvements are already being achieved when compared with the classical manual approach. One of the biggest problems is to find a simplified measurement of efficiency that truly reflects which approach is best. Factors like total mines lifted, total area cleared and effect on infrastructure measured against time, money and clearance efficiency produce results where people differ in interpretation. 22. The development problems are linked to the old military-humanitarian demining differences - military funding is more freely available. Military facilities are also absolutely essential to doing proper demining research and development. Again, mainly because of funds and culture, this research is more at home in a military research institute. Because Mechem holds the privileged position of doing all the South African National Defence Forces mine clearing research projects, one has access to their explosive testing ranges. These are operated under military rules and it is therefore possible to have live minefields in which to test techniques as a final step. 23. Transparency, co-operation and other advantages stemming from the political change in South Africa has narrowed the gap between humanitarian and military anti-mine attitudes.