Issue 7.3, December 2003
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Vegetation Clearance Equipment: Huge Potential in Productivity Improvement

Upon development of its D-1 vegetation clearance vehicle, DIGGER DTR (Demining Technologies) has successfully responded to many of the demands of the demining community. The second generation, the D-2, will feature several new upgrades and is expected to appear on the market by 2005.

by Nathan Kunz, DIGGER DTR

The Company

DIGGER DTR, a Swiss humanitarian non-profit organization with a mine clearance background in Croatia and Cambodia, has been active in the design of demining assistance tools since 1998. Its aim is to assist mine clearance personnel by developing tools to secure and accelerate mine clearance activities.

DIGGER DTR is based in Tavannes, Switzerland, an area known for its expertise in the machine industry. Two mechanical engineers and three electronic engineers compose the design team. Ten persons with different technical backgrounds handle production, while several more deal with the administrative and organizational tasks. Most of this highly motivated team are volunteer workers, which allows DIGGER DTR to provide cost-effective solutions to the humanitarian demining world.

The development of this organization has been financed by private donors and sponsors. Partnerships with the Swiss Foundation for Mine Action (FSD), the Swiss Army and two universities of applied science have helped DIGGER DTR during the development of the D-1, its first vegetation clearance vehicle.

The D-1 Concept

Our current product, the D-1, is a lightweight, remote-controlled vegetation clearance vehicle for mine clearance assistance (MCA) work. Deminers in the field stressed the need for this kind of machine. The following extract of a Geneva International Centre for Humanitarian Demining (GICHD) study shows the impact of vegetation clearance in demining: “The views of practitioners in every programme consulted for the purposes of the study reflected the assessment that vegetation clearance is one of the most time-consuming elements of the clearance task. While the time taken to conduct vegetation clearance varies by scenario, it is clear that, overall, improving the speed of vegetation clearance offers a significant increase in overall mine clearance productivity.”1

DIGGER D-1 working on the Albania-Kosovo border.

DIGGER DTR began with the design of the D-1, based on the following requirements given by the FSD; the vehicle must be:

According to these requirements, DIGGER DTR began the design of the first prototype, the D-1. One of the biggest challenges for the development team was the use of simple technologies. The use of any high-tech components in the D-1 was banned, which allows the DIGGER DTR vehicles to be easily repaired in the field.

The track design is the best example of this concept. The tracks on the D-1 were developed specifically for this application, because no existing tracks of this dimension offer enough detonation resistance. Moreover, commercial tracks could not be repaired in the field. The tracks that were especially designed for the D-1 offer a good resistance against explosion and can be repaired in the field by simple means.

DIGGER D-1 carried by a small transporter.

Another challenge was for the vehicle to maintain a good resistance against fragmentation mines, while limiting the weight. The weight of the machine is a determining factor for such a vegetation clearance unit. A lightweight vehicle can be carried to almost every minefield, even on poor road infrastructures. A second important factor is that small vehicles do not damage the soil or local environment during the cutting of vegetation. The GICHD study shows that the weight and dimensions of future vegetation clearance equipment will be increasingly important to spare soils: “Some mechanical methods for clearing vegetation can have a detrimental impact on local soil conditions and the wider environment. There is a growing awareness within the mine action community that future demining technologies should take into account not just the clearance requirement itself but the future productive use of contaminated land.”2
The four tons of the D-1 are less than the weight of an agricultural tractor; therefore, the soil will not be damaged during vegetation clearance. This weight also allows the D-1 to be transported on a small truck, even on poor roads.

Technical Description

DIGGER D-1 with mulcher unit.

The D-1 consists of an armoured, V-shaped hull, which gives it a very good resistance against anti-personnel blasts (APBs) and fragmentation mines. The vegetation cutter fixed to the front (mulcher or flail) allows it to cut trunks up to 10 cm in diameter. The mulcher unit operates at approximately 500 rpm, using 44 adjustable chisels to remove thick vegetation and trees. The minimum cutting height is two cm above ground.

To increase cutting depth, a flail unit has been developed after the first tests in Albania. The rotor operates at 500 rpm, using 42 chains. A hardened steel hammer is attached at the end of each 50-cm-long chain. The cutting depth is manually adjustable from plus five cm to minus five cm from ground. By cutting the vegetation, the flail removes tripwires and reduces risks for deminers by neutralizing mines.

The hydrostatic transmission is powered by a 2,700-cubic-cm Kubota diesel engine (46 kW/62 hp). The vehicle is remote-controlled from behind a protection shield from a distance of 50 m to over 300 m. The average working speed in light vegetation is 2,000 sq m per hour; in dense vegetation and heavy soil, the speed is 600 sq m per hour.

Tests and Evaluations

The Swiss army carried out tests of the system’s chassis and cutter unit’s resistance to explosive blasts. Six detonations of 730 g of TNT with fragmentation between 0.04 m to one m were carried out against the cutter unit. Five detonations of 200 g of TNT were fired beneath the vehicle tracks. No serious damage was reported in any of the cases.

During the summer of 2002, DIGGER DTR tested the prototype for two months in Albania and Kosovo on real minefields, in partnership with the FSD. The information collected during these tests was used for the D-1 redesign. PMA-1 explosions under the vehicle’s tracks caused no damage to the system. The protection shield was tested against fragmentation with a PMR 2A fired at six m. No serious damage was observed.

Second Generation: The D-2

In 2004, the development team will design the D-2, the second generation of this vegetation clearance vehicle. In order to answer deminers’ needs, the use of this machine will be extended to a multi-tool ground preparation vehicle for mine clearance assistance. Its main activity will continue to be vegetation clearance, but it will also manage tasks such as area reduction or spoiling debris with a shovel. Some new specific tools will be designed for the D-2.

The D-2 will be equipped with a more powerful engine (3,300 cubic cm, 51 kW/69 hp). Most improvements will be made in the assembling techniques in order to reduce production time and costs.

Length without attachment 3,500 mm
Vehicle width 1,360 mm
Width with attachment 1,600 mm
Working width 1,400 mm
Overall height 1,640 mm
Max weight with attachment 3,500 kg
Speed range 0-10 km/h
Engine 3,300 cubic cm Kubota diesel (69 hp net)
Table 1: D-2 Technical Data.

Logistics and Infrastructure

International transportation can be easily accomplished in a 20-ft container, which can also be optionally equipped as a field workshop. Its small dimensions and weight allow the D-2 to be carried by a small truck or a trailer. DIGGER DTR can provide the specific recovery equipment necessary to pull the D-2 out of a minefield in case of serious damage.

DIGGER MCA: Mine Clearance Assistance

Under this name, DIGGER will offer a special concept of renting a two-person staff and all working facilities, including logistics, which will be entirely adapted to the client’s demand. This kind of service has been developed from a humanitarian standpoint, with the aim of reducing the mine clearance costs for the deminers by using a highly efficient and skilled team. This staff, with expertise in vegetation clearance and the use of our machine, will carry out ground preparation work for the contracting organizations. Even if the two expatriates using the machine are paid more than local staff, the MCA operations will cost less than manual vegetation cutting, due to the high productivity increase offered by the D-1. When an organization rents our services, there is no need to train its staff to buy logistical means and install working facilities. The first operation in the field carried out by DIGGER MCA is planed for 2004, in partnership with the Swiss government and the Swiss army.

Selling Strategy

The D-2 will be available for sale in 2005. As a humanitarian and non-profit organization, DIGGER DTR’s goal is to make the D-2 affordable to as many demining organizations as possible, so that the safety of the deminers can be improved and global mine clearance productivity can be increased. Due to the D-2 selling price being fixed to the costs, as well as the significant voluntary development work involved, DIGGER DTR is able to sell this vehicle at a very attractive price (165,000 CHF).

*All graphics courtesy of the author.

References

  1. Mine Action Equipment: Study of Global Operational Needs (p.12), GICHD, 2002.
  2. Mine Action Equipment: Study of Global Operational Needs (p.143), GICHD, 2002.

Contact Information

Nathan Kunz
Sales Manager
DIGGER DTR
BP 59
CH-2710 Tavannes
Switzerland
Tel: +41 79 586 52 46
Fax: +41 32 944 21 32
E-mail: nkunz@digger.ch
Website: http://www.digger.ch