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Description of the Krohn Mechanical Mine Clearance System, KMMCS
ORDNANCE AND EXPLOSIVES CONSTRUCTION SUPPORT
COMBAT MANEUVER TRANING CENTER HOHENFELS, GERMANY
Field Test of a Mechanical Demining System
On an Impact Area
From 26 June to 29 July 2000, the U.S. Army Corps of Engineers (USACE) tested the effectiveness of the Krohn Mechanical Mine Clearance System (KMMCS) at an ordnance project at Combat Training Center, Hohenfels, Germany.
The KMMCS was used to assist in the subsurface clearance of an impact area
for antitank ordnance.
The site had also been used as a demolition area for many other kinds of ordnance.
Several factors led to the decision to test KMMCS.
Concentrations of unexploded ordnance (UXO), ordnance scrap and target scrap
were much heavier in the target area than had been expected.
The clearance team had spent 8 days clearing one 25- by 25-meter grid to a depth of 4 feet, removing 61 UXO items and 2450 pounds of OE scrap and target scrap.
Clearly, production was falling behind and other means of clearance must be explored.
At about the same time, USACE learned of the KMMCS through another clearance
effort that had been performed at Hohenfels.
The proposed cost for testing the KMMCS, approximately $9700 per acre, was significantly less than the estimated cost of clearing manually.
This suggested a partial solution to the production problem.
The USACE was also interested in trying innovative technology, and the customer
was supportive of the effort.
The owner claimed that this machine could withstand detonations of up to 22 pounds (10 kilograms) net explosive weight of TNT. The machine could till the soil and destroy surface and subsurface anomalies to a depth of approximately 1 foot.
It could travel at the rate of about 1 mile per hour.
Under ideal conditions this would result in a clearance rate of about 6 acres per 10-hour day.
The USACE was eager to test these claims and the Corps contractor, EODT Inc., was receptive to the prospect of trying out the system.
The description and function of the KMMCS
The KMMCS consists of an armor plated, track driven vehicle, equipped with a front mounted tiller system that includes a roller with teeth and a thick steel shroud
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attached to hydraulically operated arms. The roller is driven by two hydratilic motors, which are built into the roller for protection, and can be rotated clockwise or counterelockwise. The complete clearance system includes two different tiller systems, coarse and fine that can be interchanged in approximately 5-hours.
The machine can till the soil and destroy surface and subsurface anomalies to a depth of 30 cm, and travels at the rate of approximately 1-kilometer per hour. This results in a total clearance rate of approximarelly 40,000 square meters, per 10-hour day under ideal conditions.
The coarse tiller- system is intended for first and second pass and can be rotated at a rate between 80 rpm and 130 rpm. The roller is 3 meters long, approximately 22 cm in length, 25 cm in depth and 4 cm thick. These teeth are offset on the roller to ensure complete excavation of subsurface anomalies during each revolution. As the machine travels forward, this offset combined with a counterclockwise rotation of the roller will loosen the soil and shred Vegetation, stone, land mines and UXO from the surface and subsurface of the ground
Front View of the coarse system
Side view of the coarse system
The fine tiller system is intended for mineing the loosened soil and anomalics after the coarse system has completed its tilling. This system consists of two rollers in mounted tandem, and is attached to the vehicle similar to the coarse system. The front roller is 3 meters long, approxmtely 37cm in length, 20 cm in depth, and 3 cm thick. These teeth are mounted closer together than the coarse system with two protrusions designed to shred anomalies.
The front roller and teeth of the fine system
The second roller is mounted 15 cm behind the front roller and is much smaller in diameter, with longer teeth mounted even closer together than the front roller. The front roller rotaates clockwise at a rate of 120 rpm, and the second roller rotates counterclockwise at a rate of 700 rpm. These two rollers working together fine till the soil an all anormalies, leaving a smooth hazard free surface suitable for planting crops.
Both the coarse and fine systems have proven to withstand a blast fromanti-tank mines containing as much as 9 kg of TNT. The operator' s compartment is protected from sound, metallic fragments, as well as over pressure caused by the blast. The KMMCS eliminated the hazard from approximately 20.000 land mines, including 2.000 fragmentation mines without damage to the machine or harm to personnel.
The KMMCS is now being tested at CMTC Hohenfels, Germany on Range 5RL, which was used as adirect fire anti-tank range. The terrain is relatively flat with brush and covered with heavy grass. Because the range was used as a direct fire anti-tank range, tank hulls, APC hulls, and other armor type vehickles were placed on the range ans used. The large pieces of these targets were removed prior March 2000. However pieces of these targets, such as tank treads, tank wheels, and other thick pieces of target residue remain on the range. EODT was ableremove or flag some of these large pieces of target residue prior to commencing tilling activities. However, because of the heavy grass cover and length ot time since the range was last used, countless pieces of target residue beneath the heavy grass cannot be detected without a magnetometer. During coarse tilling operations, the large pieces of target scrap have gotten jammed between thr roller and the shroud, requiring work stoppage and mechanical removal.
The KMMCS performing coarse tilling operation at Range 5 RL
The remains of a 66mm LAW that was detonated by te KMMCS
The remains of a 3,5 inch rocket motor, after the first coarse pass
After the first pass, EODT has been removing all visible target scrap to aid in the tilling rate. In addition, EODT recommends that when tilling operations are conducted on any range that contained heavy metal targets, such as tank hulls, and APC hulls, as much of this scrap be removed prior to tilling as possible.
The remains of a tank wheel and the first coarse pass
At Range 5RL, EODT has been tasked to perform a subsurface clearance to a depth of four feet. Because Herr Krohn had a prior commitment, this tilling operation was determined to be cleared to the KMMCSs minimum depth of 30 cm (approximately 11 inches). In addition, there is countless pieces of target scrap, as well as UXO scrap EODT and the US Army Engineering and Support Center Huntsville (USAESCH) have determined not to use the fine tilling system. The fine system is designed to shred all anormalies into small pieces, which will make subsurface detection of possible anomalies below a depth of 30cm difficult to detect, with magnetometers or geophysical instruments.
After the first 12 hours of operation, and 2 hectars tilled EODT and the USAESCH have been pleased with the operation of the KMMCS and are looking forward to completing this test.
EODT UXO Technicians removing target scrap, and UXO scrap after the first coarse pass by the KMMCS
A 2,25 inch rocket motor brought to the surface during the first coarse pass of the KMMCS.
The dark area was cleared by KMMCS
KMMCS - Maschinelle Minenräumung und Bodensanierung
(KMMCS - Mechanical Mine Clearance and Soil Rehabilitation)
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