By
Mike Cecil
Head of Military Heraldry and Technology
Australian War Memorial

Mines – especially the big ones – can have a devastating effect on a vehicle and its crew. In Vietnam, the Australian Army was faced with a dilemma. The enemy was very adept at making and placing mines, and these were causing significant damage to military vehicles and their crews. Armoured Fighting Vehicles (AFVs) such as tanks and APCs were not immune. In 157 instances of operational damage recorded by Australian AFVs, 123 were caused by mines. The cost in equipment was one aspect, but the cost in crews was altogether another. Of 274 crew casualties, 113 were caused by mine blast, of these, 11 were killed outright and one died of his wounds later. By comparison, the next most frequent cause of AFV crew casualties were rocket propelled grenades (RPG), which caused 49 casualties of which 5 were killed.

Checking routes and clearing mines was a constant problem, and in an effort to improve the speed and efficiency of this task, a makeshift mine roller attachment was manufactured for a Centurion tank. Trialed in June 1969, it was not successful and further development was abandoned.

The Americans had a more sophisticated mine roller attachment for their M48A3 Paton tanks. The mine roller attachment consisted of two sets of 6 narrow rollers mounted independently below a cross-arm. Each roller had independent vertical movement but only for about 50mm – an important aspect when operating over uneven ground. It mounted to the front of the tank, and could be raised or lowered hydraulically. The hydraulics allowed the rollers to be pressed into the roadway, increasing the downward pressure in order to detonate anti-tank mines. The roller assembly did not span the whole width of the tank, covering only two paths slightly wider than the width of the tank’s tracks.

In August 1970, the Australian Task Force’s 1 Field Squadron received an M48A3 tank fitted with a mine roller attachment on loan from the US Army. Given the call sign 92T, it was put to work clearing roads and smooth tracks, as the limited independent travel of the mine rollers made it unsuitable for clearing rougher terrain. Nevertheless, the tank was used for clearing roads during the initial deployment of artillery to Fire Support Bases, ahead of resupply convoys, and on independent road clearing tasks. To overcome the gap between the roller sets, a large heavy rubber flap was attached between the roller arms to detonate any tilt-switch mines placed along the crown of the road. The mine roller attachment was effective, detonating several small mines, but did have its limitations. On 21 February, a large mine using a tilt switch detonator, slipped past the rollers and detonated under the vehicle. It damaged the hull under the driver’s compartment, fracturing his escape hatch.

The limitations of the system were again demonstrated all too effectively on 11 April 1971, when a large mine detonated under the left track, causing considerable hull damage. Mines that were detonated by a remote observer, rather than a contact switch, were immune to the roller system, and it was one of these that is thought to have caused the damage. The tank was replaced by the US Army while it was repaired on Guam, returning to the task force later in the year to continue its work. While the limitations of the system were well recognized (and amply demonstrated) during its time with the Australians, it was nevertheless effective in reducing the number of mines laid to catch unwary vehicles and their crews. There are no similar mine countermeasures that currently equip the Australian Army’s Abrams tanks.