Operation Enogerra DPR/TV/412

Australian Army engineers moved into the first operation, Operation Enoggera, carried out by the Sixth Battalion, The Royal Australian Regiment, in Phuoc Tuy Province, South Vietnam, in the fourth week in June. Main Task of the engineers, many of whom had had previous experience with the First Battalion based until recently at Bien Hoa, was to search and destroy a large and complex Viet Cong tunnel network known to exist in an enemy village in the sixth Battalion operational area. The Australian sappers entered the tunnels through a small shaft and began a systematic exploration armed only with pistols and torches, and reported constantly the height, width and bearings of the twisting system by field telephone to officers and other sappers on the surface. Each bearing and change of direction in the tunnels was carefully recorded until the engineers had compiled a complete diagram of the tunnels extending over several thousands of yards. The job was hot and tiring for the underground engineers, who named themselves "The Tunnel Rats". Frequently the tunnel roofs were so low that they were forced to crawl on their bellis to continue the exploration. In some places they were able to walk upright, but mostly they crwaled on all fours or waddled along the tunnels in a semi-upright posture. Emerging from other shafts at infrequent intervals for a breath of fresh air, the soldiers were caked with mud formed by contact with the tunnel walls and profuse sweating in the hot, humid underground atmosphere. Following mapping of the system, engineers brought in an experimental machine to force a fog of unburnt diesel fuel through the system at pressure. The purpose of the fog was to force open trapdoors in the system and reveal hitherto undiscovered entrances to the tunnels. Once the engineers were satisfied they had sealed all the entrances, charges were detonated in the tunnels to collapse them and make them useless to the Viet Cong. One access to the tunnel system was discovered leading from inside a village well. The Sappers could not reach this opening from inside a village well. The Sappers could not reach this opening from the surface, so lowered a heavy charge in a bucket to seal off the aperture. The blast detonated deep down the well shaft, and collapsped the tunnel wall. An attempt was made to collapse the whole tunnel system by filling it with unburnt diesel fuel fog, but the mixture failed to detonate. Demolition then was continued with conventional explosives.