From approximately the 24th June, reports had been received that the Headquarters and other elements of D440 were located west of Night Defence Position Kylie in an area known to the Vietcong as the Tre (Bamboo) Base. This area had been a traditional location for the Vietcong for years and recently was known to have been used by D440 on many occasions. The area which had been searched by 8 RAR before, consisted of a number of well constructed bunker systems surrounded by very thick bamboo clumps. It was well hidden from the air and was protected by the bamboo, making going for infantry and tanks particularly difficult.

The reported location was from a reliable source and the presence of the enemy headquarters made the target extremely valuable, even though the total number of enemy would probably not number more than forty. 

Lieutenant Colonel O'Neill's concept was based on deploying the maximum number of troops roundthe enemy location in as wide a cordon as practicable. Blocks in the cordon were to be provided by half platoon ambushes, with sections of APCs and tanks in depth to the infantry. Once the blocks were positioned on the best available egress routes, a massive bombardment with both guns and air would be brought down on the enemy location, covering a wide area and all suspected positions. Following the bomb ardment two companies would carry out a reconnais sance in force, one company with tanks to the main bunker systems and one on foot against a nearby location to the west.

To continue the pressure on the tri-village complex W Company, 2 RAR-NZ and the Defence and Employment Platoon of Headquarters Company 1 ATF were placed under operational control of 8 RAR. The Mortar Platoon of 2 RAR was also placed under operational control, as were a squadron minus of tanks and a troop of APCS. 

On 29th of June B Company and C Company deployed by air from Nui Dat to their blocking positions. C Company was to block in the vicinity of the Ap Cu Bi rubber on the south east side of the area with B Company blocking to the west and north west. A Company deployed by APC from Nui Dat direct to their blocks to the north and north east and D Company by air from Le Loi to the southern block position. Between each company was a sector designated for blocking fire which provided a buffer on the flank and ensured that half platoon ambushes on the extremities did not clash.

The deployment went according to plan and on the 30th the companies moved their platoon and half platoon ambushes to cover the most likely withdrawal routes. By last light the blocks were positioned with the tanks and APCs in depth to the infantry. The Mortars of 2 RAR were deployed to Le Loi and the 8 RAR Mortars were split and moved to the south west and north west of the blocks to cover the B and D Company locations. On the same day a battery of US 155 MM self propelled guns and a battery of 8 inch guns moved to Le Loi to prepare for the bombardment on the following day.

On the lst July with all companies in their platoon and half platoon blocks the bombardment of the suspected enemy locations began. The guns were followed by an air strike, which was in turn followed again by guns. In all, over 2000 105, 155 and 8in. rounds were used plus 48 5001b. bombs.

The bombardment had the desired effect as at 1020 hours D Company in the southern block', sited about ten enemy at a distance, moving south, who appeared to be reconnoitering a route out of the blocks. Tank and artillery fire were directed on them and they changed direction and moved back to the north. Results of the incident were unknown.

Immediately following the intensive artillery preparation and air strikes, platoons of A and B Companies with tank support conducted reconnaissance in force south towards the suspected enemy position. Large numbers of bunkers were located by A Company and on the following day these were destroyed as the reconnaissance continued.

One group of 20 bunkers located on the 3rd July by A Company had been occupied the previous day and on the fourth after more bunker destruction the company began to follow up tracks to the south east. That same day 1 Troop B Squadron of 3 Cavalry Regiment in one of the most northern blocks contacted eight enemy of whom three were killed by APC fire.

On the 6th July B Company after little contact of any significance, captured one enemy soldier. The soldier claimed to be a Hoi Chanh and on interrogation provided information that he was a member of the medical platoon of headquarters 274 Regiment. He also gave details of an area to the north west on the border of Phuoc Tuy and Long khan where he stated there was a large hospital complex with a number of wounded. Acting on this information the CO redeployed A and C Companies on the 7th and 8th to surround the area on three sides with the 1-5 Mechanised Battalion (US) newly arrived from Cambodia, providing the northern blocks.

On the 6th and again on the 7th 5 Platoon B Company located large caches, the second containing at least 1800 lbs. of rice and 250 lbs. of noodles which were destroyed. Also on the 6th an APC with D Company soldiers on board detonated a 101b. mine wounding four of the company and two cavalrymen. Both B and D Companies were now relocated in the area of the "triangle" and much evidence of movement was apparent.

On the 8th, C Company when moving forward with the Hoi Chanh to locate the hospital, contacted an unknown number of enemy in bunkers and were eventually relieved by 1 Troop of the Armoured Squadron who restored the situation after the Support Section had been pinned down by heavy fire.

After a number of "dry" days 2 Platoon A Company raised spirits all round by killing three enemy of 274 Regiment and wounding one, out of a party of five contacted in their block to the west. The following day another enemy was killed by 3 Platoon A Company again in its blocks.

The Hoi Chanh although he had given valuable information and had led C Company to occupied bunkers, was unable to locate the hospital complex he claimed existed in the area. On the 11 th B Company returned to ambush round Hoa Long and D Company moved back to the tri-village complex. All the remaining companies were withdrawn to Nui Dat on the 11th, ending Operation Petrie.

Although Petrie had been mounted on reliable intelligence concerning D440's location and further redeployment had taken place on detailed information from the Hoi Chanh, there was little to show by way of enemy eliminated. This was due as much to the small number involved, as to their proven elusiveness. One very notable result of Petrie and the preceding pressure on D440 was an instruction from Ba Long (VC) Province Headquarters to the Battalion to move out of Phuoc Tuy into Long Khanh. From this fact alone, the operation had achieved at least some significance. 

Results of the operation were:

Enemy

KIA 10

WIA 2

PW-Hoi Chanh 1

Weapons Captured

Small Arms 7

Chicom Mine 1

Food Captured

Rice 2014 lbs.

Salt 6 1 bs.

Miscellaneous 481 lbs.

Own Casualties