Department ol' Defense (USMC) Photo A190381
The photo shows the power of the resulting explosions. The axle
wheels of a truck that was parked at the dump are the only identifiable
remains of the vehicle seen strewn among the wreckage.
which in turn submitted a modification to MACV for approval. Following
a preliminary planning conference which included representatives from
MACV, Seventh Air Force, Seventh Fleet, III MAF, and Prov Corps, General
Creighton Abrams, the MACV commander, approved the plan on 21 June,
with D-Day set for 1 July.
To ensure that the operation, codenamed Thor, would be a success, several preparatory steps were taken. As a deceptive measure, work continued on Dyemarker or "McNamara" Line positions at A-2, A-3, and Con Thien to cover the construction of several forward artillery positions. In addition, the large amount of artillery ammunition, heavy artillery, and supporting ships were moved inro place by 30 June. The destruction of the Dong Ha ammunition dump by enemy artillery on 20 June also in an ironic way helped the deception. According to Marine staff officers, the blast at the dump "practically blew the 3d Marine Division headquarters off of the map" and left the division "desperately short" of artillery ammunition.17 The execution of a massive supporting arms attack so shortly after a huge loss of ammunition seemed out of place, especially since the bulk of the artillery forces engaged in the attack would have to depend on the Dong Ha ammunition dump for supply.
Preceded by three days of target reconnaissance by both Marine and Air Force aircraft, the first phase of the operation began as scheduled with a massive bombing effort against the sector. Controlled by Seventh Air Force, 664 Marine, Navy, and Air Force attack aircraft and 114 B-52 sorties delivered more than 4,000 tons of ordnance against predetermined enemy targets during the first two days of the operation. In phases two and three, the artillery fire of 13 batteries, composed of 59 guns, was integrated with the naval gunfire support of two cruisers and six destroyers and the continuing air attacks against target lists which were continually updated by 1st Marine Aircraft Wing reconnaissance flights.
On the morning of 8 July, the artillery batteries involved in Operation Thor began withdrawing from their forward positions and by the 10th had returned to their normal support locations.18 Also on the 8ch, control of the area reverted from Prov Corps, which since 1 July was under Army Lieu-