ground complex. A patrol was organized from the staff sections of the 1st Engineer Battalion and was led by the sympathizer to the tunnel area where he pointed out several air holes and firing ports. Further examination of the area uncovered a base camp with several tunnel entrances.

The next day, after posting security forces, a thorough search of the tunnels was begun by engineer tunnel rats with initial negative results. Then a breather hole was blown open revealing the entrance to hundreds of meters of additional tunnel. About six hundred meters into the tunnel the engineers ran into an accumulation of CS, and the exploration stopped. The many documents found in the complex were taken to the G-2 of the 1st Division; upon evaluation of the papers, the G-2 determined that the search of the tunnel complex should be continued.

Next day the engineer tunnel rats returned accompanied by their counterparts from the attached chemical platoon. After exploring an additional 800 meters of tunnel, they found and removed a trapdoor, disclosing additional chambers and documents. Over one kilometer of tunnel had now been uncovered. Further exploration revealed an exit leading to another enemy base camp.

The exploration continued the following day, and more documents were uncovered and evacuated. As the tunnel rats crawled through the complex, they heard enemy voices. A CS grenade thrown by the team flushed five Viet Cong from the tunnel; they were captured as they scrambled out. Above ground; the security elements found a former hospital base camp complex 300 meters north of the camp discovered the previous day, and an investigation of tunnels of this complex was begun.

Early the next morning, the fourth day of exploration, the tunnel rats returned to the former hospital complex. Five huts were unearthed, each dug into the ground so that the roof was at ground level. Medical textbooks and notebooks, small quantities of medicine, and medical instruments were discovered in the 300 meters of rooms and chambers. The tunnel team returned to the second tunnel complex where the Viet Cong had been flushed, but CS in the tunnel prevented further exploration. Tunnel destruction personnel from the 168th Engineers arrived that afternoon and remained at the overnight position.

On 26 January, the day CEDAR FALLS terminated, the tunnel destruction team left for the former hospital complex and the exploration team returned to the "CS tunnel" complex. Using conventional demolitions and acetylene equipment, the team rigged