16 Exploration was made early in the program to determine suitable sources of coral aggregate, and from samples tested by the Field Engineering Test Laboratory, possible reef locations were selected. As the program developed, estimates were made of the yardage of aggregate anticipated for the various areas and schedules were established for quarry and crusher opera- tions. The quarry operations were governed by the normal difficulties encountered in subaqueous excavations. Frequent shutdowns occurred because of high tides and wave action. The use of wagon drills and compressors mounted on trailers permitted drilling at a much highertide level than would have been possible if the standard wheel-mounted wagon drills had been used. To ensure maximum production with a minimum of operational interference-and as an added safety factor-all blasting was performed after regular working hours. Stockpiling of aggregate was both logical and economical. For areas re- quiring quantities of less than 1,000 cubic yards, CHAPTER I, SECTION 1 the steel components. Completion of the construction of the towers for Stations 5, 6, and 7 was held in abeyance until after the firing of the first shot due to the probability of damage. The tower and guy anchor blocks were provided for these towers, and Station 5 was built to the 75-foot level. After the first event, Station 5 was deleted from the program and construction of Stations 6 and 7 was completed on schedule - though under rigid Rad-Safe con- trol because of the widespread radioactive con- tamination of the area from thefirst event. The problems resulting from the tight construction schedule are well illustrated by those that arose in the procurement of materials for, and in theinstallation of, the pipe arrays. In the very beginning, procurement difficulties were encountered in obtaining pipe on acceptable delivery dates. After considerable canvassing of steel mills, pipe was found with acceptable delivery dates but a decision had to be made to accept certain sizes which were not in rigid aggregate was provided from the stockpiles at accordance with the specifications but were considered usable. Materials for the support sys- crete required at each site; these plants were available materials and fabrication at the Job- main production plants. Main batch plant locations were determined by the quantity of conestablished at Elmer, Fred, Yvonne, Ursula, Gene and Janet in Eniwetok Atoll, and at Nan, Tare, Fox and Charlie in Bikini Atoll. Concrete wasdelivered to the construction sites in transitmix trucks. Small concrete requirements, such as for anchor blocks and small instrument mounts, were precast at Elmer or Nan or were poured from small mixers. The amount of concrete poured monthly is shown in Figure 2-25, Chapter II. From 1 July 1954 through 1 May 1956, when concrete pouring for scientific structures was practically at an end, 210,000 sacks of cement and 2,757 tons of reinforcing steel had been used. The shot towers were designed to permit prefabrication of steel components in 25-foot modules and erection on the basis of 100-foot increments to a maximum of 300 feet. This provided for the 200-and 300-foot towers in one design, and simplified steel erection. To assure the proper matching of appropriate parts, a 75-foot section of a typical tower was first erected from parts selected at random by a Contractor’s inspector at the fabricator’s plant. Because of the time element involved, the drawings of the tower and guy anchor footings were re- leased prior to approval of the completed tower design. The site location of some towers required that several guy anchor blocks be located on reefs. In such cases a pile foundation was mandatory. This work, and the pouring of the concrete anchor blocks, was scheduled in accordance with tidal conditions and measures had to be taken to prevent loss of cement through wave action. The early release of draw- ings for the footings permitted steel erection to be undertaken immediately upon receipt of tem were late in arriving and substitution of site made it possible to maintain progress on this phase without a serious loss of time. Many of the components of the alignment system had to be rushed by air, and there was one case of jettisoning of urgently needed items by a plane in distress. An exceptionally high degree of cleanliness and freedom from rust in the interior of the pipe was required. Special measures taken before overseas shipment to ensure this cleanliness and rust freeness, accomplished during the period of record rainfall in California, proved inadequate and processing of the pipes had to be repeated at Jobsite. To accomplish this, it was necessary to airlift 12 tons of grit. Improvisations and repairs had to be effected at the Jobsite to the project-furnished vacuum pumps to make them operable. Last-minute revisions in the location of a few pipes were required. By concentrating the available competent craftsmen, using over- time and shift work, and with the acquisition of additional welding equipment on a loan basis from Military Agencies at Kwajalein and Eniwetok, the pipe arrays were readied in time, and were integrated into the test program without adjustment. The island of Yvonne, approximately 8,700 feet long with an average width of 550 feet, was thesite of 191 scientific stations. Complexity was introduced by locating so many stations in such a small area, and by the multiplicity of the changes in location and requirements for the stations and the late dates at which these were received. Many of the stations had to be completed as scheduled since they were vitally required for the first test. Continuous surveillance of all factors affecting construction Page 1-15