288 RADIOLOGICAL CLEANUP OF ENEWETAK ATOLL SOIL EXCISION AND WINDROWING After removal of brush from the Kickapoosite, the clearing was divideg into three equal areas for soil removal experiments using the front loader the grader, and the dozer. The experiments were recorded on video tape and still photographs. Where possible, excisions were made from the upwind portion of the lift area to minimize radiological hazards to the operators. Excisions were made from two sides toward the cente, resulting in elongated windrows. Each machine wastested by excisinga . inch layer over as much of its area as possible in 2-1/2 hours, placing the soil in windrowsas it was removed. Operators were aided by spotters on the ground. In soil removal, the front loader was employed in two modes. With the bucket down, closed and pushing forward, the loader operatedat a rate of 50-60 cubic yards per hour. It completed only 20 percent of its assigned area. Loader operations with the bucket open and scraping backwards achieved only half of that rate and proved to be generally inefficient. The grader completedits assigned area but stockpiled only 10 percent of the soil. In attempting to push even moderate quantities of soil to q stockpile, the grader only spun its wheels and churned ruts, mixing the underlying soil. The dozer excised and stockpiled nearly 80 percent of its area with moderate soil disturbance, which was easily corrected by backbladingthe area (Figure 6-6). It made acceptable cuts when operatedin the lowestgear and not required to push farther than 50 feet. With each successivelatera| cut, only 10 to 20 percent of the blade was used to make the new cut, and the remainingpart of the blade carried the last furrow and accumulatedsoil with it. For this 6-inch cut, it workedat a rate of 700-800 square metersper hour and accumulated a windrow ofdirt at the rate of 180-220 cubic yards per hour. With the experience gained from thesetests, it was easily recognizable that motorized scrapers would provide greater precision and efficiencyin soil excision. However, they were not available on the atoll. The dozer was easily the most efficient item of equipment on theatoll for excising soil and placing it in windrows (Figure 6-7). It was employed to complete thepilot soil removal project.64 For uninitiated dozer operators, a ground guide was used to give hand signals to direct the height of the dozer blade. After the operators acquired experience, they were generally able to obtain the desired cuts without the use of a ground guide.