Groundwater test well D was drilled to a depth of 1,950 feet with rotary and cable-tool drilling rigs. It penetrated alluvium from 0 to 1,505 feet; tuff of Tertiary age from 1,505 to 1,730 feet; talus (?) breccia from 1,730 to 1,750 feet; and rocks of Mississippian to Pennsylvanian age from 1,750 to 1,950 feet. The Paleozoic bedrock in the depth interval from about 1,750 to 1,840 feet is composed mainly of interbedded dolomite and limestone; in the interval 1,840 to 19950 feet it consists of argillite. The static water level is about 1,733 feet below the land surface (altitude, 2,417 feet). The aquifer in test well D comprises the talus (7) breccia and the carbonate rocks in the interval from 1,730.to 1,840 feet. Tests by bailing indicate that the minimum transmissibility of the aquifer is about 90 gallons per day per foot. The specific capacity was less than 0.3 gallons per minute per foot after 3 1/h hours of bailing at a rate of 18 gallons per minute. These tests also indicate that the transmissibility of the argillite stratum underlying the aquifer is extremely low. A suite of geophysical logs, a summary of contract costs, and detailed descriptions of the drilling machines, drilling operations, and the casing and cementing operations are presented.
Underground detonations may produce observable effects in surrounding aquifers and wells. The nature and the duration of the effect at any observation point seem to depend on several factors such as the amount of energy released by the detonation, the geologic environment, the position of the buried explosive device in relation to the saturated zone, aquifer characteristics, and the distance from point of detonation. Precise measurement of these effects in wells presented numerous technical problems and resulted in the development of specialized techniques. Initially, these effects were observed by measuring the fluctuation of the free water surface in wells. The current technique employs high‐resolution pressure transducers deep in the water column. Pneumatic packers may be used to restrict the movement of water into the well. Data are recorded on high‐speed oscillographs.
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