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U.S. Geological Survey,

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Determinations of the quantity of solid material carried by the Colorado River are necessary for the proper consideration of plans for the development of the resources of the river. Much of the material carried by the river will be deposited in the proposed reservoirs and eventually will occupy a large part of the capacity of the reservoirs, so that their effectiveness for flood control or river regulation will be greatly decreased. A capacity of 6,000,000 acre-feet is reserved for silt storage in plans for a reservoir in Boulder Canyon that is to have a maximum capacity of about 25,000,000 to 30,000,000 acre-feet. It has been estimated that such a silt-storage capacity will not be entirely used for nearly 100 years.1...
Categories: Publication; Types: Citation; Tags: Water Supply Paper
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This document is the result of a workshop on coal description held for the Branch of Coal Resources of the U.S. Geological Survey in March 1982. It has been prepared to aid and encourage the field-oriented coal scientist to participate directly in petrographic coal-description activities. The objectives and past and current practices of coal description vary widely. These are briefly reviewed and illustrated with examples. Sampling approaches and techniques for collecting columnar samples of fresh coal are also discussed. The recommended procedures and methodology emphasize the fact that obtaining a good megascopic description of a coal bed is much better done in the laboratory with a binocular microscope and under...
Categories: Publication; Types: Citation; Tags: Circular
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The Christmas copper deposit, located in southern Gila County, Arizona, is part of the major porphyry copper province of southwestern North America. Although Christmas is known for skarn deposits in Paleozoic carbonate rocks, ore-grade porphyry-type copper mineralization also occurs in a composite granodioritic intrusive complex and adjacent mafic volcanic country rocks. This study considers the nature, distribution, and genesis of alteration-mineralization in the igneous rock environment at Christmas. At the southeast end of the Dripping Spring Mountains, the Pennsylvanian Naco Limestone is unconformably overlain by the Cretaceous Williamson Canyon Volcanics, a westward-thinning sequence of basaltic volcanic breccia...
Categories: Publication; Types: Citation; Tags: Open-File Report
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To measure the natural groundwater recharge process, two sites in south-central Kansas were instrumented with sensors and data microloggers. The atmospheric-boundary layer and the unsaturated and saturated soil zones were monitored as a single regime. Direct observations also were used to evaluate the measurements. Atmospheric sensors included an anemometer, a tipping-bucket rain gage, an air-temperature thermistor, a relative-humidity probe, a net radiometer, and a barometric-pressure transducer. Sensors in the unsaturated zone consisted of soil-temperature thermocouples, tensiometers coupled with pressure transducers and dial gages, gypsum blocks, and a neutron-moisture probe. The saturated-zone sensors consisted...
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