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A.T. Myers

Publications and source records attributed to A.T. Myers.

7 recordsLinked to original sources
USGS1969

Determination of rhenium in molybdenite by X-ray fluorescence. A combined chemical-spectrometric technique

Rhenium in molybdenite is separated from molybdenum by distillation of rhenium heptoxide from a perchloric-sulphuric acid mixture. It is concentrated by precipitation of the sulphide and then determined by X-ray fluorescence. From 3 to 1000 μg of rhenium can be measured with a precision generally within 2%. The procedure tolerates larger amounts of molybdenum than the usual colorimetric methods.

Talanta↗
USGS1961

A comparison of analytical methods used in geochemical prospecting for copper

Analytical methods used in geochemical prospecting for copper were compared by analysis of samples of residual soil collected in duplicate near a copper -bearing vein at the Malachite mine, Jefferson County, Colo. In this area barren or "background" samples have a mean copper content of 58 ppm (parts per million) and anomalous samples containing copper derived from the vein have a mean copper content of 216 ppm. Most anomalous samples are above 100 ppm and most barren samples are below. Geochemical prospecting tests, such as the spectrographic, biquinoline, dithizone and chromograph tests for copper and the citrate soluble and acid-soluble tests for total heavy metal, are almost as sensitive but are less precise and less accurate than standard quantitative trace analysis. Statistical techniques based chiefly upon the coefficient of variation show that the geochemical prospecting tests differ considerably among themselves in sensitivity, precision, and accuracy. This study indicates that the dithizone and the biquinoline tests for copper are the best for geochemical prospecting in this area.

Colorado↗
USGS1957

A truckmounted spectrographic laboratory for use in geochemical exploration

A truck-mounted spectrographic laboratory has been designed and built by the U. S. Geological Survey to investigate the feasibility of using and transporting such equipment in the field as an aid in supplying rapid on-the-spot analytical data to geochemical exploration field parties.The laboratory is housed inside a 7- X 12-foot insulated and air-conditioned van-type truck body and carries complete equipment for making qualitative, semiquantitative, and quantitative analyses of geological materials. The spectrograph is a fixed-position 1.5-meter grating instrument of the Wadsworth type which records a range of spectra from 2063 to 4837A in the second order on a 20-inch strip of film. Companion units are a projection type comparator-densitometer, a film processor, and other accessory equipment. Trailer-mounted motor-generators supply 230 volts d-c for the arc source unit and 115 volts a-c for lights and accessories.Since its completion in May 1955, the truck-mounted laboratory has been driven over 4,000 miles. During this travel all the equipment remained in good adjustment; the laboratory was made ready for operation in less than 2 hours after arrival at the site of a field project.Because of the large number of elements that can be determined from a single spectrogram, the truck-mounted laboratory is useful in the early stages of a geochemical exploration project to determine diagnostic suites of elements, and later, to guide the day-to-day sampling.

Economic Geology↗