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Steve Ludington

Publications and source records attributed to Steve Ludington.

47 records · Page 3Linked to original sources
USGS1983

A bibliography of stockwork molybdenite deposits and related topics (with an emphasis on the North American literature)

This bibliography of 1117 citations brings together references on stockwork molybdenite deposits and related topics in a format that can be sorted by topic and(or) geographic area. Each reference is preceded by a key, or keys, which may be read and sorted visually or by computer, The bibliography is available in two formats: (1) paper- or microfiche-hardcopy, and (2) fixed format computer reasonable magnetic tape, A FORTRAN program is provided for sorting the magnetic tape version,

Open-File Report↗
USGS1983

GRANNY, a data bank of chemical analyses of Laramide and younger high-silica rhyolites and granites from Colorado and north-central New Mexico

GRANNY is a data bank containing information on 507 chemically analyzed Laramide or younger high-silica rhyolites and granites from Colorado and north-central New Mexico. The data were compiled from both published and unpublished sources. The data bank is designed to aid in the recognition of igneous rocks with a high exploration potential for the discovery of molybdenum (and other lithophile element) deposits. Information on source reference, geographic location, age, mineralogic and petrologic characteristics, major constituent analyses, and trace element analyses for each sample are given. The data bank is available in two formats: 1) paper- or microfiche-hardcopy, and 2) fixed format computer readable magnetic tape.

Open-File Report↗
USGS1978

Comparison of the Wilfley concentration table and hand panning for concentration of heavy minerals prior to geochemical analysis

Chemical analysis of heavy—mineral concentrates of stream sediments is a common geochemical exploration technique used by the U.S. Geological Survey. Generally these concentrates are prepared by hand panning at streamside or in a washtub and then further concentrated using heavy—liquid (bromoform) techniques in a laboratory. Concentration using heavy liquids is slow, tedious, and expensive for large surveys such as mineral evaluation of wilderness areas. In addition the cost of bromoform is expected to increase greatly because most if not all chemical companies in the United States have ceased production of the compound due to problems in meeting the safety standards of the U.S. Environmental Protection Agency (E.P.A.). Preliminary studies by the E.P.A. suggest a severe health hazard may be incurred by inhaling vapors of or contacting the skin with chemicals like bromoform. Heavy—liquid concentration of thousands of heavy— mineral samples carries an unavoidable risk of exposure to bromoform. The risk, expense, and time required by routine heavy—liquid concentration of heavy minerals should be eliminated by finding other methods to satisfactorily concentrate minerals whenever it is possible. Heavy—mineral concentrates can be used in several ways in geochemical exploration and each way has certain standards for the nature and quality of the mineral concentration required. The nature of the concentration refers to whether the heavy minerals are analyzed in bulk or whether they are split into magnetic fractions using a hand magnet and possibly a Frantz Isodynamic Magnetic Separator.

Open-File Report↗