"The more or less impure iron bearing mineral occurs mixed with a very tenacious clay, in which are also found chert, cretaceous quartz pebbles, pockets of sand, masses of pebbles and sand cemented by hydrous iron oxide, (which in some cases partly replaces the silica) and several varieties of fossils, such as crinoids etc. The impurities mentioned are often an integral part of the ore particles, and are present in varying quantities thruout [sic] the deposit. But, besides the foreign matter which the eye can discern, the apparently pure mineral contains a varying percentage of silica and alumina, (as well as traces of other elements) which no mechanical process could possible eliminate"--The Ore, page 3-4.
Mann, Horace T.
Mining and Nuclear Engineering
Professional Degree in Mining Engineering
Missouri School of Mines and Metallurgy
© Ernest Wander
Thesis - Open Access
Library of Congress Subject Headings
Iron ores -- Iowa
Iron ores -- Purification
Print OCLC #
Electronic OCLC #
Link to Catalog Recordhttp://laurel.lso.missouri.edu/record=b2609579~S5
Wander, Ernest, "The Goltra process of concentrating iron ores as developed at Waukon, Iowa" (1917). Professional Degree Theses. Paper 141.