A study of student loans and their relation to higher educational finance

The Elements of economic geology

Bibliographic data

Monograph

Identifikator:: 1740343360

URN:: urn:nbn:de:zbw-retromon-116014

Document type:: Monograph

Author:: Cahn, Ernst http://d-nb.info/gnd/116401265

Title:: Das Recht der deutschen Sozialversicherung nach dem neuesten Stande der Gesetzgebung

Edition:: [2. Auflage]

Place of publication:: Berlin-Lichterfelde

Publisher:: Troschel

Year of publication:: 1926

Scope:: 201 S.

Digitisation:: 2020

Collection:: Economics Books

Usage license:: Get license information via the feedback formular.

50 ECONOMIC GEOLOGY percentage of manganese ; the price in 1920 rose to 3s. 10d. per unit, and since then has varied between Is. and 2s. per unit. There is a deduction if the silica is more than 8 or 10 per cent., and the phosphorus more than ‘I per cent. ; 10 per cent. of alumina and potash is usually the maximuin accepted. The leading manganese-producing countries now are India, Brazil, Southern Russia and Georgia! and the Gold Coast. Extensive deposits are known elsewhere as in East Africa, and many low-grade ores were mined during the War in the southern part of the United States. [For literature see the monograph by Fermor, Mem. G.S. India, xxxvii, 1909; R. A. F. Penrose, Ann. Rep. G.S. Arkansas, for 1890, , 1891; and L. Demaret, Les Principaux gisements des Minerais du Manganise, Ann. Mines Belgium, x, 1905, pp. 809-001.] CHrOMIUM Curomium (Cr; at. wt., 52:5; sp. gr., 6:5 ; melting-point, above 4500° F.) is mainly used as an alloy with steel, which 2 per cent. of chromium renders very hard and so tough that it may be bent cold. The addition of 13 to 14 per cent. of chromium makes rustless steel. Chromium compounds are used in dyeing, tanning, and bleaching. The chief mineral is chromite (FeO, Cry0,), which is a primary constituent of ultra-basic igneous rocks. The ore occurs as veins, lenticular nodules, and nodular masses in pre-Palzozoic igneous rocks that have been altered into serpentine or talc- schists, and occasionally as veins in unaltered basic rocks. The most important supply at present comes from Selukwe in Southern Rhodesia, where it occurs (A. E. V. Zealley, I'v. G. Soc. S. Africa, xvii, 1916, pp. 60-74) in lenses in talc- schists, and as granular patches in serpentine. Formerly the largest production was in New Caledonia, from veins or pockets in serpentine, and residual surface accumulations. The Canadian chromite mines may be illustrated by that at Lake Caribou near Thetford, Quebec. The ore isin serpentine, in a 30-foot band which has been intensely altered and charged ! A recent account of the commercial aspect of the Georgian de- posits is given by D. Zeretelli, Manganese Ore with Special Reference to Georgian Ore, London, 1928, 136 pp.

Access restriction

Copyright

fullscreen: The Elements of economic geology

Monograph

Table of contents

Download

Monograph

Chapter

This page

Image fragment

Citation links

Citation recommendation