Author: Raymond Leroy Slovinsky

Publisher:

Published: 1958

Total Pages: 252

ISBN-13:

The term bentonite, if used in the correct mineralogical sense, refers to a clay composed essentially of the mineral montmorillonite and formed as the result of chemical alteration of volcanic ash in situ ... Two unique properties of bentonite, especially the Wyoming type bentonite with which this paper is concerned, are its ability to swell several times its original volume when placed in water and its ability to form thixotropic gels with water even when the ratio of clay to water is relatively small. These physical properties of bentonite are observed to vary considerably from one deposit to another and to vary considerably within a deposit. Since other minerals (viz. feldspar, biotite, quartz, pyroxenes, etc.) which commonly occur with the bentonite act only as diluents, it follows that observable variations in the physical properties of bentonite are due to variations in the mineral montmorillonite itself. The purpose of this study was to examine the clay mineral content of bentonites from three commercially important beds in the Black Hills Area in order to determine if possible: (1) what mineralogic variations exist (2) extent or degree of variations (3) possible effect of these variations upon the physical properties of the clay and (4) geologic significance of variations.