Economic Geology Report 2

Author(s) Date 1974-12-31


Suspension properties of bentonites from the nine areas in Alberta where deposits are thicker than 1 foot indicate that production of high-swelling bentonite probably will remain limited to deposits presently being mined. Low yields, high grit content, or thick overburden reduce the desirability of other deposits.

The paucity of glass shards and the mineralogy of the sand and silt fractions suggest rhyodacite as the composition of the parent volcanic ash for each deposit. Absence of allogenic material indicates that differences in the amount of clastic constituents within and between deposits are the result of differences of original mineralogy and diagenetic alteration. Clay content can be related to the amount of sand-and silt-sized volcanic glass altering to montmorillonite. Evidence suggests no preference for diagenesis or adsorption from groundwater to explain the origin and distribution of Na, Ca + Mg, and Fe.

Multiple regression analysis of seven compositional properties shows that 81 percent of the variation in yield (bbl/T) of 15-centipoise mud can be attributed to their concomitant variation; however, 72 percent of the variation in yield can be attributed to one property (clay content). The remaining variables ( clay, exchangeable Na, exchangeable Ca + Mg, and contents and CEC) contribute little additional precision to the regression analysis when clay content is included in the equation

Scafe, D.W. (1975): Alberta bentonites; Alberta Research Council, ARC/AGS Economic Geology Report 2, 23 p.