Helena and Ennis Talc Deposits

The purpose of this report is to collect geologic data concerning two Montana talc occurrences at Helena and Ennis and to offer some explanation as to their origin. The two deposits cited are in somewhat similar lithologic settings and both possess the same mineralogical and structural features. Because of this similarity only the Helena deposit is covered in detail.

Economic Talc Deposits of Montana and Related Firing Problems

This thesis has to do with a study of the produc­tion of talc in Montana, describing the local geology of each deposit, and a description of the laboratory tests that were made on various grades of Montana talc in an attempt to determine why some grades of talc can be burned in solid forms while others must be ground, mixed with a binder and molded.

Montana Talc; Problems in Physical Properties

General information on talc, including foreign and United States occurrences, origin, and uses is covered. Montana deposits are discussed in greater detail as to location, geology, mineralogy, and mining. Studies of talc by petrographic and x-ray methods and an experiment to determine the porosity are described and discussed.