Bentonite

Bentonite were first commercially mined and developed in the Rock River area during the 1880s. Some people moisten bentonite to be a perfect lubricant for squeaky wagon wheels. Another, early Americans found bentonite crucial to their lives. In 1920s, the first processing plant in Wyoming was built during this period. Since that the time many other processing plants have been built for the purpose of processing Wyoming sodium bentonite. In 1994, Wyoming’s bentonite industry produces over 4 million ton, and that was really amazing with 644 mine and mill employees, and 240 contractors. 

In addition, exploration for new bentonite beds is normally gifted with auger bit drilling. Once the auger drill stem reaches the soft bentonite it sinks very fast, which signifies to the driller that bentonite has been found. The auger flights are then withdrawn and the "sticky" bentonite is sampled from the flights for quality analysis. Bentonite is mined by surface "open pit" methods. Various types of heavy equipment including bull dozers and rubber-tired scrapers are used to remove the shale rock overlying the bentonite.

Topsoil, as well as the underlying material, is cautiously removed and stockpiled. These "overburden" materials as they are called will be placed back and reseeded once the bentonite has been removed. The bentonite which is bare during this process can be as little as 1 1/2 feet or as much as 10 feet thick. This is the material which is mined and processed.

Many bentonite manufactures prefer to "field dry" the exposed bentonite prior to hauling it to the processing plants. This is accomplished by plowing while taking advantage of the low humidity and sunny days to dry the bentonite prior to its removal. The moisture level prior to "field drying" can exceed 30%. This process will usually extract 15 to 20% of the moisture from the clay prior to hauling.