Clay Spur, built in 1928, was the first bentonite processing plant in northeast Wyoming. Never heard of bentonite? Not many have, but chances are, you used something today that’s connected to bentonite.
Bentonite is a volcanic clay abundant in northeastern Wyoming. What makes it special is its ability to absorb water. Originally, it was used as drilling mud for oil wells. In the late 1950s, it started to be used as a binder in the process of converting iron ore into taconite. Bentonite is also used for lining dams and reservoirs because it will absorb water, swell up, and stop leaks.