TungstenAccording to Richter, “Tungsten was discovered by the federal government in the 1930’s. The government did a mineral survey of the western United States; and what they were looking for was strategic metals. Tungsten is a totally different mineralizing event than the gold mineralization.
“Tungsten occurs in metamorphic rock and what we have here at the Stibnite mine is that you are in the middle of the Idaho batholith, which is a large body of intrusive granitic rock. As intrusive rock implaces itself into the surrounding rock, it engulfs the rock that existed here, which was sedimentary rock, and it bakes it. One of the by-products of that process is a mineral known as tungsten.
“The Trans-Challis Fault zone runs through Boise Basin, is about a 50-70 foot wide belt running north east, through the Idaho City area, through Cobalt, the Yellow Jacket mine, over outside of Challis, and up to Butte, Montana. It’s a northeast trending fault zone, a weakness in the earth’s crust. It is why the Idaho batholith is where it is.”