I have driven this stretch of I-70 hundreds of times. One day while driving passed glanced up and noticed shadowing toward the base of the plateau I thought maybe it was a cave or something. Recently I mentioned this to a friend in Green River over lunch. Turns out he knew what it was and gave me some background information on the area as it was owned by his Grandfather.
Uranium Boom
In April 1948, in order to encourage domestic discovery and mining of uranium, and thereby decreasing the United States’ reliance on uranium from other countries, the Atomic Energy Comission (AEC) established a guaranteed minimum price schedule for the purchase or uranium and bonuses of $10,000 for new discoveries of uranium ore deposits. Thousands of would-be prospectors flooded the "four corners" of the Colorado Plataue hoping to strike it rich.
Uranium prospecting was popular enough with the public that you could even purchase prospecting equipment through the Sears Roebuck catalogue. Geiger counters came in a variety of styles and prices and were even featured in summer sales.
The uranium incentive period ended in 1956, although the AEC continued its uranium procurement program until the end of 1970. The AEC was abolished in 1974, and its functions transferred to the Nuclear Regulatory Commission and to the precursor of what would become the Department of Energy. Starting in the early 1980s, the market price for uranium began to drop as military demand waned and nuclear power demand slowed.
https://blogs.loc.gov/inside_adams/2021/09/prospecting-for-uranium/
Wickiup Mine
Fred A. Dunham of Grand Junction Colorado purchased land around the Wickiup in hopes of finding and mining uranium. He had a number of different uranium mines in the area none of which ever ended up productive any real amounts of uranium. Eventually his mines went belly up and he returned to Grand Junction, Colorado where he died at the age of 82.
Turns out the "cave" I was seeing was actually an unfinished uranium mine entrance. Once you get to the cache site you can continue East along the trail to see a second sealed mine opening as well as the unfinished entrance visible from I-70. The unfinished opening is roughly 6' x 6' and 10' deep and a short 0.2 mile walk from the cache location.