The Arizona Capitol Times reports on work recently completed to plug off old copper and gold mines from the early 1900s as a threat to visitor safety in the Grandview Historical Mining District in Grand Canyon National Park. A 50-foot deep shaft next to a popular hiking trail was filled in and other entrances had grates installed to continue to allow bats to move in and out. [right, Grand View/Last Chance mine, circa 1900, along the South Rim of Grand Canyon]
AZGS geologist Brian Gootee reports he's been in that mine at least 20 times. He notes that the ore body is in a breccia pipe which also contains uranium. A century ago the miners took the copper and gold but saw no value in mining the uranium. Today, northern Arizona is recognized as one of the richest uranium areas in the world.