The Tyro Mine is near Bullhead City, Arizona. Historically the site has been associated with the Union Pass Mining District which is now part of the Mount Nutt Wilderness. The Tyro Mine is a underground mining operation. Mine operations consist of underground workings. There is one known shaft. Subsurface depth reaches a maximum of 152 meters (500 feet). The ore mined is composed of gold and silver with waste material consisting primarily of calcite and quartz. The ore is lode in form extending 1,219 meters (4,000 feet) long and 18 meters (60 feet) wide. The mineralization at this location is from the Pliocene epoch 5.33 to 2.58 million years ago. The Mexican Highland of the Intermontane Plateaus characterize the geomorphology of the surrounding area.
During 1915 and 1916, the Tyro shaft was sunk to a depth of 500 feet, and some drifting was done on the 200-foot level. Some ore was produced from small pockets near the surface. During 1933-1934, W. E. Whalley and C. F. Weeks, lessees, built a road from the mine to the Katherine highway and began production from surface cuts on the vein. Here, coarse-grained gneissic granite, cut by numerous narrow dikes of rhyolite-porphyry, forms rugged topography. The vein strikes northeastward, dips 85° SE., and forms a stringer lode with a prominent outcrop some 1,800 feet long by 20 to 35 feet wide. The stringers, according to Lausen, consist mainly of granular white quartz with platy calcite and, in places, glassy, yellowish quartz of probably the second stage of deposition. He states that the vein was not found in the deeper workings of the mine.