The first paleontological investigation of the cave deposits occurred in 1975. Kelly McGuire, then a graduate student at the University of California, Davis, excavated a 1m by 2m unit in Chamber 1.
McGuire published the results of his excavation in 1980 (see McGuire, K. R. 1980. "Cave Sites, Faunal Analysis, and Big Game Hunters of the Great Basin: A Caution," Quaternary Research 14:263-268). McGuire identified the bones of many different animal species, including those of extinct species such as shrub ox (Eucerotherium sp.), horse (Equus sp.), and the large-headed llama (Hemiauchenia sp.). McGuire also identified the bones of pronghorn (Antilocapra americana), mountain sheep (Ovis canadensis), pika (Ochotona princeps), and a variety of small carnivores and rodents, including skunk (Spilogale gracilis), fox (Vulpes vulpes), bobcat (Lynx rufus), coyote (Canis latrans), marmot (Marmota flaviventris), and woodrat (Neotoma cinerea). Although McGuire recovered charcoal from his excavations, these samples were not submitted for radiocarbon dating because of the mixed nature of the deposits in Chamber 1.
Thus, although the bones of extinct fauna indicated a Pleistocene age (sometime before 10,000 years ago), the precise age of the bones remained unknown. In 1997, the BLM, in cooperation with the Las Vegas and Reno branches of the Desert Research Institute (DRI), the Utah Geological Survey, and Intermountain Research, excavated several small test units in Mineral Hill Cave.