The 12.6 square-mile Aurora property is located in the northeastern portion of the Bodie Hills in Mineral County, Nevada, approximately 105 miles southeast of Reno, Nevada and hosts potential for the discovery of additional epithermal gold-silver deposits. Historic production of about 1.9 million ounces of gold occurred on the property from an anastomosing system of banded quartz-adularia-sericite epithermal veins.
Historical mining methods on the Aurora property include: underground mining in the 1800’s; open pits (Prospectus, Humboldt, Martinez, Juniata, Chesco, Last Chance and Ann; and underground mining (Prospectus portal and Martinez portal).The first 1.5 million ounces produced from the district averaged over 2 opt Au.
All production of precious metals in the district has come from banded quartz-adularia-sericite vines. Veins are typically composed of several generations of silica accompanied by variable amounts of adularia, sericite, pyrite, base metal sulfides, sulfosalts and electrum. Almost 100 individual veins have been identified at Aurora of which over 30 have seen production.
Aurora is located within the Walker Lane structural belt of Western Nevada. The Walker Lane is characterized by northwest-trending echelon right-lateral strike slip faults that have tilted and rotated structural blocks throughout its extent. Tectonism along the Walker Lane has occurred since at least the mid-Miocene and has continued through the Quaternary, thus encompassing the ore-forming and post-mineral period at Aurora. Most of the structures observed in Aurora can be related to shearing associated with Walker Lane tectonism.
The oldest rocks in the district are metavolcanics and granitic intrusive rocks related to the Sierra Nevada batholith. These rocks are unconformably overlain by a series of Neogene volcanic rocks and related intrusive phases that range in composition from andesite to rhyolite. These rocks are in turn overlain by local epiclastic deposits of probably Quaternary age. The youngest volcanic rocks in the district are various facies of Pleistocene basaltic eruptives.
The Aurora andesite is a sequence of andesitic volcanic rocks that lie unconformably on the Mesozoic granite intrusive rocks and are overlain by rhyolitic ash flow tuff of the rhyolite sequence. This andesite is exposed throughout the central portion of the district and virtually all precious metal production has come from veins hosted by the Aurora andesite.
The veins at Aurora are part of a large low sulfidation epithermal system consisting of an anastomosing set of quartz-adularia-sericite gold-silver mineralized veins that occurs predominantly in the N40-75E trending fractures. The highest-grade veins appear to be localized near their intersection with the N10E-striking Prospectus Fault. Fourteen major N45-70E trending veins and one large N10E trending vein occur in the main and southwestern portions of the district. The veins are hosed in the 15.5 – 13.4 Ma andesite sequence and vary in thickness from several centimeters to about 30 meters.
Three stages of veining have been identified at Aurora beginning with an early, coarse-grained quartz-dominate vein stage followed by a banded quartz-sericite-adularia veining stage with electrum, silver sulfides, sulfosalts and base metal sulfides, and lastly a coarse-grained quartz veining stage. A late stage calcite overprint is observed with vug-filling coarse calcite.
There remains a strong upside potential for new discoveries in the under explored 12.6 square mile property based on the extent of the veins systems and the unexplored extensions beyond the previous mining. In 2022, exploration drilling is planned to test high-grade vein extensions from historic production areas and the Sawtooth Ridge target area.