Mineralization at Fire Creek occurs in steeply dipping epithermal veins within Tertiary basalt flows and intrusive rocks. The mineralized basaltic rocks are a suite of mafic, extrusive rocks associated with the regional north-northwest-trending Northern Nevada Rift ("NNR") structural zone.

The deposit is a low-sulfidation epithermal deposit vertically-zoned within high-angle northwest striking structures, hosted in a mid-Miocene basalt package. Mineralization occurs as shallow structurally-controlled fault hosted gold mineralization in variably altered Tertiary basalts and as native gold in steeply dipping quartz-calcite veins or structures. A package of middle Miocene basalt and basaltic andesite flow has been cut by high-angle normal faults related to both NNR and Basin and Range extension that form grabens and half-grabens which are the structural controls in the district.

High-grade mineralization has been delineated between approximately 4,900 feet and 5,700 feet and is open both up and down dip as well as along strike. Lower-grade mineralization occurs from the surface and mineralization is open at depth. Vein textures, gangue minerals, and alteration seen at Fire Creek are typical of low-sulfidation epithermal systems. Widespread propylitic alteration changes to argillic alteration proximal to veins and/or other structural fluid conduits. Low-grade gold mineralization is often spatially associated with the argillic alteration zone surroundin ........

The Fire Creek mine is a trackless mine accessed by a decline, and has historically produced approximately 350 tons of ore per day. The mining method is primarily longhole stoping, with ramp access utilized.

Mining methods include several different techniques such as end slice stoping with delayed backfill, also referred to as longhole stoping, and drift and fill stoping.

Cemented rock fill (CRF), which consists of screened mine waste, fly ash, and cement is mixed on the surface and transported underground in the same trucks used to haul blasted rock to the surface.

Hollister includes an underground mine, former open pit mines, related mine support infrastructure, mining equipment, and administrative buildings, all of which are in operating condition.

The Hollister mine is a trackless mine accessed by a decline. Due to variability within the Hollister mine material, a selective mining approach is employed by matching mining methodology to stope characteristics. Hollister mining methods include cut and fill, ramp access and longhole stoping. The current Hollister mine plan primarily employs cut and fill stoping.

The Midas mine is a modern, mechanized narrow vein mine. The veins at Midas can vary in thickness from a few inches to over ten feet. Production at the Midas mine was suspended in the fourth quarter of 2019.

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