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United States

Hollister Mine

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Mine TypeUnderground
StatusInactive / Suspended
  • Gold
  • Silver
Mining Method
  • Cut & Fill
  • Longhole stoping
Backfill type ... Lock
Production Start... Lock
SnapshotHollister mine was acquired by Hecla Mining in July 2018. Since that time, mine's production and financial results have been included into the Nevada Operations Segment.

Production was suspended at the Hollister mine in the third quarter of 2019.

Future Plans
The Hatter Graben exploration area offers near-term potential within the district and future potential discoveries due to our advancing understanding of the controls of mineralization in the district through detailed mapping, sampling and evolution of the geologic model.
Related AssetNevada Operation


Hecla Mining Company 100 % Indirect
Klondex Hollister Mine Inc. (operator) 100 % Direct
Nevada Operations is 100% owned by Hecla Mining Company and was acquired on July 20, 2018 with the purchase of all of the issued and outstanding common shares of Klondex Mines Ltd. Nevada Operations containing operating or previously-operating mines: Fire Creek, Hollister and Midas.

Deposit type

  • Vein / narrow vein
  • Epithermal


Northern Nevada has a large number of very significant gold deposits. These are primarily related to the Carlin, Getchell, Battle Mountain – Cortez, and Northern Nevada Rift (NNR) trends. Two of these trends may be projected through or adjacent to the Mine area. The style of mineralization relating to these trends include the Epithermal Low Sulfidation mineralization along the NNR and the Carlin type mineralization.

In the Mine area, exploration and mining has been focused on three types of mineralization:
- Mercury in laterally extensive near-surface replacement silica zones and more localized sinter deposits, principally in the middle tuff unit;
- Disseminated gold in the middle and lower tuff units, andesite, and the Ordovician Vinini Formation beneath the hot spring mercury deposits; and
- Deeper high-grade gold-silver quartz-adularia veins and fracture zones in the Vinini Formation.

Hot spring-related silicification produced surface sinters, silicified bodies beneath the sinters, and widespread, generally bedding parallel, silicification in volcanic and sedimentary rocks. Cinnabar is the only ore mineral in these silica-rich deposits, and it is intergrown with chalcedony and opal (Wallace, 2003). All of the principal areas of known gold mineralization in the Mine area are associated with these silicified areas, occurring beneath them in underlying Tertiary or Paleozoic rocks at various depths below the principal silicified horizons.

Gold in the Mine orebody and in gold-bearing zones beneath the nearby Velvet and Clementine mercury mines is disseminated in the middle and lower tuff units and in an andesite. The lower tuff unit beneath the andesite is the main host rock at Hollister for disseminated mineralization. The deposit also occurs at a major facies interface, where lobes of basaltic andesite that extend from the southwest interbed with tuffs to the east, tapering north-easterly in the area of the deposit, and likely exerting a combination of both permeability-porosity control and chemical control on the position of mineralization (Rhys, 2014). Within the open pits, structural control to mineralization is secondary to stratigraphic control.

The open pit at the Mine exposes both oxidized and supergene parts of the orebody. Most of the tuffaceous rocks have been oxidized, and primary sulfides are preserved in parts of the andesite, the lower tuff unit, and in the Vinini Formation. Drill-core samples from the sulfide zone show that electrum and pyrite are the primary ore minerals, and adularia, quartz, and chalcedony are the major gangue minerals (Deng, 1991). Quartz veins in the Miocene rocks are uncommon and usually small.

Veins at the Mine contain the bulk of the high grade (greater than 0.3 opt Au) mineralization known within the property. The principal veins, Clementine and Gwenivere, comprise semi continuous vein systems with internal ore shoots, and local echelon steps or splays. The veins in mineralized areas typically range from 0.5 to 2.0 feet in width, but locally can be more than 5.0 feet in width. The veins are almost entirely hosted below the TertiaryOrdovician contact. Veins trend west northwest with steep dips and define a vein system over a strike length of more than 2,000 feet. Overall Ag:Au ratios vary within the vein system, generally increase downward, as is common in many epithermal districts.

The Hollister veins are narrow but long in strike length with ore in shallow plunging oreshoots which developed between 300 and 500 feet below the Ordovician-Miocene unconformity. The veins are dominantly extensional in character and show no significant displacement of the host stratigraphy across them. Miocene extensional west-northwest trending faults in the Vinini Formation are the primary control on vein mineralization.

Vein style is typical of low sulphidation epithermal veins and is closely comparable in mineralogy and texture to vein systems developed at the Midas deposit to the north, as well as other Miocene aged epithermal vein system in the NNR (Rhys, 2014). Metallic species in the veins include pyrite, marcasite, Ag-selenides and minor base metal sulphides (including chalcopyrite, sphalerite). Ag bearing phases, as determined by petrographic studies by Larson (1998) and Peppard (2002), are dominated by naumannite, with lesser acanthite, aguilarite, tetrahedrite, jalpaite, stromeyerite, cerargyrite, cervellite, native silver and uytenbogaardtite in decreasing abundance. Au is present mainly in electrum (Larson, 1998). Late Fe-Mn carbonate, barite and fluorite are locally present, the former two often in late voids and vugs.

The Clementine vein, the most continuous and longest vein, was the source of approximately half of the gold produced during underground mining to-date. The Gwenivere vein system contributed approximately 35% to gold production. Other veins that mainly surround the eastern Gwenivere vein, and parts of the Gloria vein in western portions of the mine, contributed the remaining portions of the Au-Ag mineralization. Oreshoots in the principal veins are developed for up to 600 feet below the Tertiary-Ordovician contact principally within the Paleozoic sequence. The Gwenivere Vein has been defined for roughly 700 feet along strike, 300 feet down dip, and is typically 0.5 to 2.0 feet wide, with local segments reaching 5.0 feet wide. The Clementine Vein has been defined roughly 500 feet along strike, 600 feet down dip, and is typically 0.5 to 2.0 feet wide. The Gloria Vein has been defined roughly 200 feet along strike, 100 feet down dip, and is typically 0.5 to 2.0 feet wide. Veins generally have a moderate degree of continuity, with the best grades occurring in ore shoots.



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Mining Methods


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Crushers and Mills

Milling equipment has not been reported.



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Hollister mine was acquired by Hecla Mining in July 2018. Since that time, mine's production and financial results have been included into the Nevada Operations Segment.
CommodityUnits2017LOM (Projected)
Gold oz 6,751
Silver oz 47,305
Gold Equivalent koz 7.4100
All production numbers are expressed as metal in doré.

Operational metrics

Ore tonnes mined 66,453 tons
Tonnes milled 28,870 tons

Production Costs

Cash costs (sold) Gold Equivalent USD 2,386 / oz  


Capital expenditures M USD 6.7  
Revenue M USD 6.7  
Operating Income M USD -24.1  

Required Heavy Mobile Equipment


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Mine Management

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