The Hollister Mine (Ivanhoe Mining District), which Hecla acquired in July 2018, is located in Elko County, approximately 130 km (~80 mi.) northeast of the town of Winnemucca, Nevada and 29 km (~18 mi.) southeast of the Midas Mine.
The Hollister Mine is a large, very well preserved low-sulfidation, epithermal gold-silver deposit associated with mid-Miocene bimodal volcanism of the NNR. Over 115,000 ounces of volcanic-hosted, low-grade gold were extracted from 2 open pits. Later drilling led to the discovery of blind, high-grade veins in the Valmy Formation, Paleozoic basement rocks, which have produced >450,000 ounces of gold and >2.5 million ounces of silver from ore averaging ~34 g/t Au (1.00 opt) and 200 g/t Ag (5.83 opt) from cut-and-fill and longhole stoping since 2007. Typical epithermal vein textures are displayed at Hollister, most commonly massive, banded, bladed quartz, and vein breccias. Other features spatially related to the highest grades include the presence of banded quartz, bladed quartz, and alunite.
The mine is located along the Northern Nevada Rift (NNR) which is a major, north-northwest to south-southeast trending structural feature that that extends for at least 300 miles, from south-central Nevada to the Oregon-Nevada border. This is on trend with the north-western end of the Carlin Trend, which is approximately 5 miles wide and 40 miles long. Mineralization is related to the Miocene period of magmatic activity associated with the NNR while gold mineralization on the Carling Trend has been dated to late Eocene/early Oligocene magmatism.
Epithermal disseminated gold mineralization is hosted in volcanic tuffaceous units, andesites, and the Ordovician Vinini Formation. High-grade gold and silver mineralization is hosted as banded quartz veins in a group of near-vertical faults and fissures that trend west-northwest to east-west. The amount of displacement across these faults is small and their strike continuity varies between one hundred to several thousand feet. Primary lithologies in the area have been strongly altered by hydrothermal fluids with large areas of chalcedonic replacement bodies at the paleo water table in addition to sinter deposits.
|(years ended December 31)|
Information with respect to measured, indicated and inferred resources is set forth below.
|(As of December 31, 2021 unless otherwise noted)|
|(000)||(oz/ton)||(oz/ton)||(000 oz)||(000 oz)|
|Total M&I Resources (1,2)||88||2.5||0.58||217||51|
|Inferred Resources (1,2)||642||3.0||0.42||1,916||273|
- (footnotes)Note: All estimates are in-situ. Resources are exclusive of reserves. Totals may not represent the sum of parts due to rounding.
(1) Mineral resources for Fire Creek, Hollister and Midas are reported using $1500/oz gold and $21/oz silver prices, unless otherwise noted. A minimum mining width is defined as four feet or the vein true thickness plus two feet, whichever is greater.
(2) Hollister mineral resources, including the Hatter Graben are reported at a gold equivalent cut-off grade of 0.238 oz/ton. Metallurgical recoveries: 88% gold, 66% silver
Reporting requirements in the United States for disclosure of mineral properties as of December 31, 2020 and earlier are governed by the SEC’s Securities Act Industry Guide 7, entitled “Description of Property by Issuers Engaged or to be Engaged in Significant Mining Operations” (Guide 7). Effective January 1, 2021, the SEC has issued new rules rescinding Guide 7. Mining companies are not required to comply with the new rules until the first fiscal year beginning on or after January 1, 2021. Thus, the Company will be required to comply with the new rules when filing its Form 10-K for the fiscal year ended December 31, 2021. The Company is also a “reporting issuer” under Canadian securities laws, which require estimates of mineral resources and reserves to be prepared in accordance with Canadian National Instrument 43-101 (NI 43-101). NI 43-101 requires all disclosure of estimates of potential mineral resources and reserves to be disclosed in accordance with its requirements. Such Canadian information is included herein to satisfy the Company’s “public disclosure” obligations under Regulation FD of the SEC and to provide U.S. holders with ready access to information publicly available in Canada.
Reporting requirements in the United States for disclosure of mineral properties under Guide 7 compared to the new SEC rules (Item 1300 of Regulation S-K under the Securities and Exchange Act of 1934) and the requirements in Canada under NI 43-101 standards are substantially different. This document contains a summary of certain estimates of the Company, not only of Proven and Probable reserves within the meaning of Guide 7, but also of mineral resource and mineral reserve estimates estimated in accordance with the new SEC rules and definitional standards of the Canadian Institute of Mining, Metallurgy and Petroleum referred to in NI 43-101. Under Guide 7, the term “reserve” means that part of a mineral deposit that can be economically and legally extracted or produced at the time of the reserve determination. The term “economically”, as used in the definition of reserve, means that profitable extraction or production has been established or analytically demonstrated to be viable and justifiable under reasonable investment and market assumptions. The term “legally”, as used in the definition of reserve, does not imply that all permits needed for mining and processing have been obtained or that other legal issues have been completely resolved. However, for a reserve to exist, Hecla must have a justifiable expectation, based on applicable laws and regulations, that issuance of permits or resolution of legal issues necessary for mining and processing at a particular deposit will be accomplished in the ordinary course and in a timeframe consistent with Hecla’s current mine plans. The terms “Measured resources”, “Indicated resources,” and “Inferred resources” are mining terms as defined in accordance with the new SEC rules and NI 43-101. These terms are not defined under Guide 7 and prior to January 1, 2021, were not normally permitted to be used in reports and registration statements filed with the SEC in the United States, except where required to be disclosed by foreign law. The term “resource” does not equate to the term “reserve”. Under Guide 7, the material described herein as “Indicated resources” and “Measured resources” would be characterized as “mineralized material” and is permitted to be disclosed in tonnage and grade only, not ounces. The category of “inferred resources” is not recognized by Guide 7. Investors are cautioned not to assume that any part or all of the mineral deposits in such categories will ever be converted into Proven or Probable reserves. “Resources” have a great amount of uncertainty as to their existence, and great uncertainty as to their economic and legal feasibility. It cannot be assumed that all or any part of such a “resource” will ever be upgraded to a higher category or will ever be economically extracted. Investors are cautioned not to assume that all or any part of a “resource” exists or is economically or legally mineable. Investors are also especially cautioned that the mere fact that such resources may be referred to in ounces of silver and/or gold, rather than in tons of mineralization and grades of silver and/or gold estimated per ton, is not an indication that such material will ever result in mined ore which is processed into commercial silver or gold.
In 2021, at Hollister, the development drift advanced at the Hatter Graben exploration area allowing completion of the first drillhole that targeted and confirmed multiple zones of banded quartz veins and veinlets south of the existing resource. In 2022 at Hollister, exploration of the Hatter Graben is expected with further development of the decline setting up exploration drilling to upgrade a portion of the current Hatter Graben resource and explore additional Hatter Graben veins both to the south and east of the current resource area. To date, 2,400 feet of development has been completed along with the necessary ventilation and dewatering infrastructure, additional footage is planned through the first half of 2022.