Deposit and Geology

DeLamar Deposit Gold and Silver Resources

ClassificationTonnesg/t Auoz Aug/t Agoz Agg/t AuEqoz AuEq


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  1. Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability.
  2. Oxidized and Transitional Mineral Resources are reported at a 0.2 g AuEq/t cut-off in consideration of potential open-pit mining and heap-leach processing. Unoxidized Mineral Resources are reported at a 0.3 g AuEq/t cut-off in consideration of potential open pit mining a milling / agitated leaching or flotation processing. The Mineral Resources are constrained by pit optimizations.
  3. Gold equivalent grades were calculated using the metal prices and recoveries presented elsewhere in this press release.
  4. Rounding as required by reporting guidelines may result in apparent discrepancies between tonnes, grades, and contained metal content.
  5. The Effective Date of the Mineral Resources is May 1, 2019.
  6. The estimate of mineral resources may be materially affected by geology, environment, permitting, legal, title, taxation, sociopolitical, marketing, or other relevant issues

The terms “mineral resource”, “measured mineral resource”, “indicated mineral resource”, “inferred mineral resource” used herein are Canadian mining terms used in accordance with National Instrument 43-101 - Standards of Disclosure for Mineral Projects (“NI 43-101”) under the guidelines set out in the Canadian Institute of Mining and Metallurgy and Petroleum (the “CIM”) Standards on Mineral Resources and Mineral Reserves, adopted by the CIM Council, as may be amended from time to time (the “CIM Definition Standards”). Inferred mineral resources’ have a great amount of uncertainty as to their existence, and as to their economic and legal feasibility. It cannot be assumed that all or any part of an inferred mineral resource will ever be upgraded to a higher category. These definitions differ from the definitions in the United States Securities and Exchange Commission (the “SEC”) Industry Guide 7 (“Industry Guide 7”). United States investors are cautioned not to assume that all or any part of measured or indicated mineral resources will ever be converted into mineral reserves. United States investors are also cautioned not to assume that all or any part of an inferred mineral resource exists, or is economically or legally mineable.

Under Industry Guide 7, a mineral reserve is defined as a part of a mineral deposit which could be economically and legally extracted or produced at the time the mineral reserve determination is made. While the terms “mineral resource”, “measured mineral resource”, “indicated mineral resource”, and “inferred mineral resource” are recognized and required by Canadian regulations, they are not defined terms under Industry Guide 7 and historically they have not been permitted to be used in reports and registration statements filed with the SEC. As such, information contained herein concerning descriptions of mineralization and resources under Canadian standards may not be comparable to similar information made public under Industry Guide 7 by U.S. companies in SEC filings.

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DeLamar Geology and Mineralization:

The DeLamar project is situated in the Owyhee Mountains near the east margin of the mid-Miocene Columbia River – Steens flood-basalt province and the west margin of the Snake River Plain. The Owyhee Mountains comprise a major mid-Miocene eruptive center, generally composed of mid Miocene basalt flows and younger, mid-Miocene rhyolite flows, domes, and tuffs, developed on an eroded surface of Late Cretaceous granitic rocks.

Earth Resources and NERCO geologists defined a local volcanic stratigraphic sequence in the DeLamar area. The mine area and mineralized zones are situated within an arcuate, nearly circular array of overlapping porphyritic and banded rhyolite flows and domes that overlie cogenetic, precursor pyroclastic deposits erupted as local tuff rings. The porphyritic and banded rhyolite flows and domes were interpreted to have been emplaced along a system of ring fractures developed above a shallow magma chamber that supplied the erupted rhyolites. This magma chamber was inferred to have been intruded within a northwest flexure of regional north-northwest trending Basin and Range faults.

Gold-silver mineralization has been recognized in two types of deposits: within 1) relatively continuous, quartz-filled fissure veins that were the focus of late 19th and early 20th century underground mining, and 2) broader, bulk-mineable zones of closely-spaced quartz veinlets and quartz-cemented hydrothermal breccia veinlets that are individually continuous for only a few feet laterally and vertically, and of mainly less than 1.3 centimeters in width. This second type of mineralization was mined in the open pits of the late 20th century DeLamar operation.

The fissure veins mainly strike north to northwest and are filled with quartz accompanied by variable amounts of adularia, sericite or clay, ± minor calcite. Much of the quartz is massive, but some has drusy or comb structure and a lamellar variety is locally abundant. Vein widths vary from a few centimeters to several meters, but persist laterally for as much as several hundreds of meters. Principal silver and gold minerals are naumannite, aguilarite, argentite, ruby silver, native gold and electrum, native silver, cerargyrite, and acanthite. Variable amounts of pyrite and marcasite, and minor chalcopyrite, sphalerite, and galena occur in some veins.

The bulk mineable type of mineralization has been delineated in four broad, lower-grade zones, two of which overlap and are centered on fissure veins. This type of mineralization has been described as zones of closely spaced veinlets and fracture fillings in porphyritic rhyolite. Most of the veinlets are less than 5 mm in width and have short lengths that are laterally and vertically discontinuous. Small veins can form pods or irregular zones up to 1- to 2-centimeters wide that persist for several centimeters before pinching down to more restricted widths. In highly silicified zones, porphyritic rhyolite is commonly permeated by anastomosing microveinlets typically less than 0.5-millimeters wide. Vein gangue minerals consist mainly of quartz, with minor amounts of adularia. Naumannite, acanthite and acanthite-aguilarite solid solution are the principal silver minerals, with lesser amounts of argentopyrite, Se-bearing pyrargyrite, Se-bearing polybasite, cerargyrite, Se-bearing stephanite, native silver, and native gold. Minor Se-bearing billingsleyite, pyrostilpnite, and Se-bearing pearceite have also been reported. Ore minerals are generally very fine grained.

In the flow banded rhyolite, scattered zones of mineralized breccia occur most frequently near the base of the unit. These breccias consist of close-packed angular fragments of flow-banded rhyolite in a chalcedonic matrix and crosscut flow layering. The gold and silver mineralization at the DeLamar project is best interpreted in the context of the volcanic-hosted, low-sulfidation type of epithermal model. Various vein textures, mineralization, and alteration features, and the low contents of base metals in the district, are typical of low-sulfidation epithermal deposits world-wide.