Atna Resources Ltd.


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Briggs Gold Mine


The Briggs gold mine is located on the west side of the Panamint Range near Death Valley, California. Briggs was initially constructed in 1995 and was a producing open pit mine through 2004 until mining ceased due to gold-market conditions. Atna re-started commercial production in mid-2009. In total the mine has produced over 700,000 ounces of gold. 

Gold market conditions negatively impacted the economic outlook for Briggs and mining operations were discontinued in July 2015 when pre-stripped ore inventory in the Briggs Main North pit was depleted. Beginning in the third quarter of 2015, production operations are focused on recovering approximately 17,100 ounces of gold inventory remaining in the plant and leach pad over the next two to three years. This operating strategy allows the Company to monetize working capital and reduce its debt. Gold production at Briggs will sequentially decline over time as inventory balances are reduced. 

Briggs is a conventional open pit mine that uses heap leach gold recovery methods. Ore is crushed to a targeted 80 percent passing a ¼-inch-screen prior to placement on the leach pad; and targeted gold recovery from the leaching process is 80 percent. Briggs has a measured and indicated resource containing over 500,000 ounces of gold. At various gold price levels some portion of this resource may support the re-commencement of ore mining at Briggs. Mine plans have been developed to extend Briggs’ mine life for several additional years, assuming sustained gold prices above $1,300 per ounce.


Estimate of Resource 



Gold Grade

Contained Ounces












Measured &








Mineral Resources include Proven and Probable Reserves.

Briggs Report, NI 43-101 Technical Report Briggs Mine, dated May 29, 2012; 0.006 opt gold cut-off, adjusted for actual production through December 31st, 2014 and other changes during production. View, NI 43-101 Technical Report

Definitions used are consistent with those adopted by the Canadian Institute of Mining, Metallurgy and Petroleum ("CIM") Council in December 2005, as amended, and prescribed by the Canadian Securities Administrators' National Instrument 43-101 and Form 43-101F1, Standards of Disclosure for Mineral Projects. The measured and indicated resources stated above include reserves, which are a sub-set of resources. Mineral resources that are not mineral reserves do not have demonstrated economic viability. Inferred resources are considered too speculative geologically to have the economic considerations applied to them that would enable them to be categorized as mineral reserves. With sustained higher gold prices The Briggs Mine has significant expansion and exploration potential at depth. Additional reserves may be developed with increased gold price


Briggs Exploration

Atna has evaluated exploration targets at Briggs to potentially expand the mine life.  The image below illustrates that with higher gold prices the Briggs Mine has significant expansion and exploration potential at depth.


Outside of the Briggs Mine permit area, Atna controls four exploration targets; Cecil R, Suitcase, Mineral Hill and Jackson, all within the Briggs area claim block. All of these projects have seen significant drilling and have historic mineral inventories; however the Cecil R property is the most advanced of these projects. 

Cecil R is located four miles north of Briggs. The Company completed an initial NI 43-101 compliant mineral resource estimate and technical report titled “NI 43-101 Technical Report Mineral Resource Estimate Cecil R Gold Deposit, Inyo County, California USA” dated March 2, 2010 (the “Cecil Report”) prepared by Fred Barnard, PhD and Robert L. Sandefur, P.E. of Chlumsky, Armbrust & Meyer LLC. Each of the foregoing persons is an independent qualified person in accordance with NI 43-101.

Work at Cecil R leading up to the NI 43-101 resource estimate included over 94 drill holes, surface geologic mapping, surface and underground sampling, and 3D geologic modeling. Gold mineralization at Cecil R is hosted by the same geologic unit which hosts the nearby Briggs gold deposit. The gently west dipping blanket-like zone of gold mineralization dips beneath Quaternary gravel cover and is distributed over an area 1,500 feet by 1,200 feet and has a thickness of 10 to 60 feet. 

In late 2012, a scoping level economic study was commenced on the Cecil R project. This non-NI 43-101 compliant report produced positive results, and the Company believes this justifies continued work on the project. Additional preliminary engineering work is planned in order to allow a Mine Plan of Operations to be submitted to regulatory authorities. The Cecil R open-pit project may be required to comply with the California Backfill Regulation and be permitted as a stand-alone project. The Cecil R Project is not permitted for operation.