Golden Minerals Reports Promising Bio-Oxidation Test Results
Golden Minerals Reports Promising Bio-Oxidation Test Results
GOLDEN, Colo., Jan. 17, 2020 -- Golden Minerals Company (NYSE American and TSX: AUMN) (“Golden Minerals”, “Golden”
or “the Company”) is pleased to announce it has received promising results from metallurgical test work conducted on pyrite-
arsenopyrite flotation concentrates from its Velardeña Properties located in Durango, Mexico.
Gold and silver recoveries of 91% and 92%, respectively, were obtained from cyanide leaching of the bio-oxidized concentrate
samples. BIOX* achieved 93% oxidation on the concentrate sample in batch tests, which the Company believes should
translate to a 5 to 6-day retention time in a commercial bio-oxidation plant.
Warren Rehn, President & Chief Executive Officer of Golden Minerals, commented, "These results confirm the previous
indications we had that bio-oxidation processing of the pyrite-arsenopyrite concentrates from Velardeña and subsequent
cyanide leaching of the oxidized product may be the key to obtaining high payable gold recoveries from Velardeña. This could
be a potential game-changer for the project. These confirmed gold and silver recoveries from the pyrite-arsenopyrite
concentrates will be included in the Preliminary Economic Assessment update that is underway on the project. The results of
this PEA are expected to be available in the first quarter of 2020.”
Metallurgical Test Work
A pyrite-arsenopyrite flotation concentrate sample was prepared from vein material that is representative of the primary veins
exposed in the current deepest accessible stopes in the San Mateo and Santa Juana mines of Golden’s Velardeña
Properties. The concentrate sample was processed at Outotec’s laboratory in South Africa using their patented BIOX process
to oxidize the sample. After oxidation, the sample was leached using a cyanide solution. The results indicate that the
Velardeña flotation concentrate tested is suitable for treatment using the BIOX process and subsequent cyanide leaching,
yielding recoveries for gold and silver of 91% and 92%, respectively.
*BIOX is a trademark of Outotec, referring to their proprietary bio-oxidation process for pre-treating sulfide material.
About Velardeña
The Velardeña Properties are comprised of two underground mines and two processing plants in northeast Durango State,
Mexico, approximately 65 kilometers southwest of the city of Torreón. Of the two underground mines comprising the
Velardeña Properties, the Velardeña mine includes five different major vein systems including the Terneras, Roca Negra, San
Mateo, Santa Juana and San Juanes systems. During 2015 the Company mined from the San Mateo, Terneras and Roca
Negra vein systems as well as the Santa Juana vein system.
Golden Minerals owns two mills at Velardeña, a 300 tonne per day flotation sulfide mill and a conventional 550 tonne per day
cyanide leach oxide mill with a Merrill-Crowe precipitation circuit and flotation circuit. In July 2015, Golden leased the oxide
plant to Hecla Mining Company to process its own material through the plant. The lease with Hecla has since been extended
through December 31, 2020.
The Company has contracted with Tetra Tech to complete an independent study to update the 2015 PEA on Velardeña using
the results from these recent metallurgical studies. The PEA update is expected to be complete in the first quarter of 2020.
Review by Qualified Person and Quality Control
The technical contents of this press release have been reviewed by Warren M. Rehn, M.Sc., a Qualified Person for the
purposes of Canadian National Instrument 43‐101. Mr. Rehn has over 33 years of mineral exploration experience and is a QP
member of the Mining and Metallurgical Society of America.
To ensure reliable sample results, Golden Minerals uses a quality assurance/quality control program that monitors the chain ‐of
‐custody of samples and includes the insertion of blanks, duplicates and reference standards in each batch of samples. Core
is photographed and sawn in half with one half retained in a secured facility for verification purposes. Sample preparation
(crushing and pulverizing) is performed at an independent ISO 9001:2001 certified laboratory in Chihuahua or Zacatecas,
Mexico. Prepared samples are direct‐shipped to an ISO 9001:2001 certified laboratory in Canada.
About Golden Minerals
Golden Minerals is a Delaware corporation based in Golden, Colorado. The Company is primarily focused on advancing its
Velardeña Properties in Mexico and its El Quevar silver property in Argentina, as well as acquiring and advancing mining
properties in Mexico and Nevada.
Forward ‐Looking Statements
This press release contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as
amended and Section 21E of the Securities Exchange Act of 1934, as amended, and applicable Canadian securities
legislation, including statements relating to the contents and timing of a preliminary economic assessment for the Velardeña
project. These statements are subject to risks and uncertainties, including unanticipated delays in completing the PEA or
the results of any further metallurgical work or analysis completed in connection with the PEA. Additional risks relating to
Golden Minerals may be found in the periodic and current reports filed with the Securities and Exchange Commission by
Golden Minerals, including the Company’s Annual Report on Form 10-K for the year ended December 31, 2019.
For additional information please visit http://www.goldenminerals.com/ or contact:
Golden Minerals Company
Karen Winkler, Director of Investor Relations
(303) 839‐5060
SOURCE: Golden Minerals Company