NYSE: GORO

Gold Resource Corporation

Mexico Production Stage Properties:

The primary production stage properties at DDGM commenced operations in 2010. Current operations include the Arista underground mine and the DDGM processing facility, which produces metal concentrates from ore mined at the Arista Mine. The Arista Mine was expanded in 2016 with the development of the Switchback vein system and again in 2025 with the development and initial production of the Three Sisters vein system. The Arista Mine portal is located approximately two kilometers from the processing facility. Additionally, underground mining was conducted from 2017 to 2019 at the Alta Gracia Mine, where limited surface drilling recommenced in the fourth quarter of 2025. Alta Gracia is approximately 32 kilometers from the DDGM processing facilities.

The Arista and Alta Gracia Mines include a total of approximately 30,000 hectares of mining concessions, access roads from a major highway, haul roads, a processing facility and adjoining buildings, an assay lab, a now depleted open pit, underground mines, tailings facilities, and other infrastructure. Please see Item 2. Properties for additional information.

Mexico Exploration Prospects:

The Company’s current land package sits within the highly prospective 55-kilometer-long San Jose structural corridor, in Oaxaca, Mexico. Multiple volcanic domes of various scales, and likely non-vented intrusive domes, dominate the district geology. These volcanogenic features are imposed on a pre-volcanic basement of sedimentary rocks. Gold and silver, as well as base metal mineralization in this district is related to the manifestations of this classic volcanogenic system and is considered epithermal in character. The Company intends to advance organic growth and to unlock the value of the mine, existing infrastructure, and its large property position by continuing to invest in exploration and development. Please see Item 2. Properties for additional information.

Processing Plant at Night

Gold Resource Corporation

Back Forty Project:

There is a long history of exploration at the Back Forty Project. After the acquisition of Aquila and the Back Forty Project by the Company in 2021, optimization work was initiated to address the mine’s footprint, potential for an underground mine, wetland mitigation, and other key construction and design decisions. This optimization work related to a change in mine design, tailings relocation, and metallurgy. The economic model was completed, and the Company released the Back Forty Project Technical Report Summary on October 26, 2023. Results of the work indicate a more robust economic project with no planned impacts to wetlands that are more protective of the environment, which should facilitate a successful mine permitting process expected to start in 2026. With much higher metal prices since the Back Forty Project Technical Report Summary was completed, the Board actively evaluates the options that could lead to the successful development of the project. Please see Item 2. Properties for additional information.

Before the Aquila acquisition, Aquila’s common shares were traded on the Toronto Stock Exchange (“TSX”) under the ticker symbol AQA. Effective December 10, 2021, Aquila ceased to be a reporting issuer in British Columbia, Alberta, Saskatchewan, Ontario, and Nova Scotia. At the same time, GRC became a reporting issuer in British Columbia, Alberta, Saskatchewan, Ontario, and Nova Scotia by virtue of the completion of the acquisition. As a Canadian reporting issuer, GRC is now required to file reports on the System for Electronic Document Analysis and Retrieval (“SEDAR”) in Canada. All financial statements filed on SEDAR conform to United States generally accepted accounting principles (“U.S. GAAP”).

Administrative Offices:

The Company’s principal executive offices are located at 7900 E. Union Ave, Suite 320, Denver, Colorado 80237, and its telephone number is (303) 320-7708. The Company maintains a website at www.goldresourcecorp.com. Information on its website is not incorporated into this annual report on Form 10-K and is not a part of this report. The U.S. Securities and Exchange Commission (“SEC”) maintains an internet site (www.sec.gov) on which the reports that the Company files with the SEC are available to review. The SEC filings can also be accessed through the Company’s website.

Gold Resource Corporation

2025 Development Highlights

For the year ended December 31, 2025, the Company reported a net loss of $6.5 million. Despite the net loss reported for the year, the Company’s operating mine is showing improvements and a turnaround in performance that is mainly attributable to higher metal prices and improved production as a result of acquired new equipment, as well as the use of a third-party mining contractor, allowing the development of higher-grade areas of the deposit. Financial results for 2025 include revenue of $99.8 million and mine gross profit of $26.8 million. The Company’s production results for the year totaled 5,300 gold ounces, 1,594,300 silver ounces, 264 copper tonnes, 1,192 lead tonnes, and 3,613 zinc tonnes.

For the eleventh consecutive year, DDGM received the prestigious ESR award from the Mexican Center for Philanthropy (“CEMEFI”). Awards are given to organizations that demonstrate a commitment to supporting social and environmental protection programs within their local communities.

The Company’s exploration activities focused on underground drilling within the Arista, Switchback, and Three Sisters vein systems of the Arista mine, along with limited surface drilling at the Alta Gracia deposit beginning in the fourth quarter. During the year, the Company completed a total of 111 diamond drill holes totaling 14,539 meters, consisting of 33 infill holes totaling 5,982 meters, and 78 grade-control holes totaling 8,557 meters. Of the infill drilling, six holes totaling 1,121 meters were completed from surface at Alta Gracia. The Company also completed more than 485 meters of underground drift development in 2025 to support ongoing infill and grade-control drilling and to facilitate planned expansion drilling in 2026.

Exploration efforts were primarily dedicated to underground drilling on multiple high-grade, polymetallic epithermal veins within the Three Sisters vein system, particularly the Sandy and Sadie vein sets, and within the Arista vein system, including the down-dip and northern extension of the Viridiana and Marena veins, as well as the northern extensions of the Splay 31 and Marena North veins. The 2025 drilling program was designed to support Mineral Reserve definition and to define additional Mineral Resources. The Three Sisters vein system lies between and north of the Arista and Switchback systems and is located near existing mine infrastructure. Following focused infill and grade-control drilling during the year, a total of 24 distinct veins and vein segments, including the Gloria vein, have now been delineated. Both the Three Sisters and northern Arista vein systems remain the primary targets for infill and expansion drilling in 2026. Updated 2025 resource models for all three vein systems incorporated tighter geologic and economic constraints, resulting in more selective and geologically constrained estimates. In particular, drilling within the Three Sisters and Arista systems resulted in an upgrade of a portion of the previously reported Inferred Mineral Resources to Measured and Indicated categories; increasing confidence in those areas. All vein systems remain open for further expansion drilling both up- and down-dip, as well as along strike to the northwest.

Surface exploration during 2025 included the initiation of a limited surface infill drilling program at Alta Gracia in mid-November. By year-end, six infill holes totaling 1,121 meters had been completed, targeting the upgrade of previously defined Inferred Mineral Resources in the upper southwestern portion of the Mirador vein. The Company also continued evaluating and prioritizing advanced-stage exploration targets within the approximately 551 square kilometer land package controlled by DDGM surrounding the Arista Mine. These activities included the reprocessing and integration of historical geologic information, including mapping, sampling, geophysical surveys, and drill data, from several projects, including Rey, Alta Gracia, Margaritas, El Fuego, Chamizo, and Jabali. Prospective areas proximal to the Arista Mine were also re-evaluated for near-term exploration potential with the objective of defining additional near-mine drill targets. These ongoing efforts support the Company’s long-term exploration strategy and continued operational presence in Oaxaca, Mexico.

Gold Resource Corporation

In connection with the Back Forty Project, the Company continues to monitor the U.S. Army Corps of Engineers’ (“USACE”) review of a petition by the Menominee Indian Tribe of Wisconsin (“MITW”) requesting that the Menominee River be designated as navigable under Section 10 of the Rivers and Harbor Act. The USACE has previously concluded, based on prior studies, that the relevant reach of the Menominee River in the project area does not meet the federal definition of navigability. The MITW has requested that the Environmental Protection Agency and the USACE evaluate whether federal agencies, rather than the State of Michigan, should exercise regulatory authority over certain activities potentially requiring federal permits. Based on the current project design and permitting framework, the Company does not presently anticipate the need for additional federal permits related to navigability of the river corridor, however any change in jurisdictional determinations could affect future permitting requirements. In response to the MITW petition, the USACE is updating its navigability study for the Menominee River, which was expected to be completed in 2023, but it’s still under final administrative review.

Recent Developments

On January 26, 2026, the Company announced that it has entered into a definitive arrangement agreement and plan of merger (the “Arrangement Agreement”) with Goldgroup Mining Inc. (“Goldgroup”), whereby Goldgroup has agreed to acquire all of the issued and outstanding shares of the Company’s common stock (the “Transaction”).

Pursuant to the Arrangement Agreement, the Company’s stockholders will receive 1.4476 common shares of Goldgroup for each share of the Company’s common stock (adjusted to 0.3619 common shares of Goldgroup for each share of the Company’s common stock as a result of a four-for-one share consolidation to be completed by Goldgroup prior to closing). The proposed Transaction will occur by way of a reverse triangular merger in which the Company will merge with a wholly owned subsidiary of Goldgroup under Colorado law and a plan of arrangement under the Business Corporations Act (British Columbia), with the Company surviving as a wholly owned subsidiary of Goldgroup. Upon completion of the Transaction, the Company’s stockholders are expected to own approximately 40% of the combined company on a fully diluted in-the-money basis.

The Transaction was unanimously approved by the boards of directors of the Company and Goldgroup. The Transaction is expected to close in the second quarter of 2026, subject to customary closing conditions (including approval by the stockholders of each of the Company and Goldgroup and approval by the Mexican National Antitrust Commission). Upon closing, the board of directors of Goldgroup will be comprised of three directors selected by Goldgroup and two directors selected by the Company. The parties anticipate that the executive management team of the Company will become the officers of the combined company.

Dividends

In February 2023, to conserve cash for development and equipment expenses, the Company announced the suspension of its quarterly dividend until such time that it may become practicable to reinstate such dividend. Please see Item 5. Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchase of Equity Securities for additional information regarding the Company’s dividend policy.

Insurance

The Company’s business is capital intensive and requires ongoing investment for the replacement, modernization, or expansion of equipment and facilities. For more information, please see Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations—Liquidity and Capital Resources below. The Company maintains insurance policies against property loss and business interruption and insure against most risks that are typical in the operation of its business in amounts that the Company believes to be reasonable. Such insurance, however, contains exclusions and limitations on coverage, particularly with respect to property loss, environmental liability, and political risk. There can be no assurance that claims would be paid under such insurance policies in connection with a particular event. Please see