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Grassy Mountain Project
Vale, Oregon, USA
Overview
Paramount’s flagship asset, the Grassy Mountain Gold Project (“Grassy”), is one of the most advanced undeveloped gold projects in the United States.
Located in eastern Oregon, the project benefits from strong infrastructure, secure land tenure, and a region with a long history of mineral exploration. Grassy is designed as a high-grade underground mining operation with a relatively small surface footprint and modern processing methods, incorporating environmental controls.
The project has received federal approvals and is in the final stages of state permitting, positioning it to become Oregon’s first modern underground gold mine.
PROJECT HIGHLIGHTS:
Feasibility Study
Grassy is supported by a 2022 Technical Report Summary on Feasibility Study outlining a high-grade underground mining operation with strong project economics.
The study contemplates an underground mine with a throughput of approximately 750 tonnes per day and an initial mine life of approximately eight years, producing gold and silver at strong grades.
The project is designed with a focus on capital efficiency, operational simplicity, and a relatively modest initial capital requirement.
Paramount is currently advancing work toward an updated feasibility study, with results expected in Q2 2026.
Technical Reports
June 2022
For additional detail, please refer to the 2022 S-K 1300 Technical Report Summary on Feasibility Study.
Additional information regarding mineral resources and reserves is available in the Company’s S-K 1300 Technical Report.
Federal (Approved)
State (Final Stage)
County (Approved)
Exploration Upside
Paramount has completed a comprehensive review of historical data and a helicopter-borne magnetic and radiometric survey across its 8,200-acre land package. This work outlined multiple high-priority targets with the potential to add new mineralized material and ultimately extend mine life beyond the 8 years defined in the 2022 Feasibility Study, enhancing the already robust project economics.
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Grassy is located within a large, underexplored land package with multiple targets that have the potential to extend mine life beyond the current mine plan.
Key targets include:
Future development may provide access for cost-effective drilling of extensions to the existing orebody and nearby targets, supporting potential resource growth and mine life extension.
Resources
Mineral Resources
Classification | Tons
| Au
| Ag
| Au
| Ag
|
Measured | 21,153 | 0.017 | 0.072 | 363,000 | 1,529,000 |
Indicated | 12,902 | 0.030 | 0.115 | 392,000 | 1,480,000 |
Measured + Indicated | 34,055 | 0.022 | 0.088 | 755,000 | 3,009,000 |
Inferred | 1,151 | 0.037 | 0.109 | 42,000 | 126,000 |
Classification | Tonnes | Au
| Ag
| Au
| Ag
|
Measured | 19,190 | 0.583 | 2.469 | 363,000 | 1,529,000 |
Indicated | 11,705 | 1.029 | 3.943 | 1,480,000 | |
Measured + Indicated | 30,894 | 0.754 | 3.017 | 3,009,000 | |
Inferred | 1,044 | 1.269 | 3.737 | 126,000 |
Mineral Resources potentially amenable to open pit mining methods are reported using a gold price of US$1,750/oz, a silver price of US$22/oz, a throughput rate of 5,000 tons/day, assumed metallurgical recoveries of 80% for Au and 60% for Ag, mining costs of US$2.50/ton mined, processing costs of US$13.00/ton processed, general and administrative costs of $2.22/ton processed, and refining costs of $5.00/oz Au and $0.50/oz Ag produced. Mineral Resources potentially amenable to underground mining methods are reported using a gold price of US$1,750/oz, a silver price of US$22/oz, a throughput rate of 5,000 tons/day, assumed metallurgical recoveries of 90% gold equivalent, mining costs of US$90/ton mined, processing costs of US$30/ton processed, general and administrative costs of $15.00/ton processed, and refining costs of $5.00/oz gold equivalent produced.
The in-pit resources were then tabulated by the application of a gold-equivalent cut-off of 0.011 opt (0.38 g/T). The gold-equivalent grades were determined using a gold to silver ratio of a 106 to 1.
Processing is assumed to consist of crushing and milling followed by Carbon in Leach (“CIL”) recovery resulting in the production of a DORE bar on site.
Mineral Reserves
Classification | Tons | Au
| Ag
| Au
| Ag
|
Proven | 259,600 | 0.181 | 0.264 | 47,000 | |
Probable | 1,651,900 | 0.202 | 0.294 | 333,000 | 486,000 |
Total Reserves | 1,911,400 | 0.199 | 0.290 | 380,000 |
Classification | Au
| Ag
| Au
| Ag
| |
Proven | 235,508 | 6.206 | 9.051 | 47,000 | 68,000 |
Probable | 1,498,594 | 6.926 | 10.080 | 333,000 | 486,000 |
Total Reserves | 1,734,011 | 6.823 | 9.943 | 380,000 | 554,000 |
An underground mining scenario is assumed using mechanized cut-and-fill methods, which following ramp-up, is expected to produce 1,300–1,400 tons/day, four days a week. This mining rate will provide sufficient material for the 750 ton/day mill and processing plant to operate at full capacity for seven days a week.
The Proven and Probable Mineral Reserves for Grassy Mountain were estimated by first calculating an economic cut-off grade of 0.1 AuEq oz/t (3.43 g/T) for mining underground stopes, then using the cut-off grade to design stope shapes centered on Measured and Indicated Mineral Resource blocks with gold grades greater than or equal to the cut-off grade. All Inferred material was considered to be waste with no value or metal content. Internal and external dilution and mining recoveries (ore loss) were estimated and applied as modifying factors based on the total tonnage of material inside of the final designs.
EXPLORATION HISTORY
Previous Operators
Companies and individuals involved in exploration prior to Paramount’s Project interest include prospectors Richard “Dick” Sherry and Eugene “Skip” Yates (1986), Atlas Precious Metals (Atlas) (1986 to 1992), Golden Predator Mines U.S. Inc., Newmont Exploration Ltd (Newmont) (1992-1996), Tombstone Exploration Company Ltd (Tombstone) (1998), Seabridge, and Calico (2000 to 2015). Work completed included reconnaissance, geological mapping, geochemical sampling (soil, float, rock chip), geophysical surveys (airborne magnetic and radiometric, ground-based gravity, gradient array (IP/resistivity) controlled-source audio-frequency magnetotelluric (CSAMT)), core and reverse circulation (RC) drilling, and Mineral Resource estimation. This work defined theGrassy Mountain deposit, on which a feasibility study was completed in 1990 by Atlas assuming a combined heap leach/milling operation and open pit mining methods.
Work Completed by Paramount
Since acquiring its Project interest in 2016, Paramount has conducted an exploration review of the available Project data, helicopter-borne aeromagnetic and radiometric and CSAMT ground geophysical surveys, drilling, Mineral Resource and Mineral Reserve estimation, baseline environmental studies, and mining studies.
In addition to the above exploration programs, Paramount has progressed the Grassy Mountain Project through several stages of the state and federal permitting process. The Project will require county level, state level and federal permits to construct, operate and close a mining operation.
2019: Paramount submitted its Consolidated Permit Application (“CPA”) to DOGAMI to enable the Company to build
and operate its proposed, high grade underground gold mine located in Malheur County. The Application was reviewed by the DOGAMI and cooperating agencies for completeness. As part of this process, the permitting agencies provided Paramount with a list of supplemental information and recommendations required to submit a modified CPA. Paramount, the DOGAMI and the permitting agencies continued to work together to discuss the additional information requested, ensuring the submission of a complete modified CPA which will trigger the 225 day maximum permit evaluation process, upon which draft permits are issued.
2020: the Company submitted a revised Plan of Operation (the ”PoO”) to the BLM outlining the Company’s plans to build and operate the proposed Grassy Mountain underground gold mine. The BLM has reviewed the PoO for completeness and has provided the Company with comments to address. The BLM has previously reviewed 19 of the baseline data reports (“BDRs”) and their requests for clarifications have all been addressed. The BLM will register a Notice of Intent (the ”Notice”) in the Federal Register once the application is deemed complete. The Notice initiates the Environmental Impact Statement (“EIS”) process under the National Environmental Policy Act.
2021: Paramount submitted a modified CPA with the State of Oregon and submitted a modified PoO to the BLM. Both modified applications incorporated additional information required by the regulators and mine design optimizations that were a result of feedback provided in Paramount’s initial application.
2022: Paramount completed an SK-1300 Technical Report Summary on Feasibility Study. The Company received approval of two critical BDRs from the States Technical Review Team and submitted an updated Plan of Operations to the BLM, which was subsequently deemed complete.
2023: Key state level permitting progressed further with approval of the final BDR, an extension of the Conditional Use Permit from Malheur County, and approval of the Environmental Evaluation outline. State agencies issued the completeness determination that resulted in Paramount receiving the Notice to Proceed from DOGAMI.
2024: The BLM issued a Notice of Intent, formally initiating the EIS process. The DOGAMI and BLM agreed to a coordinated, joint reclamation bond.
2025: Permitting momentum accelerated. State regulators approved all the components of Paramount’s mining, processing and closure scenarios., and the Company secured another two-year Conditional Use Permit extension. Grassy Mountain was selected for the US Government Fast-41 Program, expediting federal permitting. This led to two firsts for the State of Oregon: the BLM’s issuance of the draft Environmental Impact Statement and DOGAMI’s release of the first ever draft permit package for a modern- day gold mine.
2026: Success continued early in the year with the BLM issuing both itsr Record of Decision and the Final Environmental Impact Statement for the project.
Geology & MINERALIZATION
Grassy is a high-grade epithermal gold-silver system located within the Lake Owyhee volcanic field.
Mineralization is hosted in silicified volcanic and sedimentary rocks and is structurally contrlled by faulting. Gold occurs primarily in quartz adularia veins and stockwork zones, with higher-grade minerlaization concentrated at depth.
The deposit exhibits characteristics typical of epithermal systems, including strong silicification and structurally controlled mineralization, supporting both defined resources and potential for further extensions.
