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Marigold Minerals updates Lander County on Buffalo Valley project; NEPA, dewatering and permitting next steps outlined
Summary
Marigold representatives briefed the county on geology, timeline and permitting for the Buffalo Valley project, including plans to enter NEPA later this year, feasibility work through early 2026, potential dewatering needs, sage‑grouse mitigation and a multi‑year construction schedule.
Marigold Mining Company officials on April 24 updated the Lander County Board of Commissioners on the company’s existing Marigold Mine and planned Buffalo Valley expansion, describing geology, permitting steps, water management and a tentative schedule.
Richard Zagel, study manager, Jesse Barto, environmental manager, and Anton Krueger, Marigold general manager, said work to date includes a prefeasibility study that wrapped up in early 2025 and that the company is undertaking a feasibility study expected to finish in early 2026. They told the commission they plan to file a plan of operations and initiate the NEPA process in the fourth quarter of 2025, then move to detailed engineering in 2026–27 and construction in 2028–29, with a hoped‑for first pour in 2029.
Marigold said the Buffalo Valley property (acquired as part of a larger land package in 2019) includes both historic underground workings and open‑pit prospects. The company reported maiden reserves declared in Q1 2025 and estimated about 2 million ounces of reserve in its broader holdings, giving roughly a 10‑year mine life under current plans. The modern Marigold operation currently employs about 485 people.
On processing, Marigold said Buffalo Valley would be designed as a large run‑of‑mine heap‑leach operation with a cascade CIC (carbon‑in‑column) configuration on the back end and a design flow around 8,000 gallons per minute. The heap‑leach pad proposed for Buffalo Valley would be new and sizeable because the ore requires substantially longer leach time than Marigold ore; carbon will be loaded down at Buffalo Valley and shipped to Marigold for refining and return to site.
Marigold said the southern benches of the planned Buffalo Valley pit appear to be below the water table and that dewatering will be necessary. The company expects it will not be able to use all dewatering water for mine makeup and has proposed rapid infiltration basins as a discharge option while it evaluates alternatives. Marigold also discussed geotechnical and seismic studies, overburden and growth media storage plans to support reclamation, and options for leaving a pit lake versus backfilling at closure.
Biological and cultural baseline studies are underway for NEPA, the company said, and Marigold noted some sage‑grouse habitat in the area that will require mitigation planning. Marigold reported it has signed the International Cyanide Management Code and highlighted previous environmental certifications.
Commissioners asked about roads and equipment transfer; Marigold said a roughly 10‑mile road between Marigold and Buffalo Valley would be required for heavy equipment and carbon trucking. County commissioners also asked about timelines; Marigold representatives said permitting work and baseline data collection in 2025 are priorities and that feasibility and NEPA work will overlap with state permitting processes such as water pollution control and air permits.
No formal action was taken; the board received the presentation and commissioners will continue to monitor permitting milestones and public NEPA processes.
