Natural Resources and Mining Law Blog
On December 18, 2025, the House of Representatives passed H.R. 1366, the Mining Regulatory Clarity Act of 2025, legislation that seeks to overturn a 2022 Ninth Circuit Court of Appeals decision that upended more than four decades of regulatory practice governing hardrock mining on federal lands. The bipartisan bill, introduced by Representative Mark Amodei (R-NV) and co-led by Representative Steven Horsford (D-NV), creates a new statutory category of “mill sites” for ancillary mining activities and establishes an Abandoned Hardrock Mine Fund to support remediation of legacy mining sites. The bill can be viewed here.
The legislation follows President Trump’s March 20, 2025, Executive Order 14157, “Immediate Measures to Increase American Mineral Production,” (which we discuss on our blog: President Trump’s March 20 Executive Order Bolsters Domestic Mineral Production Through Permitting, Leasing, and Funding) which directed the National Energy Dominance Council to prepare recommendations to Congress “to clarify the treatment of waste rock, tailings, and mine waste disposal under the Mining Act of 1872.” The Executive Order explicitly recognized that the Rosemont decision and subsequent agency interpretations created uncertainty by requiring operators to validate all mining claims—including those used solely for waste disposal—before obtaining plan of operations approval.
The Rosemont Decision
In Center for Biological Diversity v. U.S. Fish and Wildlife Service, 33 F.4th 1202 (9th Cir. 2022), the Ninth Circuit held that the Forest Service lacked authority to permit waste disposal on lands without valid mining claims. The case involved the proposed Rosemont Copper Mine in Arizona, where the company planned to dispose of approximately 1.9 billion tons of waste rock on 2,447 acres of National Forest land where it did not hold valid mining claims.
The court ruled that before a mining operator can use unpatented lode mining claims for ancillary activities such as waste rock and tailings storage, the Forest Service must first determine that the claims are “valid”—meaning they contain a discovery of valuable minerals. This created an impossible standard: waste disposal areas by definition do not contain ore-grade mineralization.
Prior to Rosemont, federal agencies approved waste disposal on claims without verifying minerals, assuming this ancillary use was valid. Under the decision and subsequent agency interpretations, operators must now provide substantial geological evidence—core drilling, assay reports, geologic mapping, economic feasibility analysis—to validate all claims before getting a plan of operations approved.
What H.R. 1366 Does
The Mining Regulatory Clarity Act creates a new statutory category of “mill sites” for public land areas essential for activities such as waste rock or tailings disposal and other operations directly related to mineral development, provided these activities are part of an approved plan of operations. The bill imposes a five-acre limit per individual mill site but allows operators to claim multiple mill sites as needed.
The legislation also establishes an Abandoned Hardrock Mine Fund, capitalized through claim maintenance fees from active mining operations, to support remediation of legacy sites. The fund will support the reclamation program established under the Infrastructure Investment and Jobs Act, which allocated $725 million for abandoned hardrock mine reclamation.
What Happens Next
A companion bill, S. 544, was favorably reported by the Senate Energy and Natural Resources Committee in April 2025 by a vote of 14-6 but has not yet been scheduled for a floor vote. Key unresolved issues include the scope of mill site claims, environmental review requirements, remediation funding levels, and the interaction between mining claims and other public land uses.
The Mining Regulatory Clarity Act operates in tandem with the Trump Administration’s broader push to accelerate domestic mineral production. Executive Order 14157 defined the scope of priority minerals to include gold, copper, uranium, and potash, and mandated expedited permitting for priority mining projects.
The legislation’s ultimate fate will have lasting implications for the legal framework governing hardrock mining, the development of domestic mineral supply chains, and the management of federal public lands.
Kerry Shapiro chairs the Natural Resources & Mining Practice Group at Jeffer Mangels Butler & Mitchell LLP. He has represented the mining, building materials, and other resource industries on mineral extraction and land development projects for more than 25 years. Kerry also serves as General Counsel to the California Construction and Industrial Materials Association (CalCIMA). Contact Kerry at KShapiro@jmbm.com.
Ha Chung is an environmental and land use lawyer at Jeffer Mangels Butler & Mitchell LLP. He advises clients on land use, development, water resources, and environmental regulatory compliance matters. Contact Ha at HChung@jmbm.com.