S 544 · 119th Congress

Mining Regulatory Clarity Act

mining regulationabandoned mine cleanuppublic landsenvironmental protectionmining law
Share

Last action 2026-02-11

Sponsored by Sen. Cortez Masto, Catherine [D-NV] (D) — NV

Click any stage to learn more about the legislative process.

Would let hardrock mining operators locate as many mill sites — areas for waste rock and tailings disposal — as reasonably necessary for their operations on public land, regardless of whether that land itself contains valuable minerals.

The change responds to a 2022 federal appeals court ruling that limited such waste-disposal claims, and would also route mill-site fee revenue into a new fund for cleaning up abandoned hardrock mines.

What this bill would do

What it would do

The bill would amend the Mining Law's mill site provisions to let a mining claim holder locate and include in its approved plan of operations as many mill sites — land used for waste rock or tailings disposal and other activities incident to mining — as are reasonably necessary, without needing to first establish that the mill site land itself contains valuable minerals. Each mill site would be capped at 5 acres, would convey no mineral rights, and would not be eligible for patenting. It responds to a 2022 Ninth Circuit ruling involving the Rosemont Copper Mine that had cast doubt on this practice. The bill would also create the Abandoned Hardrock Mine Fund in the Treasury, depositing claim-maintenance fees collected on these new mill sites into it, to be spent by the Interior Department only on abandoned hardrock mine reclamation under existing law. It includes savings clauses preserving existing land withdrawals, environmental laws, and prior mining rights.

Key provisions

  1. 1Would let mining claim holders locate as many mill sites as reasonably necessary for waste disposal and related operations, regardless of the land's mineral characterSec. 2(a)
  2. 2Would cap each mill site at 5 acres and specify that mill sites convey no mineral rights and are not eligible for patentingSec. 2(a)
  3. 3Would establish the Abandoned Hardrock Mine Fund in the Treasury, funded by claim-maintenance fees collected on the new mill sitesSec. 2(b)
  4. 4Would restrict use of the Fund to abandoned hardrock mine reclamation activities under the Infrastructure Investment and Jobs ActSec. 2(b)(3)
  5. 5Includes savings provisions preserving existing land withdrawals, environmental laws, and prior claimant rights unaffected by the new mill site authoritySec. 2(a)(8)

Who would be affected

Hardrock mining companies operating on federal public land, the Department of the Interior and Forest Service (which approve plans of operations), and communities near abandoned hardrock mines that could benefit from reclamation funded through the new fund.

Why it matters

Mining operators would gain clearer legal footing to establish waste-disposal sites without mineral-validity examinations, addressing uncertainty created by a 2022 court ruling that threatened to complicate or halt some mining projects. The new fund would also create a dedicated, non-appropriated revenue stream for cleaning up abandoned mines.

What would change

Changes to existing law

Amends Revised Statutes Section 2337 (30 U.S.C. 42) (Sec. 2(a))

Adds a new subsection allowing multiple mill sites reasonably necessary for operations regardless of mineral validity of the land

Amends Omnibus Budget Reconciliation Act of 1993, Section 10101 (30 U.S.C. 28f) (Sec. 2(b)-(c))

Directs mill-site claim maintenance fees into the new Fund and makes clerical restructuring of fee provisions

Amends Infrastructure Investment and Jobs Act, Section 40704 (30 U.S.C. 1245) (Sec. 2(b)(3)-(4))

Ties new Fund spending and allocation to this existing abandoned mine reclamation program's rules

Agencies directed to act

Department of the InteriorDepartment of Agriculture (Forest Service)

Funding and costs

  • amounts collected from claim maintenance fees on mill sites

    Deposits into the Abandoned Hardrock Mine Fund for abandoned mine reclamationSec. 2(b)(2)

Congressional Budget Office estimate

CBO estimates S. 544 would have a negligible effect on the federal deficit, resulting in a trivial decrease in net direct spending over the 2026–2036 period, with no effect on revenues.

S. 544 would expand access to mill sites on public lands for mining claimholders and establish an Abandoned Hardrock Mine Fund, with receipts from additional mill site fees deposited there and spent without further appropriation on abandoned mine reclamation. Because the bill would increase the number of mill sites subject to the existing $200 annual fee — recorded in the budget as offsetting receipts (reductions in direct spending) — CBO expects a negligible decrease in net direct spending over the 2026–2036 period. Administrative costs for agencies to review additional mill-site requests are estimated at less than $500,000 over 2026–2031, subject to appropriations. CBO found no intergovernmental or private-sector mandates in the bill.

View the full CBO cost estimate

How implementation would work

Operators would request mill sites as part of the plan-of-operations approval process already run by the Interior Department (Bureau of Land Management regulations) or the Forest Service, depending on jurisdiction. Claim-maintenance fees collected on these mill sites would be deposited automatically into the new Abandoned Hardrock Mine Fund, which Interior could spend without further appropriations, but only for reclamation activities already authorized under the Infrastructure Investment and Jobs Act, following that law's existing allocation and transfer rules.

Legislative status & sources

Latest action

Placed on Senate Legislative Calendar under General Orders. Calendar No. 334.

2026-02-11

Official CRS summary

Show the CRS summary

This bill allows mining operators to use federal lands for activities ancillary to mining, such as waste disposal, regardless of whether those lands contain mineral deposits valuable enough to be mined (mineral validity). It also establishes the Abandoned Hardrock Mine Fund.

The bill addresses a 2022 decision in the U.S. Court of Appeals for the Ninth Circuit related to the Rosemont Copper Mine in Arizona (commonly known as the Rosemont decision, described further in CRS Report R48166). The court held that mining claims are only allowed where mineral validity has been established and that mill site claims are more appropriate means for establishing a mining waste disposal site under the Mining Act.

The bill allows a mining operator to (1) locate and include within its plan of operations as many mill site claims (e.g., areas for waste rock disposal) as are reasonably necessary for its operations, and (2) use or occupy public land in accordance with an approved plan of operations.

Additionally, the bill requires any revenue generated from fees for such mill site claims to be deposited into the Abandoned Hardrock Mine Fund. The Department of the Interior must use the fund for certain abandoned hardrock mine reclamation activities.

From the Congressional Research Service.

Legislative subjects

Environmental Protection; Government trust funds; Land use and conservation; Mining

Committee report

S. Rept. 119-105

Congressional Bill

Ask GovernmentReporter about this bill

Ask anything about this bill. The AI can look up referenced laws and statutes to provide context.

S 544: Mining Regulatory Clarity Act | Legislation Reporter