H.R. 7779 would establish a Good Samaritan pilot program and authorize the Environmental Protection Agency to issue permits for projects to remediate mine residue at abandoned hardrock mine sites. The bill would establish a remediation fund for federal agencies to administer projects carried out by Good Samaritans (entities that are not current owners or operators of an abandoned site; had no role in the creation of the mine residue; and are not potentially liable under any law for the remediation, treatment, or control of the mine residue). The spending would be funded by appropriations and by deposits from nonfederal sources, such as donations, agreements for long-term operations and maintenance costs, and insurance proceeds if a Good Samaritan fails to complete a project. The bill also would waive the applicability of all other laws with respect to the use of the fund, including the Antideficiency Act, which could allow amounts to be obligated before expected deposits into the fund are received. However, CBO expects that spending of any such advance obligations would be constrained by amounts ultimately deposited into the fund. On that basis, CBO estimates that enacting H.R. 7779 would increase net direct spending by less than $500,000 over the 2025-2034 period and have no effect on revenues. CBO has not estimated the bill’s effects on spending subject to appropriation. The bill contains no intergovernmental or private-sector mandates as defined in the Unfunded Mandates Reform Act.