The "Mining Regulatory Clarity Act of 2025" aims to clarify and expand provisions for hardrock mining operations by allowing the location of multiple mill sites. It amends existing law to permit proprietors of lode or placer claims to locate as many mill site claims as are reasonably necessary for waste rock or tailings disposal, or other operations incident to mineral development. Each mill site is limited to five acres, does not convey mineral rights, and is not eligible for patenting, ensuring these sites serve solely operational support functions. A key component of the bill is the establishment of the Abandoned Hardrock Mine Fund in the U.S. Treasury. This fund will be financed by claim maintenance fees collected from the newly authorized mill sites. The monies deposited into this fund are specifically designated for expenditures, without requiring further appropriations, to carry out abandoned mine land reclamation activities as outlined in the Infrastructure Investment and Jobs Act, thereby addressing environmental liabilities associated with past mining.