H.Amdt.876 - Amendment to clarify that "valid existing rights" associated with existing mining claims would be protected under the Act. It would clarify that in addition to paying a 4% royalty, existing operations will still need to come into compliance with the Act within 10 years; would clarify that the claim maintenance and location fees currently allotted to administration of the mining laws will continue to be so allotted with the balance going to clean-up of abandoned hardrock mines, subject to appropriations; would clarify that user fees assessed by the BLM to process mining permit applications will be used for administration of the mining law program; would limit the purview of section 504-citizen suits--to permits issued pursuant to title III of the Act; and finally, would clarify that nothing under the Act will affect the sovereign immunity of any Indian Tribe.