30 U.S.C. 601 : US Code - Section 601: Rules and regulations governing disposal of materials; payment; removal without charge; lands excluded.

The Secretary, under such rules and regulations as he mayprescribe, may dispose of mineral materials (including but notlimited to common varieties of the following: sand, stone, gravel,pumice, pumicite, cinders, and clay) and vegetative materials(including but not limited to yucca, manzanita, mesquite, cactus,and timber or other forest products) on public lands of the UnitedStates, including, for the purposes of this subchapter, landdescribed in subchapter V of chapter 28 of title 43, if thedisposal of such mineral or vegetative materials
(1) is nototherwise expressly authorized by law, including, but not limitedto, subchapter I of chapter 8A of title 43, and the United Statesmining laws, and
(2) is not expressly prohibited by laws of theUnited States, and
(3) would not be detrimental to the publicinterest.
Such materials may be disposed of only in accordance withthe provisions of this subchapter and upon the payment of adequatecompensation therefor, to be determined by the Secretary: Provided,however, That, to the extent not otherwise authorized by law, theSecretary is authorized in his discretion to permit any Federal,State, or Territorial agency, unit or subdivision, includingmunicipalities, or any association or corporation not organized forprofit, to take and remove, without charge, materials and resourcessubject to this subchapter, for use other than for commercial orindustrial purposes or resale. Where the lands have been withdrawnin aid of a function of a Federal department or agency other thanthe department headed by the Secretary or of a State, Territory,county, municipality, water district or other local governmentalsubdivision or agency, the Secretary may make disposals under thissubchapter only with the consent of such other Federal departmentor agency or of such State, Territory, or local governmental unit.Nothing in this subchapter shall be construed to apply to lands inany national park, or national monument or to any Indian lands, orlands set aside or held for the use or benefit of Indians,including lands over which jurisdiction has been transferred to theDepartment of the Interior by Executive order for the use ofIndians. As used in this subchapter, the word "Secretary" means theSecretary of the Interior except that it means the Secretary ofAgriculture where the lands involved are administered by him fornational forest purposes or for the purposes of title III of theBankhead-Jones Farm Tenant Act [7 U.S.C. 1010 et seq.] or wherewithdrawn for the purpose of any other function of the Departmentof Agriculture.