43 CFR 3597.1 - Books of account.
(a) Operators/ lessees shall maintain records which show a correct account of all ore and rock mined, of all ore put through the processing plant, of all mineral products produced and of all ore and mineral products sold. The records shall show all relevant quality analyses of ore minded, processed or sold and the percentage of the mineral products recovered or lost.
(b) Production records shall be made available for examination by the authorized officer during regular business hours. For the purpose of production verification, the authorized office may request, and the operator/lessee shall submit a copy of any portion of the production records not submitted to the Minerals Management Service as part of the operator's/lessee's production reporting.