30 CFR § 1206.258 - Washing allowances - general.
(a) For ad valorem leases subject to § 1206.257 of this subpart, ONRR shall, as authorized by this section, allow a deduction in determining value for royalty purposes for the reasonable, actual costs incurred to wash coal, unless the value determined pursuant to § 1206.257 of this subpart was based upon like-quality unwashed coal. Under no circumstances will the authorized washing allowance and the transportation allowance reduce the value for royalty purposes to zero.
(b) If ONRR determines that a lessee has improperly determined a washing allowance authorized by this section, then the lessee shall be liable for any additional royalties, plus interest determined in accordance with § 1218.202 of this chapter, or shall be entitled to a credit without interest.
(c) Lessees shall not disproportionately allocate washing costs to Federal leases.