29 CFR 2700.21: Effect of filing notice of contest of citation or order.

(a) The filing of a notice of contest of a citation or order issued under section 104 of the Act, 30 U.S.C. 814, does not constitute a challenge to a proposed penalty assessment that may subsequently be issued by the Secretary under section 105(a) of the Act, 30 U.S.C. 815(a), which is based on that citation or order. A challenge to such a proposed penalty assessment must be filed as a separate notice of contest of the proposed penalty assessment. See § 2700.26.

(b) An operator's failure to file a notice of contest of a citation or order issued under section 104 of the Act, 30 U.S.C. 814, shall not preclude the operator from challenging, in a penalty proceeding, the fact of violation or any special findings contained in a citation or order including the assertion in the citation or order that the violation was of a significant and substantial nature or was caused by the operator's unwarrantable failure to comply with the standard.