Section 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.58 FR 12164, Mar. 3, 1993, as amended at 71 FR 44207 , Aug. 4, 2006