Section 9.7 - Assessment work(a) An access permit and approved plan of operations must be obtained by a claimant prior to the performance of any assessment work required by Revised Statute 2324 (30 U.S.C. 28 ) on a claim in a unit.(b) Permits will be issued in accordance with the following:(1) In units subject to the surface disturbance moratorium of section 4 of the Act and § 9.4 , no access permits will be granted for the purpose of performing assessment work.(2) It has been determined that in all other units the Secretary will not challenge the validity of any unpatented claim within a unit for the failure to do assessment work during or after the assessment year commencing September 1, 1976. The Secretary expressly reserves, however, the existing right to contest claims for failure to do such work in the past. No access permits will be granted solely for the purpose of performing assessment work in these units except where claimant establishes the legal necessity for such permit in order to perform work necessary to take the claim to patent, and has filed and had approved a plan of operations as provided by these regulations. (For exploratory or development type work, see § 9.9 .)