Where one operator succeeds another at any uncompleted operation, either by sale, assignment, lease, or otherwise, the secretary may release the first operator from all liability under this act as to that particular operation: Provided, however, That both operators have registered and have otherwise complied with the requirements of this act and the successor operator assumes as part of his obligation under this act all liability for grading, planting and reclamation on the land affected by the former operator.
52 P.S. § 1396.18a