(a) If the development of a plan for an entire operation is not possible, the operator shall file an initial plan setting forth this proposed operation to the degree reasonably foreseeable at that time. Thereafter, the operator shall file a supplemental plan or plans prior to undertaking any operations not covered by the initial plan.

(b) At any time during operations under an approved plan of operations, the authorized officer or the operator may initiate a modification of the plan detailing any necessary changes that were unforeseen at the time of filing of the plan of operations. If the operator does not furnish a proposed modification within a time considered reasonable by the authorized officer, the authorized officer may recommend to the State Director that the operator be required to submit a proposed modification of the plan. The recommendation of the authorized officer shall be accompanied by a statement setting forth the supporting facts and reasons for his recommendations. In acting upon such recommendation, except in the case of a modification under § 3802.1-5(e) of this title, the State Director shall determine (1) whether all reasonable measures were taken by the authorized officer to predict the environmental impacts of the proposed operations; (2) whether the disturbance is or may become of such significance as to require modification of the plan of operations in order to meet the requirement for environmental protection specified in § 3802.3-2 of this title, and (3) whether the disturbance can be minimized using reasonable means. Lacking such a determination by the State Director, an operator is not required to submit a proposed modification of an approved plan of operations. Operations may continue in accordance with the approved plan of operations until a modified plan is approved, unless the State Director determines that the operations are causing impairment or unnecessary or undue degradation to surface resources. He shall advise the operator of those measures needed to avoid such damage and the operator shall immediately take all necessary steps to implement measures recommended by the State Director.

(c) A supplemental plan of operations or a modification of an approved plan of operations shall be approved by the authorized officer in the same manner as the initial plan of operations.