“Major modification” defined.

“Major modification” means: 1. A change in the postmining land use which requires reclamation techniques which are significantly different from the techniques included in the approved plan for reclamation; 2. The addition of a type of disturbance which was not previously included in the approved plan and which cannot be reclaimed in a manner that is substantially similar to the reclamation techniques included in the approved plan; 3. The proposed disturbance is equal to 25 percent or more of the acreage in the approved plan; or 4. A change in the visual appearance of the reclaimed areas that is substantially different from the visual appearance which was discussed or commented upon during the public comment period.