(a) Necessity. The applicants for the resurvey of any township are required to present satisfactory prima facie evidence of the necessity for such action, based either upon general obliteration of evidences of the original survey or upon conditions so grossly defective as to preclude the possibility of a reasonably certain identification of the subdivisions of the subsisting survey or a satisfactory local restoration thereof.

(b) Condition of original survey. Applications for the resurvey of each township must be supported by evidence in the form of a statement, preferably from the county or other competent surveyor, showing in detail that the evidences of the original survey have been obliterated to such an extent as to make it impracticable to apply the suggestions of the circular issued by the Bureau of Land Management for the necessary restoration of the lines and corners in the proper identification of the legal subdivisions occupied by the present or prospective entrymen or that the obliteration of the original monuments has become so advanced that the land boundaries can be identified only through extensive retracements by experienced engineers of the Bureau of Land Management.