43 C.F.R. § 3436.0-5
As used in this subpart, the term substantial financial and legal commitments is a relative one, and the determination whether such commitments have been made, so as to qualify a person for an exchange under this subpart, will be made on a case-by-case basis. In making this determination, the Secretary will consider the level of expenditures made prior to January 1, 1977, that are related to development of the coal resource which is offered in exchange, taken together with the damages for which the person would be liable as a result of any legal commitments made prior to January 1, 1977, in connection with development of said coal resource, and the Secretary will compare that level of expenditure to the estimated total cost of developing the coal resource to the point of establishing a producing surface coal mining operation.
43 C.F.R. § 3436.0-5