Michigan Compiled Laws, Chapter 324. Natural Resources and Environmental Protection § 324.3505

Sec. 3505. Every permit granted under this part shall be for a term as is necessary to permit the mining to exhaustion and beneficiation of all low-grade iron ore referred to in the permit application, but not to exceed 50 years. The department may prescribe in the permit such time as it considers reasonable for the commencement or completion of any operations or construction under the permit or the exercise of the rights granted in the permit. The original term of the permit or the time allowed for the performance of any condition in the permit may be extended by the department upon application of the permittee.