Md. Code, Environment § 15-829

(a) An operation is considered abandoned if no mineral has been produced or overburden removed for a period of one year, and the permittee has vacated the site of the operation covered by the permit without having complied with all the requirements of the mining and reclamation plan, verified by inspection and written report made by the Department. If the permittee, within 30 days after receiving notification from the Department terming the operation abandoned, does not submit sufficient evidence to the Department that the operation in fact is not abandoned and a reasonable timetable satisfactory to the Department regarding plans for the reactivation of the operation, the Department shall declare the operation abandoned and initiate legal proceedings against the permittee.

(b) An operation is considered halted if active work has ceased temporarily due to weather conditions, market conditions, or other reasonable cause explained in writing by the permittee to the satisfaction of the Department, and accompanied by a statement that the permittee fully intends to resume active operation when the adverse conditions have passed. All necessary pollution controls shall be properly maintained during this period. No operation may be halted for a period exceeding 24 consecutive months. On failure of the permittee to resume mining or initiate reclamation, the Department shall declare the operation abandoned and initiate legal proceedings against the permittee.