(1) The amount of the performance bond must be increased, as required by the department, as the acreage in the permit area increases, methods of mining operation change, standards of reclamation change or when the cost of future reclamation, restoration or abatement work increases. The department shall notify the permittee of any proposed bond increase and provide the permittee an opportunity for an informal conference on the proposal. The department shall review each outstanding performance bond at the time that permit reviews are conducted under ARM 17.24.414 through 17.24.416 and reevaluate those performance bonds in accordance with the standards in ARM 17.24.1102.
(2) When subsidence-related material damage to land, structures, or facilities protected under ARM 17.24.911(7) (a) through (c) occurs, or when contamination, diminution, or interruption to a domestic water supply protected under ARM 17.24.903(2) occurs as a result of underground mining activities, the department shall require the operator to obtain additional performance bond in the amount of the estimated cost of the repairs if the operator will be repairing damage, or in the amount of the decrease in value if the operator will be compensating the owner, or in the amount of the estimated cost to replace the protected water supply if the operator will be replacing the water supply, until the repair, compensation, or replacement is completed. If repair, compensation, or replacement is completed within 90 days of the occurrence of damage, no additional bond is required. The department may extend the 90-day time frame, not to exceed one year, if the operator demonstrates and the department finds in writing that subsidence is not complete, that not all probable subsidence-related material damage has occurred to lands or protected structures, or that not all reasonably anticipated changes affecting the protected water supply have occurred, and that therefore it would be unreasonable to complete within 90 days the repair of the subsidence-related material damage to lands or protected structures, or the replacement of a protected water supply.
(3) A permittee may request reduction of the required performance bond amount upon submission of evidence to the department proving that the permittee's method of operation or other circumstances not related to the completion of reclamation work will reduce the maximum estimated cost to the department to complete the reclamation responsibilities and therefore warrant a reduction of the bond amount. Bond reductions which involve undisturbed land, disturbed land previously released from reclamation liability in accordance with ARM 17.24.1111 through 17.24.1115 and 17.24.1116(6) , or revision of the cost estimate of reclamation are not considered bond release subject to procedures of ARM 17.24.1111. Any other request to reduce a performance bond must be considered as a request for partial bond release in accordance with the procedures of ARM 17.24.1111 through 17.24.1116.
(4) For bond adjustment requests on undisturbed land, the permittee shall submit a map of the area in question and shall revise the appropriate active permit maps. The department shall then conduct an inspection of the proposed area before responding to such requests.
(5) The amount of disturbance within a permit area must not exceed the amount bonded for.