(1) (a) Strip or underground coal mining operations must not interrupt, discontinue, or preclude farming on alluvial valley floors, unless:

(i) the premining land type is undeveloped rangeland that is not significant to farming; or

(ii) the area of affected alluvial valley floor is small and provides or may provide negligible support for production from one or more farms.

(b) If environmental monitoring shows that a strip or underground coal mining operation is interrupting, discontinuing, or precluding farming on alluvial valley floors, the operation must cease until remedial measures are taken by the operator.   The remedial measures must be approved by the department prior to the resumption of mining.

(2) Strip or underground coal mining and reclamation operations must not cause material damage to the quality or quantity of water in surface or underground water systems that supply alluvial valley floors.   If environmental monitoring shows that the strip or underground coal mining operation is causing material damage to water that supplies alluvial valley floors, the mining operations must cease until remedial measures are taken by the operator.   The remedial measures must be approved by the department prior to the resumption of mining operations.

(3) Sections (1) and (2) of this rule do not apply to those lands which were identified in a reclamation plan approved by the department before August 3, 1977, for any strip or underground coal mining and reclamation operation that, in the year preceding August 3, 1977:

(a) produced coal in commercial quantities and was located within or adjacent to an alluvial valley floor, or

(b) obtained specific permit approval by the department to conduct strip or underground coal mining and reclamation operations within an alluvial valley floor.