(1) The significance of the impact of the proposed operations on farming is based on the relative importance of the vegetation and water of the grazed or hayed alluvial valley floor area to the farm's production, or any more stringent criteria established by the department as suitable for site-specific protection of agricultural activities in alluvial valley floors.   The effect of the proposed operations on farming is "significant" if the operations would, over the life of the mine, have more than a negligible impact on the farm's agricultural production.   In making the determination of "significance", the department shall consult with the affected landowner(s).