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Pursuant to Rule 2.06.8, the Division is required to make specific written findings on the effect of mining on all AVF's within the permit and adjacent area. The required findings are presented below. The mining operations did not interrupt, discontinue, or preclude farming on the alluvial valley floor. The surface facilities associated with the mine are located outside of the area designated as alluvial valley floor. The operation did undermine portions of the area designated as alluvial valley floor but it did not affect farming activities. The applicant performed limited mining (the extraction ratio was between 50 and 55 percent), and, therefore, no significant surface effects from subsidence were expected. In addition, the applicant hoe a subsidence monitoring plan (Section 2.05.6(6)(f)(ii)(c) of the permit application). The mining operations would not materially damage the quantity or quality of surface and ground water which supply the alluvial valley floor. During mining operations, the underground mine slightly depleted flows in the stream/alluvial aquifer system, and the discharge of water from the underground workings affected water quality in the Carbon Ditch and in Ward Creek. After mining operations, when the natural ground water flow pattern is restored, water passing through the underground workings would affect water quality in the Williams Creek and ward Creek stream/alluvial aquifer system. A quantitative assessment of these effects ie provided in the discussion of probable hydrologic consequences contained in this findings document. That assessment predicts the stream flow depletion to be less than 2 percent of the average stream flow in Ward Creek, and less than 7 percent of the lowest stream flow observed in Ward Creek. The predicted water quality resulting from the mining activities would not prevent the use of surface water for flood irrigation. The essential hydrologic functions of the alluvial valley floors would be preserved. The most important characteristics of the Williams Creek and Ward Creek alluvial valley floors are the integrity of the present irrigation system and the ability of the surface water system to supply sufficient irrigation water to farming activities on the alluvial valley floors. As discussed above, surface disturbances were located outside of the alluvial valley floors, and mining was limited to 50-55 percent extraction to minimize surface subsidence effects. Any surface effects are anticipated to be minor, and capable of remedy. The operator hoe committed to promptly regrading depressions, swells, or cracks if any develop ae a result of subsidence. As a result, the surface topography and the integrity of the existing irrigation system would be preserved. Since no significant effect to the quantity or quality of the water which supplies the alluvial valley floor is expected, the supply of irrigation water would also be preserved. XVII. Operations on Prime Farmland A. An investigation was made in the fall of 1980 to determine if the land within the proposed permit area ie prime farmland. Pursuant to Rule 2.07.6(2)(k), the Division has made a negative determination for the presence of prime farmland for the following reasons: The land has not been historically used as cropland. The land within the permit area was wildlife habitat. The slope of the land varies from 20 to 60 percent. 23