2008-10-07_PERMIT FILE - C1981047 (4)

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• The net conclusion is that potential effects of runoff from the mine site area are not likely to have a significant effect on water quality of Hubbard Creek or the North Fork. Hydrologic studies of the mine site area and the area above indicate that no interruption of the quantity of water flowing to Hubbard Creek will result because of the mining activity. A small ephemeral drainage crosses the northwest corner of the lease area and is the only drainage channel that crosses the affected area, except Hubbard Creek. Large scale aerial photographs flown in 1975, 1976 and 1977 clearly show this. Mine aubaidence is not expected to have any significant affect on surface or groundwater. There are no permanent streams over the areas that have been or will be mined. A single ephemeral stream channel crosses the western and northern portions of the area. An examination of a portion of this channel on December 9, 1981, showed no evidence of recent flow. Soil deposits and leaf debris, similar to those on adjacent slopes, were found in the channel, along with a lack of any recent • coarser-grained stream-laid deposits, scour, or any other indications of water flow. Vegetation is well developed and mature in portions of the channel, further indicating that flow is rare and probably quite short-lived when it does occur. Subsidence could affect flow in this channel but the rarity of flow events makes it clear that any reduction due to subsidence would have virtually no affect on the average flow rate of Hubbard Creek. The apparent rarity of flow in the ephemeral drainage discussed above, together with the fact there are no known springs above the coal seam, indicate that neither sheet wash nor subsurface flov from the area above the coal seam contribute significantly to the flow of Hubbard Creek. This is further indicated by the flov rates given on pages 44 and 44i where, for the year 1980, rates are shocm to be identical above and below the mine site. Therefore, again, aubaidence should not interrupt any significant water supply to Hubbard Creek. To the date of this application, approximately 53 acres of the Hawkaneet or (E) seam coal has been mined (see Exhibit c), about 19 acres of which have been • partially or completely pillared. Very little influx of water has been observed (see discussion of mine inflow above), even where substantial caving has occurred. This 123 iii (Rev. 1-25-R2)