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Therefore, pursuant to Rule 2.06.8(5)(1), the Division finds that the <br />proposed surface coal mining operations would not interrupt, discontinue, <br />or preclude farming on an alluvial valley floor. <br />Alluvial Valley Floor Findings with Regard to Material Damage to Water <br />Quality and Quantity- <br />The first potential impact to be considered is the effect of mine inflows <br />on the quantity and quality of water flowing into the East Salt Creek AVF <br />from the McClane Canyon ephemeral tributary. <br />At the time of the initial permanent regulatory permit approval during <br />the first quarter of 1982, no water was discharged from the mine <br />workings. However, subsequent to the extension of the east mains to the <br />east fault and north mains down dip to the northeast in a parallel line <br />with the east fault, mine inflows increased gradually and required <br />periodic discharge in accordance with an approved NPDES discharge <br />permit. Mine inflows peaked at a rate of approximately 5.4 gpm two <br />months after mine progress was stopped. Since that time, seepage of <br />water into the mine has decreased to a level of approximately 1.6 gpm <br />during the first quarter of 1985. <br />The source of this water is believed to be primarily from the edge of the <br />saturated portion of the Cameo seam and to a lesser extent from the east <br />fault which is recharged by portions of the McClane Canyon drainage <br />transected by the fault at the surface and/or shallow aquifers from the <br />upper reaches of McClane Creek. <br />The water seeping into the mine is of bicarbonate, sulfate type with a <br />relatively low concentration of total dissolved solids (1,526 - 3,260 <br />mg/1), and a pH in the range of 8.2 - 8.95. These chemical <br />characteristics would indicate a similarity to the surface water quality <br />in the upper reaches of East Salt Creek. Water in the alluvial aquifer <br />of East Salt Creek at the confluence with McClane Canyon and in East Salt <br />Creek downstream on the site has a higher concentration of total <br />dissolved solids, a substantially higher amount of sulfides and generally <br />lower pH. <br />The actual water inflow into the mine has been measured at approximately <br />1.6 gpm. It is believed that a portion of the recharge to this ground <br />water system occurs when McClane Creek crosses the east fault. McClane <br />Creek is an ephemeral stream flowing only in response to snowmelt and <br />major storm events. The depletion caused by recharge occurring during <br />this period will not significantly affect the quantity of water in East <br />Salt Creek or its associated alluvium, due to the small depletion <br />relative to high flows. During dry periods when East Salt Creek is at <br />lower flows, McClane Creek is dry and no depletion is occurring. <br />-14- <br />