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„, , <br />r '' <br />3. HGLF water line <br />4. Electric substation <br />I. The Division proposes to approve surface mining activities within 100 feet <br />or through a perennial stream or stream with a biological community. <br />This decision is based on a finding that the original stream channel will be <br />restored, water quality and quantity will not be adversely affected, and <br />appropriate riparian vegetation wilt be rerstored (4.05.18(1)). <br />K: Probable Hydrologic Consequences <br />A discussion of the probable hydrologic impacts of mining and reclamation <br />operations is contained in Volume 2, Tab 15 of the permit application. <br />Probable Effects on Surface Water Quality: <br />Surface water runoff from the loadout azea passes through one of two <br />sedimentation ponds. Dischazges from these ponds aze subject to effluent <br />limits in the mine's NPDES permit. The existing ponds have performed <br />adequately and no dischazges in excess of NPDES effluent limits have been <br />reported to date. <br />Concentrations of total dissolved solids (TDS) aze four times higher for water <br />coming from the Rail Loop Pond than from the Truck Loop Pond; however, <br />TDS concentrations coming from the ponds aze generally less than ambient <br />concentrations in Dry Creek upstream. Existing water quality in Dry Creek is <br />unsuitable for irrigation and only mazginally suitable for livestock. <br />Most runoff from the rail loop, as well as the runoff from the three small area <br />exemptions, are not treated; however, runoff from these sources do not appeaz <br />to be affecting water quality. No adverse impacts from mining operations <br />were projected in the HG Mine permit application and none have been <br />observed to date. <br />Probable Effects on Surface Water Quantity: <br />Runoff from the loadout area that is not diverted azound the area of <br />disturbance is retained in sedimentation ponds for a maximum of 36 hours. <br />Water retained in these two sediment ponds result in some evaporative and <br />seepage losses. The Dn~ Creek diversion downstream could potentially be <br />impacted by loses of water due to storaee in these sediment ponds. <br />The acreage served by these two sediment ponds accounts for less than one- <br />thousandth of the acreage drained by Dry Creek. Since the azea to be affected <br />is a fraction of the total watershed, the general watershed will not be <br />