2008-05-14_REPORT - C1981014 - Laserfiche WebLink

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EFC] Southfield Mine -Year 2007 Annual Hydrology Report April 21, 2008 monitoring period. Newlin Creek was dry the remainder of the year similaz to nearly all preceding monitoring periods. Dry creek beds were observed in Magpie Creek and in Second Alkali Creek throughout the period of this report. Historic field and laboratory water quality data for the surface water monitoring stations on Newlin, Magpie, and Second Alkali Creeks are summarized in Tables 10, 11, 14, 15, and 16. The two remaining sedimentation ponds (Ponds 4 and 5) did not fill to the point of dischazge during 2007, but did contain puddles or were partially filled from April through November by periodic rain events. Therefore, no discharge water samples were collected during 2007. Requirements for water analysis parameters were clarified as part of Minor Revision 55 (MR-55, approved in October 2007. Water samples from Newlin Creek were submitted to the lab with a pazameter list inadvertently copied from an EFCI's hydrology monitoring files that omits numerous parameters or specifies dissolved rather than total species concentrations. The resulting lab analysis therefor provided limited data for the 2007 monitoring results as shown on Tables 10 and 11 for Newlin Creek. EFCI has subsequently reviewed the approved permit requirements for surface water testing and will conduct future testing in accordance with these specifications. Ongoing monitoring of surface flows for Newlin, Magpie, and Second Alkali Creeks provides for identification and evaluation of any future changes in water quality that may result from mining and related activities. Surface water quantity and quality monitoring results to date indicate no significant impacts to surface water as a result of mining and related activities. Loadout Area The Loadout and adjacent azeas fall within the lower sections of the Oak and Chandler Creek drainages, both of which aze tributary to the Arkansas River. Oak Creek is a perennial drainage above the municipal well field for the Town of Rockvale. Dependent on water demand and withdrawal levels for Rockvale, flows in Oak Creek below the well field in the 4.7 mile section above the Loadout area may be either perennial or ephemeral. In azeas adjacent to the Loadout Area, flows in Oak Creek are frequently ephemeral, and Chandler Creek is considered an ephemeral creek (refer to Section 2.04.7 of the Southfield Mining and Reclamation Plan document for more details). EFCI monitors stream flows adjacent to the Loadout Area at stations OC-1 (Lower Oak Creek) and OC-2 (Lipper Oak Creek). EFCI also monitors any stormwater runoff discharge from the two active sedimentation ponds, Ponds L-1 and L-2, in the Loadout Area. In the Loadout Area, the current surface water monitoring program includes the following monitoring stations, located as shown on Figure 2, Loadout Monitoring Locations: Station Location Designation OC-1 E'/zNE'/4, Sec 18 OC-2 W'/zNE'/<, Sec 18 OOl W'/ZNW'/<, Sec 17 002 E'/ONE'/<, Sec 19 Oak Creek Down Stream Oak Creek Upstream Pond L-l Outlet (Chandler Creek) Pond L-2 Outlet (Oak Creek) 2007 AHR.doC WP Page 19