2015-03-12_PERMIT FILE - C1981014A (2)

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EFCI's monitoring program for the Southfield Mine addresses four (4) specific areas: • Surface Water Flows in the Ephemeral Drainages of Magpie, Newlin, and Second Alkali Creeks • Surface Water Discharges from Sedimentation Structures • Groundwater in a Series of Monitoring Wells • Groundwater Inflows and Dewatering from previous mine Workings The status of monitoring surface flows at Oak Creek has changed since closure of the mine in 2000, and subsequent reclamation activities at the loadout site through 2014. Oak Creek is no longer monitored in accordance with an approved revision to the permit application. In addition, monitoring of groundwater inflows and dewatering from active workings was terminated upon sealing of the mine openings in 2000. Each component of the hydrologic monitoring program reflected different characteristics and intervals of flow. Consequently, the Southfield monitoring program was designed to provide an effective record of hydrologic conditions and identify any changes in the noted hydrologic systems. EFCI illy collects surface water quality samples and takes flow measurements on Newlin Creek on a semi- annual basis. Since Magpie Creek is tributary to Newlin Creek and flows only in response to snowmelt and storm runoff, the primary hydrologic information of relevance for Magpie Creek is peak runoff rates. Accordingly, EFCI monitored and sampled flows on a daily basis at any time significant flows occurred in Magpie Creek. As an ephemeral stream, monitoring procedures for Second Alkali Creek were essentially the same as discussed for Magpie Creek. EFCI monitored and sampled flows on an opportunistic basis at any time significant flows occured in Second Alkali Creek. All surface monitoring sites are shown on Mine Area Surface and Groundwater Hydrology Map, (Map 12), the Loadout Area Surface and Groundwater Hydrology Map, (Map 13), and the Southfield Reclamation Plan Map (Map 33). 2.05.6 -52 Revised: 8/l/14 RN -06