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EFCI Sotdhffield Mine — 2014Annual Hydrology Report February 12, 2014 <br />Well MW-NW water level data (Figure 4) indicate a dry well since monitoring was initiated in early <br />2003. Figure 4 illustrates the dry well condition with a "water level" line synonymous with the <br />total original well depth to the floor of the mine opening, approximately 375 feet. The well depth <br />that can be monitored changed in 2012 due to a failure in the last 20 feet of steel casing (see <br />following Section 3.2). Figure 4 is modified accordingly to show the current measurable depth of <br />the well of 353 feet, reported as dry. <br />Loadout Area <br />In the Loadout Area, groundwater occurs primarily in alluvial/colluvial deposits in and adjacent to <br />the Oak Creek flood plain. Due to limited surface and groundwater flows and recharge and the <br />character of the alluvial/colluvial deposits, these deposits do not appear to store or transmit <br />significant quantities of water, as indicated by the lack of sub- irrigation. A 2003 evaluation at the <br />site, performed by the Fremont County Soil Conservation Service, concluded that no AVF areas <br />exist within the Loadout permit boundary. <br />Because the alluvial/colluvial deposits associated with Oak Creek do not represent a significant <br />groundwater source or aquifer, no groundwater monitoring was ever required at the Loadout site or <br />immediate vicinity. <br />3.2 Monitoring Well Inspections <br />The condition of monitor wells is ascertained at the time each well is monitored. Typically the <br />wells have been found in good condition, although EFCI did replace several well caps in 2001/2002 <br />to assure ongoing access control and to prevent contamination from entering the wells. Monitor <br />wells MW 16, MW23, and MW-65 were performing as designed for obtaining representative water <br />samples through the period of this report. <br />The physical condition of monitoring well MW-NW changed in 2012 due to a failure in the lower <br />section of well casing as described above. EFCI maintains that MW-NW is functional for <br />monitoring groundwater and collecting water samples as is stated in the DRMS Inspection Report <br />dated April 17, 2012. <br />EFCI performed a 1,500 gallon water test in April 2012 conclusively demonstrating that the MW- <br />NW well casing is open to water flow into the mine void. An identical "percolation" test was <br />conducted on April 30, 2014 and observed by Rob Zuber (DRMS). The well was probed prior to <br />the test and found dry. Similar to the previous test, 1500 gallons of water from a water truck were <br />directed down the well through a 3 inch diameter hose. The total quantity flowed into the well in <br />just under 13 minutes. After the flow stopped, water gurgled in well casing for 55 seconds, then <br />ceased flowing in the casing. This is the approximately the same amount of time required for the <br />water to stop flowing in the casing as during the previous test. Based on the quantity of water and <br />the time flow was heard in the casing, the rate of flow through the obstruction, thus entering the <br />mine workings, was estimated at 110 GPM. <br />No other physical changes in the well's condition were observed during the reporting period. <br />2014 AHR tuLcloo Page 7 <br />