2012-07-02_REPORT - C1980007 (3)

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West Elk Mine 2011 Annual Hydrology Report 9 April 21 and June 26 and the low flow period between July 10 and October 8 as shown on Table 1. The chemical analyte suite for the first five years of sampling for both groundwater and surface water samples, including one year of baseline sampling, is presented in Table 2. After monitoring sites have been monitored for 5 years (including approximately one year of baseline monitoring), the analytical suite parameter list is typically reduced and samples are submitted for laboratory analysis of total suspended solids (TSS), total dissolved solids (TDS), conductivity, pH, and iron (Fe [dissolved & total]). The field parameters (pH, EC, temperature, and flow or water level) are also recorded. The North Fork of the Gunnison River and Middle Sylvester Gulch monitoring sites; however, have expanded analytical parameter suites, in order to provide data for the on -going characterization of the North Fork of the Gunnison River. The North Fork of the Gunnison River and Middle Sylvester Gulch lab parameters include those listed in Table 2, plus chromium, nickel, silver (total), cyanide (total), nitrite (as N), nitrate (as N), alkalinity (total CaCO carbonate, hydroxide, and ortho - phosphate. The current hydrologic monitoring plan for MCC (CDRMS, 2006) incorporates a separate baseline monitoring schedule for all new monitoring sites for approximately one year prior to the time when mine development operations expand into new potentially affected areas. The baseline monitoring schedule protocols stipulate collecting monthly field water quality data, flow or water level measurements, and collecting samples for laboratory analysis for the year prior to initiation of mining and potential impacts (Table 2). Site - specific baseline schedules are dependent on site accessibility and mine development timing. In general, baseline monitoring is conducted for consecutive months, usually from April through September, in order to provide adequate data to show seasonal variations in water quality and quantity. Winter access to most sites within the MCC permit area is not feasible and is impractical, so the baseline monthly monitoring is generally not performed from October through March. A summary of the approved baseline and routine monitoring program frequencies is presented in Table 1. June 2012 HydroGeo, Inc.