2013-07-02_REPORT - C1980007 (3)

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West Elk Mine 2012 Annual Hydrology Report 3.0 HYDROLOGIC MONITORING PLAN 0 The MCC hydrologic monitoring program is designed to collect monitoring data to assess mining - related impacts on hydrologic resources. The Colorado Division of Reclamation, Mining, and Safety (CDRMS) approved a revised hydrologic monitoring plan for the West Elk Mine permit area in June 2006 (CDRMS, 2006). The revised monitoring plan has been implemented since the latter months of WY 2006 and in WYs 2007 through 2012. A brief summary of the current monitoring plan (CDRMS, 2006) is presented in the following sections. The hydrologic monitoring plan for the permit area includes monitoring surface water resources, springs and seeps, groundwater resources, the coal refuse pile underdrains, and pertinent mine water sites. Routine monitoring (subsequent to baseline monitoring) includes collecting field water quality data (pH, electrical conductivity [EC], and temperature) and collecting a sample for independent laboratory analysis annually. Flow or water level measurements are collected three times per year corresponding with: the rising limb period between April 3rd and May 13th; the peak flow period between April 21St and June 26th; and the low flow period between July 10th and October 8th, 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), EC, pH, and iron (Fe [dissolved & total]). Field parameters (pH, EC, temperature, and flow or water level) are also recorded. The North Fork of the Gunnison River (NFGR) and Middle Sylvester Gulch monitoring sites have expanded analytical parameter suites, in order to provide data for the on -going characterization of the NFGR. The NFGR 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 CaCOA carbonate, hydroxide, and ortho- phosphate. The current hydrologic monitoring plan for MCC 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 at least six 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 2013 HvdroGeo, Inc.