2008-06-27_REPORT - C1980007 (4)

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West Elk Mine 2007 Annual Hydrology Report 6 • 3.0 HYDROLOGIC MONITORING PLAN The Project's monitoring program is designed to collect adequate hydrologic monitoring data for assessing mining-related impacts to hydrologic resources. The Colorado Division of Reclamation, Mining, and Safety (CDRMS) approved a revised hydrologic monitoring plan for the Project in June 2006. The revised monitoring plan was implemented in the latter months of WY 2006 and in WY2007. A brief summary of the revised monitoring plan is presented in the following sections. The hydrologic monitoring plan for the Project includes monitoring surface water resources, springs and seeps, ground water resources, the underdrain, and pertinent mine water sites. Routine (subsequent to one year of baseline monitoring) 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 13`h, the peak flow period, between April 21S` and June 26`h, and the low flow period, between July 10`h and October 8`h, as shown on Table 1. The chemical analysis suite for the first five years of sampling, including one year of baseline sampling, is presented in Table 2 and also includes recording field parameters (pH, is conductivity, temperature, and flow or water level). After sites have been monitored for 5 years (including one year of baseline monitoring), the analytical suite parameter list is reduced to collecting field parameters (pH, conductivity, temperature, and flow or water level) and submitting samples for laboratory analysis for total suspended solids (TSS), total dissolved solids (TDS), conductivity, pH, and iron (Fe [dissolved & total]). The North Fork of the Gunnison River and Middle Sylvester Gulch monitoring sites have expanded analytical suites, 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, cyanide, nitrite, nitrate alkalinity, carbonate, hydroxide, and ortho- phosphate. The current (revised) hydrologic monitoring plan incorporates a separate baseline monitoring schedule for 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 includes collecting monthly field water quality data, flow or water level measurements, and collecting samples for laboratory analysis (Table 2) for the year prior to potential impacts. Site-specific baseline schedules are dependent on site accessibility and mine development timing. • In general, baseline monitoring is conducted monthly, usually from April through September in order to provide adequate data to show seasonal variations in water quality and quantity. Winter June 2008 HydroGeo, Inc.