2010-06-30_REPORT - C1980007 (5)

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West Elk Mine 2009 Annual Hydrology Report 7 0 Fi ure 7. Stream Flow Data for Minnesota Creek near Minnesota Creek 140 120 w u 100 0 e~ 80 L 60 40 20 CO (USGS 091 -Average Flow WYs 1937-47,1986-2008 -0-- Average Flow WY 2009 0 - Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Adapted from USGS (2010a) • 3.0 HYDROLOGIC MONITORING PLAN MCC's hydrologic monitoring program is designed to collect 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 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 WY 2007 - WY 2009. A brief summary of the monitoring plan is presented in the following sections. The hydrologic monitoring plan for the permit area includes monitoring surface water resources, springs and seeps, ground water 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 261h; 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, including one year of baseline sampling, is presented in Table 2. After sites have been monitored for 5 years (including approximately one year of baseline monitoring), the analytical suite parameter list is reduced to collecting field parameters (pH, conductivity, temperature, and flow or June 2010 HydroGeo, Inc.