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Surface and Groundwater Monitoring <br />The surface and groundwater monitoring program has been changed since monitoring began in the <br />1970's to add hydrologic resources as the permit area was expanded, and to remove hydrologic <br />resources that were no longer providing reliable or relevant data. These changes were made with <br />approved revision applications including Technical Revision Nos. TR -54 (1987), TR -85 (1998), <br />TR -88 (1999), and TR -139 (2016), as well as Permit Revision Nos. PR -10 (2006), PR -11 (2005), <br />and PR -12 (2008). Specifics about each revision can be found in the CDRMS revision files, as well <br />as in Exhibit 18 — "Characterization of Groundwater Systems in the Vicinity of West Elk Mine", <br />Exhibit 71 — "Hydrologic Characterization of the South of the Divide/Dry Fork Lease Areas and <br />Hydrologic Monitoring Plan for Mountain Coal Company, LLC, West Elk Mine", and in Exhibit <br />71A (PR -15 (2018). <br />The comprehensive hydrologic monitoring plan for the West Elk Mine facilities and permit area is <br />presented in Exhibit 71 and with recommended additions in Exhibit 71A. The locations of all of <br />the monitored water resources are provided in these exhibits, as well as on permit Map 34 — <br />"Locations of Hydrologic Monitoring Stations". This monitoring program was designed to collect <br />the hydrologic data needed to assess mining -related impacts on hydrologic resources. The <br />monitoring schedule, including a baseline monitoring schedule and "sampling windows" <br />established to capture the rising limb, the peak, and low flow of the hydrograph in monitored <br />surface water resources, is described. The chemical analyte suite for the first five years of <br />monitoring (including the baseline period) of both surface and groundwater resources and <br />subsequent reduced analytical parameters are provided in Exhibit 71 as well. <br />Along with the quality and quantity of streams, springs, groundwater, mine inflows and mine <br />discharges, MCC, in cooperation with the U.S. Forest Service — Paonia Ranger District, has agreed <br />to informally monitor the U.S. Forest Service stockponds that are located directly over panels to be <br />mined and within the angle -of -draw per the agreement letter in Exhibit 19C. Map 37 shows the <br />locations of these ponds within MCC's permit area, as well as the locations of springs, including <br />decreed springs. <br />For mine water inflows, flow estimates through the use of a timed volume approach, field <br />parameters and a water quality sample will be collected from mine inflow locations as close to the <br />inflow source as safely possible. Flows of inflows that are roof drippers, seeps, or dispersed flow <br />will be expressed as a flow less than 5 gpm. <br />Annual Hydrology Report <br />By June 30t` each year, MCC provides an Annual Hydrology Report (AHR) that includes analyses <br />of hydrologic data gathered during the previous water year (October 01 to September 30) to assess <br />the impacts of mining on the quality and quantity of streams, springs, groundwater aquifers, mine <br />inflows and mine discharges that may have occurred in the permit area. Maps showing the <br />locations of the monitored water resources, as well as a mine map showing mine inflows are <br />provided in the AHR. Estimates of water imported for use on the mine site and within the mine, as <br />well as mine and mine site discharges (water balance) are also provided in the reports. The <br />adequacy of the current monitoring plan is also evaluated in the report. Based on the monitoring <br />2.05-71 Rev. 11/96- PR07; 04/06 -PRIG; 12/14- TR136, 08116-TR139, 08/18- PR15 <br />