2016-12-01_PERMIT FILE - C1980007A (2)

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