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Mountain Coal Company <br />West Elk Mine <br />• INTRODUCTION <br />In 1998, Mountain Coal Company (MCC) constructed new mine dewatering and treatment <br />facilities at the site of existing dewatering boreholes within the Sylvester Gulch Facilities Area <br />(SGFA) (Drawing Sheet Cl). These facilities provided a method of reducing total suspended <br />solids (TSS) in mine water prior to discharging to the West Fork of Sylvester Gulch in <br />compliance with NPDES discharge permit requirements. The installed facilities include a <br />Dewatering Pump Station and Treatment Building and a Finishing Pond (Pond 017). A current <br />plan view of the existing Sylvester Gulch mine water system is shown on the attached Drawing <br />Sheet C2. <br />Several other facilities were originally planned but not constructed, including a Presedimentation <br />Basin, Decant Return Basin and Pump Station, and Sludge Drying Lagoons. The Dewatering <br />Pump Station and Treatment Building was originally constructed to also house several pieces of <br />treatment equipment (flocculation and sedimentation units, chemical Seed equipment, and <br />chemical storage units) that were not installed or necessary given the fact that the facilities listed <br />above were not constructed. These additional facilities and treatment equipment may be installed <br />at a later date, if deemed necessary. <br />In January 2007 a new limit for total recoverable iron (Fe) of 1,000 µg /l went into effect per the <br />• NPDES discharge permit. This exhibit describes the plan for an expansion of the SGFA to <br />provide additional treatment redundancy, efficiency, and operational flexibility to facilitate <br />compliance with NPDES discharge standards for TSS and total recoverable Fe. The treatment <br />system design is flexible to allow for the use of various components as necessary to enhance <br />treatment. <br />Preliminary design drawings and a flow diagram for the proposed treatment system are also <br />included on Drawing Sheets Cl — C6 and PFl. Pond area reclamation topography is illustrated <br />on Drawing Sheet R1. A full set of construction drawings and technical specifications will be <br />developed for construction of the treatment system, as will an Operations and Maintenance <br />(O &M) Plan. <br />FACILITIES DESCRIPTION <br />Provided below is an overview of the system modifications and design parameters, planned <br />retrofits to the existing SGFA, design of a second settling pond, description of the treatment <br />process, and storin water control measures. <br />System Overview <br />Mine water will continue to be extracted from the existing dewatering boreholes and mine water <br />• sump. The surface system is designed to actively aerate and increase the dissolved oxygen <br />2 <br />Rev. 10197 -TR83, Rev. 04109 -TR116 <br />Exhibit 69 <br />lvester Gulch Facilities <br />