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TWENTYMILE COAL COMPANY - FOIDEL CREEK MINE <br />MINOR REVISION MR08-230, MINE DEWATERING MODIFICATIONS <br />TECHNICAL ADEQUACY RESPONSES 10/08 <br />1) Permit text on new pages 2.05-50.4 and 2.05-50.5 discusses the Eastern Mining District (TORT) <br />Dewatering Borehole. Included in the discussion are treatment ponds and an 8-inch discharge line <br />buried that diverts discharge to Foidel Creek. Currently these ponds and the discharge line have <br />not been constructed. In some way, the new permit text should reflect an up-to-date discussion of <br />what will actually occur with regarding to mine water handling, treatment, and discharge. Please <br />note within the permit text which activities are previously approved but have not been implemented <br />on the ground, to avoid any confusion regarding water handling procedures. <br />Response: The referenced permit text identifies those activities that have been approved but not yet <br />constructed, however to address this concern, the text has been reviewed and edited for clarity. <br />2) New permit text is detailed and descriptive but difficult to follow without a map that clearly shows <br />sump locations, discharge points, discharge volumes, treatment locations, pipeline locations and <br />flow directions in relation to the stream systems. Although, the Division agrees with the necessity <br />of including all these features on Map 24, Surface Facilities, the map contains too much detail at <br />the 1:800 scale that much of the information is indiscernible. TCC had previously provided Map <br />16, Mine Water Balance, (dated 1999) that shows only the key features regarding mine water <br />handling and treatment without the confusion and clutter of the other facilities. An update of Map <br />16 or a schematic drawing that clearly illustrates only the key features regarding mine water <br />handling and treatment. Direction of flow and amount of discharge would be helpful to include, e <br />in order to illustrate the water-handling system. <br />Response: Map 16 has been updated to show the current components of the mine water handling <br />system. Generalized mine inflow and pumped discharge volumes are identified on the drawing, with <br />the caveat that these volumes can vary significantly (both seasonally and temporally), as noted in the <br />legend, and with reference to relevant descriptive text. It is also important to note that some of the <br />mine water transfer pipelines are located and designed to move water in either direction, dependent on <br />mine water requirements and seasonal discharge considerations. Control of flow direction is achieved <br />through selective activation of transfer pumps and appropriate control valves. <br />3) Permit text discussion of flow directions on some of the sections of pipeline, both existing and <br />proposed are somewhat confusing. Some sections seem to have the ability to carry flow in both <br />directions. Please provide a map, as requested in 92 above and provide minor text edits to resolve <br />questions on flow direction through the waterline system. <br />Response: Please refer to previous response. <br />4) The applicable standards for Region 12, Yampa River are shown on current tables provided <br />through the Water Quality Control Division web site. The two segments of interest are 13f on <br />Trout Creek from the confluence with Fish Creek to the Yampa River, and segment 13c, from the <br />confluence with Fish Creek upstream to a point closer to the Edna Mine. Both of these segments <br />have a "WS" designation for sulfate, meaning "water supply". The "WS" abbreviation means <br />that the less restrictive of ambient quality on January 1, 2000 or sulfate of 250 mg1l shall be the <br />applicable in-stream standard. However, for all surface waters with a "water supply"