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COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT, Water Quality Control Division <br />Rationale - Page 4, Permit No. CO-0000906 <br />6IV, FACILITY DESCRIPTION <br />A. Industry Description <br />, Type of Industry - Thisfacility is an underground coal mine in "temporary cessation. " The coal mine has been <br />1 <br />inoperative for the entire life of the previous Po din ?o the expectations ermit applicationac when active, the mine isa capable of will <br />become active during this permit period. Ac $ P <br />processing 2 million tons per year of bituminous coal. ive mine 2. Sources to the Treatment Plant -Pond 1, from which 008A originate, respectively, uface water runoff only. <br />Ponds 4, 7 and 8, from which Outfalls 004A, 007A and <br />Note again that treated domestic sewage and treated coal preparation plant industrial wastewater, which are generated <br />at this facility, are not authorized to discharge to surface water as the facility has indicated that these sources of <br />wastewater are routed to a Pond 6, non-surface water discharging pond. <br />Note that the permit application also indicated that the facility plans to route mine water to Pond 7 during the initial <br />facility start up to ensure that mine water is within limits prior to discharge. Mine water may not be discharged via uffi <br />009uthorized to <br />OasuOutfall <br />001 a. <br />is a Outfall 007A but instead nousta ? mine water is authorized tol be di? havia rg?d onall <br />discharge only surface runoff <br />3. Chemical Usage - The permittee stated in the renewal application that they utilize one chemical in their treatment <br />process. These chemicals are summarized in the following table. <br />Table IV-3 - Chemical Additives <br />Constituents of Acceptable? <br />Chemical Name Purpose Concern Yes or No <br />• * <br />NALCO 7887 Chemically enhanced precipitation Polymer Yes <br />*Chemicals deemed acceptable for use in waters that will or may be discharged to waters of the State are acceptable only when used <br />in strict accordance with the manufacturer's site-specific instructions. <br />B. Wastewater Treatment Description <br />Wastewater treatment for industrial wastewater is accomplished in settling ponds, and settling is chemically enhanced using <br />the chemical specified in Table 111-1. For domestic sewage, wastewater treatment is accomplished in an activated sludge <br />treatment plant. <br />Table IV-I specifies discharge points, 30-day average flows, daily maximum flows, 10-year, 24-hour precipitation event <br />coming into the pon), and design <br />ati'on and/or resulted from DMRs capacities <br />volumes, pond ate. Al valuesewevolumes (the volume re supplied by the treatflows <br />where appropriate. <br />submitted during the term of the permit. <br />Table IV-1 - Dischar a Point In ormation <br />Daily Max Flow, 10 yr/24-hr Pond Working Design. <br />Outfall Avg Flow, MGD MGD Event Vol Storage Volume, MG Capacity, <br />-------------- <br />0 0 NA 4.5 MG 86MGD* <br />001 <br />004 0 0 0.153 MG 1.065 MG NA 007 0.12 0.22 2.44 MG 2.998 MG NA <br />0.011 0.018 3.878 MG 5.018 MG NA <br />008 <br />009 0 0 NA NA No data <br />* The facility has indicated that Outfall 001 will have the capacity to discharge at a maximum rate of 2500 gpm, which is <br />equivalent to 5.6 MGD. No data were provided as to the discharge capacity of Outfall 009. However, because the <br />• underground mine has portals that would be pumped to either Pond I (from whence Outfall 001 discharges) or via <br />Outfall 009, depending on the direction the facility chose to use when removing accumulated water from the mine shafts, <br />the Division has assigned a combination design flow of 5.6 MGD to both Outfalls.