1992-09-25_GENERAL DOCUMENTS - C1981017

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COLORADO DEPARTMENT OF HEALTH, Water Quality Control Division Amendment No. 2 Rationale - Page 5. Permit Number CO-0000396 V: DISCUSSION OF AMENDMENT: (Continued) New Water Treatment Plant System: (Continued) gpm, is 4.92 hours. The pond will be cleaned, as necessary, so that sediment load does not exceed 60 % of volume. Sludge removed from the pond will be disposed in the approved refuse disposal area. After treatment in the plant And "finishing" in the 020 pond, the mine water will be discharged from outfall 020 into Coal Creek. In addition to the WWTP discharge from outfall 020, outfall 028 will be retained as a possible future discharge from the wastewater treatment plant. Presently, the pipe for outfall 028 is not connected to the WWTP. The system will be equipped with automatic alarms and shut-off devices. The control panel will be located in the preparation plant. Instrumentation for the treatment plant includes indicator lights for the hydroclone pump, agitators and flocculant feeder, local on/off switches for pumps and agitators and motor trips. Alternatives: As previously indicated, the primary treatment for mine drainage waters will be the 016 ponds and the wastewater' treatment plant, with the 020 pond for "finishing." However, Mid-Continent plans to be utilizing the eight ponds of 016, 001, and 020, as well as the WWTP and the coal preparation plant, to allow maximum flexibility in management of mine water treatment so that the approved system has back-up capabilities and alternatives. The alternatives include the following seven options: 1) All flows from the 'mine will be routed to the 016 ponds for settling and discharge to Dutch Creek (Present system). 2) Mine flows will be routed between the ponds, which can be used in combination, and/or in conjunction with the WWTP (e.g. 016 and 001; 016, 001, WWTP and 020, etc. ) . 3) Mine flows will be routed to the WWTP. Overflow from the hydroclone/recycle ' sump will go to the 020 pond for "finishing" and then goes to the raw coal sump, then into the coal preparation plant cycle. (Normal operating mode when the coal preparation plant will be operating.) 4) Mine flows will be' routed to the WWTP. Overflow from the hydroclone/recycle sump will go to the 020 pond for "finishing" and then will discharge to Coal Creek. Underflow will go to the coal preparation plant's raw coal sump and thickener. (Normal operating mode when the coallpreparation plant will not be operating.) 5) Mine flows will be routed to the WWTP. Overflow from the hydroclone/recycle sump will go to the 020 pond for "finishing" and then will discharge to Coal Creek. Underflow will go to the 001 ponds and will be removed in normal pond cleaning.