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<br />Another predicted impact of the Coal Ridge No. 1 operation was <br />water quality degradation associated with the refuse disposal <br />area. This part of the operation was never approved by the <br />Division, and under this permit renewal allowing only reclamation, <br />will not be constructed. <br />It appears likely that the mine tunnels penetrate only Mancos <br />w~ Shale, which is generally not capable of producing usable <br />quantities of water. The portals will be properly sealed to <br />~"y'` ~ '` prevent mine drainage from impacting the surface water system. All <br />groundwater monitoring wells will be reclaimed to prevent mixing of <br />water from different bedrock aquifers and to prevent contamination <br />from surface water. Together with the steep dips and current lack <br />of local bedrock ground water use, these measures will prevent <br />depletion and degradation of bedrock ground water supplies. <br />Construction of the railroad and other surface facilities was <br />predicted to cause increased sediment yield from the Coal Ridge No. <br />1 site. This construction has not taken place, and will be <br />prohibited following permit renewal. <br />All runoff from the mine site is currently routed into sediment <br />pond A, which was designed to contain the 10-year/24-hour <br />precipitation event from the surface facilities and also from the <br />steep hillslope above the portals. The sediment pond has only very <br />rarely received enough runoff to discharge, and there have been no <br />exceedences of NPDES effluent limits. This sediment pond and the <br />diversion structures which are part of the sediment control system <br />will be left in place during reclamation work, and until the <br />operation's revegetation success standards are met. At such time, <br />surface runoff from the area will yield approximately background <br />levels of suspended sediment. The sediment control system will <br />then be reclaimed as a last step. Given that the system is <br />maintained during the period of reclamation, no further impacts to <br />surface water quality are expected. <br /> <br />Because the issuance of this permit renewal allows only reclamation <br />work to be performed, there is almost rro potential for additional <br />hydrologic impacts to take place. <br />b. Cumulative Hydrologic Impact Study <br />Pursuant to Rule 2.07.6(2)(c), the Colorado Mined Land Reclamation <br />Division has prepared this Cumulative Hydrologic Impact Study <br />(CH IS) in order to assess the potential cumulative impacts of the <br />Coal Ridge No. 1 operation and all other existing or anticipated <br />coal mining operations in the same area. The Eastside Mine (File <br />No. C-84-063) is the only other mining operation considered to have <br />this potential. Eastside has been under Temporary Cessation status <br />since December, 1988, however it is assumed that operation of the <br />mine will resume. <br />-8- <br />