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and the probability of future occurrence of such pollution. The evaluation concluded that all <br />reclamation has been completed in the bond release area, no water pollution is occurring, and there is <br />little potential for future water pollution. Impacts to ground water and surface water are described <br />below. <br />Ground Water Impacts <br />Excavations at the Coal Gulch Mine were less than fifty feet deep and can be expected to have been <br />above the ground water saturated zone. No seepages or discharges from the disturbed area (other <br />than from a pre-law portal area) have been found during the Division's inspections. The <br />improbability of current degradation to the saturated zone, and the absence of discharges, indicate the <br />Coal Gulch Mine is not causing ground water pollution, and the operation is in compliance with the <br />Basic Standards for Ground Water (Colorado Water Quality Control Regulation 41.5.C.6). <br />Surface Water Impacts <br />Most of the disturbed area is a flat valley bottom and is erosionally stable. Much of the runoff <br />from the valley bottom is routed through the sediment control/mine discharge treatment pond. <br />Some of the runoff from the valley bottom flows into a diversion ditch on the west side of the <br />site. <br />Gully erosion occurs where surface runoff has cut down into the side slopes of a diversion ditch <br />on the west of the site, and on the steepest slopes of a pre-law backfill slope east of the pond. <br />Sediment from gully erosion is routed to the ditch next to Highway 160. A sediment fan has <br />been deposited near the middle of the flat valley bottom of the Coal Gulch site and appears to <br />have come from the steep slope on the east side of the valley that extends up to the adjoining <br />Arness-McGriffin Mine. <br />Surface runoff from the disturbed area can be expected to be alkaline and free of contaminants as <br />there are no leachate-forming materials on the land surface. The quality of this runoff should be <br />closely similar to runoff from surrounding undisturbed lands, and therefore, does not have the <br />potential to degrade surface waters in the Coal Gulch drainage. <br />The design for the sediment control/mine water treatment pond is in the permit application in <br />Exhibit 13 and on Map 12. Map 12 refers to diagrams of the pond that are in Exhibit 13, and <br />bears a P.E. stamp. The depression covers approximately one-half acre, is a few feet deep, and is <br />not a designed structure. <br />The dimensions of the sediment control/mine water treatment pond appear similar to those <br />shown in Exhibit 13 and on Map 12. The design and early Division inspection reports indicated <br />the principal spillway was a 12-inch diameter culvert that extended through the pond's earthen <br />embankment. In recent years, the inlet end of this culvert has been found, but the outlet end of <br />the culvert on the outslope of the embankment can no longer be found, apparently having been <br />buried during regrading several years ago, as noted in Division inspection reports. The pond's <br />emergency spillway is an open channel that would discharge water down-slope to culverts <br />underneath Highway 160. The pond was reported during the Division's May 1994 inspection as