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~RMWATER MANAGEMENT PLAN WITHIN PERMIT AREA Re(`@1V~ <br />Cugnini Pit <br />M-1986-061 JAN 2 4 ~ <br />~ivisDuran9o Fe <br />On October 26, 2000 personnel from the Durango Field Office of the Division of ron °rtiAner~~a ~~C@ <br />Minerals and Geology inspected the above referenced site. The Inspection Report noted ogy <br />that stormwater was impounded in the floor of Phase I and was not in an approved <br />location. It was further noted that stormwater runoff had eroded one of the graded <br />highwalls and breached a retention berm in Phase ll. The corrective action noted in the <br />Inspection Report is to provide a statement specifying what structures and/or practices are <br />being implemented to correct the possible problems observed. This document will serve <br />as such a statement. <br />a. The stormwater impoundment in Phase I noted in the Inspection Report is an area of <br />depression in which water was standing at the time of the inspection. This azea is not <br />an intended or designed impoundment. The depression developed in the course of <br />material relocation within Phase I during a recent asphalt processing operation. This <br />depression will be regraded to preclude the retention of stormwater. It was noted that <br />this stormwater came into contact with a pile of waste asphalt present on the site. <br />There was concern that this asphalt material was new and therefore not inert. While <br />this asphalt material is recent in origin, it is by its physical properties quite stable. <br />There exists no possibility for dissolution, leeching or contamination from this pile. <br />Further, this material will be removed from the site when seasonal operations resume <br />in the spring of 2001. <br />b. The erosion of the graded highwall was the result of stormwater runoff from an <br />undisturbed pasture above the pit in Phase II. As discussed in the Inspection Report, <br />the highwall was resloped with material upon cessation of the last mining run at the <br />site. The operator has imported approximately 30 cubic yazds of 6-18" gabion rock to <br />be placed in the azea of erosion for stability and to prevent further sedimentation of <br />the pit floor. This resloped highwall marks the point where mining will resume and as <br />such is temporary. The material used to build this slope and the subsequent gabion <br />will be removed to allow for continued mining operations in the spring or summer as <br />demand dictates. <br />c. The breach in the retention berm was the result of the same stormwater erosion <br />discussed in paragraph (b). The pit floor within Phase II has been regraded as part of <br />an effort to lessen the slope of the arroyo. To accomplish this task the berm was <br />removed and will be rebuilt atop the repositioned slope. The gabion rock discussed in <br />paragraph (b) will also be placed at the point of diversion in the retention berm and <br />within the downstream structure. Additionally, sedimentation control devices will be <br />placed upstream of the point of diversion. <br />d. The actions described in paragraphs (b) and (c) will be completed following <br />acceptance from the Durango Field Office and as weather and site conditions permit. <br />