2004-01-29_REVISION - M1987113 (2)

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CHURCH RANCH ROCKY PLATS PIT - M-19B 7-1 1 3 TECHNICAL REVIHION .IANUARY 29, 2004 PAGE 4 tions in mines tend to level to the lowest point on the mine, we estimate that the floor of the mined can be taken to 6040 and still stay a minimum of 2 feet above the groundwater. At this time the operator does not plan to expose groundwater at this site and it will be operated as a dry mining operation. To accomplish this, the mine operator will begin to digging monitoring pits once the mine's floor is 40 feet lower than the existing surface. At the same time, if groundwater is exposed, it will immediately be covered with at least 2 feet of material and the site will be revaluated so a new floor elevation can be estab- lished. The operator wished to keep open an optional of having a lake if the opportunity to obtain augmentation water for the evapo- rative loss from the lake surface. An augmentation plan would be obtained prior to exposing ground water. Isolation ditches or small berms will be placed around the mine perimeter to keep surface runoff from outside the mine from enter- ing the excavated area. These isolation structures will also serve to keep any on site runoff in the mined area. Since mining will create a deep hole in the surrounding area, water will not leave the site. As the mine develops it may be necessary to construct a temporary stormwater pond on the site. Any water that accumulates in this pond will soak into the gravel or evaporate in a very short time.. The pond will be reclaimed when mining is done. e. Wildlife We do not believe the impacts to wildlife will change from what was anticipated in 1967. What has changed is the possibility, however remote, that there may be Preble's meadow jumping mouse (PMJM) habitat in the area along the Church 7 McRay ditches. According to the discussion of the west spray field (OU-11) in the report "OPERABLE UNIT 'I'I COMBINED PHASE RFURI REPORT FOR THE ROCKY FLATS ENVIRONMEN- TAL TECHNOLOGY SITE"-Final Report June 1995 there were no mice or their habitat in the OU-11 - west spray field area. The Ou-11 - west spray field area encompasses the revised permit area. At- tached are 6 pages, copied from the report dealing with the inves- tigators finding. The pertinent passages have been marked on pages 3-27 and 6-4 showing no PMJM were found in OU 11 (aka the west