2022-05-10_GENERAL DOCUMENTS - M1993041

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Dowe Flats Quarry Site Description and Future Mining Impact Analysis Mining at the south end of the currently open pit created a unique bat habitat where an exposed rock cliff face abuts a small (-2.7-acre)temporary water storage pond that is used by CEMEX, Inc. for filling their water trucks. The rock face has vertical and horizontal crevices as well as rock flakes that bats can use as day and night roosts and the pond can serve as a drinking water source. Although nearby forested habitat is lacking,there may be an opportunity to preserve potential bat habitat if the reclamation plan was revised to not fill in this area of the site and the rock face and pond became permanent features. While bald eagles (Haliaeetus leucocephalus) are no longer protected under the Endangered Species Act,they are still protected by several other federal laws. Several known bald eagle nesting and roosting sites are near to the permit boundary along the St. Vrain Creek corridor and bald eagles are commonly seen hunting on CEMEX, Inc. properties in the area.No new impacts to bald eagles are anticipated with continued mining activities at Dowe Flats. 4 Long- and Short-Term Ecological Impacts No land disturbance outside the currently permitted disturbance boundary is anticipated with the permit amendment application. The continued mining at Dowe Flats will occur in the already excavated pits that will be expanded as needed to mine additional reserves. Further, some of the areas currently impacted by mine-related activities will be reclaimed concurrent with continued mining. The primary impact to both vegetation and wildlife will be the short-term postponement of the development of a reclaimed habitat. If the permit amendment application is accepted,the Dowe Flats property will continue to be mined for an additional 15 years. During the first five years, some of the areas currently disturbed by mine-related activities will be reclaimed. After mining is complete,the entire area will be reclaimed to create a reclaimed grassland community with a small wetland area. In the long-term,the vegetation communities and wildlife habitats created at the end of mining will be no different than currently planned. While there are no new impacts to vegetation communities or wildlife habitat anticipated with the implementation of the permit amendment application,there may be some benefits to modifying the existing reclamation plan to avoid impacts that will occur under the currently approved reclamation plan. Several landforms containing established grassland vegetation will be disturbed during the final reclamation process because the material used to build the landforms would need to be used to re-create the pre-mining topography. Some of the disturbance will be unavoidable, such as distributing growth media stockpiles;however, some of these landforms could be left intact to create a more topographically diverse reclaimed surface which would in turn support a more ecologically diverse reclaimed habitat. Current temporary reclamation areas are supporting populations of prairie dogs and mule deer which were the two species of most concern during the original permitting process in 1994. Leaving even some of these areas intact would mitigate currently unavoidable impacts to these species. A reclamation plan with greater topographic and vegetative diversity would provide habitat for a greater diversity of raptor prey including lagomorphs,rodents, reptiles,bats, and other birds. Additionally, deer and elk would benefit from an enhanced habitat with expanded shelter opportunities. Habitat Management, Inc. 10 May 2, 2022