2019-02-13_REVISION - M2000077 (5)

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Mule Creck Gravel Pit - Decision Notice gold FO\S1 PaL'e N . I Mueller Stafc Park cold. if determined to he excessive. corrective measures WIII he j taken. Vlonitorlll`, tier noise and suhsequent corrective actions will be the responsibility of PK Enterprises. Dust control WOUIcf he addressed through appropriate measures defined in the Air Pollution Emission Notice and Control Plan for FLI"itivc Particulate Emissions to he submitted to the Colorado Department of Health and Environment. In the lone term. the reclamation of the new and previous minim, areas would calltrihute to all Ii11prON'elllellt Ill the air quality in the area due to a reduction in wind erosion from exposed soils. • Water Quality impacts— Water quality Impacts of mining operation and reclamation are associated with the movement of sediment from the unvegetated portions of the property into the wetlands and stream. Sediment loads and other water quality constituents should be virtually eliminated through the use of sedimentation basins during mining, and through revcgetation after mining has been completed. • Wildlife impacts— Wildlife habitat above the mined area and along the drainage will continue to degrade due to continuing erosion and accumulation of sediment, respectively. The reclalllation process will allow revc(,etation of the mined area as well as reduction of sediment accumulation in the stream, thus improving wildlife habitat in the area. In addition, the reduction of slope gradient in the property would increase the usable area for wildlife. The negative impacts of noise and human activity on wildlife would be reduced by scaling back the size of the mining operation. • Wetland Impacts—Wetland impacts from the accurnulation of sediment and possible changes in hydrology associated with the culvert being installed udder the 1 access road must be addressed. Existing wetlands within the mine property have been delineated and areas where impacts may occur have been identified in the EA and i through the review process conducted by the Army Corps of Engineers for the Clean Water Act, Section 404 Permit. Without intervention,the wetland will continue to dry out, changing the type of vegetation that can grow in the area below the culvert from wetland to upland species. the mining activity would all occur in areas to the east of the drainage, above the elevation of the wetland. PK Enterprises proposes to install silt fence and detention ponds and sedimentation basins at the bottom of the mine, thereby improving water quality leaving the site. Assuming successful reclamation, the site would be covered in a protective layer of vegetation, which would return the movement of soil to the wetland to that close to a natural rate. The Corps of Engineers has visited the site and indicated that the impacts associated with I the proposed project would be minimal, less than 200 square feet, and have been authorized under Nationwide permit No. 26 for road crossing improvements and bank stabilization. Best management practices implemented in conjunction with the project would substantially reduce sedimentation, improve drainage and stabilize the site. This would arrest the degradation that is now occurring and increase the potential for the eventual recovery of the wetlands. I I Hydrosphere Resource Consultants. 1002 Walnut Suite 200.Boulder.CO 80302