8.2. SR 11-07-2016 - Laserfiche WebLink

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The Minnesota Department of Natural Resource's Classification of Aggregate Resources for Sherburne County4 designates the Site as an identified aggregate resource which is an area containing significant aggregate deposits consisting mainly of gravel. It also highlights several gravel pits in the vicinity of the Site. The first bedrock beneath the Site is the Eau Claire Formation based on information from the Sherburne County Geologic Atlas.' The Eau Claire Formation is shaley sandstone that is approximately 70-80' thick. The Eau Claire Formation is underlain by the Mt. Simon Sandstone. The depth to bedrock is approximately 200-350 feet below the surface of the Site.6 The Site is not located in an area where there are susceptible geologic features such as shallow limestone formations, sinkholes, karst features or other significant geologic Site hazards. No impacts to geologic features are expected as a result of the Project. b. Soils and topography - Describe the soils on the site, giving NRCS (SCS) classifications and descriptions, including limitations of soils. Describe topography, any special site conditions relating to erosion potential, soil stability or other soils limitations, such as steep slopes, highly permeable soils. Provide estimated volume and acreage of soil excavation and/or grading. Discuss impacts from project activities (distinguish between construction and operational activities) related to soils and topography. Identify measures during and after project construction to address soil limitations including stabilization, soil corrections or other measures. Erosion/sedimentation control related to stormwater runoff should be addressed in response to Item 11.b.ii. According to the Natural Resources Conservation Service Soil Survey', Site soils consist of the Stonelake-Sandburn soil complex and Sanburn fine sandy loam with slopes ranging from 0 to 40 percent. A complex consists of a combination of two or more soils which are of similar properties and are combined in an intricate way. The complex found at the Site is made up of Stonelake soils, Sandburn soils, and minor components at varying ratios, shown in Table 10-1. Stonelake and Sandburn soils are both formed on glacial outwash. Both soils are in Hydrogeological Soil Group A for each slope category. Group A soils have a high infiltration rate (low runoff potential), consisting mainly of deep, well drained to excessively drained sands or gravely sands. Stonelake and Sandburn soils are not considered Prime Farmland. These soils have no limitations with regard to the proposed mining activity. Figure 6: Soil Survey, illustrates the soil types at the Site. 4 Mn Department of Natural Resources, Classification of Aggregate Resources Sherburne County Minnesota, Report 352 Plate B: 1987 5 Lusardi, Barbara A. (2013).C-32 Geologic Atlas of Sherburne County, Minnesota [Part A]. Minnesota Geological Survey. Retrieved from the University of Minnesota Digital Conservancy, http://conservancy.umn.edu/handle/11299/159393 Plate 2-Bedrock Geology. 6 Lusardi, Barbara A. (2013).C-32 Geologic Atlas of Sherburne County, Minnesota [Part A]. Minnesota Geological Survey. Retrieved from the University of Minnesota Digital Conservancy, http://conservancy.umn.edu/handle/11299/159393 Plate 5-Bedrock Topography, Depth to Bedrock, and Sand Distribution Model. ' Natural Resources Conservation Service Custom Web Soil Survey, United States Department of Agriculture,September 18,2015. Environmental Assessment Worksheet Page 11 Elk River Sand and Gravel Mines:Tiller Corporation and Max Steininger, Inc.