5.3 PCSR 01-24-2017 - Laserfiche WebLink

Home Browse Search

Mining and processing will be subject to setbacks established by the City of Elk River Mining Ordinance. Proposed setbacks include a 30 -foot setback from all road right -of -ways and parcels not permitted for mining operations. The northern border and a majority of the southern border are adjacent to permitted or future mining operations and therefore do not require a setback. No explosives will be used at the Site. 4.6 Drainage, Erosion Control, Sedimentation, Dust, Access Control and Security: The majority of the Site drains internally. There is a small area in the very northwestern portion of the Site that drains off site into the US 169 right -of -away. There is also a small portion of the Site that drains into the ditch along Baldwin. Sheet C -1: Existing Conditions, illustrates the current topography and drainage patterns of the Site. Disturbed areas of the Site will be graded to drain internally. The Site will operate under the General Minnesota National Pollutant Discharge Elimination System Permit ( NPDES) permit for non - metallic mining mineral mining and associated activities. Prior to commencing operations, a site specific Stormwater Pollution Prevention Plan (SWPPP) will be prepared forthe Site as required bythe NPDES permit. Best management practices, such use of silt fence, drainage swales and diversions and progressive reclamation will be implemented at the Site to control erosion and off -site sedimentation. Perimeter berms may be constructed within setback areas, shaped, and stabilized with vegetation. Based on information from the National Wetland Inventory Maps, there are no wetlands located on the Site. Information from the NSC soil survey indicates that there are no hydric soils on the Site. According to the Natural Resources Conservation Service Soil Survey, Site soils consist of the Stonelake - Sandburn soil complex and Sandburn fine sandy loam. Both the Stonelake and Sandburn soils are in Hydrogeological Soil Group (HSG) A. HSG A soils have a high infiltration rate (low runoff potential), consisting mainly of deep, well drained to excessively drained sands orgravely sands. Mining activity will create steep slopes on a temporary basis. The active mine face is not vegetated and therefore is subject to erosion. The active face will slope towards the interior of the mining operation with no potential for off -site sedimentation. Infiltration areas and temporary sedimentation basins will be used as needed to manage stormwater on the mine floor. The locations of these stormwater management features will move as mining progresses through the Site. Establishment of vegetation through seeding and mulching will be conducted as soon as reclaimed areas have reached final grade. Erosion control matting, sediment logs, and other erosion and sediment control practices will be used as needed throughout the mining operations. Erosion of finished slopes will be minimized by backfillingto a minimum slope of 3:1 and seeding and mulching to establish vegetation in accordance with the Reclamation Plan. Crushing equipment is fitted with spray bars to mitigate the generation of dust during processing. Processing operations are located within recessed portions of the Site which further reduces fugitive dust emissions associated with the processing equipment. Washplants are not a significant source of fugitive dust emissions. Many of the stockpiles will have sufficient moisture content from the washing process to keep fugitive dust levels low during loading operations. Fugitive dust from internal haul roads will be controlled by use of dust suppressants such as calcium chloride or by watering. A water truck will be available on -site to water as needed. Fugitive dust from exposed Tiller Corporation Sunde Engineering, PLLC Conditional Use Permit Application Page 1 6 City of Elk River