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HomeMy WebLinkAbout20240409_Narrative&Submittal Spruce Pine Quarry Request for Permit Modification Mining Permit No. 61 -13 Vulcan Construction Materials, LLC April 9, 2024 Spruce Pine Quarry Request for Permit Modification Mining Permit No. 61-13 Vulcan Construction Materials, LLC April 9,2024 SUBMITTAL CONTENTS Mine Modification Application Narrative • Introduction • Existing Conditions • Proposed Land Disturbance • Construction Sequence Project Erosion and Sediment Control • Overburden Storage Area Sediment Pond • Overburden Storage Area— Surface Water Hydrologic Report • E&S Access Road Channel • Site Entrance Road Channel Construction Specifications and Maintenance • Sediment Ponds (Basins) • Rip Rap Lines Channels • Grass Line Channels with Permanent Lining • Rock Filter Berm • Silt Fence Plan Sheets 1 of 6 Property Map 2 of 6 Operations Plan 3 of 6 Site Plan 4 of 6 Details—Fill Area and E&S Access Road 5 of 6 Details— Sediment Pond and Stockpile Fill 6 of 6 Reclamation Plan Spruce Pine•Mining Permit No. 61-13 Vulcan Construction Materials,LLC Mining Permit Modification-April 1,2024 Introduction Vulcan Construction Materials,LLC("Vulcan") operates the Spruce Pine Quarry, Permit No. 61- 13, in Mitchell County, North Carolina. The site is located at 396 Granite Lane, Bakersville, NC 28705. This mining permit modification provides an overview of the existing conditions of the quarry and a detailed plan for the proposed site improvements. The proposed activities include: • Adding a 20.63-acre tract to the permit boundary for E&S and overburden storage, • Increasing the useable Stockpile Area by adding additional fill and associated E&S, • Correct the Mine Excavation area acreage to match the geometric boundary approved in the last permit modification and additional area is added. Existing Conditions Property and Permit Boundary The existing permitted property at Enka Quarry consists of 151.52 acres of land leased from the Penland Bailey Estate, LLC by Vulcan Lands, Inc. This permitted area is shown on Operations Plan. An additional 20.63 acres has been leased from Penland Bailey. Landuse Within the 151.52-acre permitted area, Vulcan currently has approximately 123.00 acres for quarry related activities including: approximately 2.0 acre for tailings / settling pond area, 15.50 acres for stockpiles, 29.00 acres for overburden storage area, 7.70 acres for processing / haul roads area, and 68.80 acres for mine excavation area. The remaining areas are used for buffers and wildlife enhancement. Wetlands and Streams The area included in this permit modification request has been investigated for the presence of Waters of the U.S. (wetlands and streams). Any such areas have been verified and delineated using appropriate protocol and their locations surveyed. No impacts to Waters of the US are proposed by this modification request. Rockingham Quarry•Mining Permit No. 77-01 Vulcan Construction Materials,LLC Mining Permit Modification November 18,2021 Proposed Land Disturbance This mine permit modification adds 20.63 acres to the west side of the approved mine permit boundary. The purpose of this modification is to install erosion and sediment control measures to utilize this additional tract for overburden storage. Within the existing permitted area an existing stockpile will be expanded by utilizing overburden to create a level area adjacent to the existing stockpile. A rock filter berm and silt fence will be utilized for E&S control. The Mine Excavation area is increased on the south side by 5.18 acres to allow for an existing access road to be included in the quarry pit. The Mine Excavation boundary is reduced by 0.5 acre on the north side due to field delineation of the stream and buffer. Construction Sequence 1. Install silt fence around the Overburden Storage Area. 2. Grub stumps, clear vegetative debris, and remove topsoil from the area of the sediment pond and E&S access road from Sta 10+00 to Sta 17+00. The vegetative debris & grubbed stumps may be burned, provided the contractor obtains the required permits, otherwise contractor shall remove the debris and stumps from the site. 3. Commence excavation of the sediment pond and place excavated material in the pond embankment. Additional fill material is required from the Overburden Cut Area to complete the sediment pond fill embankment. Install the principal spillway, emergency spillway, and both conveyance channels entering the pond as the sediment pond is being constructed. 4. Once the sediment pond is completed and fully functional, continue linear construction of the E&S access road with road-side channel from Sta 17+00 to its completion at Sta 33+00. Incrementally grub ahead of the access road construction. Additional fill material is required from the Overburden Cut Area to complete the E&S access road. There are two options to line the E&S access road channel, one proposed lining is class 2 rip rap and the other is SC-250 permanent geosynthetic lining, bid both on the bid sheet. Rockingham Quarry•Mining Permit No. 77-01 Vulcan Construction Materials,LLC Mining Permit Modification November 18,2021 5. Incremental seeding of the project is required. Place 6 inches of topsoil on fill area vegetated slopes then apply seed & amendments as per the vegetation plan. Topsoil and vegetate the sediment pond and safety berm along the E&S access road once finished grades are achieved. 6. Commence grubbing stumps, clearing vegetative debris, and removing topsoil from the lowest western pad in the Overburden Area. Once a large enough area is grubbed,cleared, &topsoil removed, commence placing fill in the embankment adjacent to the sediment pond and continue working uphill to the east. 7. Install the 18" corrugated double wall culverts in the ditch line to provide access to each of the pad areas from Granite Lane as the pads are developed. 8. Place 5 inches of compacted non-spec ABC stone, as the finished surface, on each of the completed 3 pads and the E&S access road driving surface. Install 2— 14' wide farm gates to block access onto the E&S access road from Granite Lane. Continue filling and vegetating the proposed overburden storage area to the grades shown on the site plan. 9. Install the rock filter berm and silt fence at the Stockpile Fill Area. Commence placing fill in this area. Once finished grades are achieved place 6 inches of topsoil on the slopes and vegetate,place 5 inches of compacted non-spec ABC stone on the pad area. 10. Remove any accumulated sediment from the pond, silt fence, and rock berms. Haul and place the accumulated sediment in the Overburden Storage Area `A'. 11. Vegetate disturbed areas as soon as final grades are achieved. Spruce Pine Quarry•Mining Permit No. 61-13 Vulcan Construction Materials,LLC Mining Permit Modification—April 7,2024 Overburden Storage Area SEDIMENT POND The Overburden Storage Area Sediment Pond is designed to control runoff from t he 15- acre Overburden Storage Area. The Sediment Pond consists of a principal spillway with a skimmer dewatering device and an emergency spillway, refer to the included site plan and details for dimensional data and location. The Sediment Pond will be installed according to the requirements of the included construction specifications and maintenance plans SEDIMENT CHANNELS,ROCK WEIR OUTLETS,and OUTLET PROTECTION. Sediment Storage Volume The disturbed drainage area for this sediment pond is the Overburden Storage Area. This sediment pond is designed to provide a sediment storage volume of at least 3,600 cubic feet per acre of disturbed drainage area. The proposed Sediment Pond provides 78,638 cubic feet of storage volume; if the entire overburden fill was disturbed the required volume is only(17.34 ac x 3,600 cubic ft/ac=62,424 cubic feet),which provides 1.2 6 times required storage.Porous baffles are not included in this pond since the sediment storage capacity is 3,600 cubic feet per disturbed acre instead of the normal 1,800 cubic feet per disturbed area. Refer to the included Overburden Storage Area— Surface Water Hydrologic Report. Watershed Modeling The SCS method was utilized to predict surface runoff utilizing the Hydraflow Hydrographs Extension for Autodesk® Civil 3DO by Autodesk, Inc. v2024. Design Storm Events The principal spillway riser is designed to safely pass the peak flow of runoff from the 2- 10-, & 25-year storms without utilizing the emergency spillway. The 100-year storm will pass through the emergency spillway with over 1.5 feet of freeboard remaining. 1 Overburden Storage Area - Surface Water Hyrogolic Report Hydraflow Hydrographs Extension for AutodeskO Civil 3D®by Autodesk, Inc.v2024 3 Watershed Model Schematic Legend Hvd• Origin Description 1 SCS Runoff E&S Access Road Channel 2 SCS Runoff Site Entrance Road Channel 3 Combine Sediment Pond Inflow 4 Reservoir Sediment Pond Outflow Project: Basin Design.gpw Saturday, 04/6/2024 Hydraflow Table of Contents Basin Design.gpw Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Saturday,04/6/2024 Watershed Model Schematic...................................................................................... 1 Hydrograph Return Period Recap............................................................................. 2 2 - Year SummaryReport......................................................................................................................... 3 HydrographReports................................................................................................................... 4 Hydrograph No. 1, SCS Runoff, E&S Access Road Channel.................................................. 4 Hydrograph No. 2, SCS Runoff, Site Entrance Road Channel................................................ 5 Hydrograph No. 3, Combine, Sediment Pond Inflow................................................................ 6 Hydrograph No. 4, Reservoir, Sediment Pond Outflow............................................................ 7 PondReport - Pond No.1.................................................................................................... 8 10 - Year SummaryReport....................................................................................................................... 10 HydrographReports................................................................................................................. 11 Hydrograph No. 1, SCS Runoff, E&S Access Road Channel................................................ 11 Hydrograph No. 2, SCS Runoff, Site Entrance Road Channel.............................................. 12 Hydrograph No. 3, Combine, Sediment Pond Inflow.............................................................. 13 Hydrograph No. 4, Reservoir, Sediment Pond Outflow.......................................................... 14 25 - Year SummaryReport....................................................................................................................... 15 HydrographReports................................................................................................................. 16 Hydrograph No. 1, SCS Runoff, E&S Access Road Channel................................................ 16 Hydrograph No. 2, SCS Runoff, Site Entrance Road Channel.............................................. 17 Hydrograph No. 3, Combine, Sediment Pond Inflow.............................................................. 18 Hydrograph No. 4, Reservoir, Sediment Pond Outflow.......................................................... 19 100 - Year SummaryReport....................................................................................................................... 20 HydrographReports................................................................................................................. 21 Hydrograph No. 1, SCS Runoff, E&S Access Road Channel................................................ 21 Hydrograph No. 2, SCS Runoff, Site Entrance Road Channel.............................................. 22 Hydrograph No. 3, Combine, Sediment Pond Inflow.............................................................. 23 Hydrograph No. 4, Reservoir, Sediment Pond Outflow.......................................................... 24 OFReport.................................................................................................................. 25 2 Hydrograph Return Period Recap draflow Hydrographs Extension for AutodeskO Civil 3D®by Autodesk,Inc.v2024 Hyd. Hydrograph Inflow Peak Outflow(cfs) Hydrograph No. type hyd(s) Description (origin) 1-yr 2-yr 3-yr 5-yr 10-yr T25-yr 50-yr 100-yr 1 SCS Runoff ------ ------- 6.114 ------- ------- 13.98 19.39 ------- 28.90 E&S Access Road Channel 2 SCS Runoff ------ ------- 4.188 ------- ------- 9.458 13.06 ------- 19.41 Site Entrance Road Channel 3 Combine 1,2 ------- 9.792 ------- ------- 22.25 30.87 ------- 46.02 Sediment Pond Inflow 4 Reservoir 3 ------- 0.000 ------- ------- 3.040 13.49 ------- 30.88 Sediment Pond Outflow Proj. file: Basin Design.gpw Saturday, 04/6/2024 3 Hydrograph Summary Report Hydraflow Hydrographs Extension for AutodeskO Civil 3D®by Autodesk,Inc.v2024 Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph No. type flow interval Peak volume hyd(s) elevation strge used Description (origin) (cfs) (min) (min) (cult) (ft) (cuft) 1 SCS Runoff 6.114 2 742 36,833 ------ ------ ------ E&S Access Road Channel 2 SCS Runoff 4.188 2 732 19,156 ------ ------ ------ Site Entrance Road Channel 3 Combine 9.792 2 738 55,989 1,2 ------ ------ Sediment Pond Inflow 4 Reservoir 0.000 2 n/a 0 3 2796.47 55,989 Sediment Pond Outflow Basin Design.gpw Return Period: 2 Year Saturday, 04/6/2024 4 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Saturday,04/6/2024 Hyd. No. 1 E&S Access Road Channel Hydrograph type = SCS Runoff Peak discharge = 6.114 cfs Storm frequency = 2 yrs Time to peak = 12.37 hrs Time interval = 2 min Hyd. volume = 36,833 cuft Drainage area = 11.370 ac Curve number = 68 Basin Slope = 5.8 % Hydraulic length = 2665 ft Tc method = LAG Time of conc. (Tc) = 40.60 min Total precip. = 3.47 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 E&S Access Road Channel Q (cfs) Hyd. No. 1 --2 Year Q (cfs) 7.00 7.00 6.00 6.00 5.00 5.00 4.00 4.00 3.00 3.00 2.00 2.00 1.00 1.00 0.00 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Hyd No. 1 Time (hrs) 5 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Saturday,04/6/2024 Hyd. No. 2 Site Entrance Road Channel Hydrograph type = SCS Runoff Peak discharge = 4.188 cfs Storm frequency = 2 yrs Time to peak = 12.20 hrs Time interval = 2 min Hyd. volume = 19,156 cuft Drainage area = 5.970 ac Curve number = 68 Basin Slope = 7.7 % Hydraulic length = 2017 ft Tc method = LAG Time of conc. (Tc) = 28.26 min Total precip. = 3.47 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 Site Entrance Road Channel Q (cfs) Hyd. No. 2 --2 Year Q (cfs) 5.00 5.00 4.00 4.00 3.00 3.00 2.00 2.00 1.00 1.00 0.00 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Hyd No. 2 Time (hrs) 6 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Saturday,04/6/2024 Hyd. No. 3 Sediment Pond Inflow Hydrograph type = Combine Peak discharge = 9.792 cfs Storm frequency = 2 yrs Time to peak = 12.30 hrs Time interval = 2 min Hyd. volume = 55,989 cuft Inflow hyds. = 1, 2 Contrib. drain. area = 17.340 ac Sediment Pond Inflow Q (cfs) Hyd. No. 3 --2 Year Q (cfs) 10.00 10.00 8.00 8.00 6.00 6.00 4.00 4.00 2.00 2.00 0.00 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Time (hrs) Hyd No. 3 Hyd No. 1 Hyd No. 2 7 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Saturday,04/6/2024 Hyd. No. 4 Sediment Pond Outflow Hydrograph type = Reservoir Peak discharge = 0.000 cfs Storm frequency = 2 yrs Time to peak = n/a Time interval = 2 min Hyd. volume = 0 cuft Inflow hyd. No. = 3 - Sediment Pond Inflow Max. Elevation = 2796.47 ft Reservoir name = Pond No.1 Max. Storage = 55,989 cuft Storage Indication method used. Sediment Pond Outflow Q (cfs) Hyd. No. 4 --2 Year Q (cfs) 10.00 10.00 8.00 8.00 6.00 6.00 4.00 4.00 2.00 2.00 0.00 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Time (hrs) Hyd No. 4 Hyd No. 3 Total storage used = 55,989 CA Pond Report 8 Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Saturday,04/6/2024 Pond No. 1 - Pond No.1 Pond Data Contours-User-defined contour areas.Conic method used for volume calculation.Begining Elevation=2791.50 ft Stage/Storage Table Stage(ft) Elevation(ft) Contour area(sqft) Incr.Storage(cuft) Total storage(cuft) 0.00 2791.50 8,724 0 0 0.50 2792.00 9,199 4,480 4,480 1.50 2793.00 10,188 9,688 14,168 2.50 2794.00 11,226 10,702 24,870 3.50 2795.00 12,299 11,757 36,627 4.50 2796.00 13,421 12,855 49,482 5.50 2797.00 14,572 13,991 63,473 6.50 2798.00 15,769 15,165 78,638 7.50 2799.00 16,994 16,376 95,014 8.50 2800.00 18,512 17,746 112,760 Culvert/Orifice Structures Weir Structures [A] [B] [C] [PrfRsr] [A] [B] [C] [D] Rise(in) = 18.00 0.00 0.00 0.00 Crest Len(ft) = 12.57 0.00 0.00 0.00 Span(in) = 18.00 0.00 0.00 0.00 Crest El.(ft) = 2797.00 0.00 0.00 0.00 No.Barrels = 1 0 0 0 Weir Coeff. = 3.33 3.33 3.33 3.33 Invert El.(ft) = 2791.50 0.00 0.00 0.00 Weir Type = 1 --- --- --- Length(ft) = 100.00 0.00 0.00 0.00 Multi-Stage = Yes No No No Slope(%) = 3.70 0.00 0.00 n/a N-Value = .012 .013 .013 n/a Orifice Coeff. = 0.60 0.60 0.60 0.60 Exfil.(in/hr) = 0.000(by Wet area) Multi-Stage = n/a No No No TW Elev.(ft) = 0.00 Note:Culvert/Orifice outflows are analyzed under inlet(ic)and outlet(oc)control. Weir risers checked for orifice conditions(ic)and submergence(s). Stage/Storage/ Discharge Table Stage Storage Elevation Clv A Clv B Clv C PrfRsr Wr A Wr B Wr C Wr D ExfiI User Total ft cuft ft cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs 0.00 0 2791.50 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 0.05 448 2791.55 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 0.10 896 2791.60 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 0.15 1,344 2791.65 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 0.20 1,792 2791.70 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 0.25 2,240 2791.75 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 0.30 2,688 2791.80 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 0.35 3,136 2791.85 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 0.40 3,584 2791.90 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 0.45 4,032 2791.95 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 0.50 4,480 2792.00 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 0.60 5,449 2792.10 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 0.70 6,417 2792.20 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 0.80 7,386 2792.30 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 0.90 8,355 2792.40 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 1.00 9,324 2792.50 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 1.10 10,293 2792.60 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 1.20 11,262 2792.70 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 1.30 12,230 2792.80 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 1.40 13,199 2792.90 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 1.50 14,168 2793.00 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 1.60 15,238 2793.10 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 1.70 16,308 2793.20 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 1.80 17,379 2793.30 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 1.90 18,449 2793.40 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 2.00 19,519 2793.50 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 2.10 20,589 2793.60 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 2.20 21,659 2793.70 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 2.30 22,729 2793.80 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 2.40 23,800 2793.90 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 2.50 24,870 2794.00 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 2.60 26,046 2794.10 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 2.70 27,221 2794.20 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 Continues on next page... 9 Pond No.1 Stage/Storage/ Discharge Table Stage Storage Elevation Clv A Clv B Clv C PrfRsr Wr A Wr B Wr C Wr D ExfiI User Total ft cuft ft cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs 2.80 28,397 2794.30 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 2.90 29,573 2794.40 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 3.00 30,748 2794.50 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 3.10 31,924 2794.60 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 3.20 33,100 2794.70 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 3.30 34,276 2794.80 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 3.40 35,451 2794.90 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 3.50 36,627 2795.00 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 3.60 37,913 2795.10 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 3.70 39,198 2795.20 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 3.80 40,483 2795.30 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 3.90 41,769 2795.40 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 4.00 43,054 2795.50 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 4.10 44,340 2795.60 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 4.20 45,625 2795.70 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 4.30 46,911 2795.80 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 4.40 48,196 2795.90 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 4.50 49,482 2796.00 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 4.60 50,881 2796.10 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 4.70 52,280 2796.20 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 4.80 53,679 2796.30 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 4.90 55,078 2796.40 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 5.00 56,477 2796.50 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 5.10 57,876 2796.60 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 5.20 59,276 2796.70 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 5.30 60,675 2796.80 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 5.40 62,074 2796.90 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 5.50 63,473 2797.00 0.00 --- --- --- 0.00 --- --- --- --- --- 0.000 5.60 64,989 2797.10 1.33 is --- --- --- 1.33 --- --- --- --- --- 1.326 5.70 66,506 2797.20 3.80 is --- --- --- 3.75 --- --- --- --- --- 3.749 5.80 68,022 2797.30 6.89 is --- --- --- 6.89 --- --- --- --- --- 6.888 5.90 69,539 2797.40 10.60 is --- --- --- 10.60 --- --- --- --- --- 10.60 6.00 71,055 2797.50 14.82 is --- --- --- 14.82 --- --- --- --- --- 14.82 6.10 72,572 2797.60 18.78 is --- --- --- 18.78 s --- --- --- --- --- 18.78 6.20 74,088 2797.70 19.34 is --- --- --- 19.34 s --- --- --- --- --- 19.34 6.30 75,605 2797.80 19.70 is --- --- --- 19.69 s --- --- --- --- --- 19.69 6.40 77,121 2797.90 19.98 is --- --- --- 19.98 s --- --- --- --- --- 19.98 6.50 78,638 2798.00 20.22 is --- --- --- 20.21 s --- --- --- --- --- 20.21 6.60 80,276 2798.10 20.44 is --- --- --- 20.44 s --- --- --- --- 4.700 25.14 6.70 81,913 2798.20 20.64 is --- --- --- 20.63 s --- --- --- --- 9.400 30.03 6.80 83,551 2798.30 20.84 is --- --- --- 20.83 s --- --- --- --- 14.10 34.93 6.90 85,188 2798.40 21.03 is --- --- --- 21.02 s --- --- --- --- 18.80 39.82 7.00 86,826 2798.50 21.21 is --- --- --- 21.19 s --- --- --- --- 23.50 44.69 7.10 88,464 2798.60 21.39 is --- --- --- 21.37 s --- --- --- --- 28.20 49.57 7.20 90,101 2798.70 21.57 is --- --- --- 21.55 s --- --- --- --- 32.90 54.45 7.30 91,739 2798.80 21.74 is --- --- --- 21.74 s --- --- --- --- 37.60 59.34 7.40 93,376 2798.90 21.91 is --- --- --- 21.87 s --- --- --- --- 42.30 64.17 7.50 95,014 2799.00 22.08 is --- --- --- 22.03 s --- --- --- --- 47.00 69.03 7.60 96,789 2799.10 22.24 is --- --- --- 22.19 s --- --- --- --- 57.60 79.79 7.70 98,563 2799.20 22.41 is --- --- --- 22.40 s --- --- --- --- 68.20 90.60 7.80 100,338 2799.30 22.57 is --- --- --- 22.52 s --- --- --- --- 78.80 101.32 7.90 102,112 2799.40 22.73 is --- --- --- 22.69 s --- --- --- --- 89.40 112.09 8.00 103,887 2799.50 22.89 is --- --- --- 22.81 s --- --- --- --- 100.00 122.81 8.10 105,661 2799.60 23.05 is --- --- --- 22.98 s --- --- --- --- 110.60 133.58 8.20 107,436 2799.70 23.21 is --- --- --- 23.13 s --- --- --- --- 121.20 144.33 8.30 109,211 2799.80 23.37 is --- --- --- 23.29 s --- --- --- --- 131.80 155.09 8.40 110,985 2799.90 23.52 is --- --- --- 23.44 s --- --- --- --- 142.40 165.84 8.50 112,760 2800.00 23.67 is --- --- --- 23.66 s --- --- --- --- 153.00 176.66 ...End 10 Hydrograph Summary Report Hydraflow Hydrographs Extension for AutodeskO Civil 3D®by Autodesk,Inc.v2024 Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph No. type flow interval Peak volume hyd(s) elevation strge used Description (origin) (cfs) (min) (min) (cult) (ft) (cuft) 1 SCS Runoff 13.98 2 740 75,664 ------ ------ ------ E&S Access Road Channel 2 SCS Runoff 9.458 2 732 39,350 ------ ------ ------ Site Entrance Road Channel 3 Combine 22.25 2 736 115,015 1,2 ------ ------ Sediment Pond Inflow 4 Reservoir 3.040 2 818 51,541 3 2797.17 66,062 Sediment Pond Outflow Basin Design.gpw Return Period: 10 Year Saturday, 04/6/2024 11 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Saturday,04/6/2024 Hyd. No. 1 E&S Access Road Channel Hydrograph type = SCS Runoff Peak discharge = 13.98 cfs Storm frequency = 10 yrs Time to peak = 12.33 hrs Time interval = 2 min Hyd. volume = 75,664 cuft Drainage area = 11.370 ac Curve number = 68 Basin Slope = 5.8 % Hydraulic length = 2665 ft Tc method = LAG Time of conc. (Tc) = 40.60 min Total precip. = 4.91 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 E&S Access Road Channel Q (cfs) Hyd. No. 1 -- 10 Year Q (cfs) 14.00 14.00 12.00 12.00 10.00 10.00 8.00 8.00 6.00 6.00 4.00 4.00 2.00 2.00 0.00 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Hyd No. 1 Time (hrs) 12 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Saturday,04/6/2024 Hyd. No. 2 Site Entrance Road Channel Hydrograph type = SCS Runoff Peak discharge = 9.458 cfs Storm frequency = 10 yrs Time to peak = 12.20 hrs Time interval = 2 min Hyd. volume = 39,350 cuft Drainage area = 5.970 ac Curve number = 68 Basin Slope = 7.7 % Hydraulic length = 2017 ft Tc method = LAG Time of conc. (Tc) = 28.26 min Total precip. = 4.91 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 Site Entrance Road Channel Q (cfs) Hyd. No. 2 -- 10 Year Q (cfs) 10.00 10.00 8.00 8.00 6.00 6.00 4.00 4.00 2.00 2.00 0.00 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Hyd No. 2 Time (hrs) 13 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Saturday,04/6/2024 Hyd. No. 3 Sediment Pond Inflow Hydrograph type = Combine Peak discharge = 22.25 cfs Storm frequency = 10 yrs Time to peak = 12.27 hrs Time interval = 2 min Hyd. volume = 115,015 cuft Inflow hyds. = 1, 2 Contrib. drain. area = 17.340 ac Sediment Pond Inflow Q (cfs) Hyd. No. 3-- 10 Year Q (cfs) 24.00 24.00 20.00 20.00 16.00 16.00 12.00 12.00 8.00 8.00 4.00 4.00 0.00 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Time (hrs) Hyd No. 3 Hyd No. 1 Hyd No. 2 14 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Saturday,04/6/2024 Hyd. No. 4 Sediment Pond Outflow Hydrograph type = Reservoir Peak discharge = 3.040 cfs Storm frequency = 10 yrs Time to peak = 13.63 hrs Time interval = 2 min Hyd. volume = 51,541 cuft Inflow hyd. No. = 3 - Sediment Pond Inflow Max. Elevation = 2797.17 ft Reservoir name = Pond No.1 Max. Storage = 66,062 cuft Storage Indication method used. Sediment Pond Outflow Q (cfs) Hyd. No. 4-- 10 Year Q (cfs) 24.00 24.00 20.00 20.00 16.00 16.00 12.00 12.00 8.00 8.00 4.00 4.00 0.00 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Time (hrs) Hyd No.4 Hyd No. 3 Total storage used = 66,062 CA 15 Hydrograph Summary Report Hydraflow Hydrographs Extension for AutodeskO Civil 3D®by Autodesk,Inc.v2024 Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph No. type flow interval Peak volume hyd(s) elevation strge used Description (origin) (cfs) (min) (min) (cult) (ft) (cuft) 1 SCS Runoff 19.39 2 740 102,536 ------ ------ ------ E&S Access Road Channel 2 SCS Runoff 13.06 2 732 53,326 ------ ------ ------ Site Entrance Road Channel 3 Combine 30.87 2 736 155,862 1,2 ------ ------ Sediment Pond Inflow 4 Reservoir 13.49 2 766 92,388 3 2797.47 70,577 Sediment Pond Outflow Basin Design.gpw Return Period: 25 Year Saturday, 04/6/2024 16 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Saturday,04/6/2024 Hyd. No. 1 E&S Access Road Channel Hydrograph type = SCS Runoff Peak discharge = 19.39 cfs Storm frequency = 25 yrs Time to peak = 12.33 hrs Time interval = 2 min Hyd. volume = 102,536 cuft Drainage area = 11.370 ac Curve number = 68 Basin Slope = 5.8 % Hydraulic length = 2665 ft Tc method = LAG Time of conc. (Tc) = 40.60 min Total precip. = 5.79 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 E&S Access Road Channel Q (cfs) Hyd. No. 1 --25 Year Q (cfs) 21.00 21.00 18.00 18.00 15.00 15.00 12.00 12.00 9.00 9.00 6.00 6.00 3.00 3.00 0.00 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Hyd No. 1 Time (hrs) 17 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Saturday,04/6/2024 Hyd. No. 2 Site Entrance Road Channel Hydrograph type = SCS Runoff Peak discharge = 13.06 cfs Storm frequency = 25 yrs Time to peak = 12.20 hrs Time interval = 2 min Hyd. volume = 53,326 cuft Drainage area = 5.970 ac Curve number = 68 Basin Slope = 7.7 % Hydraulic length = 2017 ft Tc method = LAG Time of conc. (Tc) = 28.26 min Total precip. = 5.79 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 Site Entrance Road Channel Q (cfs) Hyd. No. 2 --25 Year Q (cfs) 14.00 14.00 12.00 12.00 10.00 10.00 8.00 8.00 6.00 6.00 4.00 4.00 2.00 2.00 0.00 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Hyd No. 2 Time (hrs) 18 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Saturday,04/6/2024 Hyd. No. 3 Sediment Pond Inflow Hydrograph type = Combine Peak discharge = 30.87 cfs Storm frequency = 25 yrs Time to peak = 12.27 hrs Time interval = 2 min Hyd. volume = 155,862 cuft Inflow hyds. = 1, 2 Contrib. drain. area = 17.340 ac Sediment Pond Inflow Q (cfs) Hyd. No. 3--25 Year Q (cfs) 35.00 35.00 30.00 30.00 25.00 25.00 20.00 20.00 15.00 15.00 10.00 10.00 5.00 5.00 0.00 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Time (hrs) Hyd No. 3 Hyd No. 1 Hyd No. 2 19 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Saturday,04/6/2024 Hyd. No. 4 Sediment Pond Outflow Hydrograph type = Reservoir Peak discharge = 13.49 cfs Storm frequency = 25 yrs Time to peak = 12.77 hrs Time interval = 2 min Hyd. volume = 92,388 cuft Inflow hyd. No. = 3 - Sediment Pond Inflow Max. Elevation = 2797.47 ft Reservoir name = Pond No.1 Max. Storage = 70,577 cuft Storage Indication method used. Sediment Pond Outflow Q (cfs) Hyd. No. 4--25 Year Q (cfs) 35.00 35.00 30.00 30.00 25.00 25.00 20.00 20.00 15.00 15.00 10.00 10.00 5.00 5.00 0.00 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Time (hrs) Hyd No. 4 Hyd No. 3 Total storage used = 70,577 CA 20 Hydrograph Summary Report Hydraflow Hydrographs Extension for AutodeskO Civil 3D®by Autodesk,Inc.v2024 Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph No. type flow interval Peak volume hyd(s) elevation strge used Description (origin) (cfs) (min) (min) (cult) (ft) (cuft) 1 SCS Runoff 28.90 2 740 150,232 ------ ------ ------ E&S Access Road Channel 2 SCS Runoff 19.41 2 730 78,131 ------ ------ ------ Site Entrance Road Channel 3 Combine 46.02 2 736 228,363 1,2 ------ ------ Sediment Pond Inflow 4 Reservoir 30.88 2 754 164,889 3 2798.22 82,197 Sediment Pond Outflow Basin Design.gpw Return Period: 100 Year Saturday, 04/6/2024 21 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Saturday,04/6/2024 Hyd. No. 1 E&S Access Road Channel Hydrograph type = SCS Runoff Peak discharge = 28.90 cfs Storm frequency = 100 yrs Time to peak = 12.33 hrs Time interval = 2 min Hyd. volume = 150,232 cuft Drainage area = 11.370 ac Curve number = 68 Basin Slope = 5.8 % Hydraulic length = 2665 ft Tc method = LAG Time of conc. (Tc) = 40.60 min Total precip. = 7.24 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 E&S Access Road Channel Q (cfs) Hyd. No. 1 -- 100 Year Q (cfs) 30.00 30.00 25.00 25.00 20.00 20.00 15.00 15.00 10.00 10.00 5.00 5.00 0.00 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Hyd No. 1 Time (hrs) 22 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Saturday,04/6/2024 Hyd. No. 2 Site Entrance Road Channel Hydrograph type = SCS Runoff Peak discharge = 19.41 cfs Storm frequency = 100 yrs Time to peak = 12.17 hrs Time interval = 2 min Hyd. volume = 78,131 cuft Drainage area = 5.970 ac Curve number = 68 Basin Slope = 7.7 % Hydraulic length = 2017 ft Tc method = LAG Time of conc. (Tc) = 28.26 min Total precip. = 7.24 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 Site Entrance Road Channel Q (cfs) Hyd. No. 2-- 100 Year Q (cfs) 21.00 21.00 18.00 18.00 15.00 15.00 12.00 12.00 9.00 9.00 6.00 6.00 3.00 3.00 0.00 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Hyd No. 2 Time (hrs) 23 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Saturday,04/6/2024 Hyd. No. 3 Sediment Pond Inflow Hydrograph type = Combine Peak discharge = 46.02 cfs Storm frequency = 100 yrs Time to peak = 12.27 hrs Time interval = 2 min Hyd. volume = 228,363 cuft Inflow hyds. = 1, 2 Contrib. drain. area = 17.340 ac Sediment Pond Inflow Q (cfs) Hyd. No. 3-- 100 Year Q (cfs) 50.00 50.00 40.00 40.00 30.00 30.00 20.00 20.00 10.00 10.00 0.00 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Time (hrs) Hyd No. 3 Hyd No. 1 Hyd No. 2 24 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Saturday,04/6/2024 Hyd. No. 4 Sediment Pond Outflow Hydrograph type = Reservoir Peak discharge = 30.88 cfs Storm frequency = 100 yrs Time to peak = 12.57 hrs Time interval = 2 min Hyd. volume = 164,889 cuft Inflow hyd. No. = 3 - Sediment Pond Inflow Max. Elevation = 2798.22 ft Reservoir name = Pond No.1 Max. Storage = 82,197 cuft Storage Indication method used. Sediment Pond Outflow Q (cfs) Hyd. No. 4-- 100 Year Q (cfs) 50.00 50.00 40.00 40.00 30.00 30.00 20.00 20.00 10.00 10.00 0.00 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 Time (hrs) Hyd No.4 Hyd No. 3 Total storage used = 82,197 CA 25 Hydraflow Rainfall Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Saturday,04/6/2024 Return Intensity-Duration-Frequency Equation Coefficients(FHA) Period (Yrs) B D E (N/A) 1 0.0000 0.0000 0.0000 -------- 2 69.8703 13.1000 0.8658 -------- 3 0.0000 0.0000 0.0000 -------- 5 79.2597 14.6000 0.8369 -------- 10 88.2351 15.5000 0.8279 -------- 25 102.6072 16.5000 0.8217 -------- 50 114.8193 17.2000 0.8199 -------- 100 127.1596 17.8000 0.8186 -------- File name:SampleFHA.idf Intensity= B/(Tc+ D)^E Return Intensity Values(in/hr) Period (Yrs) 5 min 10 15 20 25 30 35 40 45 50 55 60 1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2 5.69 4.61 3.89 3.38 2.99 2.69 2.44 2.24 2.07 1.93 1.81 1.70 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5 6.57 5.43 4.65 4.08 3.65 3.30 3.02 2.79 2.59 2.42 2.27 2.15 10 7.24 6.04 5.21 4.59 4.12 3.74 3.43 3.17 2.95 2.77 2.60 2.46 25 8.25 6.95 6.03 5.34 4.80 4.38 4.02 3.73 3.48 3.26 3.07 2.91 50 9.04 7.65 6.66 5.92 5.34 4.87 4.49 4.16 3.88 3.65 3.44 3.25 100 9.83 8.36 7.30 6.50 5.87 5.36 4.94 4.59 4.29 4.03 3.80 3.60 Tc=time in minutes.Values may exceed 60. Preci .file name:E:\Vulcan\STANDARDS\H drolo \Asheville NC Precipitation Data.pc Rainfall Precipitation Table (in) Storm Distribution 1-yr 2-yr 3-yr 75-yr 10-yr 25-yr 50-yr 100-yr SCS 24-hour 0.00 3.47 0.00 3.30 4.91 5.79 6.80 7.24 SCS 6-Hr 0.00 2.91 0.00 0.00 4.10 4.83 0.00 6.04 Huff-1st 0.00 0.00 0.00 2.75 0.00 0.00 6.50 0.00 Huff-2nd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-3rd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-4th 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-Indy 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Custom 0.00 0.00 0.00 2.80 0.00 0.00 6.00 0.00 Spruce Pine Quarry•Mining Permit No. 61-13 Vulcan Construction Materials,LLC Mining Permit Modification—April 7,2024 E&S ACCESS ROAD CHANNEL The E&S Access Road Channel is designed to convey runoff from the Overburden Storage Area. The proposed channel is 2 feet deep and 4 feet wide at the bottom with 2:1 side slopes. The design includes two proposed channel linings,one is 30 inches of class 2 rip rap or North American Green SC-250 Permanent Synthetic Lining. The E&S Access Road Channel will be installed according to the requirements of the included construction specifications and maintenance plans for RAP RAP LINED CHANNELS AND GRASS LINED CHANNELS WITH PERMANENT LINING. Watershed Modeling The SCS method was utilized to predict surface runoff utilizing the Hydraflow Hydrographs Extension for Autodesk0 Civil 3DO by Autodesk, Inc. v2024. Desizn Storm Events The E&S Access Road Channel is designed to safely pass the peak flow of runoff from a 25 year — 24 hour storm with a minimum of 0.5 feet of freeboard. Please refer to the included capacity and stability calculations. Desi,-n Summary Applicable design information about the E&S Access Road Channel is provided in the following computations and is shown on the Plans and Details sheets. E&S Access Road Channel 6.37 % Minimum Channel Slope Spruce Pine Quarry Watershed Characteristics Total Drainage Area - 11.37 Acres Disturbed Drainage Area - 11.37 Acres Runoff Coefficient- 0.48 Time of Concentration - 30 Min 2 Year 10 Year, 25 Year Rainfall Intensity(in/hr) - 2.64 3.67 4.28 Runoff V (cfs) - 6.1 14.0 19.4 Channel Characteristics Depth - 2 ft Bottom Width - 4 ft Left Side Slope - 2 :1 Right Side Slope - 2 :1 Channel Slope - 6.37 % Design Computations d (ft) A(sq ft) R (ft) n V (fps) V*R Q(cfs) Comments Retardance Class 'D' 0.87 4.99 0.63 0.037 7.5 4.7 37.4 V>VP & Q>Q25 Retardance Class 'C' 0.91 5.30 0.66 0.040 7.1 4.7 37.6 V>VP & Q>Q25 Permanent Lining Design 0.70 3.78 0.53 0.040 6.2 3.3 23.3 Q>Q2 Shear Stress - Td for Q2= 2.8 Use SC-250 Rip Rap Lining Design 1.00 6.00 1 0.71 0.078 3.8 2.7 23.0 Q>Q2 Shear Stress - Td for Q2= 4.0 Use Class 2 Rip Rap E&S Access Road Channel 9.28 % Maximum Channel Slope Spruce Pine Quarry Watershed Characteristics Total Drainage Area - 11.37 Acres Disturbed Drainage Area - 11.37 Acres Runoff Coefficient- 0.48 Time of Concentration - 30 Min 2 Year 10 Year, 25 Year Rainfall Intensity(in/hr) - 2.64 3.67 4.28 Runoff V (cfs) - 6.1 14.0 19.4 Channel Characteristics Depth - 2 ft Bottom Width - 4 ft Left Side Slope - 2 :1 Right Side Slope - 2 :1 Channel Slope - 9.28 % Design Computations d (ft) A(sq ft) R (ft) n V (fps) V*R Q(cfs) Comments Retardance Class 'D' 0.74 4.06 0.55 0.036 8.5 4.7 34.5 V-VP & Q>Q25 Retardance Class 'C' 0.78 4.34 0.58 0.039 8.1 4.7 35.1 V-VP & Q>Q25 Temporary Lining Design 0.60 3.12 0.47 0.040 6.8 3.2 21.3 Q>Q2 Shear Stress - Td for Q2= 3.5 Use SC-250 Rip Rap Lining Design 0.87 4.99 1 0.63 0.078 4.3 2.7 21.4 Q>Q2 Shear Stress - Td for Q2= 5.0 Use Class 2 Rip Rap Spruce Pine Quarry•Mining Permit No. 61-13 Vulcan Construction Materials,LLC Mining Permit Modification—April 7,2024 SITE ENTRANCE ROAD CHANNEL The Site Entrance Road Channel is designed to convey runoff from the Overburden Storage Area. The proposed channel is 2 feet deep and 2 feet wide at the bottom with 2:1 side slopes. This is an existing channel that will be left in place and extended on the eastern end. The Site Entrance Road Channel will be installed according to the requirements of the included construction specifications and maintenance plans for RAP RAP LINED CHANNELS. Watershed Modeling The SCS method was utilized to predict surface runoff utilizing the Hydraflow Hydrographs Extension for Autodesk® Civil 3DO by Autodesk, Inc. v2024. Desi,an Storm Events The Site Entrance Road Channel is designed to safely pass the peak flow of runoff from a 25 year — 24 hour storm with a minimum of 0.5 feet of freeboard. Please refer to the included capacity and stability calculations. Design Summary Applicable design information about the Site Entrance Road Channel is provided in the following computations and is shown on the Plans and Details sheets. Existing Site Entrance Road Channel 9.05 % Channel Slope Spruce Pine Quarry Watershed Characteristics Total Drainage Area - 5.97 Acres Disturbed Drainage Area - 5.97 Acres Runoff Coefficient- 0.48 Time of Concentration - 30 Min 2 Year 10 Year, 25 Year Rainfall Intensity(in/hr) - 2.64 3.67 4.28 Runoff V (cfs) - 4.2 9.5 13.1 Channel Characteristics Depth - 2 ft Bottom Width - 2 ft Left Side Slope - 2 :1 Right Side Slope - 2 :1 Channel Slope - 9.05 % Design Computations d (ft) A(sq ft) R (ft) n V (fps) V*R Q(cfs) Comments Retardance Class 'D' 0.65 2.15 0.44 0.041 6.3 2.8 13.5 V>VP & Q>Q25 Retardance Class 'C' 0.70 2.38 0.46 0.048 5.6 2.6 13.3 V>VP & Q>Q25 Rip Rap Lining Design 0.90 3.42 0.57 0.078 3.9 2.2 13.5 Q>Q2 Shear Stress - Td for Q2= 5.1 Use Class 2 Rip Rap Spruce Pine Quarry•Mining Permit No. 61-13 Vulcan Construction Materials,LLC Mining Permit Modification—April 7,2024 Sediment Pond (Basin) CONSTRUCTION SPECIFICATION 1. Site preparations- Clear, grub, and strip topsoil from areas under the embankment to remove trees, vegetation, roots, and other objectionable material. Delay clearing the pool area until the dam is complete and then remove brush, trees, and other objectionable materials to facilitate sediment cleanout. Stockpile all topsoil or soil containing organic matter for use on the outer shell of the embankment to facilitate vegetative establishment. Place temporary sediment control measures below the basin as needed. 2. Cut-off trench- Excavate a cut-off trench along the center line of the earth fill embankment. Cut the trench to stable soil material,but in no case make it less than 2 feet deep. The cut-off trench must extend into both abutments to at least the elevation of the riser crest. Make the minimum bottom width wide enough to permit operation of excavation and compaction equipment, but in no case less than 2 feet. Make side slopes of the trench no steeper than 1:1. Compaction requirements are the same as those for the embankment. Keep the trench dry during backfilling and compaction operations. 3. Embankment- Take fill material from the approved areas shown on the plans. It should be clean mineral soil, free of roots, woody vegetation, rocks, and other objectionable material. Scarify areas on which fill is to be placed before placing fill. The fill material must contain sufficient moisture so it can be formed by hand into a ball without crumbling. If water can be squeezed out of the ball, it is too wet for proper compaction. Place fill material in 6 to 8 inch continuous layers over the entire length of the fill area and compact it. Compaction may be obtained by routing the construction hauling equipment over the fill so that the entire surface of each layer is traversed by at least one wheel or tread track of heavy equipment, or a compactor may be used. Construct the embankment to an elevation 10 percent higher than the design height to allow for settling. 4. Conduit spillways- Securely attach the riser to the barrel or barrel stub to make a watertight structural connection. Secure all connections between barrel sections by approved watertight assemblies. Place the barrel and riser on a firm, smooth foundation of impervious soil. Do not use pervious material such as sand, gravel, or crushed stone as backfill around the pipe or anti-seep collars. Place the fill material around the pipe spillway in 4-inch layers and compact it under and around the pipe to at least the same density as the adjacent embankment. Care must be taken not to raise the pipe from firm contact with its foundation when compacting under the pipe haunches. Place a minimum depth of 2 feet of compacted backfill over the pipe spillway before crossing it with construction equipment. Anchor the riser in place by Spruce Pine Quarry•Mining Permit No. 61-13 Vulcan Construction Materials,LLC Mining Permit Modification—April 7,2024 Sediment Pond (Basin) -continued concrete or other satisfactory means to prevent flotation. In no case should the pipe conduit be installed by cutting a trench through the dam after the embankment is complete. 5. Emergency spillway- Install the emergency spillway in undisturbed soil. The achievement of planned elevations, grade, design width, and entrance and exit channel slopes are critical to the successful operation of the emergency spillway. 6. Inlets- Discharge water into the basin in a manner to prevent erosion. Use diversions with outlet protection to divert sediment-laden water to the upper end of the pool area to improve basin trap efficiency. 7. Erosion control-Construct the structure so that the disturbed area is minimized. Divert surface water away from bare areas. Complete the embankment before the area is cleared. Stabilize the emergency spillway embankment and all other disturbed areas above the crest of the principal spillway immediately after construction. 8. Porous baffles are not included in this pond since the sediment storage capacity is 3,600 cubic feet per disturbed acre instead of the normal 1,800 cubic feet per disturbed area. 9. Safety- Sediment basins may attract children and can be dangerous. Avoid steep side slopes, and fence and mark basins with warning signs if trespassing is likely. Follow all state and local requirements. MAINTENANCE Inspect temporary sediment basins at least weekly and after each significant(1/2 inch or greater)rainfall event and repair immediately. Remove sediment and restore the basin to its original dimensions when it accumulates to one-half the design depth. Place removed sediment in an area with sediment controls. Check the embankment, spillways, and outlet for erosion damage, and inspect the embankment for piping and settlement. Make all necessary repairs immediately. Remove all trash and other debris from the riser and pool area. Spruce Pine Quarry•Mining Permit No. 61-13 Vulcan Construction Materials,LLC Mining Permit Modification—April 7,2024 Rip Rap Lined Channels CONSTRUCTION SPECIFICATION 1. Construction will be carried out in such a manner that erosion and sediment loss will be minimized. 2. Prior to commencing construction, appropriate temporary erosion and sediment control structures will be installed. Temporary control structures include (but are not limited to) silt fence, rock check dams and straw bale barriers. 3. Remove all trees, brush, stumps, and other objectionable material from the foundation area and dispose of properly. 4. Excavate the channel foundation and shape in line, grade and cross section as designed, free of irregularities, which impede normal flow. Bring over excavated areas to grade by backfilling with moist soil compacted to the density of the surrounding material. 5. Grade soil away from channel so that surface water may enter freely. 6. Place filter cloth and/or any other bedding material to line and grade as designed. Place filter and bedding material immediately after slope preparation. For filter fabrics, overlap the downstream edge by at least 12 inches over the upstream edge that is buried in a minimum 12-inch trench. Space anchor pins every 3 feet along the overlap. Spread granular materials in a uniform layer. When more than one gradation is specified, spread the layers so there is minimal mixing. 7. All earth material not needed in construction shall be spread or disposed of so that it will not interfere with the functioning of the diversion. 8. Apply lime, fertilizer and seed the disturbed areas around the channel in accordance with the Vegetation Plan. MAINTENANCE Inspect rip rap lined channels at regular intervals as well as after major rains, and make repairs as soon as practical. Give special attention to the outlet and inlet sections and other points where concentrated flow enters. Carefully check stability at road crossings and look for indications of piping,scour holes or bank failures. Maintain all vegetation adjacent to the channel in a healthy, vigorous condition to protect the area from erosion and scour during high flow periods. Spruce Pine Quarry•Mining Permit No. 61-13 Vulcan Construction Materials,LLC Mining Permit Modification—April 7,2024 Grass Lined Channels with Permanent Lining CONSTRUCTION SPECIFICATION I. Construction will be carried out in such a manner that erosion and sediment loss will be minimized. 2. Prior to commencing construction, appropriate temporary erosion and sediment control structures will be installed. Temporary control structures include (but are not limited to) silt fence, rock check dams and straw bale barriers. 3. Remove all trees, brush, stumps, and other objectionable material from the foundation area and dispose of properly. 4. Excavate the channel and shape in line, grade and cross section as designed, free of irregularities,which impede normal flow. 5. Grade soil away from channel so that surface water may enter freely. 6. Fills shall be compacted as needed to prevent unequal settlement that could cause damage in the completed diversion. 7. All earth material not needed in construction shall be spread or disposed of so that it will not interfere with the functioning of the diversion. 8. Install permanent lining materials and anchor per manufacturer's instructions. 9. Apply lime, fertilizer and seed the channel and adjoining area in accordance with the Vegetation Plan. MAINTENANCE Check grass-lined channels after every substantial rainfall event.It is particularly important to check the channel outlet and all road crossings for bank stability and evidence of piping or scour holes. Remove all significant sediment accumulations to maintain the designed carrying capacity. Keep the grass in a healthy,vigorous condition at all times since it is the primary erosion protection for the channel. Repairs will be made as soon as practically possible. Spruce Pine Quarry•Mining Permit No. 61-13 Vulcan Construction Materials,LLC Mining Permit Modification—April 7,2024 Rock Filter Berm INTRODUCTION Rock Filter Berm consists of a berm of stone constructed along a constant elevation. The purpose of the Rock Filter Berm is to intercept sheet flow and shallow concentrated flow, filter this flow through rock and then release the flow as sheet flow. Rock Filter Berms shall intercept only small drainage areas with small flows.They may be applied to address conditions encountered in the field. On shallow slopes (0%—3%) the stone size may be 2" (-). On steeper slopes (3% -5%)the stone size shall be 2"—6" surge stone. CONSTRUCTION I. Clear the foundation area of trees, stumps, roots, loose rock, and other objectionable material. 2. Establish a level top elevation for the berm. Construct berms at a constant elevation and in accordance with the detail. 3. Perform all Rock Filter Berm construction to keep erosion and water pollution to a minimum.Immediately upon completion of the Rock Filter Berm,vegetate all disturbed areas per the approved Reclamation Plan or as stated otherwise to protect them against soil erosion. MAINTENANCE I. Inspect Rock Filter Berm protection at regular intervals as well as after major rains and make repairs promptly. Give special attention to the outlet and inlet sections and other points where concentrated flow enters. Carefully check stability and look for indications of piping, scour holes, or bank failures. Make repairs immediately. Maintain all vegetation adjacent to the Rock Filter Berm in a healthy, vigorous condition to protect the area from erosion and scour during out-of-bank flow. Spruce Pine Quarry•Mining Permit No. 61-13 Vulcan Construction Materials,LLC Mining Permit Modification—April 7,2024 Silt Fence CONSTRUCTION SPECIFICATION MATERIALS 1. Use a synthetic filter fabric at least 95%by weight of polyolefins or polyester, which is certified by the manufacturer or supplier as conforming to the requirements in ASTM D 6461. Synthetic filter fabric should contain ultraviolet ray inhibitors and stabilizers to provide a minimum of 6 months of expected usable construction life at a temperature range of 0 to 1200 F. 2. Ensure that posts for sediment fences are 1.25 lb/linear ft minimum steel with a minimum length of 5 feet. Make sure that steel posts have projections to facilitate fastening the fabric. 3. For reinforcement of standard strength filter fabric, use wire fence with a minimum 14 gauge and a maximum mesh spacing of 6 inches. CONSTRUCTION 1. Construct the sediment barrier of standard strength or extra strength synthetic filter fabrics. 2. Ensure that the height of the sediment fence does not exceed 24 inches above the ground surface. (Higher fences may impound volumes of water sufficient to cause failure of the structure. 3. Construct the filter fabric from a continuous roll cut to the length of the barrier to avoid joints. When joints are necessary, securely fasten the filter cloth only at a support with 4 feet of minimum overlap to the next post. 4. Support standard strength filter fabric by wire mesh fastened securely to the upslope side of the posts. Extend the wire mesh support to the bottom of the trench. Fasten the wire reinforcement, then fabric on the upslope side of the fence post. Wire or plastic zip ties should have minimum 50 pound tensile strength. 5. When a wire mesh support fence is used, space posts a maximum of 8 feet apart. Support posts should be driven securely into the ground a minimum of 24 inches. 6. Extra strength filter fabric with 6 feet post spacing does not require wire mesh support fence. Securely fasten the filter fabric directly to posts. Wire or plastic zip ties should have minimum 50 pound tensile strength. 7. Excavate a trench approximately 4 inches wide and 8 inches deep along the proposed line of posts and upslope from the barrier(Figure 6.62a). Spruce Pine Quarry•Mining Permit No. 61-13 Vulcan Construction Materials,LLC Mining Permit Modification—April 7,2024 Silt Fence-Continued 8. Place 12 inches of the fabric along the bottom and side of the trench. 9. Backfill the trench with soil placed over the filter fabric and compact. Thorough compaction of the backfill is critical to silt fence performance. 10. Do not attach filter fabric to existing trees. SEDIMENT FENCE INSTALLATION USING THE SLICING METHOD Instead of excavating a trench, placing fabric and then backfilling trench, sediment fence may be installed using specially designed equipment that inserts the fabric into a cut sliced in the ground with a disc. INSTALLATION SPECIFICATIONS 1. The base of both end posts should be at least one foot higher than the middle of the fence. Check with a level if necessary. 2. Install posts 4 feet apart in critical areas and 6 feet apart on standard applications. 3. Install posts 2 feet deep on the downstream side of the silt fence, and as close as possible to the fabric, enabling posts to support the fabric from upstream water pressure. 4. Install posts with the nipples facing away from the silt fabric. 5. Attach the fabric to each post with three ties, all spaced within the top 8 inches of the fabric. Attach each tie diagonally 45 degrees through the fabric, with each puncture at least 1 inch vertically apart. Also, each tie should be positioned to hang on a post nipple when tightened to prevent sagging. 6. Wrap approximately 6 inches of fabric around the end posts and secure with 3 ties. 7. No more than 24 inches of a 36 inch fabric is allowed above ground level. 8. The installation should be checked and corrected for any deviations before compaction. 9. Compaction is vitally important for effective results. Compact the soil immediately next to the silt fence fabric with the front wheel of the tractor, skid steer, or roller exerting at least 60 pounds per square inch. Compact the upstream side first, and then each side twice for a total of 4 trips. Spruce Pine Quarry•Mining Permit No. 61-13 Vulcan Construction Materials,LLC Mining Permit Modification—April 7,2024 Silt Fence-Continued MAINTENANCE Inspect sediment fences at least once a week and after each rainfall. Make any required repairs immediately. Should the fabric of a sediment fence collapse, tear, decompose or become ineffective, replace it promptly. Remove sediment deposits as necessary to provide adequate storage volume for the next rain and to reduce pressure on the fence. Take care to avoid undermining the fence during cleanout. Remove all fencing materials and unstable sediment deposits and bring the area to grade and stabilize it after the contributing drainage area has been properly stabilized.