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HomeMy WebLinkAbout20240529_ADI_Response DocuSign Envelope ID: 1OC7CE7F-CCD9-4198-9643-FBE9D8F5DOB1 SMITH GARDNER aooeEss TEL WEB 14 N.Boylan Avenue,Raleigh NC 27603 919.828.0577 www.smithgardnerinc.com May 24, 2024 Mr. Adam Parr, P.E. State Mining Engineer Division of Energy, Mineral Land Resources Department of Environmental Quality 1612 Mail Service Center Raleigh, NC 27699-1612 RE: ARBD,LLC Response to Comments— Mine Application Chatham County,North Carolina Dear Adam: On behalf of ARBD, LLC, Smith Gardner, Inc. (S+G) is responding to comments dated April 22, 2024 (copy attached) for the new mine permit application. Please find each comment in italics followed by current response or progress in bold below. Mining Program Comments 1. Please clearly indicate and label on the mine map the location of the fuel tanks any and solvent storage. Fuel tanks and any solvent storage will be located near the current site entrance and is marked on the updated mine map. ARBD will maintain the necessary secondary containment methods for any solvents stored on site. 2. There are a number of parks and recreation areas within 1 mile of the proposed operation. Please clarify how any potential adverse effects will be mitigated. Proposed mining activities in the expansion areas would involve excavation using on-site equipment. ARBD would leave in-situ rock in place if it is encountered during excavation activities. No rock blasting is planned for this site, so there should be minimal noise disturbing the nearby parks. Additionally, ARBD will mitigate dust during landfill or mining operations using a water truck or equivalent, which would mitigate potential air quality issues nearby. The mine excavation grades are the same as the proposed LCID landfill subgrade, which is 4-feet above inferred groundwater per NC solid waste rules. Perimeter controls are proposed around the excavation and waste areas to route on-site stormwater runoff into four (4) constructed stormwater basins for erosion and sedimentation control. These controls should mitigate any potential surface water or groundwater quality issues for nearby parks. DocuSign Envelope ID: 1OC7CE7F-CCD9-4198-9643-FBE9D8F5DOB1 Mr.Adam Parr, P.E. May 24, 2024 Page 2of3 Other safety strategies related to severe weather, fire, gas emissions, etc. are provided in the operations manual as part of the site's solid waste permit expansion application (NC Solid Waste Permit 19-09, FID 1776955). 3. Please see the attached comments from the Raleigh Regional Office. Please provide additional details as requested. Responses to the Raleigh Regional Office Comments are provided below. Raleigh Regional Office Comments 1. During our site visit on April 4, 2024, Mr. Stone stated that the mining map provided in the permit application does not accurately reflect the intended clearing and mining boundaries because the plans show a larger mining boundary footprint than what is anticipated. DEMLR staff were informed that there are no plans to mine beyond the parcels labeled #7, #13, #20, and #21. Clearing is also anticipated across the parcels labeled#4 and #18. Therefore, we recommend requesting they submit a revised mine map that reflects accurate mining boundaries, vegetative buffers, screening, clearing limits, etc. Mr. Stone has no immediate plans to use parcels 7, 13, 20, and 21 for mining and landfill operations. However, these parcels will still be incorporated into the Long- term design of the mine and LCID landfill, so the mine map boundaries and associated buffers shall remain the same. 2. Provide additional erosion and sediment control measures along the northern boundary of the site adjacent to the riparian buffer and stream to ensure adequate protection in this critical area. Drainage channels have been added to the northeast section of the landfill to divert stormwater runoff to basins SB-B and SB-D. 3. The sediment basin calculations provided are based on a 10-yearstorm. Provide design calculations for peak discharge rate for the 25-year storm. Provide all supporting data for the computation methods used frainfall data for required storm events, time of concentration/storm duration, and runoff coefficients used). The sediment basin calculations have been updated to provide results for the 25- year, 24-hour storm. The revised stormwater management plan is attached for reference. DocuSign Envelope ID: 1OC7CE7F-CCD9-4198-9643-FBE9D8F5DOB1 Mr.Adam Parr, P.E. May 24, 2024 Page 3of4 4. Sediment Basin A is labeled but not completely shown on plan Sheet 3. Show the entirety of the basin's dimensions and the accompanying erosion control measures f baffles, skimmer, emergency spillway, diversion ditches, inlet/outlet protection, etc.). Basin A features and more pronounced existing contours are provided in drawings S2 and S3. Additional information and dimensions of the requested features (baffles, skimmer, emergency spillway, ditches, etc.) are provided in the detail sheets. 5. The baffles shown for Basin E are spaced too closely. Target percentage of surface area for each section of the baffle is as follows: inlet zone 25%, first cell 25%, second cell 25%, outlet zone 25%. Relocate diversion ditch outlet and/or baffle configuration to satisfy this requirement. Basin E baffle placement has been revised in drawings S2 and S3. 6. Include the baffles within the footprint of the skimmer basin for all basins [A, B, and D) on the plan sheet. Flow is required to pass through a minimum of three baffles before reaching the skimmer cell. Baffle configuration for Basins A and B and proposed baffle configuration for Basin D have been added to drawings S2 and S3. 7. Identify the location of the emergency spillway for Basin B on the plan sheet. Please note, the skimmer outlet structures/conduits should not be placed within the footprint of the emergency spillway. The Basin B emergency spillway location has been added to drawings S2 and S3. 8. The Skimmer Basin plan detail shows the skimmer pipe running through the emergency spillway structure. Please note, the skimmer outlet structures should not be placed within the footprint of the emergency spillway. Revise the plan detail shown for the standard skimmer basin to include an approved plan detail for the skimmer and emergency spillway. The skimmer basin detail has been replaced and is provided as detail 1/EC2. 9. Discharge into the skimmer basin should enter before the baffle farthest from the skimmer[inlet zone.) Sheet flow into basins is discouraged. Discharge water into the basin in a manner to prevent erosion. Provide a stable conveyance from diversions into basins [i.e. rip rap lined channel, properly-sized slope drain, tarp, etc.). Additional diversion berms have been added upslope of the basins as needed to Limit the amount of sheet flow. Rip rap lined channels are proposed for the basin inlets. Stone baffles are proposed for the sediment basins to increase stormwater retention time. DocuSign Envelope ID: 1OC7CE7F-CCD9-4198-9643-FBE9D8F5DOB1 Mr.Adam Parr, P.E. May 24, 2024 Page 4of5 10. Include the basin surface area dimensions, depth, side slopes, dam height, embankment width, length of emergency spillway, skimmer size, skimmer orifice size, and dewatering time on the plan sheets where they occur. Basin information is provided in drawing EC2. 11. Provide stable conveyance(extend pipe, provide tarp or otheracceptable practice)from outlet of skimmer to perimeter silt fence/silt fence outlet. All pipe outlets shall have rip rap protection with dimensions given in detail 5 of drawing EC2. 72. Provide adequate measures in diversion ditches/swales to limit excess erosion (i.e. wattles or rock check dams)and show them on the plan sheet with adequate symbology or labels. Rock check dams have been added to the site plan with the detail provided in drawing EC1. 13. There are no plan details shown for the silt bags, slope drains, tracking methods, downpipes, and inlet protection. Provide a plan detail, construction specifications, and specific maintenance requirements for all proposed sediment and erosion control structures included on the plan. Recommend placing maintenance requirements with the associated construction detail. Inlet protection to the basins has been added to the site plan. Details for the inlets and other stone-lined channels are provided in detail 5/EC3. Notes on inlet protection are provided in detail 2/EC2. Down pipe and side slope swale details are provided in drawing FC1. 14. Provide a plan detail and construction specifications for the silt fence and silt fence outlet that complies with the skirt trench requirements per the Erosion and Sediment Control Planning and Design Manual. The skirt is to be trenched in, at a minimum, 8 inches vertically and 4 inches horizontally. Include the maintenance requirements for the silt fence and silt fence outlets. The Chatham County standard details for the silt fence and silt fence outlet (Details 1/EC1 and 2/EC1) have been replaced with details that comply with the NCDEQ erosion and sediment control planning and design manual. The maintenance requirement for silt fence and silt fence outlets are provided in drawing EC1 under the "Erosion & Sedimentation Control Maintenance Notes". DocuSign Envelope ID: 1OC7CE7F-CCD9-4198-9643-FBE9D8F5DOB1 Mr.Adam Parr, P.E. May 24, 2024 Page 5of5 15. Provide a detailed/specific construction sequence related to erosion and sediment control that addresses all phases of construction on the plan sheets. Construction sequence has been added to drawing EC1. 16. Include the rip rap apron outlet dimensions on the plan sheets and show outlet protection for each down pipe on the reclamation plan. Rip rap apron outlet dimensions have been added to detail 5/EC2 on sheet 8. Outlet protections for each down pipe have been added to drawing S3 and dimensions for those are provided in drawing FC1. 77. Provide the tacking method and rates within the Seeding Specifications on Sheet 9. Tacking methods have been added to #3 (A) in the seeding specifications on sheet 9. The application rates are specified in details 3/EC3 and 4/EC3 on sheet 9. 18. Specify that a staged seeding approach will be used on slopes within the construction sequence and the Seeding Specifications on Sheet 9. This has been added to #3 (B) in the seeding specifications on sheet 9 and to the construction sequence on drawing EC1, sheet 7. 19. Please verify that mining boundary limit markers will be marked on 100-ft spacing. Please include this verification as a detail on the construction sequence on the mine maps. A note about the 100-ft spacing has been added to the mine boundary marker detail and has been included in the construction sequence Sincerely, SMITH GARDNER,INC. 1J DocuSigned by: DocuSigned by: cyu C. U 527B482DRA09438...f" Q. SM& C95C937E4AC... Jesse C. Li, P.E. Stacey A. Smith, P.E. Project Engineer, Ext. 170 Senior Engineer, Ext. 127 jesse(asmithgardnerinc.com stacey(dsmithgardnerinc.com sas/jcl CC: Alan Stone, ARBD, LLC Att. DEQ Comments dated 4/22/2024 File HAProjects\ARBD LCID Landfill(Chatham County]\ARBD-23-1 [Mine Pemit]\Response to Comments\ARBD Mine- Response to Comments 4-22-24.docx DocuSign Envelope ID: 1OC7CE7F-CCD9-4198-9643-FBE9D8F5DOB1 This page intentionally left blank. DocuSign Envelope ID: 1OC7CE7F-CCD9-4198-9643-FBE9D8F5 DOB 1 ROY COOPER Governor ? i' ELIZABETH S.BISER Secretary Q AM VIOL WILLIAM E.TOBY VINSON,JR. NORTH CAROLINA Interim Director Environmental Quality April 22,2024 Certified Mail Return Receipt Requested 7022 0410 0003 1066 6815 Mr. Alan Stone ARBD,LLC 5180A Big Woods Rd. Chapel Hill,NC 27517 RE: Stone LCID Landfill&Mine Chatham County Cape Fear River Basin Dear Mr. Stone: We have reviewed the application your company submitted for the referenced mine site. In order for this office to complete its review of the referenced project in accordance with N.C.G.S. §74-50 and§74-51 of the Mining Act of 1971,please provide the additional or revised information in accordance with the following comments: 1. Please clearly indicate and label on the mine map the location of the fuel tanks any and solvent storage. 2. There are a number of parks and recreation areas within 1 mile of the proposed operation. Please clarify how any potential adverse effects will be mitigated. 3. Please see the attached comments from the Raleigh Regional Office. Please provide additional details as requested. Please note, this office may request additional information, not included in this letter as the mining application review progresses. Be advised that our review cannot be completed until all of the items listed above have been fully addressed. D E Q North Carolina Department of Environmental Quality I Division of Energy,Mineral and Land Resources 512 North Salisbury Street 1 1612 Mail Service Center I Raleigh,North Carolina 27699-1612 NORhI CAROLINA - oaaa�emaienmronmenmiuuality /`� 919.707.9200 DocuSign Envelope ID: 10C7CE7F-CCD9-4198-9643-FBE9D8F5 DOB 1 Certified Mail 7022 0410 0003 1066 6815 Mr. Stone Page 2 In order to complete the processing of your application,please forward two(2)copies of the requested information to my attention at the following address: Division of Energy,Mineral and Land Resources Department of Environmental Quality 1612 Mail Service Center Raleigh,NC 27699-1612 If hand delivering or delivering by shipping company(e.g.,FedEx,UPS),please deliver to our physical address: Division of Energy, Mineral, and Land Resources Department of Environmental Quality 512 N. Salisbury Street, 5th Floor Raleigh,NC 27604 As required by 15A NCAC 513.0113,you are hereby advised that you have 180 days from the date of your receipt of this letter to submit all of the requested information. If you are unable to meet this deadline and wish to request additional time,you must submit information,in writing,to the Director clearly indicating why the deadline cannot be met and request that an extension of time be granted. If an extension of time is not granted, a decision will be made to grant or deny the mining permit based upon the information currently in the Department's files at the end of the 180-day period. Though the preceding statement cites the maximum time limit for your response,we encourage you to provide the additional information requested by this letter as soon as possible. Your prompt response will help us to complete processing your application sooner. Please contact me at(919) 707-9220 if you have any questions. Sincerely, r_ Adam Parr, PE State Mining Engineer Enclosures: Raleigh Regional Office Comments cc: Mr. Bill Denton, PE DocuSign Envelope ID: 1OC7CE7F-CCD9-4198-9643-FBE9D8F5DOB1 Raleigh Regional Office Comments 1. During our site visit on April 4, 2024, Mr. Stone stated that the mining map provided in the permit application does not accurately reflect the intended clearing and mining boundaries because the plans show a larger mining boundary footprint than what is anticipated. DEMLR staff were informed that there are no plans to mine beyond the parcels labeled#7,#13,#20, and #21. Clearing is also anticipated across the parcels labeled#4 and#18.Therefore, we recommend requesting they submit a revised mine map that reflects accurate mining boundaries, vegetative buffers, screening, clearing limits, etc. 2. Provide additional erosion and sediment control measures along the northern boundary of the site adjacent to the riparian buffer and stream to ensure adequate protection in this critical area. 3. The sediment basin calculations provided are based on a 10-year storm. Provide design calculations for peak discharge rate for the 25-year storm. Provide all supporting data for the computation methods used (rainfall data for required storm events,time of concentration/storm duration, and runoff coefficients used). 4. Sediment Basin A is labeled but not completely shown on plan Sheet 3. Show the entirety of the basin's dimensions and the accompanying erosion control measures (baffles, skimmer, emergency spillway, diversion ditches, inlet/outlet protection, etc.). 5. The baffles shown for Basin E are spaced too closely. Target percentage of surface area for each section of the baffle is as follows: inlet zone 25%,first cell 25%, second cell 25%, outlet zone 25%. Relocate diversion ditch outlet and/or baffle configuration to satisfy this requirement. 6. Include the baffles within the footprint of the skimmer basin for all basins (A, B, and D) on the plan sheet. Flow is required to pass through a minimum of three baffles before reaching the skimmer cell. 7. Identify the location of the emergency spillway for Basin B on the plan sheet. Please note,the skimmer outlet structures/conduits should not be placed within the footprint of the emergency spillway. 8. The Skimmer Basin plan detail shows the skimmer pipe running through the emergency spillway structure. Please note, the skimmer outlet structures should not be placed within the footprint of the emergency spillway. Revise the plan detail shown for the standard skimmer basin to include an approved plan detail for the skimmer and emergency spillway. 9. Discharge into the skimmer basin should enter before the baffle farthest from the skimmer(inlet zone.) Sheet flow into basins is discouraged. Discharge water into the basin in a manner to prevent erosion. Provide a stable conveyance from diversions into basins (i.e. rip rap lined channel, properly-sized slope drain,tarp, etc.). 10. Include the basin surface area dimensions, depth, side slopes, dam height, embankment width, length of emergency spillway, skimmer size, skimmer orifice size, and dewatering time on the plan sheets where they occur. DocuSign Envelope ID: 1OC7CE7F-CCD9-4198-9643-FBE9D8F5DOB1 11. Provide stable conveyance (extend pipe, provide tarp or other acceptable practice)from outlet of skimmer to perimeter silt fence/silt fence outlet. 12. Provide adequate measures in diversion ditches/swales to limit excess erosion (i.e. wattles or rock check dams) and show them on the plan sheet with adequate symbology or labels. 13. There are no plan details shown for the silt bags, slope drains,tracking methods, downpipes, and inlet protection. Provide a plan detail, construction specifications, and specific maintenance requirements for all proposed sediment and erosion control structures included on the plan. Recommend placing maintenance requirements with the associated construction detail. 14. Provide a plan detail and construction specifications for the silt fence and silt fence outlet that complies with the skirt trench requirements per the Erosion and Sediment Control Planning and Design Manual.The skirt is to be trenched in, at a minimum, 8 inches vertically and 4 inches horizontally. Include the maintenance requirements for the silt fence and silt fence outlets. 15. Provide a detailed/specific construction sequence related to erosion and sediment control that addresses all phases of construction on the plan sheets. 16. Include the rip rap apron outlet dimensions on the plan sheets and show outlet protection for each down pipe on the reclamation plan. 17. Provide the tacking method and rates within the Seeding Specifications on Sheet 9. 18. Specify that a staged seeding approach will be used on slopes within the construction sequence and the Seeding Specifications on Sheet 9. 19. Please verify that mining boundary limit markers will be marked on 100-ft spacing. Please include this verification as a detail on the construction sequence on the mine maps.