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Home My WebLink About20211111_ADI_Response11SUNROCK� CAROLINA SUNROCK LLC Scott Martino Manager Environmental Compliance 200 Horizon Drive, Suite 100 Raleigh, NC 27615 CERTIFIED MAIL No. 7015 0640 0007 8085 1130 Return receipt Requested November 11, 2021 Mr. Adam Parr Assistant State Mining Engineer Department of Environmental Quality Division of Energy, Mineral, and Land Resources — Land Quality Section 1612 Mail Service Center Raleigh, NC 27699-1612 RE: Carolina Sunrock LLC — Prospect Hill Quarry and Distribution Center 1238 Wrenn Road Prospect Hill, Caswell County, North Carolina 27314 Dear Mr. Parr: The purpose of this letter is to provide you and your department the additional information to Carolina Sunrock LLC's application for a mining permit as requested per your letter dated November 08, 2021. Please find attached to this letter a memo prepared by our consult, Piedmont Geologic whom issued and conducted the hydro study associated with our permit application (May 7, 2020). This Memo Summarizes the discrepancies identified within the ADI, and supplies the corrected information. In addition, it should be noted, as identified within the memo, no figures, nor calculations were impacted by the updated information and thus all previously supplied figures and calculations are accurate. Thank you for the opportunity to address your and other agency comments provided on our latest application submittal. Please feel free to contact me if you or your department have any further questions. Thank you for your assistance. Sincerely, Carolina Sunrock, LLC Scott Martino Manager Environmental Compliance Enclosure Hydro Study Memo smartino@thesunrockgroup.com Phone: 919.747.6336 Fax: 919.747.6305 PIEDMONT GEOLOGIC SMART EARTH SOLUTIONS November 9, 2021 Mr. Scott Martino The Sunrock Group 200 Horizon Drive, Suite I00 Raleigh, North Carolina 27615 RE: Response to NCDEQ Letter Date November 8, 2021 Proposed Quarry Site Prospect Hill, North Carolina Dear Mr. Martino: 6003-145 Chapel Hill Rd. Raleigh, NC 27607 P. 919-854-9700 F: 919-854-9532 www.piedmontgeologiccom This letter is in response to a November 8, 2021 letter from the North Carolina Department of Environmental Quality (NCDEQ) to Carolina Sunrock regarding the Revised Hydrogeological Study Report (the `report") completed by Piedmont Geologic (dated May 7, 2020) for the proposed Carolina Sunrock quarry site in Prospect Hill, North Carolina (the "site"). The report presented the results of field efforts completed in April -May 2019, along with subsequent data evaluations completed in 2019-2020 to evaluate hydrogeologic parameters for the site as well as potential hydrogeological effects on local water -supply wells and indirect impacts to site and offsite surface waters. The NCDEQ letter references a June 15, 2020 email correspondence from Mr. Nat Wilson to Ms. Judy Wehner and Mr. Michael Bauer (NCDEQ). In the email, Mr. Wilson notes discrepancies between drawdown data summarized in Tables 4 and 5 of the report, and the observation well hydrographs presented in Appendix D. Static depth -to -water levels (i.e., pre -pumping conditions), final depth -to -water levels (i.e., at the cessation of pumping), as well as the calculated drawdown for each site observation and pumping well, are summarized in Table 4 (Area 2 wells) and Table 5 (Area 1 wells) of the report. Values presented for the static depth -to -water levels were based on water level measurements collected manually immediately prior to pumping using an electronic water level meter. Values presented for the final depth -to -water levels for the observation wells were based on data obtained from the pressure transducers, as there were no manual depth -to -water measurements collected immediately prior to cessation of pumping, with the exception of observation wells OW 1-1 and OW 1-2. Pressure transducers were not used in the pumping wells, so the static and final depth -to -water values for those wells reflects that of manual depth - to -water measurements. As Mr. Wilson correctly noted, groundwater levels in observation wells OW 1-1 OW 1-2 fell below the depth of the pressure transducers in those wells during the Area 1 pumping test, so the final depth -to -water values reported in Table 5 are incorrect (the reported values would represent the depths of the pressure transducers). In addition, an erroneous final depth -to -water value was reported in Table 4 for observation well OW2-2. For consistency, Tables 4 and 5 have been revised to utilize observation well pressure transducer data for both the static and final depth -to - water measurements, with the exception of the final depth -to -water measurements in OW 1-1 and OW 1-2. Since the groundwater levels in OW 1-1 and OW 1-2 were below the pressure transducers at the cessation of Area 1 pumping, the manual gauging data collected immediately prior to cessation of pumping is utilized. The revised tables are presented as follows, with corrections shown in strikethrough type (deletions) and red type (additions). Response to NCDEQ Letter Date November 8, 2021 Proposed Quarry Site, Prospect Hill, North Carolina November 9, 2021 Table 4: Summary of Area 2 Drawdown in Pumping/Observation Wells Well Distance from Pumping Well (ft) Static Depth- to -Water (ft below T Final Depth -to- Water (ft below TOC) Drawdown (ft) Specific Capacity (gpm/ft) PW-2 0 33.80 (I) 96.340) 62.54 0.44 OW2-1 31 34..9 34.10 (2) 86.25(2) 524052 - OW2-3 1 86 9444 30.60 (2) 81.73(2) 50.99 51.13 1 - OW2-2 1 254 3044 30.07 2) 15" 44.15 (2) 29-.0 14.08 -- (1) Depth -to -water as measured by manual gauging with electronic water level meter. (2) Depth -to -water as measured by pressure transducer. Table 5: Summary of Area 1 Drawdown in Pumping/Observation Wells Well Distance from Pumping Well ft Static Depth- to -Water ft below TO Final Depth-tc- Water ft below TOC Drawdown (ft) Specific Capacity ( m/ft PW-1 0 34.47(I) 174.04(1) 137.57 0.18 OW 1-3 31 2-7-. 09 2 6.9 4 (2) 1 53.45(2) 2&-36 26.51 -- OW 1-2 100 25.94 25.91(2) 87.4 90.59 (1) 1 64.52 64.68 - OW 1-I 292 29-06 28.90 (2_)_1 93-54 92.04 (1) 36-43 63_14_ (1) Depth -to -water as measured by manual gauging with electronic water level meter. (2) Depth -to -water as measured by pressure transducer. The data summarized in Tables 4 and 5 is not incorporated into any other aspects of the report, including estimations of hydrogeologic parameters or the calculations for radii of influence due to quarry dewatering, so the above corrections do not change any of the conclusions or figures presented in the report All hydrogeologic parameter estimates were obtained via curve -matching of the raw hydrograph data using AQTESOLV software (by HydroSOLVE) and the subsequent radii of influence calculations were based on those estimated parameters. Mr. Wilson's email also suggests that the notations for Area 1 observation wells may have been incorrectly assigned, based on the fact that the observation well nearest to the pumping well showed a lesser magnitude of drawdown as compared to the remaining two Area I observation wells located at greater lateral distances from the pumping well. The subject well notations were checked/reviewed for accuracy, and it is concluded that all well notations presented in the report correspond to the correct hydrograph data. In addition, the report does note the anisotropic/heterogenetic nature of the site's fractured -rock aquifer system, so such occurrences would not be entirely unexpected. If you have any questions, please do not hesitate to call. Sincerely, JQnadlatv c7. Murphwey Jonathan D. Murphrey, P.G. Staff Geologist cc: Peter Dressel, Piedmont Geologic Attachment PIEDMONT GEOLOGIC, P.0 "01111"16111% ,i G A ,.��►�`� , p4 EN$Fo��'Ly's � r 0 2482 w ss3�9� CF�LD��S�Q��'s y..._.»..�