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Home My WebLink AboutAppendix A_Water_supply_MitigationPiedmont Lithium Carolinas, Inc. I Response to Additional Information Request (dated January 14, 2022) Appendix A: Water Supply Well Mitigation Plan PIEDAA'ONT LITHIUM Appendix A: Water Supply Well Mitigation Plan This page intentionally left blank. Water Supply Well Mitigation Plan Carolina Lithium Project Enter Project Description or Caption Gaston County, North Carolina December 2, 2021 Revised February 4, 2022 Page intentionally left blank. 1 Introduction Piedmont Lithium Carolinas, Inc. (PLCI) is proposing to construct an open pit mine in the Carolina Tin-Spodumene Belt (TSB) of North Carolina where lithium -bearing pegmatites have been identified. The Concentrate Operations and the Lithium Hydroxide Conversion Plant (the Site) is in the TSB of the Piedmont physiographic province in south-central North Carolina. The approximately 1,548-acre Site is in an unincorporated area of Gaston County, on private land surrounding portions of Hephzibah Church Road, Whitesides Road, and St. Mark's Church Road, approximately 1 mile east of Cherryville, North Carolina. The overall Concentrate Operations are composed of three components: the Piedmont Lithium Carolinas Mine #1, a Concentrate Plant, and an Industrial Minerals Plant. The Piedmont Lithium Carolinas Mine #1 will consist of four open pits of varying sizes, a waste rock disposal area, topsoil stockpiles areas, haul roads, and other mine support areas. Mining will occur through open pit excavations which will require dewatering. On behalf of PLCI, HDR Engineering, Inc. of the Carolinas (HDR) performed groundwater modeling to estimate the rate of water withdrawal during pit dewatering and evaluate possible effects pit dewatering may have on local water resources and water users. The base groundwater model was developed by HDR for PLCI and documented in a Technical Memorandum Groundwater Model dated July 2, 2019 (HDR, 2019). HDR subsequently updated the model to a transient model to better evaluate potential pumping effects with more than one pit in operation at a time. The results of the updated modeling were presented in a Technical Memorandum Groundwater Model dated August 27, 2021, which was also included as Appendix G of the Mine Permit Application submitted to DEMLR in August 2021. Results of modeling indicate that dewatering, as currently proposed, may result in localized lowering of the groundwater potentiometric surface in areas north of the North Pit, east of the East Pit, and south of the South and East Pits. Based on data obtained from Gaston County, private water supply wells registered with the County may be located in each area potentially affected by mine dewatering (Figure 1). Thus, PLCI has developed this Water Supply Well Mitigation Plan to provide details regarding PLCI's commitment to take action if an off -site supply well is impacted to the extent that it no longer provides adequate capacity or quality of water for residential use. Strategies for mitigating the effects of mine dewatering on surface and groundwater resources may be collectively or individually administered for the protection of existing water supply wells. 2 Water Well Inventory In 2018, HDR contacted the Gaston County Environmental Health Department to request records of private water supply wells in the vicinity of the mine permit boundary. The County provided spatial data for 15 private wells registered with the County; however, PLCI suspects that additional private supply wells exist in the area based on the current lack of access to a municipal water supply. Additional wells were noted in field surveys conducted by Deep Earth Logic in 2019 and 2020 within a 1,500-foot radius of the proposed open pit areas of the Site for which property owner participation was voluntary; thus, wells noted during this survey were located only with property owner permission. For the purpose of groundwater modeling, HDR used locations and well construction data provided by the County for registered wells, and added possible domestic wells observed during field surveys to evaluate potential effects of drawdown resulting from dewatering activities. Well construction details for the 15 wells registered with the County are provided in Table 1. 3 Response Plan The groundwater modeling completed for the Project provides estimates of drawdown resulting from dewatering through the life of the mine, and potential effects to residential water supply wells may be predicted based on the model results. While effects to these wells are expected to be minimal, PLCI has developed the following response plan for evaluation and mitigation of groundwater well effects that may require action. Note that an actionable effect on a residential water supply well is considered to be a long-term change in water level which negatively impacts the ability of the well to provide adequate water to the resident. If an actionable water level decline occurs in a residential water supply well, the well owner should notify PLCI of the water supply well issue. In lieu of notifying PLCI, the well owner may also notify the North Carolina Department of Environmental Quality (NCDEQ), Division of Energy, Mineral, and Land Resources (DEMLR) Mining Program at (919) 707-9220. Subsequent to notification, PLCI will work with DEMLR to conduct an assessment of the reported decline to include the following: 1. Comparison of the well location to the location of ongoing mining activities and to predicted groundwater level drawdown contours from the groundwater model, as well as comparison to groundwater levels in nearby observation wells (Figure 2). 2. Examination of the condition of the well and measurement of the groundwater level in the well by a PLCI representative and/or a qualified hydrogeologist or well repair/installation specialist. If a determination is made by PLCI and/or NCDEQ that the water -supply well in question has failed due to mechanical reasons not related to drawdown from dewatering activities, the procedures outlined in this Mitigation Plan will not be applicable. The property owner will be notified of the findings of this determination and will be responsible for any necessary repairs. If a determination is made by PLCI and/or NCDEQ that the water supply well in question has been affected by dewatering activities, and that the decline is an effect that will result in long- term change in groundwater level which negatively impacts the ability of a residential water supply well to provide adequate water to the resident, PLCI will initiate the following mitigation plan in successive order. Where municipal water service has been brought to a practical distance from the affected property, PLCI may assist the affected resident with connection to municipal water supply. PLCI will pay for the cost of connection; however, ongoing utility expense will be the responsibility of the affected property owner. PLCI is currently working with local municipalities to evaluate options for bringing municipal water to the area (Attachment A). The outcome of that study is pending. If a private well is affected by the mining operation prior to availability of municipal water, PLCI will implement options 2 and/or 4, on a case -by -case basis and at their discretion. 2. Where municipal water service is not within a practical distance of the affected property, PLCI may commission a certified well driller to install a deeper residential water supply well for normal household use. 3. If a deeper residential water supply well will not yield a reliable source of water, PLCI may either: a. Continue to work with municipal water providers to extend water service to the area; or, b. Negotiate in good faith to acquire the affected property 4. Depending on the time required to mitigate the affected water supply concern, PLCI may provide a short-term water supply replacement for potable/consumable purposes by the user(s) of the affected well. Short-term water supply will be in the form of a clean water tank or container that is refilled, as necessary, by delivery truck or some other means (e.g. bottled water) and must be provided by a licensed water distributor. The result of mitigation activities must meet the minimum water volume used or needed by the resident prior to the groundwater level decline. The activities required to fulfill the requirements of mitigation will be completed at PLCI's expense and PLCI will determine the outside vendors to be used for these tasks. This Mitigation Plan relies on the use of qualified outside vendors to satisfy the needs of a temporary water supply and to develop a permanent water source. As licensed reputable companies, they are expected to accomplish and carry out their assigned duties in a manner that ensures that all work is completed within a predetermined time period, as shown in the table below. If for any reason, this work is not completed to an acceptable level of quality and/or within the time frame agreed upon by all parties, the outside vendor will be replaced by another company designated by PLCI. Once all activities have been completed and owner is satisfied with the outcome of the mitigation, PLCI will notify NCDEQ that the complaint is resolved. PLCI Response Plan Mitigation Measure Maximum Response Timeframe once notified Notification of Well Owner Concern to DEMLR 24 hours Interim Mitigation Provided to Potentially Affected Well Owner (e.g., provision of bottled water, water tank 48 hours PLCl/DEMLR Assessment of Well Owner Concerns 7 days New Supply Well Installation* 45 days Connection to Munici al Water Line* 45 days Notification of Completion of Mitigation 24 hours * Results of PLCl/DEMLR assessment will determine the most appropriate permanent mitigation measure(s) on a case -by -case basis, and as mitigation measures are available. Page intentionally left blank. Table 1. Well Construction Details for Private Wells Registered with Gaston County Well Well Total Static Well Well Owner Address* Latitude Longitude Constructio Installation Diameter Casing Well Water Yield n Date Method (in) Depth Depth Level (ft) (gpm) ft ft Denton, Anna Gail 921 Whitesides Rd.* 35.3933 -81.297682 1991 Drilled 6.25 70 150 30 8 Hastings, Calvin R. and 210 Hastings Rd.* 35.379616 -81.282877 2017 Bored 24 50 50 25 10 Terresa M. Hyleman, Marvid D. and 732 Whiteside Rd. 35.385206 -81.298376 1992 Drilled 6.25 125 166 20 25 Cynthia M. Jarrett, Brian Frank 1121 He hzibah Church Rd.* 35.394472 -81.292983 1995 Drilled 6.25 101 300 40 3 Knowles, Patrician and Dallas 1029 Hephzibah Church Rd.* 35.397076 -81.29344 1901 Unknown Unknown Unknown Unknown Unknown Unknown Knowles, Doug 1021 He hzibah Church Rd.* 35.397794 -81.295147 1994 Bored 24 45 45 35 3 Leonhardt, Timothy Dale 129 George Pa seur Rd. 35.380405 -81.295369 1971 Bored 24 63 63 33 4 35.377052 -81.295019 1998 Drilled 6.25 30 550 40 4 Locke, Bill 534 Whitesides Rd. 35.377052 -81.295019 Unknown Drilled 6.25 69 690 Unknown 150 Lovelace, Freddie and Hal 633 Aderholdt Rd. 35.391994 -81.279303 1999 Unknown Unknown Unknown Unknown Unknown Unknown Maune , Ronald Jame 663 Aderholdt Rd. 35.393967 -81.27992 1996 Drilled 6.25 62 105 40 20 McLamb, Ransom W. and 1523 R W McLamb Dr.* 35.386299 -81.296342 1998 Drilled 6.25 115 185 15 20 Wendi S. Payne, William E. 901 Whitesides Rd.* 35.393774 -81.299542 2012 Bored 24 56 56 25 5 Reynolds, Paul David 1266 He hzibah Church Rd.* 35.387603 -81.286978 2002 Drilled 6.25 126 300 Unknown 30 Starks, Paul 819 Whitesides Rd.* 35.389721 -81.299089 1998 Drilled 6.25 41 180 34 25 * Denotes wells that are located within the proposed Mine Boundary and would not be used as a drinking water source. 0 5 n, HCArrf[ II } 3{7{TH FA2T _ � Ny �i o•" � '1� III' � •k �4 .. Soucas, EE ER arrnln�ILtrr3 nciernent � C rd USGS, AO P5, N Geoff, IGN, I�ada6Le�r L, ;urveX, srf MAE3� Esrl fllna i Hoag I oN , Wssl: } OpenSgeLAM3 rtributars, andlhe I&61MrCommunly Figure 1. Model -predicted Drawdown during Operating Years 14-20 iGeaMEe, -E, Gwmlr.. IP ., D, NPu, tGN, } Ire-- I� Legend Domain Drawdown IM ® Planned Pits x Simulated WnecPitArea 7 1 -Receptor Wells 11 - 15 lil 8 Possible Damesbc W.n 15-21 I Steams I I + tor. hih�a� tLdorr �1F4 97001 nPL 1 WB - ^.. ti. i -9 r± MODEL PREDICTED aRAWDOWN s FROM DEWATERING YEARS 14-20 0 -.2 4.! „GEHC PIEDMONT 'JMrdn 1.11 x 4u r p0. L � FIGURE 1 'IMF Anthony G Page intentionally left blank