Revised Proposed Groundwater Monitoring - Snow Camp (1)

REVISED
GROUNDWATER MONITORING PLAN
FOR THE PROPOSED SNOW CAMP QUARRY
SNOW CAMP, ALAMANCE COUNTY, NORTH CAROLINA
Prepared for:
Mr. Chad M. Threatt
Alamance Aggregates, LLC
PO Box 552
Snow Camp, NC 27349
Prepared by:
Robert Christian Reinhardt, P.G.
Geologist - Hydrogeologist
Environmental Scientist
7620 Mine Valley Road
Raleigh, North Carolina, 27615
March 22, 2019
Robert Christian Reinhardt — NC Geologist License # 1044

Revised Groundwater Monitoring Program
For The Proposed Snow Camp Quarry
Snow Camp, Alamance County, North Carolina
GROUNDWATER MONITORING PROGRAM
FOR THE PROPOSED SNOW CAMP QUARRY
SNOW CAMP, ALAMANCE COUNTY, NORTH CAROLINA
Geologists have previously submitted a hydrogeologic study in the vicinity of the proposed
Snow Camp Quarry located between Clark Road and Quackenbush road, approximately 2
miles south of the unincorporated town of Snow Camp in Alamance County, North
Carolina. The preliminary investigation was based on site observations and measurements
by Chris Reinhardt, PG (RCR) and on information provided by Alamance Aggregates, LLC
and Carolina Geological Services, Inc. to support work in the preliminary permitting
process for the proposed quarry. The scope of work primarily included the compilation of
existing data and the evaluation of new data and field observations collected during
several site visits. The report describes the hydrogeology of the area and estimates
potential impacts of quarry development on local ground- water resources.
As the quarry operations will require de -watering of the quarry pit, a condition of the
mining permit for this facility will require a Groundwater Monitoring Program to be
implemented prior to beginning mining operations. Based on conversations with North
Carolina Department of Environmental Quality (NCDEQ) personnel in the Division of
Energy, Mineral, and Land Resources (DEMLR) and the Division of Water Resources
(DWR), the permit will require monitoring groundwater levels and conditions in the vicinity
of the quarry. The NCDEQ is especially concerned where private water supply wells may
be impacted by quarry operations.
Expanded Well Survey
Based on a review of the Alamance County GIS aerial map for the vicinity surrounding the
proposed quarry, there do not appear to be any residential properties within 500 feet of
the proposed mining limit. The DMLR has requested a water supply well survey for
properties within a 1,500 foot radius of the proposed permit boundary (Figure 1).
Following an extensive review of Alamance County records, 89 individual properties were
identified as being wholly or partly within the 1,500 foot radius. A public water supply is
not available in the area. County records for existing water supply wells are incomplete
and only extend back to 1990 when their permitting process began.
After viewing recent aerial photography for the properties (Alamance County GIS — 2018),
RCR determined that 21 of the properties are currently undeveloped and are not likely to
have an active water supply well. A review of county records for the area confirmed water
supply wells exist on at least 45 of the properties within the search radius. These records
2

Revised Groundwater Monitoring Program
For The Proposed Snow Camp Quarry
Snow Camp, Alamance County, North Carolina
consisted of water supply well permits and requests for groundwater analysis from
individual wells.
On February 25 and March 5, 2019 and on behalf of Alamance Aggregates, LLC, RCR sent
Certified letters to 29 local property owners where there was no information or very
limited information concerning potential water supply wells on their properties. The letter
requested that they confirm if a well was on that property and, if so, provide any details
they had concerning the well(s). To date (March 21, 2019) RCR has received Return
Receipts for 24 of the 29 letters and has received a response from 8 of the recipients. One
letter was returned as undeliverable and we are currently trying to determine how to get
information on that property. Figure 1 indicates the properties within the 1,500 foot
radius of the proposed permit boundary and shows properties with confirmed and/or
suspected water supply wells. Appendix I tabulates the residential properties the within
search radius and provides available details for wells on those properties. Appendix II
includes a compilation of the Certified Mailing and Return Receipts as well as the
responses received to date.
Dewatering Influence on Area Water Supplies
The submitted mining permit application has proposed that the quarry may discharge as
much as 500,000 gallons per day for dewatering purposes in the mine. In this geologist
experience, the potential for a discharge of that volume of water is unlikely to occur unless
there was a catastrophic rain event or significant rainfall for extended periods. The water
discharged from the pit will be a combination of groundwater and rainwater, however, the
majority of water in the pit is rainwater. Based on the average annual rainfall for the
Burlington area (http://usclimatedata.com), 1 acre of active quarry pit will receive an
average of approximately 3,350 gallons of rainwater per day. As an example, the Martin
Marietta Burlington quarry, located 13 miles northwest and in a similar geologic situation,
is permitted to discharge 340,000 gallons per day. The active mining area is 211 acres,
yielding an average daily rainfall of about 700,000 gallons. Evaporation will account for
the loss of much of the rainwater in the pit and part of the water is used for dust control
and washing the crushed stone. The dust control and wash water seeps back into the
ground and is effectively recycled on the property. A review of the permit for this quarry
indicates that groundwater pumping from the pit is minimal. Records for the East
Alamance quarry (18 miles north) show that pit water was only discharged to the surface
receptor after periods of heavy rainfall and that daily discharge didn't exceed
approximately 25,000 gallons per day. Based on this information, it is obvious that the
amount of groundwater being pumped is relatively small and the pumping does not
significantly impact groundwater conditions away from the quarry pit. Monitoring wells
3

Revised Groundwater Monitoring Program
For The Proposed Snow Camp Quarry
Snow Camp, Alamance County, North Carolina
installed at quarries with similar hydrogeologic conditions have shown little to no impact
800 feet from the pit. As part of the permitting process, Alamance Aggregates, LLC will
register, monitor, and report water withdrawals from the pit in excess of 100,000 gallons
per day in accordance with G.S. 143-215.22H.
Monitoring Plan
The proposed groundwater monitoring well network for the Snow Camp Quarry will, if
possible, incorporate at least 1 of the 3 existing in -active water supply wells located on the
quarry property. During the site reconnaissance, water levels were measured in 2 existing,
in -active water supply wells on the property near the southern and northern edges of the
property (Figure 2). Construction details or other information about the wells such as
total depth, casing depth, and yield were not available. However, the drilled water supply
wells could be converted to monitoring wells and at least one is located at a prime spot for
continued long term monitoring of the site. Before incorporating existing wells into a
monitoring network, the wells will need to be sounded for depth and obstructions, and we
recommend a down -hole video screening of each well to confirm well conditions and
suitability for conversion to monitoring wells. If any of the wells are in an acceptable
condition, they could be converted to monitoring wells. The monitoring well network will
be installed to determine the influence of quarry dewatering on the adjacent properties.
Any well that is not in a suitable condition for conversion to a monitoring well should be
abandoned in accordance with the NC Well Construction Standards (15A NCAC .2C).
The recommended monitoring plan will include 2 monitoring wells at each of the proposed
monitoring locations north, south, east, and west of the quarry pit (Figure 2). One well at
each location will be completed in the overburden/saprolite and will likely be
approximately 30 feet to 40 feet deep. This zone acts as a storage reservoir and recharge
source for the underlying fractured rock aquifer. A second well at each location will be
completed in fractured bedrock and should extend to a depth similar to the projected
depth of the proposed quarry. The shallow monitoring wells will be constructed of 2 inch
ID PVC screen and riser, with a coarse sand filter pack, bentonite seal and grout to land
surface. The deep monitoring wells can be completed as open hole wells into bedrock.
Each water bearing fracture zone should be noted in the log as the borehole is advanced.
All wells should be completed with riser extending above land surface with a protective
steel casing. Additional protective structures (bollards, etc.) should be placed around the
wellheads to protect from vehicular traffic. All wells will be installed under the supervision
of a licensed NC Geologist and constructed by a certified driller in accordance with North
Carolina Well Constructions Standards (15A NCAC .2C).
E

Revised Groundwater Monitoring Program
For The Proposed Snow Camp Quarry
Snow Camp, Alamance County, North Carolina
As the main concern for groundwater impact to surrounding properties is the lowering of
the water table, periodic monitoring of water levels in the wells will be required. The
frequency for monitoring and reporting will be included in the permits issued for quarry
operations. The Division of Water Resources has recommended monthly water level
measurements, beginning at least 2 months prior to any dewatering activities. Monthly
water level measurements would be recorded and reported with the pumping data from
the quarry dewatering. No water quality monitoring is recommended for the monitoring
well network.
Adverse Impact Letter
In addition to monthly groundwater monitoring, the DWR has requested an "adverse
impact" letter be provided by Alamance Aggregates, LLC to local residents. This letter
would state "how the mine would rectify the situation if they impact their neighbors'
wells". The DWR also suggested language for such a letter. On behalf of Alamance
Aggregates, LLC, we suggest the following revision of the DWR suggested lette:
To Whom it may concern: (needs legal review)
If the proposed mine named Snow Camp Quarry, operated by Alamance Aggregates, Inc.,
should be shown to adversely impact any existing water supply wells within the
surrounding area due to quarry dewatering activities, then Alamance Aggregates, Inc. will
promptly take action to correct the adverse impact and notify the NC Division of Water
Resources - Groundwater Management Branch. Alamance Aggregates, Inc. will take action
to determine the direct cause of the issue(s) and will work to promptly resolve the
issue(s).
Sincerely:
(Title)
Alamance Aggregates, LLC
Original Monitoring Plan dated 09/22/2018
Revised Monitoring Plan dated 03/22/2019
5

Revised Groundwater Monitoring Program
For The Proposed Snow Camp Quarry
Snow Camp, Alamance County, North Carolina
Figures

Revised Groundwater Monitoring Program
For The Proposed Snow Camp Quarry
Snow Camp, Alamance County, North Carolina
Appendix I

Revised Groundwater Monitoring Program
For The Proposed Snow Camp Quarry
Snow Camp, Alamance County, North Carolina
Appendix II