NCG020793_Reissuance-COC-Special-Conditions_2015-Renewal

North Carolina Department of Environmental Quality
Pat McCrory
Governor
Andrew Bradley
Unimin Coporation
258 Elm Street
New Canaan, CT 06840
Dear Mr. Bradley:
Donald R. van der Vaart
Secretary
November 16, 2015
Subject: General Permit No. NCG020000
Unimin Corporation Quartz Operation
COC NCG020793
Mitchell County
In accordance with your request for a discharge permit received on May 30, 2014, we are forwarding
herewith the subject certificate of coverage to discharge under the subject state — NPDES general permit.
This permit is issued pursuant to the requirements of North Carolina General Statute 143-215.1 and the
Memorandum of Agreement between North Carolina and the US Environmental Protection Agency dated
October 15, 2007 (or as subsequently amended).
Please take notice that this certificate of coverage is not transferable except after notice to the
Division of Energy, Mineral, and Land Resources. The Division may require modification or revocation and
reissuance of the certificate of coverage (COC).
Coverage under this General Permit for this particular facility is granted with the condition that the
permittee performs additional sampling requirements as outlined in the amended conditions to the COC.
These special provisions were prompted by results of sampling at this facility during the week of June 8,
2015, as requested by EPA Region 4 staff who performed a Compliance Sampling Inspection (CSI) at the end
of March 2015. Sample concentrations raised concerns about metals levels in the discharges. The DEQ
concluded that more data was needed to evaluate these discharges and potential water quality impacts. The
additional provisions for this COC include:
1) In addition to the parameters in NCG020000, sample each stormwater discharge outfall (SDO)
quarterly for five metals, fluoride, chloride, and total hardness listed in Table 1 as amended on page 2
of the COC. Benchmark values apply for many of these added parameters, and the permittee must
follow tiered responses as outlined in the permit.
2) In addition to the parameters in NCG020000, sample each wastewater discharge quarterly for five
metals, fluoride, chloride, and total hardness listed in Table 7 as amended on page 3 of the COC.
Division of Energy, Mineral, and Land Resources
Energy Section • Geological Survey Section • Land Quality Section
512 North Salisbury Street, Raleigh, North Carolina 27604 • Internet: hftp://portal.ncdenr.org/web/Ir/
eb/Ir/
Mailing Address: 1612 Mail Service Center, Raleigh, North Carolina 27699-1612.919-707-9200 / FAX: [phone]
An Equal Opportunity 1 Affirmative Action Employer— 50% Recycled 110% Post Consumer Paper

NCG020793 Renewal COC
November 16, 2015
Page 2
These additional parameters include metals and other constituents which may be present or will
help us interpret the measurements (such as estimating the amounts of metals that are in dissolved form).
The Division will consider the data upon submittal to determine the most appropriate permitting actions. It
is possible that this facility will be directed to apply to the Division of Water Resources (DWR) for an
individual NPDES discharge permit (or modification of its existing wastewater individual permit) prior to the
expiration of this General Permit in 2020.
This permit does not affect the legal requirements to obtain other permits which may be required by the
Division of Energy, Mineral, and Land Resources, or permits required by the Division of Water Resources
(DWR), Coastal Area Management Act, or any other federal or local governmental permit that may be
required. If the conditions as stipulated in the COC are unacceptable to you, you may apply sooner for an
individual NPDES discharge permit.
If you have any questions concerning this permit, please contact Bradley Bennett at telephone number
[phone], or Bethany Georgoulias at telephone number [phone].
Sincerely,
Original signed by Bradley Bennett
for Tracy E. Davis, P.E., CPM
cc: Toby Vinson, DEMLR Land Quality Section
Tom Belnick, DWR Water Quality Permitting Section
Stan Aiken, DEMLR Asheville Regional Office RE
Linda Wiggs, DWR Asheville Regional Office
Kip Tyler, EPA Region IV NPDES Permitting and Enforcement Branch
Stormwater Permitting Program Files
DWR Central Files

STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENTAL QUALITY
DIVISION OF ENERGY, MINERAL, AND LAND RESOURCES
GENERAL PERMIT NO. NCGO20000
CERTIFICATE OF COVERAGE No. NCGO20793
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NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM
In compliance with the provision of North Carolina General Statute 143-215.1, other lawful
standards and regulations promulgated and adopted by the North Carolina Environmental
Management Commission, and the Federal Water Pollution Control Act, and the North
Carolina Administrative Code in NCAC 15A 02H .0114(b)(1), as amended,
Unimin Corporation
is hereby authorized to discharge stormwater and wastewater from a facility located at
Unimin Corporation Quartz Operation
7638 NC Hwy 226 S
Spruce Pine
Mitchell County
to receiving waters designated as Bear Creek, Little Bear Creek, and the North Toe River, a
class C;Tr water in the French Broad River Basin, in accordance with the effluent
limitations, monitoring requirements, and other conditions set forth in Parts I, II, III, and IV
of General Permit No. NCG020000 as attached, and as amended in pages 2-3 of this
Certificate of Coverage.
Amended conditions
1. This Certificate of Coverage (pp. 1-4) is an enforceable part of the permit.
2. In accordance with 15A NCAC 02H .0114(b)(1), the monitoring program in Part IV
Section A, Table 1 Analytical Monitoring Requirements for Stormwater from
Mining Activities, and Section D, Table 7 Monitoring Requirements for
Wastewater Discharges of this permit are amended as follows:

Table 1 Analytical Monitoring Requirements for Stormwater Discharges from Mining
Activities
Discharge
Characteristics
Units
Measurement
Fre uenc 1
Sample
Type2
Sample
Location3
Benchmark
Settleable Solids
MI/I
Quarterly
Grab
SDO
0.1 MI/I
Total Suspended Solids
m /l
Quarterly
Grab
SDO
50 m /l
Turbidit 4
NTU
Quarterly
Grab
SDO, U & D4
10 NTU
Aluminum, Total Recoverables
m /l
Quarterly
Grab
SDO
0.75 m /l
Copper, Total Recoverables
m /l
Quarterly
Grab
SDO
0.010 m /l
Lead, Total Recoverables
mg/1
Quarterly
Grab
SDO
0.075 mg/1
Nickel, Total Recoverables
mg/1
Quarterly
Grab
SDO
0.335 mg/1
Zinc, Total Recoverables
Mg/1
Quarterly
Grab
SDO
0.126 mg/1
Total Chlorides
mg/1
Quarterly
Grab
SDO
860 m
Total Fluorides
Mg/1
Quarterly
Grab
SDO
6 m
Total Harness as CaCO3 5
Mg/1
Quarterly
Grab
SDO
N/A
Total Rainfall6
inches
Quarterly
--
--
N/A
Footnotes:
1. Measurement Frequency: Quarterly (unless other provisions of this permit require monthly sampling)
during a measureable storm event, until either another permit is issued for this facility or until this
permit is revoked or rescinded. If the facility is monitoring monthly because of Tier Two or Three
response actions under the previous General Permit, the facility shall continue a monthly monitoring and
reporting schedule in Tier Two or Tier Three status until relieved by the provisions of this permit or the
Division.
2. Grab samples shall be collected within the first 30 minutes of discharge. Where physical separation
between outfalls prevents collecting all samples within the first 30 minutes, the permittee shall begin
sampling within the first 30 minutes, and shall continue until completed.
3. Sample Location: Samples shall be collected at each stormwater discharge outfall (SDO) unless
representative outfall status (ROS) has been granted. A copy of the Division's letter granting ROS shall be
kept on site with the SPPP.
4. Turbidity must be monitored at the stormwater discharge outfall (SDO). In addition to the SDO, the
permittee may elect to also monitor turbidity in the receiving water, directly upstream (U) and
downstream (D) of the stormwater discharge outfall or group of outfalls to demonstrate the discharge
has not caused a water quality standard violation of turbidity. If SDO turbidity level exceeds the
benchmark, and the permittee cannot demonstrate the discharge has not caused a violation of the
instream water quality standard, the Division may require the permittee to monitor turbidity up -
and downstream as part of a Tier 2 or 3 response.
5. Benchmark values apply for these parameters and prompt Tier responses as outlined in the General
Permit. Benchmark values for metals are based on one half the Final Acute Value (1/z FAV), a threshold
used to protect against acute impacts to aquatic life.
6. For each sampled measureable storm event the total precipitation must be recorded. An on-site rain
gauge or local rain gauge reading must be recorded.
2 I COC No. NCG020793
effective November 16, 2015

Table 7 Monitoring Requirements for Wastewater Disc har es in Section D - 1., 2., 3., & 4.
Discharge
Characteristics
Units
Measurement
Fre uenc 1
Sample
Type
Sample
Location3
Receiving
Waters
pH2
Standard
Quarterlyl
Grab
E
All
Total Suspended Solids2, 4
mg/l
Quarterlyl
Grab
E
All
Turbidit 2, 3
NTU
Quarterlyl
Grab
E, U & D3
All
Settleable Solids2, 5
ml/1
Quarterlyl
Grab
E
HQW, ORW, SA, SB,
PNA, Tr
Aluminum, Total Recoverable6
mg/l
Quarterlyl
Grab
E
All
Copper, Total Recoverable6
mg/1
Quarterlyl
Grab
E
All
Lead, Total Recoverable6
m /l
Quarterlyl
Grab
I E
All
Nickel, Total Recoverable6
mg/l
Quarterlyl
Grab
E
All
Zinc, Total Recoverable6
m /l
Quarterlyl
Grab
E
All
Total Chloride6
mg/l
Quarterlyl
Grab
E
All
Total Fluoride6
mg/1
Quarterlyl
Grab
E
All
Total Harness (as CaCO3)6
mg/l
Quarterlyl
Grab
E
All
Daily Flow Rate7
cfs
Quarterlyl
-
E
All
Footnotes:
1. The monitoring frequency is quarterly.
2. Except for mine dewatering of clay pits, a grab sample is not required for these parameters from a
basin/pond designed to contain or treat mine dewatering wastewater that only discharges in
response to rainfall in excess of the 10 -yr, 24 -hr storm.
3. Sample Location: E - Effluent, U - Upstream, D - Downstream. Turbidity must be monitored at the
effluent (E). If effluent levels exceed the Water Quality Standard of the receiving water, the permittee
must begin sampling turbidity directly upstream (U) and downstream (D) of the effluent outfall or group
of outfalls, in addition to the effluent, upon the next monitoring period. The permittee may contact the
DEMLR Regional Office for assistance in determining the best instream sample points. The RO may also
advise the permittee to relocate self -established instream sample points if appropriate.
4. All facilities that are mining Industrial Sand are required to monitor TSS and are subject to the TSS
limits in Table 8. All other types of mines covered by this permit are also required to monitor TSS, but
are not necessarily subject to the TSS limits in Table 8, unless discharge is to HQW, ORW, or PNA waters.
S. Only facilities discharging to waters classified as HQW, ORW, SA, SB, Tr, or PNA are required to monitor
for settleable solids.
6. No effluent limitation applies to these parameters.
7. Daily flow rate shall be recorded by a continuous flow measurement instrument. Alternatively, pump
curves and pump logs may be used as a means to calculate the daily flow rate.
3 I COC No. NCGO2O793
effective November 16, 2015

This Certificate of Coverage shall become effective November 16, 2015.
This Certificate of Coverage shall remain in effect for the duration of the General Permit.
Signed this day, November 16, 2015.
Original signed by Bradley Bennett
for Tracy E. Davis, P.E., Director
Division of Energy, Mineral, and Land Resources
By the Authority of the Environmental Management Commission
4 I COC No. NCG020793
effective November 16, 2015