NC0000175_Permit (Modification)_20080211

1:4!
Michael F. Easley, Governor
State of North Carolina
William G. Ross, Jr., Secretary
Department of Environment and Natural Resources
Coleen H. Sullins, Director
Division of Water Quality
February 11, 2008
Mr. Jeffrey S. Ferguson, P.E.
Unimin Corporation
136 Crystal Drive
Spruce Pine, North Carolina 28777
Subject: NPDES Permit Modification
NPDES Permit No. NC0000175
Unimin Quartz/Feldspar Facility
Mitchell County
Dear Mr. Ferguson:
The Division of Water Quality (DWQ) has reviewed your request for
modification of the subject permit by deletion of the effluent limits for the pesticides,
heptachlor and lindane. In the permit issued on November 1, 2006, supplemental
conditions allowed a review of twelve months of data to determine if reasonable
potential to exceed the allowable concentration still existed.
DWQ commends the efforts that Unimin has made to determine the source of
pesticides by working through Waste Reduction Partners. DWQ understands that
upstream land use (primarily Christmas tree farming) may be a contributing source.
A review of the discharge monitoring reports submitted to the Division of Water
Quality provided the data used in the updated reasonable potential analysis. Based
on results of the analyses, the following changes have been made to be permit:
■ The limit and monitoring for heptachlor has been deleted from the permit. All
reported values for heptachlor from November 2006 through November 2007
were below detection and indicated no reasonable potential to exceed the
allowable effluent concentration.
The limit for lindane has been deleted from the permit, however quarterly
monitoring has been required. The Division accepts the recommendation from
Waste Reduction Partners that the source of the pesticides in Unimin's effluent
is beyond the control of the facility. WRP indicates that the pesticide levels in
the intake water likely come from upstream Christmas tree farms but that these
levels should continue to diminish over time. However, since there are still
detectable amounts in Unimin's effluent, DWQ will recommend that quarterly
monitoring for lindane remain in the permit.
No other changes to the permit have been made.
1617 Mail Service Center, Raleigh, North Carolina 27699-1617 Telephone [phone] FAX [phone] I4AO Carolina
512 N. Salisbury Street, Raleigh, North Carolina 27604 on the Internet at http://h2o.enr.state.nc.us/
Equal Opportunity/Atfinnative Action Employer

Letter to Jeffrey S. Ferguson •
page 2
Please find enclosed the amended effluent pages for outfall 001, which should
be inserted into your permit. The old pages should be discarded. 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 U.S. Environmental
Protection Agency. Please take notice that this permit is not transferable. Part II, E.4.
addresses the requirements to be followed in case of change in ownership or control of
this discharge.
If you have any questions or need additional information, please contact
Jacquelyn M. Nowell at telephone number [phone], extension 512.
Sincerely,
- -.'Coleen H. Sullins, Director
Attachments
cc: Central Files
Asheville Regional Office/Surface Water Protection Supervisor
WDES Me is

Permit Number NC0000175
PART L SECTION A
A. (1). EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS -FINAL
During the period beginning on the effective date of the permit and lasting until expiration,
the Permitbee is authorized to discharge process wastewater from mineral extraction of ore
from outfall 001. Such discharges shall be limited and monitored by the Permitbee as
specified below:
Effluent
Characteristics
EFFLUENT LIMITATIONS
Monitoring Requirements
Morift
Average
Daily Maximum
Measurement
Frequency
Sample
Type
Sample
Location'
Flow
3.6 MGD
Continuous
Recording
I or E
Total Fluoride
109.0 lb/day
218.0 lb/day
Day
Composite
E, U, D
Total Suspended
Solids
1320.0 lb/day
2640.0 lb/ day
Day
Composite
E, U, D
Settleable Solids
Daily
Grab
E
Turbidity2
Daily
Grab
E, U, D
pH3
Daily
Grab
E, U, D
Oil and Grease
Monthly
Grab
E
Chloride4
Quarterly
Composite
E
Chronic Toxicity5
Quarterly
Composite
E
Lindane6
Quarterly
Grab
E, I
Notes:
1. Sample locations: E- Effluent, I- Influent, U - Above the facility intake, D - Penland
bridge. Instream samples shall be grab samples and shall be conducted 3/week. ✓
2. This discharge shall not cause the turbidity of the receiving waters to exceed 10 NTU. If
the turbidity exceeds 10 NTU due to natural conditions, the discharge shall not cause
any increase in turbidity.
3. The pH shall not be less than 6.0 standard units nor greater than 10.0 standard units.
4. Chloride shall be monitored quarterly during the same months as toxicity testing.
5. Chronic Toxicity (Ceriodaphnia) Pass/ Fail at 11 %: January, April, July and October. See
Special Condition A (2).
6. See Special Condition A (7).
There shall be no discharge of floating solids or visible foam in other than trace amounts.

Permit Number NC0000175
A. (7). LINDANE CONDMON
After twelve (12) months of sampling for lindane, Unimin may request in writing that the
Division review the data to determine if reasonable potential to exceed the allowable
concentration exists. If reasonable potential does not exist then the lindane limit may be
removed from the permit.
SECTION B. STORMWATER BEST MANAGEMENT PRACTICES (BMPS) PLAN
1. The per nittee shall implement stormwater BMPs to ensure that contaminants do not
enter surface waters via stormwater that comes in contact with any unstabilized
overburden, raw materials, intermediate products, finished products, byproducts or waste
products located on the site covered by this permit. A BMP Plan shall be developed in
accordance with the requirements of this section. The BMP Plan requirement, or portions of
the plan requirement, may be met by utilizing appropriate requirements in other
documented plans specific to the permitted facility.
2. Management of Stormwater Runoff and Runon The pemnittee shall maintain stormwater
BMPs for land disturbance areas and outside process areas. In addition, controls should be
used to limit or isolate selected land disturbance and process areas and limit the amount of
off site stormwater runon to those areas. Appropriate Best Management Practices (BMPs)
should be used to divert, infiltrate, reuse or otherwise manage stormwater runoff and
runon in a manner that reduces pollutants in stormwater discharges leaving the site.
Appropriate BMPs may include but are not limited to: vegetative swales, berms, use of
reclaimed mine areas, and reuse of collected stormwater (such as for an industrial process
or as an irrigation source).
3. BMP Controls Inspection and Maintenance. All stormwater BMPs shall be inspected by
or under the direction of the permittee at least once every seven calendar days and within
24 hours after any storm event that results in a discharge. The BMPs implemented shall be
operated and maintained so that they are cleaned out when the sediment storage capacity
has been reduced by 50%. If any visible sedimentation is leaving the property, corrective
action shall be taken to reduce the discharge of sediments. Visible sedimentation found
offsite shall be recorded with a brief explanation as to the measures taken to prevent future
releases as well as any measures taken to remove the sediment that left the site. All other
stormwater specific controls (e.g. oil /water separators) shall be inspected and qualitatively
monitored on a semiannual schedule, once in the fall (September -November) and once
during the spring (AprilJune). A log of sampling data and of activities taken to implement
BMPs associated with the vehicle maintenance activities shall be maintained and
incorporated into the BMP Plan and kept onsite for the duration of the permit term and
made available to the Director upon request.

REASONABLE POTENTIAL ANALYSIS
Unimin - Quartz /Feldspar Plant
NC0000175
7k* FWW 2004-2oos
Qw (AGD) 3.6
wwrp Cass IV
7Q10S (ow a
1M (%) ®7Q10S 11 A32
7Q10W(dW tits
a 70106V 9211
30Q2 (aft) 0
A 3002 WA
AW Sbwn RM QA ON 270
a QA Lou$
Rw,vft S hwn North Too RMr
Sbiom Cbn C-Trout
Outfall 001
Ow = 3.6 MGD
STANDARM
PARAMETER
WM
CR"EM (2)
Pm
unit
REASONABLE POTENML RESULTS
ftE00Mf1 40M AC710N
NC*=/ %FAY/
a #DA HwAvdCr AIwWCW
(1)
CArasie ArsM
Awlr. WA
AWM
C
0.05
nWL
0 0
WA
.........................................
Awh: WA
Max. prod. Vokle is WooW !hen chronic gowable. Two hMr
L kwww
NC
0.010
uyL
17 2
0.500
_ - _ _
_112 3_2I0_7. PPEA review- no pests in proom or and
---
owmft 0.001
PesbMw bekwd prosW it intake water.
QuMeAy mc-wr ended.
AcvM: WA
AN vokm Wow detection. Max. prod. Value < ahronia &%v
Ftaprachlor
C
0.060
nWL
17 0
0.001
...........
No 6MtormoNloftmcmwrmwed.----------
---- --------
CWw& 3.0610
Awls WA
Il-H-ngrj'nr
NC
0.030
U9&
0 0
WA
_-_
-----------------------------
I
i Chronic: 0 272
'gale
C = Cadrwperrc
NC s AkN CwcblogWft
A a AeWha fe
no000017&pa2007.no
Wr2m

REASONABLE POTENTIAL ANALYSIS
1 2 1 3 1
Lindane
Heptachlor
a
Date Data
BDL=1/2DL
Results
Date Data
BDL=1/2DL
Results
1
Nov-2006
0.090
0.045
Std Dev.
0.0382
1
Nov-2006
0.00004
0.00002
Std Dev.
0.0000
2
Nov-2006
0.110
0.110
Mean
0.0531
2
0.00004
0.00002
Mean
0.0000
3
Dec-2006
0.090
0.045
C.V.
0.7197
3
0.00004
0.00002
C.V.
1.0416
4
0.090
0.045
n
17
4
0.00004
0.00002
n
17
5
Nov-2007
0.090
0.045
5
0.00004
0.00002
6
0.090
0.045
Mult Factor =
2.8300
6
0.00004
0.00002
Mult Factor =
3.9800
7
0.090
0.045
Max. Value
0.180 ug/L
7
0.00004
0.00002
Max. Value
0.00014 ng/L
8
0.090
0.045
Max. Pred Cw
0.509 ug/L
8
May-2007
0.00027
0.00014
Max. Pred Cw
0.00054 ng/L
9
0.090
0.045
9
0.00027
0.00014
10
0.027
0.014
10
0.00009
0.00005
11
0.027
0.014
11
0.00009
0.00005
12
0.090
0.045
12
0.00004
0.00002
13
0.090
0.045
13
0.00004
0.00002
14
Feb-2007
0.180
0.180
14
0.00004
0.00002
15
0.090
0.045
15
0.00004
0.00002
16
0.090
0.045
16
0.00004
0.00002
17
0.090
0.045
17
0.00004
0.00002
18
18
19
19
20
20
21
1
21
22
22
23
23
24
24
nc0000175rpa2007, data
- 1 - 1 /9/2008

Unimin — Quartz Feldspar Plant jmn
NC0000175 1/16/2008
Permit Mod request to remove lindane and heptachlor limits
Unimin was given limits for these pesticides in the last permit renewal based on results of
RPA. Unimin has insisted no pesticides onsite, believe pesticides are in the intake water
and coming from Christmas tree farms upstream. DWQ recommended they contact
Pollution Prevention for a consultation on how pesticides may be getting into the effiuent.
12/27/2007 received request to remove lindane and heptachlor based on a new RPA
using data submitted for past two years. Also submitted report from Terry Albrecht of
Office of Waste Reduction, about the visit and review of the Unimin Quartz facility.
Telecon with Terry Albrecht—1/15/2008
He works with Waste Reduction Partners, a professional engineer who has been doing
professional audits for 15 years. Visited Unimin plant in Feb. 2008 with 2 other
scientists. There was so evidence of any uses of pesticides, no precursors, no
chemical use whatsoever within their operation.
There are over 100 Christmas tree farmers upriver from the Unimin site. Cooperative
extectoon looked at it and some farmers still using their stored up pesticides. Coop Ext
said that they would talk to fanners and write an article in their newletter about pesticide
use.
Albrecht thinks that there will be less and less detection of these pesticides over
time. He thinks the hits are totally beyond Unimin's control. They were very
cooperative during the review and showed them everything.
Didn't think that upstream samples were composite. Crab only. Did not think that
there was anyplace where groundwater intrusion could get into their effluent.
Effluent hits did not seem to correlate to when pesticides are applied to Christmas trees.
His opinion on the pesticide hits is that maybe its a spill, far upstream that is
leaching out on occasion. He thinks that there is a long retention time of 2 days or so
when the water comes into Unimin's system and maybe it's a plug that goes through
periodically.
He doesn't think that Unimin has any control over this issue or where the pesticide is
coming from. No economical or realistic way for Unimin to treat for removal. Would
need advanced carbon filter/breatrnent (`. to treat at this level. It would be too costly for
Unimin to try to remove.
Based on this information: Recommend removal of lindane, and heptachlor limits.
Analysis showed no reasonable potential for exceedance for heptachlor. Will drop limit
and monitoring for heptachlor. Concerning lindane, RPA showed reasonable potential to
exceed limit based on hits in Nov. 2006 and Feb. 2007. Recommend quarterly
monitoring for lindane. ?v
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Unimin
Unimin Corporation
136 Crystal Dave • Spruce Pine, NC 28777
(PHONE) 828/766-6081 • (FAQ 828/765-4755
CERTIFIED MAIL
RETURN RECEIPT REQUESTED
Ms. Susan A. Wilson
NCDENR - Division of Water Quality
1617 Mail Service Center
Eaoiroomeata/A/iiirs Dcp"nwnt
December 14, 2007
V
i
DEC 2 7 �L7
Raleigh, North Carolina 27699-1617 - ����;«►
Subject. Request for Removal of Pesticide Sampling Requirements
Unimin Corporation's Quartz/ Feldspar Facility
NPDES Permit NC0000175
Dear Ms. Wilson:
Per the cover letter dated September 26, 2006 issuing NPDES Permit NC0000175
to Unimin Corporation's Quartz/Feldspar facility, Unimin requests that you remove the
pesticide monitoring requirements as there is no reasonable potential to exceed the
allowable concentration, nor does Unimin have any control over the minute amount of
pesticides that are being pulled into the process from the N. Toe River.
As included with my recent letter to Jackie Nowell (dated October 9, 2007), please
review the attached letter from Terry Albrecht, P.E., Waste Reduction Parters Program
Director, NC Division of Pollution Prevention and Environmental Assistance, regarding
permit limits imposed for Heptachlor and Lindane contained in the NPDES Permit issued
to Unimin Corporation's Quartz/Feldspar Facility effective November 1, 2006.
Per your cover letter with issuance of the NPDES permit, we contacted the Office
of Pollution Prevention and Environmental Assistance to perform a consulation/inspection
to help determine the source of the pesticides found in the effluent as well as found in the
influent to the facility. Mr. Albrecht, along with Elaine Martin and Park Flick of Waste
Reduction Partners met with Mitch Snyderman and myself of Unimin on February 13,
2007. We reviewed the entire facility and discussed operation practices conducted at the
plant and mining During our inspection of the facility, there were no issues that arose that
may indicate pesticide use or creation on site or in any of our processes. As you will note
from the Review Summary contained in the attached letter, the Waste Reduction Partners
agree that none of Unimin's raw materials, mined residues, processing reagents used in the
flotation and product isolation processes, wastewater treatment chemicals, or any other
onsite chemical use could be the sources of lindane or heptachlor found in effluent
analyses. The Waste Reductiion Partners further agree that any traces of these pesticides

Ms. Susan A. Wilson
December 14, 2007
Page 2
must already be present in influent water, which have, in fact, been detected in the source —
influent water from the North Toe River.
Since the permit was issued last November, we have experienced only one hit for
lindane in November, 2006. The result was 0.11 ppb just above the lab detection limit of
0.09 ppb. Although the lab results are unreliable at such low levels, we are certain that the
pesticides are due to stormwater runoff from the numerous Christmas tree farms located
upstream in both Avery & Mitchell counties.
Unimin continues to protest the imposition of effluent monitoring requirements for
Lindane and Heptachlor due to the fact that any positive analyses for these pesticides are
beyond our control. Unimin has continued to monitor and incur the unnecessary expenses
associated with these pesticide monitoring requirements and have had no further hits to
date. Unimin requests that your Division review the data to determine if reasonable
potential to exceed the allowable concentration exists. Your Division should concur with
the Waste Reduction Partners and remove the sampling requirements from the permit.
If you have any questions or require further information, please do not hesitate to
contact me at [phone] ext. 13.
Sincerely,
;eeffrey&rguson, P. E.
Environmental Engineer
UNIMIN CORPORATION
c: EA Files; Carl Horvat Steve VV&m

i
UnImIn
Unimin Corporation
136 Crystal Drive • Spruce Pine, NC 28777
(PHONE) 828/766-6081 • (FAQ 828/765-4755
CERTIFIED MAIL
RETURN RECEIPT REQUESTED
Ms. Jackie Nowell
NCDENR - Division of Water Quality
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
Bawimmnental Affairs Department
October 9, 2007
fD �C EVE
OCT 16 2007
of". QUALlT)'
Po1Ni SOURCE BRANCH
Subject. OPP Comments Regarding Pesticides
Unitnin Corporation's Quartz/Feldspar Facility
NPDES Permit NC0000175
Dear Ms. Nowell:
Please note the attached letter from Terry Albrecht, P.E., Waste Reduction Parters
Program Director, NC Division of Pollution Prevention and Environmental Assistance,
regarding permit limits imposed for Heptachlor and Lindane contained in the NPDES
Permit issued to Unimin Corporation's Quartz/Feldspar Facility effective November 1,
2006.
Mr. Albrecht, along with Elaine Martin and Park Flick of Waste Reduction Partners
met with Mitch Snyderman and myself of Unimin on February 13, 2007. We reviewed the
entire facility and discussed operation practices conducted at the plant and mining During
our inspection of the facility, there were no issues that arose that may indicate pesticide use
or creation on site or in any of our processes. As you will note from the Review Summary
contained in the attached letter, the Waste Reduction Partners agree that none of Unimin's
raw materials, mined residues, processing reagents used in the flotation and product
isolation processes, wastewater treatment chemicals, or any other onsite chemical use could
be the sources of lindane or heptachlor found in effluent analyses. The Waste Reductiion
Partners further agree that any traces of these pesticides must already be present in influent
water, which have, in fact, been detected in the source — influent water from the North Toe
River.
Since the permit was issued last November, we have experienced only one hit for
lindane in November, 2006. The result was 0.11 ppb just above the lab detection limit of
0.09 ppb. Although the lab results are unreliable at such low levels, we still believe that the
pesticides are due to stormwater runoff from the numerous Christmas tree farms located
upstream in both Avery & Mitchell counties.

i
Ms. Jackie Nowell
October 9, 2007
Page 2
Unimin continues to protest the imposition of effluent limitations for Undane and
Heptachlor due to the fact that any positive analyses for these pesticides are beyond our
control. Unimin will continue to monitor for these pesticides as per the NPDES effluent
monitoring requirement, however, per permit stipulations, within 12 months of sampling
these pesticides Unimin will request that your Division review the data to determine if
reasonable potential to exceed the allowable concentration exists. The Division should
concur with the Waste Reduction Partners and remove the sampling requirements from the
permit.
If you have any questions or require further information, please do not hesitate to -
contact me at [phone] ext. 13.
c: LA Files; Cad Horvst Mtch Saydermw
Sincerely,
Jeffrey S. Ferguson, P. E.
Environmental Engineer
UNIMIN CORPORATION

ATLMA
NCDENR
North Carolina Department of Environment and Natural Resources
Division of Pollution Prevention and Environmental Assistance
Michael F. Easley, Governor
March 5, 2007
Jeff Ferguson
Environmental Engineer
Unimin
P.O. Box 588
136 Crystal Drive
Spruce Pine, NC 28711
William G. Ross Jr., Secretary
Gary Hunt, Director
Re: Review of Lindane and Heptachlor Detection in Unimin Wastewater
Dear Mr. Ferguson,
The following report summarizes our findings and feedback during the February 13, 2007, on -
site visit and facility review at Unimin.
Summary: On -site Assessment Findings & Next Steps:
On February 13, 2007 a Waste Reduction Partners/NCDPPEA team of engineers and
scientists visited the Unimin, Spruce Pine, facility to review the issue of sporadic detection of
heptachlor and lindane in their NPDES permitted wastewater discharge. Based on our review
of the facility and practices, it is our opinion that Unimin is not contributing any amount of
lindane or heptachlor constituents from their facility operations, processes, or wastewater
treatment.
The sales and use of heptachlor, an insecticide, have been banned for many years, and
Unimin has not detected heptachlor in recent years. Sales of lindane, another highly -effective
insecticide, were banned about 5 years ago, but farmers can still use existing supplies.
Lindane has been detected in Unimin's source intake water from the North Toe River.
NCSU's Cooperative Extension agents have confirmed that some of the approximately 300
Christmas tree farmers in this watershed are still legally using on -hand supplies of lindane.
As an outreach approach to the issue of lindane detection in the North Toe River, the NCSU
Cooperative Extension agents have agreed to make tree farmers in Mitchell and Avery
counties aware of this issue, proper practices and precautions, and disposal options for any
remaining lindane supplies. This outreach is to be conducted through their outreach
publications to farmers in these counties, through IPM workshops and other training
opportunities. Cooperative Extension agents have also made NCDA Pesticide Inspectors in
these counties aware of this issue.
Nne
orthCarolina 1639 Mail Service Center, Raleigh, North Carolina 27699-1639
Naturally Phone: [phone] FAX: [phone] Internet: www.p2pays.org
An Equal Opportunity 1 Affirmative Action Employer —100% Recycled 1100% Post Consumer Paper

On -site Visit Background
On February 13, 2007, the Waste Reduction Partners (WRP) program members met with
Unimin - Spruce Pine staff, Jeff Ferguson and Mitch Snyderman, to explore reasons for the
occasional detections of lindane and heptachlor in their NPDES wastewater discharge.
Representatives from WRP included WRP Director & NC Division of Pollution Prevention and
Environmental Assistance (DPPEA) staff member, Terry Albrecht, PE; Elaine Martin, Ph.D., a
retired research chemist with WRP; and Parke Flick, Ph.D., a retired biochemist serving with
WRP.
Unimin requested the visit per the NC Division of Water Quality's suggestion that a third party
review the insecticide detection issue and provide feedback.
Unimin provided the DPPEA / WRP team with all pertinent records of analytical sampling
results for both discharge wastewater and intake water; raw material usage information,
MSDS, and other research documents collected about lindane and heptachlor production and
their uses.
Unimin Raw Material Review
In an effort to ascertain possible sources of lindane and heptachlor contamination periodically
found in Unimin wastewater, the raw materials used in Unimin's manufacturing process were
revealed and reviewed with Waste Reduction Partners scientists and engineers during the
meeting. Most of these materials are inorganic chemicals produced commercially in very
large quantities and provided to Unimin in bulk. Undane and heptachlor are both organic
chlorine compounds. ;None of the inorganic raw materials in use by Unimin even contain
chlorine and it is quite unreasonable that they would be contaminated with these very specific
pesticide materials produced by totally different methods. Indeed, neither lindane nor
heptachlor is currently produced in the United States, although some old stocks of these now -
banned chemicals still exist.
Of the two classes of organic raw materials used by Unimin, neither contains chlorine or
aromatics, both of which would be expected if lindane and heptachlor contamination were
originating in them. The fact that lindane and heptachlor contamination has been found in the
intake water for Unimin's process strongly suggests that this is the source of the
contamination.
Unimin personnel are completely aware of each of the raw materials in use at their facility and
have dealt continuously with only a few reputable suppliers. Unimin personnel have also
reviewed ancillary use chemicals and MSDS, finding no causal effects. It is the opinion of
Waste Reduction Partners that none of these materials could reasonably be a source of
lindane and heptachlor contamination in Unimin wastewater.
Unimin Wastewater Treatment Review
A tour of the wastewater treatment facility was taken with UNIMIN environmental
professionals, and a review of reagents used, processing adjustments, and daily monitoring
was conducted.

Environmental personnel at UNIMIN are vigilant toward all aspects of wastewater quality.
Their awareness of factors influencing process water purity is very evident. Consistently and
effectively removing contaminants and meeting permit limits are major objectives. The water
treatment process is efficient and well controlled. It accomplishes a thorough removal of the
processing chemicals used in mineral separation and purification.
Best Available Technology Currently Applied in Wastewater Treatment
To treat the very large volumes of water required for the mineral separation, UNIMIN is using
the best available and practical technology. Progress to decrease the volume of process water
needed has already been significant. Further efforts to streamline the system through reuse of
process water are underway. We conclude that UNIMIN has been conscientious in their
action to ensure the best effluent water quality within their capabilities. They continue to
develop novel enhancements to their purification process.
No Potential for Insecticide Contamination in Mined Materials
There have been no changes in the footprint for the mineral quarries where raw materials are
extracted. There are no agricultural activities in the vicinity of the 'restricted access' quarries
where minerals are mined, thus ruling out that the Unimin ore itself would be contaminated
with these insecticides.
Unimin Review Summary:
None of Unimin's raw materials, mined residues, processing reagents used in the flotation and
product isolation processes, wastewater treatment chemicals, or any other onsite chemical
use could be the sources of lindane or heptachlor found in effluent analyses. Any traces of
these pesticides must already be present in influent water, which have, in fact, been detected
in their source — influent water from the North Toe River.
Next Steps to Address Known Agricultural Sources of Lindane and Heptachlor
The sale and use of heptachlor, an insecticide, have been banned for many years, and Unimin
has not detected heptachlor in recent years. Sales of lindane, another highly -effective
insecticide, were banned about 5 years ago, but farmers can still use existing supplies.
Lindane has been detected in Unimin's source intake water from the North Toe River.
NCSU's Cooperative Extension agents have confirmed that some of the 300 Christmas tree
farmers in this watershed are still legally using on -hand supplies of lindane.
As an outreach approach to the issue of lindane detection in the North Toe River, the NCSU
Cooperative Extension agents have agreed to make tree farmers in Mitchell and Avery
counties aware of this issue, proper practices, and disposal options for any remaining lindane
supplies. This outreach is to be conducted though their outreach publication to farmers in
these counties, through IPM workshops and other training events. They have also made
NCDA Pesticide Inspectors in these counties aware of this issue.

Please let us know if we can be of further assistance.
Sinc�ty',
Terry Albrecht, PE
WRP Program Director
NC Division of Pollution Prevention and Environmental Assistance
Land -of -Sky Regional Council — Partnership

1./F005 Crcer
Unimin
Unimin Corporation
136 Crystal Drive • Spruce Pine, NC 28777
(PHONE) 828/766-6081 • (FAX) 828/765-4755
CERTIFIED MAIL
RETURN RECEIPT REQUESTED
Ms. Jackie Nowell
NCDENR - Division of Water Quality
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
Environmental Affain Department
November 2, 2006
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NOV -
8 2006
DENR • WATER �!IALITY
?ieirT S(1URrE RQANr�{
Subject. Comments to NPDES Permit NC0000175
Unimin Corporation's Quartz/Feldspar Facility
Dear Ms. Nowell:
Please note the following comments regarding permit limits imposed for Heptachlor
and Lindane contained in the NPDES Permit issued to Unimin Corporation's
Quartz/Feldspar Facility effective November 1, 2006 (cover letter dated September 26,
2006).
As stated in my comments to the draft permit, dated May 31, 2006, Unimin protests
the imposition of effluent limitations for Lindane and Heptachlor due to the fact that any
positive analyses for these pesticides is beyond our control. It is Unimin's understanding
that these pesticides are used by numerous local Christmas tree farms in the Mitchell, Avery
and Yancey County area. During the past two years we have continued to sample our intake
and effluent for each pesticide twice per month and have incurred a substantial cost for
doing so. Unimin contends the sporadic and limited results experienced to date support the
position that these chemicals do not originate on the Quartz — Feldspar Plant property.
Unimin believes these pesticides originate in storm water run-off from local tree farming
activity. As such, they are beyond Quartz — Feldspar Plant control.
Further to our earlier conversations, Unimin will contact the Office of Pollution
Prevention and Environmental Assistance in order to request assistance with this matter.
During the interim period, the Quartz — Feldspar Plant will continue to comply with
NPDES permit requirements; however, should permit limits for either Lindane and / or
Heptachlor be exceeded, they must be considered beyond Unimin control.
Unimin would appreciate an opportunity to work with the NCDENR — Division of
Water Quality to mitigate this matter in a way that does not unduly impact Quartz —
Feldspar Plant operations. As such, Unimin's immediate plans are to follow NCDENR
recommendations and make every effort to conclude this matter to our mutual satisfaction.

Ms. Jackie Nowell
November 2, 2006
Page 2
Thank you very much for the opportunity to provide comments to the permit If
you have any questions or require further information, please do not hesitate to contact me
at [phone] ext. 13.
Sincerely,
11h
Jeffrey S. Ferguson, P. E.
Environmental Engineer
UNIMIN CORPORATION
c: EA Files; Cad Horvat; Mitch Snydennan