NC0085839_Fact Sheet_20081114 (2)

DENR/DWQ
FACT SHEET FOR NPDES PERMIT DEVELOPMENT
NPDES No. NC0085839
Facility Information
Applicant/ Facility Name:
Unimin Corporation -Red Hill Quartz Plant
Applicant Address:
P.O. Box 588, Hwy 226N Spruce Pine NC 28777
Facility Address:
Highway 197N Bakersville NC 28705
Permitted Flow
2.0 mgd
Type of Waste:
Industrial
Facility/Permit Status:
Modification
Facility Classification
Physical/Chemical Class II
County:
Mitchell
Miscellaneous
Receiving Stream:
North Toe River
Regional Office:
Asheville
Stream Classification:
C Trout
USGS Topo Quad:
C9SE
303(d) Listed?:
No
Permit Writer:
Jim McKay
Subbasin:
04-03-06
Date:
11/14/2008
Drainage Area (mi2):
340
41111CIPP
Summer 7Q10 (cfs)
90.7
Winter 7Q10 (cfs):
125.6
Average Flow (cfs):
510
IWC (%):
3.3%
Primary SIC Code:
1499
SUMMARY OF FACILITY INFORMATION AND WASTELOAD ALLOCATION
Unimin Corporation is requesting a permit modification for its Red Hill Quartz Plant to increase
flow to 2.0 mgd from it's currently permitted flow of 0.682 mgd in order to increase production.
The Red Hill Quartz Plant performs extraction and mineral processing to produce high purity
quartz. No mining is done at this site. The facility is permitted to discharge into the North Toe
River, class C-Trout waters, in French Broad River Basin. Outfall 001 discharges process
water. Outfall 002 is an intermittent stormwater discharge.
The wastewater treatment plant consists of:
• Mix -reactor tanks;
• Lime and polymer feed systems;
• 2 thickeners;
• 2 drum filters
• pH adjustment;
• flow measurement and,
• 2 emergency ponds.
Processes for treatment include neutralization, precipitation, settling, vacuum filtering of solids
and disposal of solids by land filling.
RECEIVING STREAM INFORMATION:
The North Toe River downstream of the facility has a bioclassification rating of Good.
According to the US Fish and Wildlife office, that stretch of North Toe River is designated
critical habitat for the federally endangered Appalachian elktoe. We have records of the
federally endangered Alasmidonta raveneliana (Appalachian elktoe), the state listed Lampsilis
fasciola (Wavy rayed lamp mussel), and Etheostoma acuticeps (Sharphead darter) listed as a
federal species of concern all occuring in that reach of the North Toe.
A section of the North Toe River upstream of this facility is listed on North Carolina's 2006-
303(d) list, based on turbidity and riparian area loss. This upstream segment has a
bioclassification rating of Fair. The Red Hill Quartz Plant is located approximately 15 miles
downstream of the impaired segment of the North Toe River.
Unimin Corporation — Red Hill Facility Fact Sheet
NPDES Modification NC0085839
Page 1

At this time, DWQ proposes no changes to the previously developed load allocations. Neither
the impairment nor the turbidity violation is directly attributable to this downstream discharge.
Likely, the upstream discharges will be re-evaluated in the future.
INSTREAM MONITORING:
Upstream: Upstream at least 50 feet
Downstream: Downstream at least 300 feet.
Parameters: Fluoride, Turbidity, pH
The fluoride instream standard of 1.8 mg/ L was exceeded both upstream and downstream of
the discharge in 2005, with 7 instances of upstream exceedance in 2005, none in 2006, none
in 2007 and none through March 2008.
A review of instream data for 2005 through March 2008 showed no exceedances of the
turbidity standard of 10 NTU for trout streams.
Per Unimin, the cause of the exceedances upstream are unknown. It is speculated that some
quality control problems with upstream discharges occurred and caused sporadic exceedances
of Total Fluoride. Extreme drought conditions could have also been a contributing factor.
Because of the sporadic upstream exceedances, the Division of Water Quality used the 95'th
percentile of the previous 2 years of upstream data for fluoride to calculate the upstream value
for use in calculating the allowable fluoride limit (See explanation under proposed changes).
TOXICITY TEST RESULTS:
Existing: Quarterly Chronic P/F, 1.2% Ceriodaphnia test. JAN APR JUL OCT
Facility has passed all tests since January 2002 except for one failure in January 2004. It was
followed by two passed tests in Feb. and March 2004 and all subsequent tests through July
2007.
Recommendation: Renewal of quarterly chronic test @ 3.3% based on increased flow.
COMPLIANCE REVIEW:
The facility has been in compliance with nearly all permit limits consistently in 2005, 2006
2007 and 2008 YTD. One NOV was issued in November 2006 for exceeding the TSS Limit and
one NOV in 2007 for exceeding the flow limit.
Unimin is no longer required to conduct the Priority Pollutant analysis based on category of
discharger.
Chlorine is added for disinfection of the intake water. A TRC limit of 28 ug/L was added on
permit renewal in November, 2006 based on trout classification of receiving stream and NC
standard for TRC. An 18 month compliance schedule was given, the TRC limit began June 1,
2008. The TRC limit will continue with this permit modification.
PROPOSED CHANGES:
At the request of the permittee, flow is increased to 2.0 MGD from 0.682 MGD. TSS
concentration limits were kept the same at 25 mg/ L, based on 40 CFR 436 for similar type
operations. The new mass limit is 417 lb/ day monthly average for TSS, and 834.0 lb/ day
daily max. North Carolina's DWQ has determined that this increase in TSS loading is
necessary to accommodate an important economic development in the area in which the
receiving water is located, per 40 CFR Part 131.12 (a) (2).
Unimin Corporation — Red Hill Facility Fact Sheet
NPDES Modification NC0085839
Page 2

The new fluoride limit is based on the NC WQ Standard of 1.8 mg/L. Instream data for April
2006, 2007 through March 2008 was reviewed. A background upstream fluoride concentration
of 1.07 mg/L was calculated based on the 95'th percentile of the data range. A standard
material balance limit calculation results in an allowable discharge concentration of 23 mg/L,
or 384.0 pounds per day, which is given as a weekly average based on the chronic WQ
standard. A daily maximum limit of two times the weekly average (768.0 lb/day) has been given
based on discussion with Marshall Hyatt of EPA Region 4, Jeff Ferguson of Unimin, and their
attorney, Steve Levitas. The existing fluoride limit is 200.0 pounds per day monthly average
and 400.0 pounds per day daily maximum at a flow of 0.682 MGD. These limits were based on
BPJ of Best Available Control Technology of 27 mg/L when the permit was first issued.
PROPOSED SCHEDULE FOR PERMIT ISSUANCE:
Draft Permit to Public Notice: 9/24/2008
Permit Scheduled to Issue: (Tentative) 11/14/2008
Projected Effective Date of Permit: 12/01/2008
STATE CONTACT:
If you have any questions on any of the above information or on the attached permit, please
contact Jim McKay at [phone].
NAME: DATE:
REGIONAL OFFICE COMMENT:
NAME: DATE:
REGIONAL SUPERVISOR:
NAME: DATE:
Unimin Corporation — Red Hill Facility Fact Sheet
NPDES Modification NC0085839
Page 3

NPDES SUPERVISOR COMMENT:
NAME: DATE:
Unimin Corporation — Red Hill Facility Fact Sheet
NPDES Modification NC0085839
Page 4