NC0000175_Three Feldspar Operations in Mitchell County_19800331

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MEMORANDUM
North Carolina Department of Natural
Resources &Community Development
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DIVISION OF ENVIRONMENTAL MANAGEMENT
March 31, 1980
TO: Ogden Gerald
Asheville Regional Office
THRU: Forrest Westall, Head
Technical Services Branch
FROM: Mark Lewis, Environmental Engineer
Technical Services Branch
SUBJECT: Three Feldspar Operations in Mitchell County
During our telephone conversation on March 25, 1980, you informed me that the
three feldspar operations in Mitchell County (Sobin, Lawson and Feldspar Corp.)
discharge relatively small volumes of water and thus do not contribute
significantly to any dilution of fluorides. Thus, any dilution would have to
come from the natural 30/2 of the North Toe River. The point on the North Toe
River just downstream from all the fluoride dischargers is the North Toe
immediately beyond it% confluence with Little Bear Creek. The 30/2 at this
point is 85.2 cfs.
According to EPA Document # 904/9- 77-01i, the background fluoride concentrations
on the North Toe are 0.2 mg /1. Thus, With a flow of 85.2 cfs, this would give a
loading of 91.8 lbs /day of natural fluoride. The ambient water quality standard
is 1.8 mg /1 which represents a total loading of 826.2 lbs /day of fluoride which
would be allowable under a 30/2 flow. Thus, the three dischargers would collectively
be able to discharge 734.4 lbs /day of fluoride, above the ambient level, without
violating water quality standards.
We at Technical Services are not concerned with exactly how the 734.4 lbs /day are
allocated among the dischargers so long as water quality limits are not violated.
(Please see addendum). For example, if almost all the capacity would be given
to Feldspar Corp., the actual poundage may have to be lowered due to the lower
30/2 flow above Spruce Pine. Also, if Sobin continues discharging to Little Bear
Creek, rather than discharging directly to the North Toe, then their allocation
would be severely limited by the 30/2 of Little Bear Creek. With these concerns
In mind, we feel that officials from the field office, in meeting with industry
representatives, can best determine the most equitable distribution of the 734.4
lbs /day fluoride among the three companies.
Please inform us as to the exact allocations, once, they have been determined.
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Addendum - Schematic
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maximum Poundage Fluoride (above ambient levels) that may be given
separately at each discharge point.
Feldspar Corp 651.6 lbs
Lawson 716.3 lbs
Sob iri X34.4
(assuming Sobin discharges to N. Toe, however, if
they discharge to Little Bear-Creek they will be
limited to 3.4 lbs above ambient level)
In no case may the sum of the three allucations exceed 734.4 lbs of fluoride
above ambient level.