Discussion of the geologic non-suitability of the U.S. Department of Energy's SE-5 area for disposal of high-level radioactive waste : a supplement to the Geology of the Sandymush and Canton quadrangles, North Carolina

              c. SI-DISCUSSION
OF THE GEOLOGIC
NON-SUITABILITY OF THE U.S. DEPARTMENT
OF ENERGY'S SE-5 AREA FOR DISPOSAL OF
HIGH-LEVEL RADIOACTIVE WASTE:
A SUPPLEMENT TO THE GEOLOGY OF THE
SANDYMUSH AND CANTON QUADRANGLES,
NORTH CAROLINA
N.C. DOCUMENTS
CLEARINGHOUSE
MAR 13 1989
by N.C. STATE LIBRARY
RALEIGH
Carl E. Merschat and Leonard S. Wiener
SUPPLEMENT TO BULLETIN 90
NORTH CAROLINA GEOLOGICAL SURVEY
DIVISION OF LAND RESOURCES
DEPARTMENT OF NATURAL RESOURCES
AND COMMUNITY DEVELOPMENT
RALEIGH
1988
GEOLOGICAL SURVEY SECTION
The Geological Survey Section shall by law "...make such examination, survey, and mapping
of the geology, mineralogy, and topography of the state, including their industrial and economic
utilization as it may consider necessary."
In carrying out its duties under this law, the Section promotes the wise conservation and use
of mineral resources by industry, commerce, agriculture, and governmental agencies for the general
welfare of the citizens of North Carolina.
The Section conducts a number of basic and applied research projects in environmental
geology, mineral resource exploration, mineral statistics, and systematic geologic mapping. Serv-ices
constitute a major portion of the Section's activities and include identifying rock and mineral
samples submitted by the citizens of the State and providing consulting services and specially
prepared reports to agencies that require geological information.
The Geological Survey Section publishes results of research in a series of Bulletins,
Economic Papers, Information Circulars, Educational Series, Geologic Maps, and Special Publica-tions.
For a complete list of publications or more information about the Section please write:
Geological Survey Section, P.O. Box 27687, Raleigh, North Carolina 276 1 1 . The telephone number
is: (919) 733-2423.
Jeffrey C. Reid
Chief Geologist
DISCUSSION OF THE GEOLOGIC
NON-SUITABILITY OF THE U.S. DEPARTMENT
OF ENERGY'S SE-5 AREA FOR DISPOSAL OF
HIGH-LEVEL RADIOACTIVE WASTE:
A SUPPLEMENT TO THE GEOLOGY OF THE
SANDYMUSH AND CANTON QUADRANGLES,
NORTH CAROLINA
by
Carl E. Merschat and Leonard S. Wiener
SUPPLEMENT TO BULLETIN 90
NORTH CAROLINA GEOLOGICAL SURVEY
DIVISION OF LAND RESOURCES
DEPARTMENT OF NATURAL RESOURCES AND COMMUNITY DEVELOPMENT
RALEIGH
1988
Digitized by the Internet Archive
in 2013
http://archive.org/details/discussionofgeol1988mers
CONTENTS
Page
Introduction 1
Design Criteria 2
Sources of Geologic Data 4
Comparison of Rock Types with
Crystalline Rock Definition 4
Intrusive Igneous Rocks 4
Metamorphic Rocks 6
Page
Other Negative Factors 7
Foliation 8
Joints 8
Mylonitic Rocks 8
Evidence for Deep Circulation
of Groundwater 8
Mountainous Terrain 9
Tungsten 9
Conclusion 9
References Cited 10
ILLUSTRATIONS
Page
Figure 1. Location of the Department of Energy's proposed crystalline
rock sites
2. Location map of the SE-5 area in western North Carolina
3. Outline map of the SE-5 area showing distribution of the
four major rock groups
2
3
TABLES
Pace
Table 1. Description of lithologic groups in the SE-5 area
2. Comparison of the SE-5 area's metamorphic rocks with the
acceptability requirements of metamorphic grade, texture,
and lithologic composition
DISCUSSION OF THE GEOLOGIC NON-SUITABILITY OF THE U.S. DEPART-MENT
OF ENERGY'S SE-5 AREA FOR DISPOSAL
OF HIGH-LEVEL RADIOACTIVE WASTE
By Carl E. Merschat and Leonard S. Wiener
INTRODUCTION
Safe disposal of waste radioactive materials
is a significant problem of our age. Aside from
social questions, which are certainly complex and
of major concern, the technical challenge is to
isolate hazardous nuclear waste from humanity for
long into the future, perhaps even a millennium or
more. Deep burial of waste is considered to be one
feasible solution to the technical problem. Indeed,
the Nation's Nuclear Waste Policy Act of 1982
authorized and mandated the U.S. Department of
Energy to identify places in the country that have
potential for the safe burial of high-level radioac-tive
waste. l One of the requirements of the Act was
for the Department of Energy to investigate poten-tial
burial sites in the eastern United States that fit
the category of "crystalline rock".
In January 1986, the Department of Energy
announced selection of twelve areas in crystalline
rock as "proposed potentially acceptable sites" for
disposal of high-level nuclear waste (figure 1).
One of these areas is in western North Carolina and
was designated "Candidate Area SE-5" (figure 2)
(U.S. Department of Energy, 1986, p. 3-577).2
Subsequently, with the strong support and encour-agement
of local residents and groups, the State's
Geological Survey began a detailed, field-based
mapping project of the area in March 1986. In
June, the Department of Energy announced an
indefinite postponement of its crystalline rock
program. However, the State's geologic investiga-tion
continued, although for convenience the
boundaries of the detailed study area were adjusted
to coincide with the limits of the Sandymush and
Canton 7.5-minute Quadrangles. These two ad-joining
quadrangle maps cover 122 square miles
and include the central and major part of the irregu-larly
bounded Department of Energy site. After the
June postponement, both Congress and the Depart-ment
of Energy reconsidered the need and practi-cality
of an eastern United States repository. Fi-nally,
in December 1987, federal legislation effec-tively
abandoning this aspect of the Nation's nu-clear
waste program was approved. By this time,
the North Carolina Geological Survey's field and
laboratory work was completed. The final scien-tific
report, including detailed geologic maps of the
two quadrangles, was published in 1988 (Merschat
and Wiener, 1988).
The field-based investigation provides ba-sic,
factual data showing that local geologic condi-tions
do not meet the criteria for acceptability as a
high-level radioactive waste repository. In the
following pages, geologic requirements for a safe
repository are compared on a point-by-point basis
with actual properties of the site as now docu-mented
by the detailed field investigation (Mer-schat
and Wiener, 1988).
The Department of Energy's area SE-5,
located in Buncombe, Haywood, and Madison
1 High-level radioactive waste is produced by nu-clear
reactions that take place in the fuel of commercial and
military defense reactors. It is characterized by high-level
radiation from isotopes that decay relatively rapidly. Some
high-level waste may also contain transuranic elements that
have long half-lives.
2 Through misconception of Blue Ridge stratigra-phy,
most of the area's rocks were termed "Elk River Com-plex"
by the Department of Energy. As this terminology is
neither formally established, nor even appropriate for much
of the strata in the region, it is not used in this report.
1
Counties, extended over 105 square miles and
covered parts of six, 7.5-minute quadrangles (fig-ure
2). The centrally located Sandymush and
Canton Quadrangles include nearly three-fourths
of the area. About 1 1 percent lies east of these
quadrangles on the Leicester and Enka Quadrangles,
and about 16 percent is to the west on the Fines
Creek and Clyde Quadrangles.
DESIGN CRITERIA
"Crystalline rocks" are defined by CRP (Crys-talline
Repository Project) as intrusive igneous
and high-grade metamorphic rocks, rich in sili-cate
minerals, with a grain size sufficiently
coarse that individual minerals can be distin-guished
with the unaided eye.
"Metamorphic rocks are includetl if they can be
characterizxd as:
(1) having been metamorphosed to upper
amphibolite facies grade (e.g., sillimanitc plus
potassium feldspar);
Crucial to safe interment ofradioactive waste
is the integrity and stability of the enclosing rock.
In proceeding with its assignment, the Department
of Energy developed a definition or set of criteria
to describe an acceptable crystalline rock. The
final definition is technically specific and detailed,
and is reasonably conservative for the mandated
purpose. As stated in the Final Southeastern Re-gional
Geologic Characterization Report (U.S.
Department of Energy, 1985, p. 1-1):
(2) exhibiting chiefly granoblastic texture
(nonschistose); and
(3) forming a cartographic unit consisting of
mixed lithologies, having less than 50 percent
marble, calc-silicatc, and pelitic schist or schist
with amphibolite."
To allow for the anticipated volume of waste
material, the Department of Energy's proposed
design required the underground excavation to
isf\
Explanation
• Proposed Potentially
Acceptable Sites (12)
O Candidate Areas (
Figure 1. Location of the Department of Energy's proposed crystalline rock sites (U.S. Department of Energy, 1986).
E xplanation
Preliminary candidal*
Lake and/or retenroirt
Streams and/or riveri
35° 3C-
83° 00
35* 30
82° 45'
Figure 2. Location map of the SE-5 area in western North Carolina (U.S. Department of Energy, 1986). Seven- and one-half-
minute quadrangles covering the area are also shown and identified by the following symbols: A - Fines
Creek; B - Sandymush; C - Leicester; D - Clyde; E - Canton; F - Enka.
encompass 2,200 acres. The excavation was to be
located within a larger area of no more than 39
square miles which would accommodate surface
facilities as well as provide a buffer and control
area. In addition, the underground excavation was
to be at least 1,150 feet below ground surface to
insure an adequate overburden shield. To keep
earth pressures from being excessive, the excava-tion
was to be no more than 2,620 feet deep (U.S.
Department of Energy, 1986, p. 1-13 through 1-
18).
The definition of crystalline rock, the area
requirements, and the depth limitations provide an
objective set of criteria to use in judging the geo-logic
suitability or non-suitability of a specific rock
mass for consideration as a repository site.
SOURCES OF GEOLOGIC DATA
Evaluation of the bedrock suitability was
fundamental to the site selection procedure. The
screening process used by the Department of En-ergy
to pick out potentially acceptable crystalline
rock sites involved an exhaustive literature review
of published or otherwise available geologic data.
For some areas, detailed geologic work existed, but
in the case of the SE-5 area, no comprehensive
geologic study had ever been made. Two geologic
maps covered the SE-5 area and were used by the
Department of Energy. However, they are both
non-detailed, regional reconnaissance works (Keith,
1904 [scale 1:125,000]; Hadley and Nelson, 1971
[scale 1:250,000]). These maps are useful in de-picting
regional relations, but are much too gener-alized
for critical site-specific evaluation. Now,
however, detailed field data presented in the com-panion
to this report (Merschat and Wiener, 1988)
permit a much more rigorous and thorough geo-logic
review. The following paragraphs compare
geologic requirements as defined by the Depart-ment
of Energy with the actual properties of the site
as now documented by the field-based investiga-tion.
COMPARISON OF ROCK TYPES WITH
CRYSTALLINE ROCK DEFINITION
Field and laboratory work shows that there
are numerous types and varieties ofrocks in the SE-
5 region (Merschat and Wiener, 1988). To facili-tate
comparison of the rocks with the Department
of Energy's requirements, they are organized here
into four major lithologic groups. The four groups
are termed:
I. Granitic Gneiss Group
II. Pelitic Metasedimentary Group
III. Amphibolite-Bearing Layered Biotite
Gneiss and Schist Group
IV. Aluminous Metasedimentary and
Metavolcanic Group
Figure 3 is an outline map showing the
distribution of the four groups in the SE-5 area.
Table 1 identifies the individual formations that
compose each group, lists the component rock
types, and identifies each group's outcrop area.
INTRUSIVE IGNEOUS ROCKS
Two classes of rocks are mentioned in the
Department of Energy's definition—intrusive
igneous rocks and high-grade metamorphic rocks.
The entire SE-5 area underwent regional metamor-phism
at least once. The rock units that evolved
from intrusive bodies still retain some relics of
their original magmatic nature, but even these relic
igneous rocks exhibit a gneissic fabric. Based on
mineral composition and other features, only the
Spring Creek Granitoid Gneiss of Group I might
possibly meet the "intrusive igneous" part of the
definition. A narrow band in the northwest corner
of the SE-5 area, approximately 3 miles long and
averaging about 1 mile wide, is largely underlain by
biotite granitic gneiss of the Spring Creek (Mer-schat
and Wiener, 1988, plate 1). However, the
Spring Creek is by no means a uniform, monolithic
unit. It includes interlayers of undesirable amphi-bolite
and calc-silicate granofels, as well as abun-dant
mylonitic zones. Furthermore, the limited
Figure 3. Outline map of the SE-5 area showing distribution of the four major rock groups (see table 1 for description of
groups). Kyanite-sillimanitc isograd shown by long-dashed line. Geologic data sources: Sandymush and Canton
Quadrangles - Merschat and Wiener, 1988; Leicester Quadrangle - Wiener, unpublished mapping; Fines Creek,
Clyde, and Enka Quadrangles - reconnaissance mapping, Merschat and Wiener.
extent of the Spring Creek is not sufficient to allow
for siting of the needed 2,200-acre underground
facility.
The other formation in Group I is the Doggett
Gap Protomylonitic Granitoid Gneiss. It also origi-nated
as an intrusive igneous rock; however, the
unit has been so severely deformed and myloni-tized
that it now has the attributes of a coarsely
foliated gneiss. Further, within the SE-5 area, the
4-mile-long outcrop belt of the Doggett Gap, in-cluding
its two mapped amphibolite bodies, is
nowhere more than 1.2 miles wide. Thus, it too,
does not meet the Department of Energy's suitabil-ity
requirements.
METAMORPHIC ROCKS
The remainder of the SE-5 site is underlain
by rocks that come under the part of the crystalline
rock definition dealing with metamorphic rocks.
Included here are the rocks of Groups II, III, and
IV. The Department of Energy's definition states
three criteria forjudging the acceptability of meta-morphic
rocks: 1) metamorphic grade; 2) texture;
and 3) lithologic character. In the following dis-cussion,
these properties of the area's metamor-phic
rocks are listed for comparison with the
Department of Energy's criteria (also see table 2).
Group II. Pelitic Metasedimentary Group (Snow-bird
Group):
(1) is not metamorphosed to the upper amphi-bolite
facies;
(2) exhibits lepidoblastic (schistose) textures,
not granoblastic texture;
(3) is overwhelmingly dominated by pelitic
schist.
Thus, when compared with the three criteria
for metamorphic rocks, these pelitic rocks obvi-ously
do not qualify as acceptable "crystalline
rock".
Table 1. Description of lithologic groups in the SE-5 area
I. Granitic Gneiss Group. Includes the Spring Creek
Granitoid Gneiss and the Doggett Gap Protomylonitic Gran-itoid
Gneiss.
The prevalent rock types are megacrystic and protomy-lonitic
biotitc granitic gneiss, myloniuft granitic gneiss, and
biotite granitic gneiss. Pervasive mylonitization is especially
well developed throughout the Doggett Gap Protomylonitic
Granitoid Gneiss.
This group occurs in the northwestern part of the SE-5
area, mainly in Madison County.
II. Pelitic Metasedimentary Group. Includes the Snow-bird
Group.
Kyanite-garnet-mica schist dominates, with lesser
metagraywacke, metaconglomerate, and calc-silicate rock.
These rocks occur in the western part of the area, mainly
along the Buncombe-Madison County line in the vicinity of
Sandymush Bald and Little Sandymush Bald.
III. Amphibolite-Bearing Layered Biotite Gneiss and
Schist Group. Includes the Sandymush Felsic Gneiss and
the Earlies Gap Biotite Gneiss.
This is a very heterogeneous group of rocks. It includes
layered biotite gneiss, biotite schist, felsic gneiss, abundant
interlayered amphibolite, and minor calc-silicate rock.
These rocks underlie the central part of the area. They
extend from the Little Pine Creek section of Madison County
through the Sandymush community and North Turkey Creek
section of Buncombe County, and into the Crabtrec Creek
and Beaverdam sections of Haywood County.
IV. Aluminous Metasedimentary and Metavolcanic
Group. Includes the Ashe Metamorphic Suite.
These rocks are mostly muscovite-biotitc gneiss and
schist, kyanite-garnet-muscovite-biotitc gneiss and schist,
biotitc-feldspar-quartz gneiss, and sillimanite-garnet gneiss
and schist. Minor amounts of several other rock types are also
present.
This group occurs in the south and southeastern part of
the SE-5 area in both Haywood and Buncombe County.
Group III. Amphibolite-Bearing Layered Biotite
Gneiss and Schist Group (Sandymush Felsic Gneiss
and Earlies Gap Biotite Gneiss):
Table 2. Comparison of the SE-5 area's metamorphic rocks with the acceptability requirements of me(amorphic grade,
texture, and lithologic composition
METAMORPHIC: GRADE TEXTURE COMPOSITION
ROCK GROUP
Arc the rocks of sufficiently Do rocks exhibit granoblastic Are rock types acceptable?
high metamorphic grade? texture? (Less than 50 percent marble,
(Above sillimanite isograd?) calc-silicate, and pelitic
Group II
schist or amphibolite.,)
No - all are below sillimanite No - lepidoblastic texture No - pelitic schist dominates.
isograd. dominates.
Group III Almost entirely below Mostly gneissic lepidoblastic Schist and amphibolite compose
sillimanite isograd. to nematoblastic textures. 10-20 percent of group.
Group IV All, except three small areas, Lepidoblastic and nematoblastic Fifty percent of group is schist.
are below sillimanite isograd. textures arc widespread and
locally dominant.
(1) mostly is not metamorphosed to the upper
amphibolite facies;
(2) chiefly exhibits gneissic lepidoblastic to
nematoblastic textures rather than granoblastic
texture;
(2) exhibits diverse textures, but lepidoblastic
(schistose) and nematoblastic textures are wide-spread
and locally dominant;
(3) contains about 50 percent aluminous pe-litic
schist.
(3) includes abundant, widespread schist and
amphibolite. Schist and amphibolite are esti-mated
to constitute 10 to 20 percent of the group.
Thus, this group does not qualify as an
acceptable crystalline rock, mainly on the basis of
criteria 1 and 2. Also, the presence of so much
schist and amphibolite, though less than the dis-qualifying
limit of 50 percent, is a significant factor
that reduces the group's acceptability.
Group IV. Aluminous Metasedimentary and
Metavolcanic Group (Ashe Metamorphic Suite):
(1) has been metamorphosed, in part to lower
amphibolite facies, and in part to upper amphi-bolite
facies as indicated by the presence of silli-manite.
Upper amphibolite facies rocks of this
group are present in only three small separated
areas. One area comprises about 1.25 square
miles, and another about 1 square mile. The third
area covers about 1.5 square miles on the Canton
Quadrangle and about 3.5 square miles on the
adjoining Enka Quadrangle (figure 3).
Most of the area underlain by Group IV is
metamorphosed below upper amphibolite facies as
kyanite, not sillimanite, is present (note location of
sillimanite-kyanite isograd in figure 3). The rocks
in only three, small, isolated areas attained upper
amphibolite facies. However, in these areas too
much schistose and non-granoblastic material is
present to meet the stated criteria. Furthermore,
two of the areas are not nearly extensive enough to
meet the design requirement of 2,200 acres (about
3.4 square miles). The third, and largest area, is
along the southeast border of the SE-5 site where
there is not enough space for the requisite buffer
and control zone.
OTHER NEGATIVE FACTORS
In addition to the failure of strata in the SE-
5 area to adequately meet the Department of
Energy's crystalline rock criteria, several other
geological factors indicate that the area is not
suitable for use as a high-level nuclear waste re-pository.
These include pervasive foliation sur-
faces, abundantjoints and fractures, mylonitic rocks,
the likelihood of deep circulation of groundwater,
and the mountainous terrain of the area. Also,
tungsten, a strategic and critical commodity, was
discovered in the area. This new find should be
evaluated prior to committing the area to a single-use
purpose.
Foliation
Subsequent to their original deposition or
intrusion, rocks in this region underwent several
episodes of deformation and metamorphism. Each
event left its own imprint on the rocks, usually in
the form of various folds and faults as well as
abundant and widespread foliation planes. Each of
these ubiquitous foliation planes defines a me-chanical
weakness in the rock mass and poses a
potential, troublesome slip surface during design,
construction, and maintenance of any bedrock
excavation.
The mica-rich rocks, or schists, have the
best developed and most closely spaced foliation
planes. Foliation in the gneissic units is more
irregular and more coarsely spaced. But even in
these rocks, the foliation surfaces are planes of
mechanical weakness.
Joints
Joints, as well as non-systematic fractures,
exist at almost every outcrop in the SE-5 area and
certainly extend some distance into the earth.
Shallow core drilling for foundation and road de-sign
in nearby places frequently reveals weather-stained
fractures at depths of 200 feet or more.
Several 200- to 300-foot-deep road cuts in western
No'th Carolina also show that joints occur well
below the original ground surface. Two deep cuts
near the SE-5 area where joints are present are the
extensive excavations east of Marshall along U.S.
25 and U.S. 70 in Madison County, and the Inter-state-
240 cut through Beaucatcher Mountain in
Asheville. Some joints must also be present much
further below the surface based on the known deep
circulation of groundwater in the general region
(see following discussion on groundwater circula-tion).
Joints are undesirable for two reasons. First,
they are discontinuity surfaces with zero tensile
strength and may thereby contribute to failure of an
excavation. Second, in hard, coherent, otherwise
impermeable rocks, joints provide openings and
conduits for groundwater accumulation and move-ment.
Even if persistent joints are not already open
and permeable to underground water, it seems
inevitable that the creation and maintenance of
extensive subsurface openings, such as necessary
for a deep subsurface repository, would lead to the
formation or propagation of joints (Konya and
Walter, 1985).
Mylonitic Rocks
Mylonites and protomylonites are locally
present throughout the area. These rocks are in-dicative
of ancient faults or deformation zones.
They are characterized by their anisotropic, anas-tomosing,
statistically planar fabric and the flat-tened,
elongated and recrystallized nature of the
constituent mineral grains. This planar fabric is a
significant weakness that may also lead to unstable
conditions in excavations — a significant concern
for an underground repository.
Evidence For Deep Circulation
of Groundwater
Over long periods oftime circulating ground-water
has the very undesirable potential to leach
waste radioactive material and carry it well beyond
the confines of a repository's controlled area. This
contaminated water may thus diffuse into the re-gion's
groundwater supply or ultimately enter local
streams and rivers. Thus, it is essential that a re-pository
be impervious to through-circulating
groundwater.
8
Two lines of evidence indicate that ground-water
circulates to considerable depth in the re-gion.
Some water wells in the Blue Ridge and
Piedmont are known to produce water from depths
of 1,200 feet or more (Daniel, 1987). This is direct
evidence for deep circulation, undoubtedly through
persistent joint openings (Daniel, 1987).
A slightly less direct line of evidence is
based on the presence of warm-water springs in the
town ofHot Springs, North Carolina (Trapp, 1970).
The town is in northwestern Madison County,
within a dozen miles of area SE-5. The tempera-ture
of the flowing spring water is about 100"F
(Oriel, 1950). The comprehensive geologic report
by Oriel (1950) and a more recent analysis by
Hobba and others (1979), support the concept of
geothermal heating of deep-circulating meteoric
water in the Hot Springs area. Hobba and others
(1979, p. 20) estimated the water circulates to a
depth of at least 4,000 feet. Based on a presumed
geothermal gradient of about 70 feet per 1°F, plus
a substantial allowance for cooling as the hot water
rises toward the surface, Oriel (1950, p. 58) con-cluded
that the meteoric water might circulate as
deep as 5,500 to 6,000 feet. North Carolina Geo-logical
Survey well-file information for a 3,200-
foot drill hole near Spruce Pine, North Carolina,
indicates geothermal heating to be about 1°F per
1 14 feet. Use of this value leads to an estimated
minimum circulation depth of 5,700 feet in the Hot
Springs area. To allow for cooling as the water
returns back to the surface, an even greater circula-tion
depth to reach warmer rocks is necessary.
Clearly then, groundwater is able to circu-late
to considerable depth in places near the SE-5
area. This indicates that the rock mass in the area
is not as impervious to groundwater as might be
first assumed. This poses a very serious question
about the hydrologic suitability of any large under-ground
site in the western Blue Ridge area.
Mountainous Terrain
The steep, mountainous terrain of area SE-
5 imposes important constraints on the siting of an
underground nuclear waste repository. The peak
elevation within the SE-5 area is 5,152 feet on
Sandymush Bald; the lowest is about 2,100 feet
along Sandymush Creek. Within the area, eleva-tion
differences are as great as 2,800 feet in less
than 2.5 miles of surface distance. These great
elevation differences make it virtually impossible
to locate a 2,200-acre underground site so that it
would be entirely within the maximum and mini-mum
depth requirements of 2,620 and 1,150 feet,
respectively. The terrain limitation is clearly an
adverse condition that permits little flexibility in
selecting the configuration or location of a large
underground facility in the area.
Tungsten
Stream sediment samples collected from the
Sandymush and Canton Quadrangles area revealed
the widespread presence throughout the central
part of the area of the mineral scheelite. Scheelite
is not only an unusual mineral, but also a major ore
mineral of the metal tungsten. Tungsten is a
strategic and critical commodity that is in short
supply in domestic deposits, thereby forcing the
United States to import much of its annual con-sumption.
From 1983 through 1987, the United
States' net import reliance compared to apparent
consumption was about 68 percent (U.S. Bureau of
Mines, 1988, p. 172-173). This new discovery in
the SE-5 area warrants a follow-up investigation to
determine the extent of the tungsten resource.
Certainly, it is not in the country's best interest to
preempt the area for a single-purpose use, thereby
effectively removing a potential critical mineral
resource from the Nation's limited inventorv.
CONCLUSION
Scientific information collected during the
detailed geologic investigation of the Sandymush
and Canton Quadrangles (Merschat and Wiener.
1988) is used to evaluate the suitability of the U.S.
Department of Energy's SE-5 area for an under-
ground, "crystalline rock", high-level radioactive
waste repository. The area's rocks are mostly
layered metamorphic types that do not meet the
well-defined criteria for acceptable crystalline rock.
Other factors also indicate the area is not suitable.
They are: the presence of ubiquitous foliation sur-faces
and joints in all of the rocks; mylonite and
protomylonite zones; the possibility of deeply cir-culating
groundwater; a geographic setting in
mountainous terrain; and the possibility of a new
tungsten resource, Thus, failure of the area's rocks
to meet acceptability criteria, along with numerous
other geologically negative factors, makes the area
unsuitable for consideration as an underground,
high-level nuclear waste repository.
Merschat, C.E., and Wiener, L.S., 1988, Geology
of the Sandymush and Canton Quadrangles,
North Carolina: North Carolina Geological
Survey Bulletin 90, 66 p.
Oriel, S.S., 1950, Geology and mineral resources
of the Hot Springs window, Madison County,
North Carolina: North Carolina Division of
Mineral Resources Bulletin 60, 70 p.
Trapp, Henry, Jr., 1970, Geology and ground-water
resources of the Asheville area, North
Carolina: North Carolina Department ofWater
and Air Resources, Division of Ground Wa-ter,
Ground Water Bulletin 16, 127 p.
REFERENCES CITED
U.S. Bureau of Mines, 1988, Tungsten, in Mineral
commodity summaries 1988: p. 172-173.
Daniel, C.C., III, 1987, Statistical analysis relating
well yield to construction practices and siting
of wells in the Piedmont and Blue Ridge
Provinces of North Carolina: U.S. Geological
Survey Water Resources Investigations Re-port
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