Scrap mica resources of North Carolina

              c
C.2
NORTH CAROLINA
DEPARTMENT OF CONSERVATION AND DEVELOPMENT
GEORGE R. ROSS, DIRECTOR
DIVISION OF MINERAL RESOURCES
JASPER L. STUCKEY, STATE GEOLOGIST
Bulletin Number 66
THE SCRAP MICA RESOURCES
of NORTH CAROLINA
BY SAM D. BROADHURST AND LEWIS J. HASH
PREPARED AND PUBLISHED IN COOPERATION WITH
THE TENNESSEE VALLEY AUTHORITY
RALEIGH
1953
North Carolina
Department of Conservation and Development
George R. Ross, Director
Division of Mineral Resources
Jasper L. Stuckey, State Geologist
Bulletin Number 66
THE SCRAP MICA RESOURCES
of NORTH CAROLINA
By
Sam D. Broadhurst and Lewis J. Hash
Prepared and Published in Cooperation with
The Tennessee Valley Authority
Raleigh
1953
MEMBERS OF THE BOARD OF CONSERVATION
AND DEVELOPMENT
Governor Wm. B. Umstead, Honorary Chairman... Raleigh
Miles J. Smith, Chairman...:.....!... Salisbury
Walter J. Damtoft, Vice Chairman Canton
Charles S. Allen Durham
W. B. Austin Jefferson
Aubrey L. Cavenaugh Warsaw
Ferd Davis Zebulon
Staley A. Cook _ Burlington
C. Sylvester Green Chapel Hill
Charles H. Jenkins Ahoskie
Fred P. Latham Belhaven
Mrs. Roland McClamroch___ —Chapel Hill
Hugh M. Morton Wilmington
J. C. Murdock Troutmans
S. W. Enloe, Jr. Spruce Pine
Buxton White Elizabeth City
LETTER OF TRANSMITTAL
Raleigh, North Carolina
March 25, 1953
To His Excellency, Honorable Wm. B. Umstead
Governor of North Carolina
Sir:
I have the honor to submit herewith manuscript for publica-tion
as Bulletin 66, "The Scrap Mica Resources of North Caro-lina."
This Bulletin is another made possible by the cooperation
of the Tennessee Valley Authority.
A number of short reports on mica have been included in
various Economic Papers during the past fifty years but Bulletin
43 issued in 1944 and Bulletin 49 issued in 1946 were the first
major reports on mica published by the State of North Carolina.
These reports dealt almost entirely with sheet mica.
The report presented herewith covers the scrap mica re-sources
of the State. Scrap mica is used in the production of both
wet and dry ground mica. The ground mica industry of the State
began in a small way about 1870. During the past twenty years
it has grown rapidly. This report should be of considerable value
to the producers of scrap and ground mica in North Carolina.
Respectfully submitted,
George R. Ross,
Director
in
TABLE OF CONTENTS
, Page
Abstract 1
Introduction 1
Purpose and scope . 2
Field work and acknowledgments 3
Previous work 3
Economic aspects 3
Evaluation of scrap mica deposits 3
Mining and concentrating 5
Mining 5
Concentration 5
Washer plant 5
Humphrey Spirals 6
Processing and specifications 7
Wet ground mica 7
Dry ground mica 8
Micro mica 8
Properties and uses . 9
Production and value 10
Scrap mica resources of North Carolina 11
General geology 1
Metamorphic rocks 11
Igneous rocks 1
1
Pegmatites 12
Alaskite 12
Granite 12
Weathering 12
The scrap mica industry of North Carolina 13
History and production 13
Occurrence of scrap mica in North Carolina 14
Reserves 15
Future outlook 1
5
Principal producing areas 16
Spruce Pine district 16
Geologic setting 1?
Description of deposits 18
Autry—Robinson deposit 18
Bailey scrip mica deposit 18
Blue Rock deposit 20
Bowditch deposit 22
Briggs-Woody deposit 22
Brushy Creek deposit 24
Burleson deposit 24
Burnsville Mica Company deposit 25
Butler Gap deposit 26
Cox Knob deposit 26
IV
TABLE OF CONTENTS—CONTINUED
Page
Crabtree Creek deposits _. 26
DeWeld deposits 27
Ed Edge deposits . 29
Ed Young scrap mica deposits 30
Fawn Knob deposit 32
Freeman deposit 33
Gusher Knob deposit 33
H. W. Young deposits 35
Long Branch deposit 36
Mayberry deposit 37
Micaville deposit 39
Newdale scrap mica deposit 39
Nichols-Grindstaff deposit 41
Phipps Branch deposits 42
Robinson-Brewer deposit 43
Robinson's Dairy deposit 44
S. M. Edge deposits __ 44
Sparks-Robinson scrap mica deposit 46
Spruce Pine deposits 48
English Creek area 48
Graveyard Creek deposit 49
Silver Run Creek area 50
Grassy Creek deposits .. 50
Other deposits 51
Sullins Creek deposit 51
Threemile Creek deposit .. 51
Kranklin-Sylva district 52
Geologic setting . 53
Description of deposits 54
Iotla Bridge 55
Grassy Ridge or Big Flint 55
Mill Knob 57
Shepherd Knob _.. 57
Lyle Knob ... 60
Chalk Hill 60
Other deposits 60
Shelby district . 61
Geologic setting 62
Description of deposits . 63
J. Bun Patterson 63
Charlie Moss 63
Jack Baxter 64
Small pegmatite deposits 64
Other areas 65
Bibliography 66
TABLE OF CONTENTS—CONTINUED
FIGURES
Page
Figure 1. Principal scrap mica districts in North Carolina _. 2
2. Flowsheet of washer type concentrating plant ... 6
3. Flowsheet of Humphrey Spirals concentrating plant... 7
4. Chart showing scrap and ground mica sold in
United States 1923-1948 .. 10
5. Location Map—Spruce Pine district 16
6. Location Map—Franklin-Sylva district 52
7. May of Iotla-Bradley Mine, Macon County 54
8. Map and sections of the Lyle Knob Mine, Macon County... 59
9. Location Map—Shelby district 61
PLATES
Plate 1. Bailey scrap mica deposit 19
2. Blue Rock scrap mica deposit 21
3. Briggs-Woody scrap mica deposit 23
4. DeWeld scrap mica deposit 28
5. Ed Young scrap mica deposit 31
6. Freeman scrap mica deposit 34
7. Mayberry scrap mica deposit 38
8. Newdale scrap mica deposit 40
9. S. M. Edge scrap mica deposit 45
10. Sparks-Robinson scrap mica deposit 47
11. Map and sections of the Big Flint Mine, Macon County... 56
12. Map and sections of the Shepherd Knob Mine, Macon County 58
TABLES
I. Properties of wet ground mica 9
II. Average annual production of scrap mica in the United States
By States from 1945-1949 10
III. Ground mica sold by producers in the United States, 1945-1949,
By methods of grinding 11
IV. Scrap mica production of North Carolina 1901-1950. 13
V. Comparison of volume of scrap mica sold or used by producers
in North Carolina and the United States 14
VI
THE SCRAP MICA RESOURCES OF NORTH CAROLINA
By *Sam D. Broadhurst and (Lewis J. Hash
ABSTRACT
North Carolina produces over 75 percent of all scrap mica consumed in the United States. Most of it
comes from the Spruce Pine, Franklin-Sylva, and Shelby districts. Within recent years the rapidly expand-ing
industrial demand for scrap has resulted in an intensified mining and prospecting program in North
Carolina. During the period from 1940 to 1950 annual production quadrupled and since 1930 it has increas-ed
eight fold.
Although this increased rate of production is making rapid inroads on sources of supply, reserves ap-pear
adequate to meet the demand for some years. Indicated reserves in the three major districts exceed
26,000,000 tons of ore containing an average of from 12 percent to 18 percent mica.
In North Carolina scrap mica is obtained as waste from the sheet mica industry, as a by-product of the
feldspar and kaolin industries, and is mined directly from primary scrap mica deposits. Reserves are
confined largely to the latter sources, especially the primary scrap mica deposits. These deposits occur as
highly weathered portions of alaskites and pegmatites and along the border phases of certain granites. In
general the highest quality mica occurs in pegmatites, but, because of the size and character of the average
pegmatite, the available scrap is limited. The alaskites, containing a somewhat lower grade of mica but
having large volumes, are the mainstay of the scrap mica industry.
Conventional washer type scrap mica concentrating plants, used for many years in North Carolina, are
able only to recover economically mica larger than Vd inch in diameter. The finer size mica, representing
up to 50 percent of the mica in some ores, is discarded as tailings along with quartz, kaolin, and semi-kaolin-ized
feldspar. Such plants can usually operate successfully on ores containing from 6 to 8 percent plus !/8
inch mica. The large loss of fine mica will be felt by the industry in the near future as the better deposits
are worked out. A process utilizing the Humphrey Spirals, already in use in several plants, appears to be
particularly effective in recovering much of the mica normally lost in a washer plant. Scrap can be con-centrated
by flotation, but its economic recovery by this process is dependent largely upon marketable by-products.
It is now being recovered by flotation but only as a by-product of the feldspar industry.
North Carolina not only produces large quantities of scrap mica but also processes it. There are 16
concentrating plants, 6 wet grinding plants, and 5 dry grinding plants in the State. Research by the North
Carolina State College Minerals Research Laboratory in Asheville has resulted in important advances in both
concentrating and grinding practices.
INTRODUCTION
Scrap mica is a term loosely applied to all mica, exclusive of mica schist, which is, because of size, color.
or quality, below specifications for sheet mica, and which can be satisfactorily processed for industrial use as
ground mica. It is limited to the muscovite and phlogopite varieties unless specifically designated otherwise.
Various breakdowns of the term are in general usage, most of them designating grade according to source
or method of processing. Some of these are mine scrap, bench scrap, trimming waste, jig mica, reclaimed
mica, roofing mica, wet ground mica, dry ground mica, and clay bank mica. Flake mica refers to mica
mined directly from primary deposits and concentrated for grinding purposes. It is estimated that from 70
to 90 percent of the total mica content of most mica deposits is of scrap grade.
North Carolina is the leading producer of scrap mica in the United States, furnishing over 75 percent of
the domestic supply. Although a small amount of chlorite is mined and ground in the State, the bulk of
the scrap is of the muscovite variety. It is obtained from (1) mining, grading, trimming, and punching
sheet mica, (2) produced as a by-product of feldspar mining and processing, (3) recovered during the re-
*Assistant State Geologist. North Carolina
tFormerly Geologist, Tennessee Valley Authority
TABLE OF CONTENTS—CONTINUED
FIGURES
Page
Figure 1. Principal scrap mica districts in North Carolina 2
2. Flowsheet of washer type concentrating plant 6
3. Flowsheet of Humphrey Spirals concentrating plant 7
4. Chart showing scrap and ground mica sold in
United States 1923-1948 .. 10
5. Location Map—Spruce Pine district 16
6. Location Map—Franklin-Sylva district 52
7. May of Iotla-Bradley Mine, Macon County_ __ 54
8. Map and sections of the Lyle Knob Mine, Macon County
_
59
9. Location Map—Shelby district 61
PLATES
Plate 1. Bailey scrap mica deposit 19
2. Blue Rock scrap mica deposit 21
3. Briggs-Woody scrap mica deposit 23
4. DeWeld scrap mica deposit 28
5. Ed Young scrap mica deposit 31
6. Freeman scrap mica deposit 34
7. Mayberry scrap mica deposit 38
8. Newdale scrap mica deposit 40
9. S. M. Edge scrap mica deposit __ 45
10. Sparks-Robinson scrap mica deposit 47
11. Map and sections of the Big Flint Mine, Macon County— 56
12. Map and sections of the Shepherd Knob Mine, Macon County 58
TABLES
I. Properties of wet ground mica 9
II. Average annual production of scrap mica in the United States
By States from 1945-1949 10
III. Ground mica sold by producers in the United States, 1945-1949,
By methods of grinding 11
IV. Scrap mica production of North Carolina 1901-1950— 13
V. Comparison of volume of scrap mica sold or used by producers
in North Carolina and the United States . 14
VI
THE SCRAP MICA RESOURCES OF NORTH CAROLINA
By *Sam D. Broadhurst and (Lewis J. Hash
ABSTRACT
North Carolina produces over 75 percent of all scrap mica consumed in the United States. Most of it
comes from the Spruce Pine, Franklin-Sylva, and Shelby districts. Within recent years the rapidly expand-ing
industrial demand for scrap has resulted in an intensified mining and prospecting program in North
Carolina. During the period from 1940 to 1950 annual production quadrupled and since 1930 it has increas-ed
eight fold.
Although this increased rate of production is making rapid inroads on sources of supply, reserves ap-pear
adequate to meet the demand for some years. Indicated reserves in the three major districts exceed
26,000,000 tons of ore containing an average of from 12 percent to 18 percent mica.
In North Carolina scrap mica is obtained as waste from the sheet mica industry, as a by-product of the
feldspar and kaolin industries, and is mined directly from primary scrap mica deposits. Reserves are
confined largely to the latter sources, especially the primary scrap mica deposits. These deposits occur as
highly weathered portions of alaskites and pegmatites and along the border phases of certain granites. In
general the highest quality mica occurs in pegmatites, but, because of the size and character of the average
pegmatite, the available scrap is limited. The alaskites, containing a somewhat lower grade of mica but
having large volumes, are the mainstay of the scrap mica industry.
Conventional washer type scrap mica concentrating plants, used for many years in North Carolina, are
able only to recover economically mica larger than 1/8 inch in diameter. The finer size mica, representing
up to 50 percent of the mica in some ores, is discarded as tailings along with quartz, kaolin, and semi-kaolin-ized
feldspar. Such plants can usually operate successfully on ores containing from 6 to 8 percent plus Vs
inch mica. The large loss of fine mica will be felt by the industry in the near future as the better deposits
are worked out. A process utilizing the Humphrey Spirals, already in use in several plants, appears to be
particularly effective in recovering much of the mica normally lost in a washer plant. Scrap can be con-centrated
by flotation, but its economic recovery by this process is dependent largely upon marketable by-products.
It is now being recovered by flotation but only as a by-product of the feldspar industry.
North Carolina not only produces large quantities of scrap mica but also processes it. There are 16
concentrating plants, 6 wet grinding plants, and 5 dry grinding plants in the State. Research by the North
Carolina State College Minerals Research Laboratory in Asheville has resulted in important advances in both
concentrating and grinding practices.
INTRODUCTION
Scrap mica is a term loosely applied to all mica, exclusive of mica schist, which is, because of size, color,
or quality, below specifications for sheet mica, and which can be satisfactorily processed for industrial use as
ground mica. It is limited to the muscovite and phlogopite varieties unless specifically designated otherwise.
Various breakdowns of the term are in general usage, most of them designating grade according to source
or method of processing. Some of these are mine scrap, bench scrap, trimming waste, jig mica, reclaimed
mica, roofing mica, wet ground mica, dry ground mica, and clay bank mica. Flake mica refers to mica
mined directly from primary deposits and concentrated for grinding purposes. It is estimated that from 70
to 90 percent of the total mica content of most mica deposits is of scrap grade.
North Carolina is the leading producer of scrap mica in the United States, furnishing over 75 percent of
the domestic supply. Although a small amount of chlorite is mined and ground in the State, the bulk of
the scrap is of the muscovite variety. It is obtained from (1) mining, grading, trimming, and punching
sheet mica, (2) produced as a by-product of feldspar mining and processing, (3) recovered during the re-
*Assistant State Geologist, North Carolina
tFormerly Geologist, Tennessee Valley Authority
2 The Scrap Mica Resources of North Carolina
fining of kaolin, and (4) mined directly from primary deposits having high contents of small mica, the latter
being referred to as "scrap mica deposits."
Over 95 percent of all scrap mica produced in North Carolina comes from three principal areas located
in the western third of the State. These are known as the Spruce Pine, Franklin-Sylva, and Shelby districts.
(See Figure 1.) Although scrap mica occurs in limited quantities in other areas, the known deposits are
small and production is negligible.
10 20 10
/GRAHAM
_.'i
SWAIN
Figure 1. Principal Scrap Mica Districts in North Carolina
PURPOSE AND SCOPE
Scrap mica has been produced in North Carolina for more than 75 years, but only in comparatively re-cent
times has the industry grown significantly. During the past ten years production has quadrupled and in
the last twenty years it has increased over eight fold. Such rapid expansion has resulted in serious inroads
on the sources of supply, making a review of concentrating practices and a revaluation of potential reserves
necessary for competent future planning of the industry.
This report is an economic geological appraisal of the major scrap mica producing districts of North
Carolina. Its purpose is to present a factual account of the present industry, a description of the geologic
occurrence of primary scrap mica deposits, and an evaluation of overall reserves as related to future pro-duction.
It is not an exhaustive work since time and finances were not sufficient for such a study. How-ever,
information presented reflects representative conditions.
This work is a compilation of three unpublished reports, summarizing field investigations carried out
between 1947 and 1950 by the Division of Mineral Resources, North Carolina Department of Conservation
and Development, and the Minerals Research Section, Tennessee Valley Authority. Investigations were
prompted by industrial demands for information concerning the potentialities of primary scrap mica de-posits
as competent sources of supply to back a rapidly expanding industry. The report is designed as an
aid to the future production of scrap mica in North Carolina.
The Scrap Mica Resources of North Carolina 3
FIELD WORK AND ACKNOWLEDGMENTS
Field investigations of the scrap mica deposits were carried out in two stages. The first was an investi-gation
of the Franklin-Sylva and Shelby districts made during the summer of 1947 by Sam D. Broadhurst,
geologist with the Tennessee Valley Authority, aided by student assistants Lewis J. Hash and Robert S.
Houston of the North Carolina Department of Conservation and Development. The second stage was a sur-vey
of the Spruce Pine district during the summers of 1950 and 1951 and was headed by Lewis J. Hsah,
geologist with the Tennessee Valley Authority. Assisting Mr. Hash were Evan K. Greene, Tennessee Valley
Authority geologist, L. H. Bryant, Jr., Ben B. Hoskens, James L. Resor, Frank Dillard, R. E. Fulweiler and
Thomas Henderson, student assistants, employed by the North Carolina Department of Conservation and
Development.
All work was under the supervision of Charles E. Hunter, Tennessee Valley Authority geologist. The
project was under the general direction of Jasper L. Stuckey, State Geologist of North Carolina, and the
late H. S. Rankin, Head of the Minerals Research Section, Tennessee Valley Authority, until his death in
1949, and by his successor, Dr. Benjamin Gildersleeve. Valuable aid was given by members of the North
Carolina State College Minerals Research Laboratory in Asheville and by Thomas B. Murdock, former As-sistant
State Geologist of North Carolina. The writers wish also to acknowledge the great assistance given
by members of the scrap mica industry and property owners throughout the State.
Maps of deposits in the Spruce Pine district were prepared by the Maps and Survey Branch of the Ten-nessee
Valley Authority. Maps of the pegmatites in the Franklin-Sylva district, prepared by members of
the United States Geological Survey, were obtained from Bulletin 49 of the North Carolina Department of
Conservation and Development. Production figures were derived from United States Bureau of Mines Min-eral
Yearbooks and from individual production records.
PREVIOUS WORK
The geology and mineral resources of portions of the areas covered by this report have been investigated
previously. Of the more recent works, those of Hunter and Mattocks, Hunter, Kesler and Olsen, Olsen, and
Parker are of particular interest. Others include publications by Keith, Maurice, Watts, Hunter and White,
Hash and Hunter, Ries, Parker, Bayley, Strerrett, and Kesler. A selected bibliography is at the end of this
report.
An unpublished map of the alaskite formations of the Spruce Pine district prepared by Hunter and Mat-tocks
has been of great practical aid to the local mining industry and to the present investigation. Recently
members of the United States Geological Survey completed detailed mapping of portions of the Spruce Pine
and Shelby districts. A description of some of the pegmatites of the Piedmont region of the State is in
United States Geological Survey Professional Paper 248 A.
ECONOMIC ASPECTS
Mica sold as scrap is obtained from three principal sources. These are the sheet mica fabricating in-dustry,
the kaolin and feldspar industries, and the primary or flake mica deposits. Scrap derived from the
first two sources is clean and ready for processing, while that mined from the primary deposits must be
separated from the gangue, washed, and dried before it is acceptable. Once concentrated, scrap from all
three sources is often blended during processing. Since scrap from the first two sources is largely a by-product
from other industries and cannot be controlled directly by the mica grinders, the scrap industry is
dependent upon mica from the primary deposits for stabilization. Over three-fourths of all scrap comes
from this source. Of major importance, therefore, are the economic and geologic factors affecting this source
of supply, some of which are discussed in the following paragraphs.
EVALUATION OF SCRAP MICA DEPOSITS
Any natural occurrence of mica which may be worked profitably for its scrap content is referred to as
a scrap mica deposit. Since mica occurs in various formations it is difficult to standardize a procedure for
accurate evaluation purposes. Many geologic and economic variables, one depending upon another, must be
4 The Scrap Mica Resources of North Carolina
analyzed in the process. Among the more important factors to be considered are quantity, quality, avail-ability,
and proposed method of concentrating the mica.
The quantity of mica depends upon the average mica content and volume of the deposit. Most deposits
average from 5 to 18 percent recoverable muscovite, although some are as low as Sjpercent. Economic limits
of mica content vary with size and availability of the deposit. A large easily mineable, favorably located
deposit having a low mica content might be worked more profitably than a smaller one containing a higher
percentage of mica but in a less favorable location ad with a more difficult ore to mine. In general deposits
of the alaskite type can be worked with a lower mica content than most pegmatites because the alaskites
usually contain greater volumes of ore and are wide enough to allow large-scale production.
Actual size of the deposit is relative, the total mineable ore being of primary concern. However, cer-tain
restrictions are obvious. The deposit must be of such size and shape to warrant mining by open-cut
methods utilizing power driven or hydraulic equipment. Ordinarily any deposit less than 20 feet wide and
50 feet long would not be considered a competent source of scrap since it would be quite difficult to mine to
any appreciable depth. The cost of mining increases rapidly with depth causing the abandonment of some
narrow deposits before they are worked out. This is especially true of the smaller pegmatites. Since rock
formations plunge and dip at various angles, overburden may increase rapidly at depth and will be a de-ciding
factor in the economics of such deposits. An average deposit is from 50 to 100 feet wide and several
hundred feet long, although much larger ones occur.
The quality of mica is an important consideration. The mica must be relatively free of clay, stain and
other impurities that would discolor or increase the weight of the finished product. Biotite is acceptable
up to approximately 2 percent of the total mica content. The crude mica must be readily separated from
quartz and other gangue, although a small amount of quartz is permissible in the concentrate. The size of
the mica is not of major importance, although some processors believe that pieces smaller than 1.4 inch do
not always grind as well as the larger ones. This idea, although widely accepted by grinders, has not been
borne out by test work. Data obtained from controlled grinding tests, both in the Minerals Research Lab-oratory
and in actual plant operation, indicates that size is of little importance in grinding efficiency or
quality of products. Mica suitable as sheet or punch is highly desirable in a deposit since it is easily recov-ered
by screening at little cost.
The commercial aspects of a scrap deposit are directly dependent upon the availability of mica. This
covers a broad field which includes the ease with which the scrap can be mined and separated from the
gangue and the accessibility of the deposit. Hard rock deposits are seldom economical because of high min-ing
and milling costs. The most desirable type of deposit is well kaolinized and contains a relatively uni-form
mica content throughout. Such a deposit is mined easily, does not require excessive crushing and
screening, and affords an even flow of mica through the plant.
The deposit must also be accessible to suitable transportation facilities and to the plant site. A long
haul or much access road building would be too expensive to warrant working the average deposit. How-ever,
the economic values vary radically with location. If it is in an area where a plant is already in opera-tion,
the problem is chiefly one of mining and haulage. If a plant must be constructed, reserves must be such
as to warrant the investment. In most instances a deposit should contain sufficient reserves for two or more
years' production prior to the erection of a plant.
One of the factors which is gaining rapidly in importance in appraising scrap mica deposits is the pro-posed
methods of concentration. In most conventional scrap washer plants, mica smaller than eight mesh
cannot be recovered profitably. As a result, many plants are able to concentrate only about 40 percent of
the mica in the ore. In some cases the recovery is as low as 20 percent. Therefore, from 60 to 80 percent
of the available mica is often lost. Such losses will become major economic factors in the near future as
readily available reserves of coarse mica are depleted. If the spiral method of concentration is to be used,
then the size is of lesser importance, and initial plant costs and efficiency of mica recovery are primary
factors. Spiral concentration methods require controlled grinding but often recover up to 80 percent of the
mica in the feed-
Concentration by flotation may result in possible higher recoveries than the washer plant or spiral
methods. However, the process is more expensive and requires closer control. The economic recovery of
scrap mica alone by flotation is in some doubt. However, it is being concentrated by this method as a by-product
of the feldspar industry.
The Scrap Mica Resources of North Carolina
MINING AND CONCENTRATING
MINING
The size, attitude, and irregularity of most scrap mica deposits prevent the employment of large-scale
or very systematic mining procedures. Open-pit quarry methods are used, the ore being mined hydraulic-ally
or by power-driven equipment, or by a combination of the two. Overburden is stripped ahead of the
working face by bulldozer.
Hydraulic methods are used when possible. In this type of mining, water under pressure is directed
against the quarry face by means of jets. The ore, broken up by the force of the water, is washed from the
face into a sump from which it is flumed to the plant. In semi-kaolinized material, black powder is used to
fracture the ore prior to its being subjected to the hydraulic process. Equipment consists of one or more
nozzles or jets, hose or pipe, and water under moderate pressure. Two or three men are all that are neces-sary
for the operation. In some cases a bulldozer is employed to push the ore from the face into the sump,
and the ore is then flumed to the plant.
When hydraulic methods are not practical, power-driven equipment is employed. Mining is carried
out in one of three ways : a bulldozer scrapes up the ore and pushes it into loading bins, from which it is
loaded into dump trucks ; the ore is loaded directly from the face into trucks by power shovels ; or tractor
pulled drag pans mine and haul the ore. Where pow initial and operating costs. However, a deposit must
more flexibility of action and can mine deposits unfavorably situated for hydraulic mining.
The advantage of hydraulic mining is in the low initial and operating costs. However a deposit must
have a suitable topographic location, be near a satisfactory water supply, and have ample reserves to supply
a plant for two or more years. Its principal disadvantages are that the plant must be moved quite often, the
water is subject to freezing in winter, and grinding plants cannot be located economically at the concentrat-ing
plants. By using power-driven equipment, a greater number and smaller deposits can be worked profit-ably,
a steady supply of ore assured, and the plant located at a central point favorable to water supply, ore
deposit, and transportation facilities. Many of the scrap mica deposits located favirably for mining by
hydraulic methods have been worked out, and most of the larger operations utilize power-driven equipment.
CONCENTRATION
Scrap mica is hauled or flumed from the mines to concentrating plants, where it is washed and separated
from gangue materials. The process is carried out by one of two methods : differential crushing and screen-ing
in washer (jig) plants, or by differential grinding and utilization of the Humphrey Spirals for concen-tration.
The latter method has been perfected recently and, although must more effective in many instances.
is not as yet in widespread usage.
WASHER PLANT
Conventional washer plants are simple in design and often of temporary construction. In general they
consist of a series of roll crushers and trommel screens, a rotary drier, and storage facilities. Electric or
Diesel power is used. Ore is moved through the plant by gravity methods or bucket elevators. Large
amounts of wash water are required, and the accessibility of a suitable supply often determines the plant
location.
The flowsheet of a typical washer plant is shown in Figure 2. If the mine-run ore is blocky. it is first
crushed to minus two inch sizes in a jaw crusher and then washed through a series of roll crushers and
trommel screens. Quartz and feldspar are quite brittle and when passed through the rolls are reduced to
fine sizes. Mica, being flat and platy, is affected little. After reduction in a roil crusher, the ore moves onto
a trommel, equipped with Vs incn screens. The coarse particles, principally mica, are retained on the screen.
and the fine mica, quartz, feldspar, and clay are washed through and discarded. This procedure is repeated
one or more times, until as much of the quartz and feldspar has been removed as is practical. The concen-trate
is then dried in a wood or oil-fired rotary drier. There is a tendency for small pieces of quartz to
adhere to wet mica. Therefore, after being dried, the concentrate is passed through a final set of rolls and
screens prior to its being sent to storage. Concentrates are essentially free from most impurities with the
exception of quartz, which may be present in amounts ranging from 5 to 10 percent.
The Scrap Mica Resources of North Carolina
-(undersize)-
(undersize)
(undersize)-
(undersize)
( water
)
(undersize)
Waste
MINE RUN ORE
I
1" to 2" Trommel Screen-
I
Trommel Screen
(%", punched metal)
I
Roll Crusher
I
Trommel Screen
(i/a", wire)
i
Roll Crusher
I
Trommel Screen
(i/
8 ", wire)
i
Roll Crusher
I
Trommel Screen
(i/
8 ", wire)
I
Bucket Elevator
I
Drainage Bins
(oversize)-
Large Mica
and Quartz
1
Rotary Dryer
Roll Crusher
I
-Trommel Screen
(i/
8 ", wire)
1
SCRAP MICA CONCENTRATE
Figure 2. Flowsheet for Conventional Scrap Mica Washer Plant
The washer plant is a relatively low cost unit and is quite effective for the recovery of plus Vs inch mica.
It has been used successfully for many years in North Carolina. However that mica finer than V» inch, often
representing up to 50 percent of the mica in an ore, cannot be recovered economically in the conventional
washer plant and is discarded.
HUMPHREY SPIRALS
Within the past few years a new process for the recovery of scrap mica has been developed by the North
Carolina State College Minerals Research Laboratory at Asheville. It consists of reducing the ore to ap-proximately
16 mesh in a rod mill and passing it over Humphrey Spirals. A general flowsheet is given in
Figure 3.
This process must be more closely controlled than that used in the washer plant, but when operating
properly will recover approximately 80 percent of the mica in the ore. Four mineral concentrating plants
in North Carolina are now using spirals to recover scrap mica. The process is expected to be adopted more
widely in the future.
The Scrap Mica Resources of North Carolina
SCRAP MICA ORE OR TAILINGS
FROM CONVENTIONAL WASHER PLANT
I
2" Trommel Screen or Grizzly (oversize)
!
(overflow) Classifier (optional) Large Mica
7 and Quartz
Rod Mill*
-(undersize) Launder Screen
I
Cyclone, Drainage Bin
or both
I
14 Mesh Trommel Screen —( oversize )-
I
Humphrey Spirals
I
Tails Cone Mids
I
Waste i
Rotary Dryer
I
SCRAP CONCENTRATE
Figure 3. Generalized Flowsheet for Humphrey Spirals Scrap Mica Concentrating Plant
PROCESSING AND SPECIFICATIONS
Since mica sold as scrap comes from a variety of sources, individual lots differ as to condition and
quality. Requirements for such mica, prior to its being processed, are not rigid although some restrictions
are necessary. It must be of the muscovite or phlogopite variety, washed free of clay and mud, have a min-imum
amount of staining, and contain little or no grit. Biotite is increasingly detrimental if present in
amounts exceeding 1 percent, since it results in a discolored product unsuitable for many specialized uses. Two
percent is usually the maximum amount acceptable. In some instances small scrap derived from unweathered
ore resists delamination to such a degree that it presents processing problems, while that in extremely wea-thered
deposits may have excessive stain.
Scrap mica is processed by being ground to a powder meeting certain size, color, and bulk lensity speci-fications.
Blending of the raw scrap is often necessary to produce the desired product. In preparing the
mica for market three grinding processes are used : wet grinding, dry grinding, and micronizing. The mar-keted
product is classified roughly according to the grinding process used in its preparation, which in turn
indicates quality, properties, and general price brackets.
WET GROUND MICA
Scrap which has been processed by wet grinding methods is a high quality material of exacting size.
sheen, and color specifications. It is prepared by a batch grinding process in which considerable technique
is required on the part of the operator to make the desired product. This process is described in some detail
by Horton as follows
:
"Wet grinding is done in chaser mills consisting of annular steel or wooden pans up to 10 feet
in diameter and 40 inches in depth, in which wooden rollers rotating on horizontal arms revolve
about a central shaft. The bottoms of the pans are lined with and the rollers made of end-grain
wooden blocks, oak, maple, and black gum being preferred. The mills may be equipped with 2.
8 The Scrap Mica Resources of North Carolina
3, or 4 rollers ranging in diameter from 30 to 40 inches. The roller faces are generally 20
to 24 inches wide, and the rollers are so arranged that they can be raised or lowered according to
the depth of charge in the mill. Steel plows following each roller turn the charge to present new
material to the grinding action of the succeeding roller and to keep the mica in the path of the
rollers. The mills usually operate at 20 to 40 revolutions per minute, varying with the dimensions
of the mill and the weight of the charge, and consume about 20 horsepower. Complete grinding of
1-ton charge of mica requires 4 to 8 hours ; the time varies with the physical character of the mica
and speed of the mill. The mica, unless it is clean shop scrap, is washed thoroughly to remove fine
rock and dirt before it is ground. . . . Grinding is started without water, but as the mica breaks
up water is added gradually to form a stiff paste and the grinding is continued under carefully reg-ulated
conditions until the charge is completely ground. The friction generated in the charge pro-duces
so much heat that the water actually boils, and care must be taken to prevent the mica from
becoming too dry and 'burning.' The water content of the charge must therefore be watched care-fully.
If too much water is used proper grinding is precluded, and if too little is used, the mica will
burn and lose its sheen.
The ground charge is sluiced from the mill into wooden sand boxes or launders, where the
gritty impurities and coarse mica settle. The overflow carries the fine mica to wooden vats, where
it is allowed to settle and the clear water is siphoned off. The mica sludge is then transferred direct
to steam tables, or it may be filter-pressed before drying. The dried mica is run over a vibrating
scalper screen, usually of about 60- or 80-mesh, to remove heavy particles that would injure the fine
silk cloths of the bolting machines on which it is sized. The bolting machines are similar to those
employed in bolting flour ; replacement of the expensive silk cloths is a large item in the cost of
screening mica. The mica is bolted through 160- to 300-mesh cloths according to specifications, and
the oversize is returned to the mills for regrinding. Normally 80 to 85 percent of the mica is recov-ered
as a finished product. In all of the operations great care is exercised to keep the mica clean and
free from oil and iron stain.
A grinding plant with three mills makes about 2 tons of finished product in a 10-hour day. . . .
About 85 horsepower is required to operate the mills, pumps, elevators, and screens in such a
plant. . .
."
The process described above, although slow and cumbersome, has been used with little basic change for
many years.
Recently, the North Carolina State College Minerals Research Laboratory, in cooperation with the Ten-nessee
Valley Authority and private industry, has developed a continuous method for wet grinding mica
which has proved very effective on some micas. This patented process is now being used under exclusive
license in one plant in North Carolina.
Specifications for wet ground mica vary with the consumer. In general the material must be very white,
have high reflective properties, and be within given size ranges. Some slightly colored mica is marketed.
Most requirements specify that certain percentages pass 80, 160, and 325 meshes, the latter sizes being more
widely designated. A bulk density not to exceed 11 pounds per cubic foot is desired.
DRY GROUND MICA
In the preparation of dry ground mica the raw scrap is reduced to proper size in hammer or attrition
mills, and screened by means of vibrating deck screens. Hammer mills are the more widely used. The process
is simple and large volumes of scrap can be handled rapidly and at relatively low costs. In general a lower
grade of scrap can be used in preparing dry ground mica than that required for wet ground.
Most specifications require size ranges between 20 and 250 meshes, 80, 140, and passing 140 being stan-dard
in some plants. A bulk density of less than 18 pounds per cubic foot is usually required.
MICRO MICA
"Micro Mica" is an extremely fine powder derived by a special grinding process referred to as microniz-ing
which involves the use of steam under high pressure. As described in the July 1947 issue of Rock
Product*, the process consists of ". . . injecting high pressure super heated steam into a shallow, circular,
grinding chamber which contains a steady flow of mica already reduced to Vs inch size or finer. Steam enters
through tiny jets set at an angle to whirl the mica around and cut across the rotating mica. This reduces it
to a very fine powder. ... As the particles become finer, the centrifugal force no longer keeps them to the
The Scrap Mica Resources of North Carolina 9
outside and they gravitate toward the center where they are collected."' The resulting material is a flat white
powder theoretically passing 1000 and 3000 mesh. "The 1000 mesh mica has an average particle size of 10
to 20 microns in diameter while the 3000 mesh mica has an average particle size of 5 to 10 microns in di-ameter."
PROPERTIES AND USES
When ground to a powder, scrap mica has unique properties which make it a highly desirable product
suitable for many industrial uses. Among the more important properties are its ability to retain its flat
platy structure after extremely fine grinding, which results in a powder having great covering power, and
its retention of a high luster after water grinding, giving it excellent reflective and certain lubricative prop-erties.
Its relative inertness, insulative properties, toughness, flexibility, and color are also important assets.
Wet ground mica is usually white, has a greasy unguent feel, and a pronounced sheen. Individual par-ticles
are highly polished and have rather smooth edges. Some of the more outstanding physical properties,
as presented in Technical Bulletin 1 of the Wet Ground Mica Association, are shown in Table I.
Table I
—
Properties of Wet Ground Mica
pH 6 to 8
Hardness 2.5
Particle size, range ___ 2 . . 100 microns, 100 to 325 mesh
Specific gravity 2.7 to 3.0
Pounds per cubic foot 10 to 11
Wet bulking value 0.0426 gallons per pound
Index of refraction 1.58
Melting point .. 2800
T
Oil adsorption, range 40 - 60 percent
Sphericity factor 0.1
Color white to grey or green or pink
Effect by common acids slight
Dry ground mica is a rather flat white powder having little luster. Individual particles have rough
hackly edges and little or no polish on flat surfaces. Color and size ranges are not too closely controlled.
However dry ground mica retains many of the properties of wet ground mica, and is available at much lower
costs. Its adaptability to a wide variety of industrial uses is indicated by the fact that it accounts for about
85 percent of all mica ground in the United States.
The uses of ground mica are too numerous to be discussed in detail and, therefore, only the more out-standing
are given. Most of the wet ground and considerable amounts of high grade dry ground mica are
used in the manufacture of paint. The wallpaper industry consumes sizeable amounts of wet ground mica,
using it in design printing. Dry ground mica is used principally in the manufacture of roll roofing, and
over 50 percent of the total production of dry ground mica is marketed for this purpose. Purer grades of
both wet and dry ground mica are utilized as inert fillers and dusting powder by the rubber industry. Other
uses of ground mica are in the manufacture of plastics, cable and telephone wire insulation, artificial snow.
oil and axle grease, pipe line enamels, textiles, bonded glass, wallboard cement, asphalt landing mats, house
insulation, in annealing, and oil well drilling.
During the period 1945-1949 the approximate distribution of sales of ground mica to the various leading-industries,
by percentages of volume sold, as computed from the United States Bureau of Mines Yearbooks is
as follows
:
Roofing...... ...53% Paint ..,15%
Wallpaper ._ 4 Plastics . . 2
Rubber . 8 Miscellaneous 18
Within the past few years the uses of ground mica increased considerably, and many new uses are expected
to be developed. Of particular note is the increased consumption in wallboard joint cement and oil well
drilling muds. Considerable research is in progress on utilizing scrap in the preparation of a mica board
for certain uses in the electrical industry.
10 The Scrap Mica Resources of North Carolina
PRODUCTION AND VALUE
In the United States raw scrap mica is obtained from both domestic and foreign sources. However,
imports represent less than 10 percent of the scrap consumed. During the period 1945-1949, annual imports
of scrap averaged only 4,762 tons valued at $62,697.00. Of this, approximately 1,884 tons were of the phlogo-pite
variety. Canada, India, and the Union of South Africa are the chief sources of imports.
60
56
52
Modified from U 5 Bureau of Mines Minerals Yearbooks
Dry Ground
I Wet Ground
1923 1925 1927 1929 1931 1933 1935 1937 1939 1941 1943 1945 1947
Figure 4. Scrap and Ground Mica Sold in the United States, 1923-1948.
Approximately 91 percent of the mica consumed by grinders is of domestic origin. North Carolina
furnishes over 75 percent of the raw scrap used to manufacture ground mica in the United States and is
followed by South Dakota. Comparative production figures by States are shown in Table II.
Table II. Average Annual Production of Scrap Mica in the United States by States From 1945-1949
State Tons Value Unit Value
North Carolina ....-35,533 $814,800 $22.95
South Dakota .. 1,524 36,450 23.65
Other States .. 8,839 116,110 13.70
A breakdown of ground mica production in the United States for the period 1945-1949 is given in Table
III. Of particular interest is the ratio of wet ground to dry ground production tonnages as compared with
corresponding values.
The Scrap Mica Resources of North Carolina 11
Table III. Ground Mica (Including mica from kaolin and schist) Sold By Producers in the United States,
1945-49, By Methods of Grinding
Year
Dry Ground Wet ground Total
Short tons Value Short tons Value Short tons Value
1945
1946
1947
1948
1949
43,686
53,908
55,731
55,494
49,133
$1,243,075
1,582,974
1,852,768
2,035,618
1,850,400
8,120
8,205
8,809
9,148
7,260
$ 752,894
933,044
1,114,945
1,197,014
1,010,556
51,806
62,113
64,540
64,642
56,393
$1,995,969
2,516,018
2,967,713
3,232,632
2,860,956
A summary of the production of scrap and ground mica in the Untied States from 1923 to 1948 is shown
graphically in Figure 4. North Carolina's dominant position in the scrap mica industry is clearly indicated.
Prices for raw scrap and ground mica from North Carolina as quoted by the Engineering and Mining
Journal Metal and Markets Report for November 1952 are as follows: Scrap—$32 to $35 per ton depending
upon quality. Wet Ground—$140 to $155 per ton depending upon fineness and quality. Dry ground
—
$32.50 to $70.00 per ton.
SCRAP M3CA RESOURCES OF NORTH CAROLINA
GENERAL GEOLOGY
Geology relating to the occurrences of scrap mica in North Carolina is for all practical purposes identi-cal
with that of the occurrences of sheet mica, feldspar, and kaolin, since all are a part of the same rock forma-tions.
Detailed accounts of the various relationships have been well covered in other publications (see Bibli-ography)
and are not considered as being within the scope of this report. The descriptions which follow are
therefore for general orientation purposes only.
The scrap mica districts, although quite widely separated geographically, have somewhat similar geo-logic
settings. All are located within a great complex of metamorphic and igneous rocks which underlie most
of the Mountain and western Piedmont provinces of the State. The region has been subjected to the several
major periods of folding, faulting, intrusion, uplift, and erosion associated with the formation of the Appa-lachian
Mountain system, of which it is a part. Throughout the districts gneisses, schists, and granites are
the predominating rock types.
METAMORPHIC ROCKS
The most extensive of the metamorphic rocks are mica gneisses and schists, composed principally of mus-covite,
biotite, quartz, and some garnet. These occur interlayered in varying proportions with hornblendic
gneisses and schists and are generally considered to represent sediments of pre-Cambrian age which have
been altered greatly by regional metamorphism. Zones of kyanite, sillimanite, and graphite schists occur
sporadically, as do lenses of dolomite. The major trend of the gneiss-schist series is northeastward and the
dip southeastward, although extreme variations occur locally. Igneous solutions have invaded the meta-morphic
rocks over wide areas, causing much change in the composition and structure of the formations.
IGNEOUS ROCKS
Large bodies of granite and allied silicic rocks were intruded into the gneiss-schist series, in some in-stances
highly disrupting it, and in others absorbing large quantities of it. Although age relationships of
the rocks have not been established definitely, at least two stages of intrusion of silicic rocks are recognized.
One is considered to be pre-Cambrian and the other late Paleozoic, the latter apparently accounting for most
of the pegmatitic activity which resulted in the formation of the major deposits of feldspar and mica. Ultra-mafics,
principally dunite and diabase, also intrude the metamorphic series, but in much smaller quantities
12 The Scrap Mica Resources of North Carolina
than do the granitic rocks. The age of the dunites has not been established definitely, although it is gen-erally
conceded to be pre-Mesozoic. The diabase is considered as belonging to the Triassic or a later period.
Of particular importance in the formation of scrap mica deposits are the silicic rocks and their relation-ships
with the surronding schistose formations. These intrusives occur as quartz yeins, aplite dikes, pegma-tites,
large coarse-textured masses termed "alaskite," and massive granite bodies. Of these the latter three
are important sources of scrap mica.
PEGMATITES
Pegmatites are elongated, somewhat tabular dike-like bodies, thought to represent a late stage in the
intrusion of silicic rocks. They transect most of the other rocks, including the granites, alaskites, and rocks
of the gneiss-schist series. Those occurring in the granitic rocks appear as instrusives in some places and
as segregations in others. These bodies are usually quite coarse grained, and are composed principally of
feldspar, quartz, and mica. For the purpose of this report they are limited to the smaller type of silicic
instrusive, usually ranging in width from less than an inch to a hundred or more feet and in length from a
few feet to as much as 500 feet. They occur as individual deposits within the gneisses and schists, within the
alaskite formation into which they sometimes grade, and in and near the granites. When associated with the
latter they are especially prevalent along border zones.
The emplacement of the pegmatites was probably the most important phase of igneous activity directly
responsible for economically valuable deposits of mica and feldspar. Not only did the rising solutions form
individual deposits of extremely high-grade mica-bearing pegmatites, but, in passing through certain of
the alaskites and granites, enriched them to such a degree that their commercial value was enhanced greatly.
ALASKITE
"Alaskite" is a term here applied to a coarse-textured granitic rock which is common in the Spruce Pine
district. It is composed principally of feldspar, muscovite, and quartz, very few of the ferromagnesian min-erals
being present. A general mineralogical composition is as follows: plagioclase feldspar 40 %, microcline
feldspar 20%, quartz 30%, and mica 10 to 20%. Garnet and biotite are found in very small amounts in most
of the rock, the amounts increasing as contacts with the country rock are approached. Its texture is finer
than that of a pegmatite but coarser than that of most granites.
Although the rock does not fit exacting scientific specifications for alaskite, the name was applied to
the material some years ago by Hunter and has been accepted generally by the local mining industry. It
is retained here, not as a strict classification of a rock type, but as the most practical term, since the rock
approximates the requirements for alaskite and the term is already in common usage among the miners and
operators within the Spruce Pine district.
GRANITE
Granite occurs in limited amounts in all of the scrap mica producing areas, being especially prevalent
in the Shelby district. When compared with pegmatite and alaskite, granite is a medium to fine-grained
rock and, like them, is composed principally of feldspar, mica, and quartz. However, the iron-bearing min-erals
such as biotite, garnet, and hornblende are much more common. Granite occurs as somewhat irregular
masses ranging in diameter from a few feet to several miles. Two or more ages of granite have been recog-nized
in the districts.
WEATHERING
Throughout the scrap mica districts of the western Piedmont province, the rocks are usually highly
weathered, at least to local drainage levels and often to greater depths. In many places weathered mate-rials
extend 30 to 50 feet below the surface and could be expected to extend to a hundred feet or more. Out-crops
are for the most part confined to areas adjacent to the larger streams.
In the Mountain province where erosion is usually quite rapid, most of the rocks are relatively fresh and
outcrops are numerous. The greatest degree of weathering is along the lower slopes and in the major valleys
where erosional forces have been delayed temporarily. In such areas the rocks are often weathered to depths
of 50 or more feet, 10 to 20 feet being common. Deep weathering in the mountains is usually quite restrict-ed,
but has been encountered to depths of 200 feet in some mines.
The Scrap Mica Resources of North Carolina 13
THE SCRAP MSCA INDUSTRY OF NORTH CAROLINA
HSSTORY AND PRODUCTION
The early history and development of the scrap mica industry in North Carolina is associated closely
with kaolin and sheet mica mining, but actual records are scarce. The first scrap mica grinding plant is
reported to have been built on Beaver Creek near Spruce Pine, about 1870. Shortly after, Mr. David T.
Vance erected a grinding plant at Plumtree, and soon other plants were built near Penland, North Carolina
and Richmond, Virginia. In 1908 the English Mica Company constructed a grinding plant in Spruce Pine.
Mica used by these early plants was waste from sheet mica mining and processing, much of it being obtained
by reworking old sheet mica mine dumps. Soon after the close of the last century most of the old dumps had
been worked out, and scrap mica mining developed rapidly.
In 1907 the Franklin Kaolin and Mica Company was operating a kaolin and mica recovery plant at the
Iotla Mine in Macon County. This plant was soon taken over by the Southern Mica Company. In 1910 Mr.
Charley Gunter constructed the first scrap mica concentration plant in the Spruce Pine area and furnished
the English Mica Company with his product. Since these early beginnings the scrap mica industry has grown
rapidly. Scrap is now produced directly from 16 scrap mica concentrating plants and as a by-product from 3
kaolin recovery plants and 4 feldspar flotations plants. It is processed by 6 wet grinding plants and 5 dry grind-ing
plants operating within the State. The rapid rise in productive ability of the industry is in a large part
due to its ready adaptation of new mining methods and techniques, its capitalization on results of geologic
investigations of the deposits, and on research studies on new concentration and grinding practices.
The development and present status of the scrap mica industry in North Carolina are best reflected by
records of production. Table IV shows the production of scrap in North Carolina for the period 1901-1950.
Of special interest is the rapid increase in tonnages and values since 1930. During World War II a sizeable
amount of high-grade scrap was produced as a result of the Government sponsored sheet mica program.
Table IV. Scrap Mica Production of North Carolina 1901-1950
Year Short Tons Value Value/ Ton Year Short Tons Value Value/ Ton
1901 1,775 $ 14.200 $ 8.00 1925 7,095 $124,818 $17.59
02 324 2,219 6.84 26 5,314 124,048 23.34
03 300 2,400 8.00 27 5,409 113,670 21.01
04 341 3,410 10.00 28 8,739 132,119 15.12
1905 275 3,375 12.27 29 8,346 153,722 18.42
06 1,129 11,940 10.58 1930 5,904 97,600 16.53
07 1,371 15,250 11.12 31 6,872 84,818 12.34
08 1,308 13,330 10.25 32 6,237 71,842 11.52
09 2,607 26,178 10.04 33 8,968 102,830 11.47
1910 3,074 37,237 12.11 34 7,255 101,985 14.06
11 2,347 29,798 12.69 1935 11,831 153,553 12.98
12 2,492 36,675 14.72 36 10,840 131,138 12.10
13 2,729 37,239 13.65 37 12,988 209,212 16.11
14 1,789 23,900 13.36 38 11,959 161,598 13.51
1915 2,840 33,943 11.95 39 13,913 184,377 13.25
16 2,755 41,880 15.20 1940 11,595 173,327 14.95
17 2,180 34,134 15.66 41 18,234 268.596 14.73
18 1,046 12,930 12.36 42 24,145 485.560 20.11
19 1,639 32,338 19.73 43 25.295 516.637 20.41
1920 2,823 91,653 32.47 44 29,775 750,285 25.20
21 1,353 30,496 22.54 1945 30,682 709.334 23.12
22 4,205 65,923 15.68 46 39,100 887.901 22.78
23 5,005 95,128 19.01 47 38,655 844.086 21.83
24* 6,641 115,774 17.43 48 44,428 992.303 20. SO
49 24,801 640.374 25.85
1950 48,193 1.281.000 26.5S
"Figures since 1924 include mica recovered from kaolin, as a by-product, and from mica schists.
14 The Scrap Mica Resources of North Carolina
However, this source was cut off in 1945 when the program was terminated. Much of the production since
that time has been from primary scrap mica deposits. In 1951 the United States Government initiated its
Defense Minerals Exploration Administration which has aided in the production of sheet mica. Production
has not as yet provided sufficient by-product scrap to influence the scrap supply appreciably. The Spruce
Pine district accounts for approximately 75 percent of the State's production of scrap mica.
The status of North Carolina as a major producer of scrap mica is shown in Table V. As indicated,
North Carolina produced 65 percent of the raw scrap consumed in the United States during the period 1940-
1949. More significant, however, is that with increased production throughout other sections of the United
States, North Carolina produced 55.6 percent of the total domestic supply for the 1940-1945 period and in-creased
this to 77.4 percent for the 1945-1950 period. The ability not only to reach this status but to main-tain
it is an indication of the future possibilities of the scrap mica industry of North Carolina.
Table V. Comparison of Volume OF Scrap Mica Sold OR Used by Pro-ducers
in North Carolina and the United States
Year United States North Carolina N. C. Production
(Short Tons) (Short Tons) % Total
1940 22,386 11,595 51.8
1941 32,500 18,234 56.1
1942 43,262 24,145 57.7
1943 46,136 25,295 54.8
1944 51,727 29,774 57.6
1945 41,060 30,682 74.7
1946 53,602 39,100 73.9
1947 49,797 38,655 77.6
1948 52,157 44,428 85.2
1949 32,856 24,801 75.5
OCCURRENCE OF SCRAP MICA IN NORTH CAROLINA
Mica is a common constituent of many metamorphic and igneous rocks, but its occurrence in quantities
and qualities of economic significance is limited. In North Carolina those occurrences that are sources or
potential sources of scrap mica may be classed into four general groups: (1) as small flakes in lenses of very
high-grade muscovite mica schist, (2) as small flakes and books in some granites, (3) as small to medium
flakes and book; in alaskite, and (4) as small to large flakes and books in pegmatites. Of these the latter
two are by far the most important and constitute most of the proven reserves.
In some areas of North Carolina, especially in the Spruce Pine district, small lenses of high-grade mica
schist occur in which the muscovite content is 90 percent or more. Individual flakes are generally small
and crenulated, making fine-grinding of the material rather difficult. Attempts have been made to mine and
process mica schist in North Carolina, but these attempts have been unsuccessful. Such occurrences do not
appear to be of particular value to the scrap mica industry in the immediate future.
Most granites have too low a muscovite content and contain too many iron-bearing minerals to be suit-able
sources of scrap mica, although they constitute tremendous reserves of material. Biotite, usually quite
prevalent, is especially harmful since it cannot be separated economically from the muscovite. In some in-stances,
however, considerable concentrations of muscovite mica and feldspar occur along the border and
internal fracture zones of granite bodies and adjacent to mica schist inclusions and wall rock. Such con-centrations
have been formed largely by pegmatitic action, by assimilation of parts of the country rock by
the granite, or by a combination of pegmatitic activity and assimilation. Granite has limited potentialities
as a source for scrap mica if it has been sufficiently enriched. That occurring in the Kings Mountain area
appears to offer the best possibilities.
The alaskite formations of the Spruce Pine district represent the greatest reserves of scrap mica in the
State. Muscovite mica occurs throughout the rock, often making up from 10 to 20 percent of the total weight.
The Scrap Mica Resources of North Carolina 15
Biotite and other iron-bearing minerals are usually present in very small quantities, being more prevalent
along the border phases. The great volume and relative uniformity of alaskite make it a highly valuable
rock to the scrap mica, feldspar, and kaolin industries. In its unweathered state, alaskite is mined and
processed for feldspar, scrap mica being recovered as a by-product. In deeply weathered parts of the
formation in which the iron-bearing minerals are negligible, the rock is mined for its kaolin content, and
scrap mica is recovered during processing. Those highly weathered zones richest in muscovite mica are
mined directly for scrap.
Mica occurring in pegmatites is usually much larger and of a higher quality than that occurring else-where.
Most mica mining in pegmatites is carried out primarily for sheet, scrap being saved where possible.
In some of the larger pegmatites, mining may be for the high quality scrap, and sheet is recovered during
mining and concentration. Scrap obtained from pegmatites is usually most desirable for wet grinding.
However many pegmatites containing high contents of excellent muscovite are too small to be worked prof-itably.
The scrap mica deposits in pegmatites are, therefore, limited to the larger bodies which contain
in excess of about 8 percent recoverable mica and which are sufficiently weathered to allow easy mining.
Although pegmatites are mined for scrap in all districts, usually in conjunction with granite and alaskite,
only in the Franklin-Sylva district do large individual bodies constitute the bulk of the scrap mica reserves.
RESERVES
An estimate of scrap mica reserves is at best highly speculative since there are many uncontrollable
economic and geologic variables to be considered. Th3 present investigation was confined to the more out-standing
primary scrap mica deposits, and reserve figures apply only to these sources.
It is estimated that the primary scrap deposits contain a minimum of 31,000,000 tons of ore averaging
from 12 to 18 percent mica. Of this amount approximately 25,000,000 tons are in the Spruce Pine district
and are present as indicated in the following breakdown
:
Plus 8 mesh Mica
In excess of 6%
_
- 1,500,000 Tons
Between 5 and 6%_ . 1,200,000 Tons
Toted Mica Content
Ore containing between 12 and 15 per cent mica.- ___15,000,000 Tons
Ore containing between 15 and 18 per cent mica- _10,000,000 Tons
This does not include that mica in the many sub-marginal deposits, in the large kaolin deposits, nor the po-tential
to be derived from feldspar and sheet mica mining and processing. Hunter estimates the kaolin de-posits
to contain approximately 51,000,000 tons of kaolin. Many of these deposits, although fine grained,
contain from 12 to 18 percent mica.
The Shelby district has not been prospected thoroughly but is estimated to contain a minimum of 5,000,-
000 tons of mineable ore. Reserves in the Franklin-Sylva district are confined to a few large pegmatites
which are estimated to contain in excess of 1,000,000 tons of high-grade ore.
These figures are conservative and are expected to be revised upward as more thorough prospecting is
carried out or if the lower-grade deposits now considered as sub-marginal are worked in the future. The
amount of material containing in excess of 5 percent plus 8 mesh mica is quite limited.
FUTURE OUTLOOK
The reserves of scrap mica in North Carolina appear sufficient to back the expanding scrap mica industry
for a considerable period of time. However, the ore containing sizeable percentages of plus 8 mesh mica is
definitely limited, and may well be depleted within the foreseeable future. There are large reserves of mate-rial
containing from 12 to 18 percent mica, most of which is fine. Future production, therefore, will
depend largely upon industrial demand. Presinet indications are that this demand will continue to increase,
and that producers will be forced to recover the fine m.ca to supply the market.
16 The Scrap Mica Resources of North Carolina
Although a considerable amount of high quality mica will continue to be mined from pegmatites and
coarse alaskite deposits, the principal production in the future will likely be from the large deposits of fine-grained
material. The mica smaller than % inch must be recovered if these bodies are to be economically
profitable. Many of the present producers could recover up to twice their norma^ production by recovery of
the fines. However, this does not appear possible in the conventional washer plant.
The trend toward the use of the Humphrey Spirals method of concentration is expected to continue, al-though
a considerable initial cost is involved which makes the process prohibitive in the case of small opera-tions.
PRINCIPAL PRODUCING AREAS
All scrap produced from primary scrap mica deposits in North Carolina comes from three major dis-tricts
located in the western third of the State. These are the Spruce Pine, Franklin-Sylva, and Shelby.
There are other small areas from which some scrap may be produced, but these have not been investigated
thoroughly, and therefore are only briefly discussed.
CE PINE D1STRSCT
The Spruce Pine district is an irregular shaped northeastward-trending area approximately 9 miles
wide and 18 miles long, which covers parts of Yancey, Mitchell, and Avery Counties. It is located in the
Mountain province of the State, approximately 35 miles northeast of Asheville. The district is the leading
producer of primary kaolin, feldspar, sheet mica, and scrap mica in North Carolina. Its known reserves of
scrap mica exceed by far the combined known reserves of other districts throughout the State. Although
Figure 5. Location Map—Spruce Pine District
The Scrap Mica Resources of North Carolina 17
the quality of "alaskite mica" is not in every case as high as that from other sources, its great quantity makes
it the mainstay of the scrap mica industry. The Spruce Pine district produces over 75 percent of all scrap
mined in North Carolina.
GEOLOGSC SETTING
Scrap mica deposits of the Spruce Pine district consist of mica-rich portions of deeply kaolinized alas-kite.
This rock type underlies a large part of the district and is exposed as a series of irregular bodies
which are, in places, as much as two miles wide and over two and one-half miles long. These bodies intrude
a series of highly contorted gneisses and schists and both are intruded by pegmatites. In most cases the
alaskites are conformable with the regional northeastarly strike and southeasterly dip of the gneiss-schist
series. The largest bodies are in the vicinity of Spruce Pine, and they become smaller toward the northeast
and southwest.
Exposures indicate that the deposits have very irregular contacts which, in some instances, are clearly
defined, and in others, appear to grade into the surrounding rock formation. Although contacts or "walls"
may roll locally, most are very steep. Inclusions, principally mica and hornblende schists, are present in
varying proportions and sizes throughout most alaskite bodies.
Pegmatites are common in the alaskite, especially in the more highly fractured areas. Solutions form-ing
the pegmatites also permeated the adjacent rock, resulting in zones of coarse material. These zones are
important in economic development of the alaskite.
Although there is an overall uniformity of mineral content and texture in the alaskite formations, locally
wide differences occur. The scrap deposits are composed for the most part of mica, kaolin, and quartz. Bio-tite
and garnet, usually present in small amounts, increase near hornblendic inclusions and the wall rock.
In the vicinity of some mica-schist inclusions, the mus20vite size and content increase. This is also true
where pegmatitic materials have invaded the alaskite.
Most of the deposits in the immediate vicinity of and toward the northeast from Spruce Pine are rela-tively
fine grained. The residual kaolin deposits in this part of the district seldom contain over 3 or 4 per-cent
of plus 8 mesh mica. Toward the southwest, especially in the Micaville-Celo area, the rock is coarser
and many deposits contain from 5 to 7 or more percent of plus 8 mesh mica. However, within this area the
content of coarse mica varies considerably between adjacent deposits.
In general the larger deposits are finer grained, and those in excess of 200 feet wide seldom contain
enough coarse mica to be recovered profitably by the conventional washer plant now operating in the district.
However, those deposits which have been subjected to later magmatic solutions contain zones of coarser
materials in which the mica is recoverable.
The workable depth of a deposit is often controlled by the depth of weathering. Those areas most
suitable for scrap mica mining are confined to the more highly kaolinized coarse phases of the alaskite,
usually occurring along the lower ridges. In many parts of the district these ridges represent old stream
terrace levels, and are capped with unsorted sand, silt, and gravel. These caps have retarded erosion and.
by furnishing large amounts of ground water over long periods of time, accelerated the rate of weathering
of the underlying rocks. Where alaskite bodies underlie such terraces, they are usually well kaolinized and
are, therefore, the most desirable for scrap mica deposits.
Many alaskite bodies are deeply weathered to more than 100 feet, while others are relatively fresh at or
near the surface. Such conditions are apparently controlled for the most part by a deposit's topographic
position and the accessibility of the rock to the weathering and erosive agencies. Many deposits located
along the crests or sides of hills having gentle slopes and those near the crests of some of the steeper hills
are weathered relatively deep. Those along the sides of steep ridges and in valleys close to local drainage
levels are seldom weathered to appreciable depths. Bottom limits of soft material are quite erratic within
individual deposits and appear related to fracture systems within the alaskite mass. The more schistose
zones in the alaskites offer easy access to percolating waters and are usually more deeply weathered than
the massive zones.
Overburden may be as thick as 25 feet locally, but in most cases it is less than 5 feet. The thick over-burden
is often composed of old stream terrace material or talus but is seldom present in such quantities
as to affect mining seriously.
18 The Scrap Mica Resources of North Carolina
DESCRIPTION OF DEPOSITS
AUTRY-ROBJNSON DEPOSIT
The deposit is on the property of the heirs of John H. Robinson in eastern Yancey County, 1.3 miles
N43°E of Celo. (Figure 5, Location 1). It is located on the north side of Bailey Mountain, south of the
South Toe River. At present it is not accessible by road. Numerous small sheet mica mine and prospect
pits have been dug in and near the deposit.
Pegmatites and narrow bands of alaskite occur in Shanty Ridge and in the ridge to the east. The alas-kite
is narrow, having a maximum width of 25 to 30 feet. Most of the material contains a high percent of
plus 8 mesh mica, averaging 5 percent or more.
There does not appear to be sufficient reserves of ore in the deposits to justify the erection of a con-centrating
plant. The ore could be hauled by trucks to a nearby plant.
BAILEY SCRAP MICA DEPOSIT
The Bailey Scrap Mica deposit is located in southern Mitchell County, 2.5 miles N55°W of Spruce Pine
and 0.6 of a mile N38°E from Penland. (Figure 5, Location 2). It can be reached by following U. S. High-way
No. 26 northwestward from Spruce Pine to a point 0.4 of a mile west of Little Bear Creek and taking
the old mine road for 0.4 of a mile south. The deposit is located on the property of Harry Bailey, Jr., of
Penland. Kaolin has been produced from this deposit intermittently since about 1905 by Harris Clay Com-pany
and Carolina China Clay Company, the latter suspending operations about 10 years ago. The prop-erty
was not being worked as late as 1952.
Present workings consist of six large pits and ma ay smaller mines and prospects. The principal pit
shown on Plate 1 is approximately 500 feet in diamebr and, in places, more than 60 feet deep. Others not
shown on the map are located 300 feet to the southwest and 1200 feet to the east. Numerous mine and pros-pect
pits occur along the ridge above the old road. Sheet mica and feldspar have been produced from peg-matites
near the contacts and within the alaskite body. An example of such an occurrence is in the Deer
Park Feldspar mine south of the river.
The country rock is principally mica schist, but narrow zones of hornblende gneiss are present in inclu-sions
and along the contacts. In some areas, especially along the eastern contact, the alaskite grades into
the schist. This resulted from impregnating granitic solutions altering and apparently dissolving some of
the schist. Numerous alaskite pods and stringers were also intruded into the schist, and in some places
make up 30 to 40 percent of it. The country rock, observed in inclusions and along the western contact,
strikes from due north to N10°E. Along the eastern contact of the area, shown on Plate 1, it strikes from
N25°W to N35°W. Inclusions observed in cuts are folded but in general dip from 70 to 80 degrees to the
east.
The alaskite body is 2000 feet wide near the North Toe River and increases to over 3000 feet near High-way
26. A large inclusion occurs near the center of the deposit. East of the main cut this inclusion has a
width of from 300 to 500 feet and is about 1200 feet wide near the highway. Other inclusions found
throughout the alaskite body vary from a few feet to several hundred feet across. However, zones of alas-kite
up to 400 feet wide occur without inclusions. Most inclusions are so small in comparison to the size of
the alaskite that they should not interfere with mining. All detail investigation was done west of the in-clusion,
shown as the eastern contact of the alaskite body on Plate 1. This section is over 1500 feet wide
at the north end of the cut and extends some distance farther to the west than is shown on Plate 1. It was
drilled over a distance of 400 feet north of the cut, an:l indications are that similar material occurs for
several hundred feet north of this point. Sufficient work was not done to estimate the size and percent of
mica throughout the entire deposit.
The alaskite is finer grained than most deposits being worked for scrap mica but is unusually coarse
grained for a body of this size. The coarser material occurs in the north face of the open cut and extends
in a northeasterly direction. This zone, from 300 to 350 feet wide, contains an average of from 4 to 5 per-cent
plus 8 mesh mica with higher concentrations locally. The alaskite, both to the east and west, is finer
The Scrap Mica Resources of North Carolina 19
I
J 3fl»«^oo^o-
S 5 V " ° <
£ I 2 i
|SE(
DBSQ \ ; -U*U
H— <
c/) z
O J
0. o
Q 3 1
— o
5 z -
0. >-' =
< z "1"
u o
to u
-i ..
w> dr
_—J uh-
< 5 m
e<
PL.
H
pq
20 The Scrap Mica Resources of North Carolina
grained, averaging from 2 to 3 percent plus 8 mesh mica but containing some coarser material in narrow
zones. A trench sample from the open cut on the hill contained 4 percent plus 8 mesh mica.
The great value of this deposit lies in its size and total mica content. The mica content of fourteen
samples varied from 8.82 to 24.4 percent, averaging 15.15 percent. This is slightly over four times the
average percent of plus 8 mesh mica in the ore. The alaskite on the hill northeast of the large cut contains
even a higher proportion of fine mica. In the areas sampled, the mica was of a high quality.
It is difficult to estimate the depth of weathering in some areas of the deposit. In the large cut rela-tively
soft material occurs to a depth of about 60 feet in places, but hard alaskite was encountered at a much
shallower depth on the southern end. Indications are that hard rock will be reached at a shallow depth be-tween
the cut and the river. The alaskite is apparently weathered to a depth of from 40 to 60 feet northeast
of the open cut. Semi-kaolinized feldspar was encountered at some places on the hill northeast of the open
cut. It is estimated that the average depth of weathering on the hill is from 30 to 40 feet. Hard rock was
encountered in drill holes at numerous places along the ridge southeast of the large cut and east of the old
road.
The production possibilities of this deposit are as good as that for any deposit examined. A power line
extends across the deposit, and the North Toe River and the Clinchfield Railroad are approximately 650 feet
south of the large cut. Most of the material could be mined hydraulically and washed to a plant at the rail-road
with a minimum amount of excavation. The large quantity of material obtainable would enable a rela-tively
permanent operation. However, the economic development of this deposit would necessitate the recov-ery
of fine mica. There is also a possibility that considerable kaolin might be produced.
Of the part of the property examined in detail and shown on Plate 1, reserves are estimated to be from
600,000 to 850,000 tons of material averaging above 4 percent plus 8 mesh mica and from 1,000,000 to 1,500,-
000 tons of material containing a total mica content of approximately 15 percent. It is estimated that the
entire deposit contains between 3,000,000 and 4,000,000 tons of ore.
Sample Results—-(See Plate 1 for results on samples 1 through 14) :
Sample No. Plus 8 Mesh Mica Minus 8 Mesh Mica Total Mica
15 4.8% 12.1% 16.9%
16 5.4 15.0 20.4
17 2.7 13.2 15.9
Sample No. 15. A trench sample from the large open cut on the ridge west of Little Bear Creek.
Sample No. 16. A trench sample from the smaller open cut on the ridge west of Little Bear Creek.
Sample No. 17. A trench sample taken over a distance of approximately 100 feet along the road bank
of Highway 26. It was obtained west of the crest of the ridge at the small tunnel.
BLUE ROCK DEPOSIT
The deposit is located in eastern Yancey County 1.6 miles S60°E of Micaville. It is on the west side of
the South Toe River and can be reached by following the Blue Rock Road to the Blue Rock Church, turning
west on the old road and following it for about 0.75 of a mile west of the river. It is accessible by the Rice
Road south from Highway No. 19E. The property is reportedly owned by the Newdale Mica Company,
Kona, North Carolina. (Figure 5, Location 3).
Numerous pits and tunnels, made while prospecting for sheet mica, are found in the deposit and in the
several adjacent pegmatites. The southern alaskite body is well exposed in two tunnels which traverse it.
Most of the old workings are confined to the small pegmatites.
The country rock is mica schist which has a geneeral strike of from N10°W to N40° W, but owing to
some large folds, it strikes in places to the northeast. The schist observed in tunnels dips approximately 30
degrees to the southwest. Much of the schist has been impregnated with granitic solutions and consequent-ly
contains many small stringers and pods of alaskite.
The deposit consists of several relatively narrow alaskite bodies, the two largest of which are shown on
Plate 2. The maximum width of the bodies is about 60 feet, the average width being between 20 and 30
The Scrap Mica Resources of North Carolina 21
SAMPLE RESULTS - PERCENT
ample 8 Mesh -8 Mesh Total
No- Mica Mica Mica
1 8 12 37 20 37
2 7 15 12.08 19 23
3 13 34 10 61 23.95
4 16 04 15 66 31.70
5 4 9 14.4 19.3
6 9 9 12.5 22 4
7 4.8 18 8 23 6
8 13 3 10.6 23 9
EXPLANATION
IV y
V
| Alaskite With Relatively High Mica Content
I*."/ I Alaskite With Efher Fine Mica or Low Mica Content
I.' Sij Alaskite Not Weathered to Sufficient Depth for Mining
E Vil Mica Schist
Contact
Approximate Contact
Sampled Hand Auger Holes
Strike and Dip of Formation
Rim of Open Cut
'/{$• Dump
Trait
BLUE ROCK SCRAP MICA DEPOSIT
YANCEY COUNTY, NORTH CAROLINA
150
Scale m Feet
Bulletin 66
—
Plate 2
22 The Scrap Mica Resources of North Carolina
feet. The largest body has a length of approximately 500 feet. Numerous small deposits occur in the area,
especially to the east and northeast of the ones shown on Plate 2. Most of these are rather well exposed in
old workings, are relatively narrow, and contain varying quantities of hard rock. Indications are that in-clusions
make up at least 10 percent of the deposit. *
The deposit, in general, contains a high percent of plus 8 mesh mica, but there are zones of fine-grained
material. The plus 8 mesh mica content of the eight samples taken varied from 4.8 to 16.34 percent with
an average of 9.67 percent. The total mica content varied from 19.23 to 31.70 percent, averaging 23.05
percent. None of these samples are representative of the fine-grained material shown on Plate 2. Some
biotite was observed, especially near the contacts and inclusions.
Indications are that the depth of weathering varies considerably for different parts of the deposit. Near
the crest of the hill the rock is probably weathered to 30 or 35 feet, but hard rock will be encountered at a
shallower depth along the slopes and may vary from a few feet to 25 or 30 feet.
The individual deposits, although containing a high percent of plus 8 mesh mica, are relatively narrow.
There does not appear to be sufficient ore to justify the erection of a scrap mica concentrating plant unless
additional supplies of ore are found in the vicinity.
Assuming an average depth of weathering of 25 feet it is estimated the deposit contains from 30,000 to
40,000 tons of ore.
Sample results are given on Plate 2.
EOWDITCH DEPOSIT
This location is in eastern Yancey County, one mile S72°W of Bowditch, on the property of Blue Ridge
Mining Company of Burnsville, North Carolina. (Figure 5, Location 4). Two small prospect pits on the
northwest side of the deposit are the only workings at present. The country rock is hornblende gneiss, the
foliation of which strikes N30°E and dips from 40 to 50 degrees to the northwest.
The deposits consists of a lens-shaped pegmatite approximately 175 feet long and from 50 to 55 feet
wide near the center section. The width decreases rather uniformly from the center toward both ends. One
inclusion, approximately 5 feet wide, occurs near the center of the deposit. Other smaller inclusions prob-ably
exist.
The material ranges in mica content from 10 to 15 percent, of which about 5 percent is larger than 8
mesh. Some mica books up to 2 inches across were encountered in drilling and indications are that a con-siderable
amount of punch and some sheet mica might be present.
Weathering probably extends to a depth of 25 to 30 feet.
The reserves are estimated to be from 12,000 to 15,000 tons of ore.
Sample Results
Sample No.
1
2
Plus 8 Mesh Mica
5.1%
1.6
Minus 8 Mesh Mica
9.9%
6.97
Total Mica
15.0%
8.57
Sample No. 1. A composite sample from four hand auger holes taken across the strike of the deposit.
Sample No. 2. A composite sample of five hand auger holes taken near the contacts on both sides of the
deposit.
BRIGGS-WOODY DEPOSIT
The deposit is located in the eastern part of Yancey County, 1.5 miles N60°E of Celo and approximately
700 feet west of the South Toe River. (Figure 5, Location 5). The best route to the deposit is along the
Browns Creek Road eastward from Celo to the South Toe River and from this point along the west side of
the river for 0.6 of a mile. The deposit is located about 300 feet northwest of an old barn. In 1950 mineral
rights were owned by Green Woody, Burnsville, North Carolina, and Clarence Briggs, Alexandria, Virginia.
„a nF NORTH CAROLINA
THE SCRAP M.CA^0^^^^^
o?aSun
Z
UJ
O
(t
u)
a.
S 3 - pa3
10
Ul
a.
u
j
o.
2
<
£ i!2
<fl rti —
k- cp
c e
c S
k
CO
"*"
O i \
5 <=>
O>
o o
m tz
z X u S *2 >*
H > 1 -o 4 £
z 2 a3 C
4
J
n.
a € z C uJ ? „
5 -g^ N '
co
% 6 _ rsj">
CO
IS
W
P
PQ
24 The Scrap Mica Resources of North Carolina
Present workings consist of a few small prospect pits which are seldom over three feet deep and some
larger pits in pegmatites west and north of the alaskite body. The country rock is mica schist which strikes
approximately N10°E and dips steeply to the northwest. Many small pegmatites occur in the schist near the
alaskite body, some of which have been prospected for sheet mica.
The deposit is from 110 to 120 feet wide and approximately 400 feet long. It strikes N10°E, roughly
paralleling the foliation of the country rock. The area southwest of the small branch is covered with clay
and loose rock overburden, and some exploration work will be necessary to determine if scrap mica underlies
it. Indications are that the deposit does extend southwest of the branch, and that this extension may be
rather large. No inclusions were observed in the deposit.
Much of the deposit is relatively coarse grained, containing around 5 percent plus 8 mesh mica. A zone
along the northeast contact (see Plate 3) is composed of fine-grained alaskite, which averages about 2 per-cent
plus 8 mesh mica. The highest percentage of coarse mica encountered was near the fence on top of the
small ridge. A composite sample from seven hand auger holes taken at this locality contained 6.0 percent
plus 8 mesh mica. Most of the material is progressively finer grained northeast of this point. Practically
no biotite was encountered.
The alaskite north of the branch is believed to be weathered to a depth of 30 to 35 feet. Along the
branch and to the southwest indications are that hard rock will be encountered at a much shallower depth.
The deposit is believed to have good production possibilities, especially if it is found to contain a sizeable
amount of ore southwest of the branch. There does not appear to be sufficient material north of the branch
to justify the erection of a plant, although mica could be mined along with some other deposits in the area
and washed or hauled to a central plant.
With a small amount of bulldozer work, the material can be mined hydraulically and washed to a num-ber
of different locations along the South Toe River, however, additional reserves should be considered in
selecting a plant location.
It is estimated that the deposit shown on Plate 3 contains 90,000 tons of ore. Material south of the
branch should increase the reserves a substantial amount.
Sample results are given on Plate 3.
BRUSHY CREEK DEPOSIT
This deposit, located in the southwest part of Avery County 4.5 miles N60E of Spruce Pine, (Figure 5,
Location 6) has been mined for kaolin by the Harris Clay Company for several years. Scrap mica is a by-product.
The deposit was first worked for kaolin by Kaolin, Incorporated, about 1937.
A large area adjacent to Brushy Creek is underlain by weathered alaskite. The material is fine grained,
and the mica content is variable. Most of the alaskite apparently contains a total mica content of between
10 and 15 percent.
The deposit was not examined in detail and no samples were taken.
BURLESON DEPOSIT
A relatively large alaskite body is located in eastern Yancey County, 3.2 miles S50°E of Micaville on
a ridge 0.4 of a mile S45°E of Fawn Mountain. There are no accessible roads to the deposit. The property
is owned by Milton Burleson, Spruce Pine, North Carolina. (See Figure 5, Location 7).
The alaskite, as exposed by numerous pits, tunnels, and shafts along the crest and southeast side of the
ridge, appears to be at least 200 feet wide. It strikes northeast across the ridge.
The deposit is relatively fine grained. The four samples taken varied from 2.36 to 5.2 percent plus 8
mesh mica with an average of 3.29 percent. The average total mica content is approximately 18.00 percent.
The material along the crest of the ridge appears to be weathered to a depth of 30 or 35 feet, although
hard rock will be encountered at a shallow depth on both sides of the ridge.
The Scrap Mica Resources of North Carolina 25
Sample Results
Sample No. Plus 8 Mesh Mica Minus 8 Mesh Mica Total Mica
1 3.20% 12.95% 16.15%
2 2.40 14.80 17.20
3 2.36 15.30 17.66
4 5.20 15.60 20.80
Sample No. 1. Trench sample taken from a tunnel on the side of the ridge and from a mine pit above
the tunnel.
Sample No. 2. Composite sample from five hand auger holes and one mine pit along the ridge above the
tunnel.
Sample No. 3. Composite sample from four hand auger holes and one mine pit near the crest of the
ridge.
Sample No. 4. Composite sample from four mine pits and one tunnel near the crest of the ridge north
of the location of Sample No. 1.
BURNSVILLE MICA COMPANY DEPOSIT
The deposit is located in the eastern part of Yancey County 1.5 miles N65E of Celo, on the east side
of the Blue Rock Road. (Figure 5, Location 8). The mineral rights are owned or leased by the Burnsville
Mica Company, Burnsville, North Carolina.
In 1950 this company erected a scrap mica concentrating plant on the deposit and has been producing
scrap mica from it since then. The ore is broken up either by blasting or with a bulldozer and washed tc
the plant.
A large body occurs east of the plant and extends a considerable distance eastward, although all of the
deposit was not examined in detail. The main body is relatively fine grained, but local zones in it and num-erous
smaller bodies found near it contain a high percent of plus 8 mesh mica. Of the four samples taken
the plus 8 mesh mica content averaged 7.0 percent, but this is not representative of the finer material which
makes up the main body. The total mica content of the samples averaged 18.69 percent.
Numerous schist inclusions occur throughout the deposit, some of which are exposed in the open cut.
They appear to be much more numerous near the contacts.
Some semi-kaolinized feldspar was encountered and it is likely that the depth of wgathering varies for
different areas of the deposit. Most of the material appears to be weathered to a sufficient depth for mining
but some bulldozer work or light blasting may be necessary to break it up.
Minus 8 Mesh Mica Total Mica
15.32 % 22.52 rr
8.95 15.75
12.30 17.90
9.91 18.61
Sample No. 1. Composite sample from three hand auger holes taken approximately 100 feet apart from
160 to 360 feet east of the open cut.
Sample No. 2. Composite sample from five hand auger holes taken approximately 80 feet apart from
20 to 340 feet southeast of the open cut.
Sample No. 3. Composite sample from one hand auger hole and the bulldozer cut located about 50 feet
southeast of the open cut.
Sample No. 4. A sample from the open cut mine at the plant.
Sample Results:
Sample No.
1
2
3
4
Plus 8 Mesh Mica
7.2%
6.8
5.6
8.7
26 The Scrap Mica Resources of North Carolina
butler gap deposit
The deposit is located in the eastern part of Yancey County, 2.9 miles S70°E of Micaville, and can be
reached from Highway 19E by following the Ed Young Road 1 mile southeast. (Figure 5, Location 9). In
the spring of 1950, the Southeastern Mica Company worked the deposit on a small *scale, the ore being hauled
by truck to their plant near Crabtree Creek in Mitchell County. No mining was carried out in 1951 or
1952.
The deposit has a maximum width of about 200 feet and a general northeasterly strike. The plus 8 mesh
mica content varies considerably for different areas of the deposit. Some sections contain a relatively high
percentage. A trench sample taken across the strike of the deposit contained 5 percent plus 8 mesh mica
with a total mica content of 16.8 percent.
The depth of weathering of the deposit appears to be irregular. Hard rock will probably be encountered
within 25 or 30 feet.
COX KNOB DEPOSIT
Several zones of alaskite, containing high percentages of plus 8 mesh mica, traverse a ridge 0.3 of a mile
northwest of Cox Knob in eastern Yancey County. (Figure 5, Location 10). The deposit is 2.7 miles S80°E
of Micaville. Contacts of individual alaskite bodies were not determined and, therefore, an estimate of their
size or available tonnage cannot be given with any degree of accuracy.
Auger holes were drilled at right angles to strike of the formation for a distance of 225 feet, and a con-siderable
amount of schist was encountered. Indications are that the schist may occur in such quantities as
to make mining unprofitable. Where the holes penetrated the alaskite, especially in the western part of the
deposit, the plus 8 mesh mica was quite abundant.
Sample Results:
Sample No. Plus S Mesh Mica Minus 8 Mesh Mica Total Mica
1 9.5% 6.2% 15.7%
Sample No. 1. A composite sample taken from 7 hand auger holes, representing the quality of the ore
only. Quantity was not determined. However, the deposit appears to warrant more exploration.
Narrow bands of alaskite and mica schist occur along the ridge northwest of the above described deposit,
on the property of Mills Edge of Newdale, North Carolina. The alaskite is exposed by numerous pits and
shafts dug while prospecting for sheet mica. The bands of alaskite are narrow, seldom exceeding 20 feet in
width. The mica content of the individual bands varies considerably.
CRABTREE CREEK DEPOSITS
One deposit is located in the southwest part of Mitchell County 0.4 of a mile east of Crabtree Creek on
the north side of Highway 19E. (Figure 5, Location 11). The mineral rights on the property belong to
Harris Clay Company, Spruce Pine, North Carolina.
Both kaolin and scrap mica have been produced from the weathered alaskite body. Kaolin was mined
from the two large pits near the crest of the small ridge by Harris Clay Company, and the Southern Mica
Company produced scrap mica from the smaller pit adjacent to the road.
The deposit consists of a series of lens-shaped alaskite bodies which vary from a few feet to about 200
feet in width. The general strike ranges from due north to N45°E. However, the alaskite was intruded
into folds in the mica schist and hornblende gneiss and therefore has a northwest strike locally. Most of the
bodies have irregular contacts due to the folding of the country rock. The principal deposit is near the crest
of the small ridge in which the largest pit occurs. Westward from this body, the alaskite becomes narrowed.
The major portion of weathered alaskite has been mined. The largest remaining deposit appears to be
on the northeast side of the large open cut. A northeasterly striking alaskite body, approximately 150 feet
wide, is exposed in the side of the cut. The extent of this deposit is not known since much of the area to the
northeast is covered with overburden. However, it is believed to extend for 100 feet and possibly a greater
distance toward the northeast. Some material could be mined with a power shovel from other zones in this
pit and from the two pits to the west.
Sample Itesults:
mple No. Plus 8 Mesh Mica
1 4.5%
2 6.5
3 7.0
4 5.1
5 4.2
The Scrap Mica Resources of North Carolina 27
The alaskite is relatively coarse grained, containing an average plus 8 mesh mica content of between ."i
and 5.5 percent. The average total mica content is approximately 15 percent.
Minus 8 Mesh Mica Total Mica
11.04% 15.54%
9.25 15.75
10.68 17.68
8.27 13.27
6.8 11.0
Sample No. 1. Trench sample taken from the road bank above the open cut mine that was worked by
Southern Mica Company.
Sample No. 2. Trench sample taken from the east side of the long open cut on the crest of the hill.
Sample No. 3. Trench sample taken from the northeast side of the large open cut on top of the hill.
Sample No. 4. Trench sample taken from the southeast side of the large open cut on top of the hill.
Sample No. 5. Composite sample from six hand auger holes taken along the fence northeast of the large
open cut. A thorough reconnaissance was not made of this area, and it is probable that other deposits occur
in the vicinity.
Two other deposits occur near Crabtree Creek. One is on the side of the hill east of Crabtree Creek and
south of Highway 19E, and the other is located .4 of a mile west of Crabtree Creek. The northwest end of
the latter deposit traverses Highway 19E. However, the major part of the deposit is southeast of the road.
The former deposit is being worked at present by the Southeastern Mica Company.
The deposits consist of a sedies of lens-shaped alaskite bodies, seldom exceeding 50 feet in width and
occurring close together. These bodies are separated by narrow zones of schist. In general, the deposits
contain a relatively high percent of plus 8 mesh mica. The area southwest of the old workings on the latter
deposit is believed worthy of a detailed examination. A thorough investigation was not made of either de-posit
and samples were not taken.
DEWELD deposits
The DeWeld Scrap Mica Deposits are in eastern Yancey County, 1.6 miles N55°E of Celo, along the
northeast side of Bailey Mountain southwest of the South Toe River. They can be reached by following the
Blue Rock Road to near Halls Chapel and crossing the river at the low water bridge. The mineral rights on
most of the property are owned or leased by the DeWeld Mica Company.
In 1949 the Asheville Mica Company started mining scrap mica from one of the deposits. The ore was
mined hydraulically, washed over a mud screen, and hauled by trucks to their plant, about 1.5 miles to the
south. In the spring of 1950, the DeWeld Mica Company erected a concentrating plant on the property and
has been producing scrap mica since that time.
Hornblende gneiss and mica schist compose the major portion of the country rock. They occur as sepa-rate
formations and also as narrow interlayered bands. The general strike is from N30°E to N40E and,
where exposed in cuts, the dip is from 60 to 80 degrees toward the northwest.
Three separate alaskite bodies occur in the immediate area. Two are above the concentrating plant and
the third, all of which was not mapped in detail, is located on the ridge to the southwest. The bodies are
relatively large, varying up to 200 feet in width and more than 800 feet in length (see Plate 4.) Two of
the three alaskite bodies are well exposed by open cut mines, but the one to the southwest contains only
small prospect pits.
Some inclusions are present but probably do not make up over 5% of the deposits. Most inclusions are
small and do not interfere with mining. Indications are that the deposit to the southwest contains larger
inclusions than the other two.
The deposits contain a relatively high percent of plus 8 mesh mica, averaging between 6 and 8 percent,
and having a total mica content of approximately 20 percent. Since little work was done on the southwestern
28 The Scrap Mica Resources of North Carolina
o» 3S8
t- £ 2^3
7
ijl
1)
cr m LT> CD
^> O <£>
0)
u. >
(XI
O)
H
_l
3 _c
CO V)
fTJ
S 2
The Scrap Mica Resources of North Carolina 20
deposit and on the northern part of the deposit on top of the ridge above the plant, an accurate estimate of
the mica size and content or the boundaries of the deposits cannot be given. The mica size and content
are relatively uniform where exposed in cuts, and it is possible that all of the alaskite shown on Plate 4 con-tains
a high percent of plus 8 mesh mica. Very little biotite is present in alaskite exposed by prospect pits
and open cuts.
The depth of weathering varies considerably for different areas, in general being much greater near the
crest of the hill. Indications are that hard rock will be encountered at a depth of from 50 to about 80 feet,
northeast of the lower cut. Some semi-kaolinized feldspar was observed in the deposits to the southwest, as
shown on Plate 4, and it is likely that hard rock will be encountered at a shallow depth in portions of this
deposit. The average depth of weathering of all deposits is estimated to be from 30 to 35 feet but should
be deeper near the crest of the ridge.
Assuming an average depth of weathering of from 30 to 35 feet the reserves of material shown on Plate
4 are estimated to be as follows : the deposit above the plant, from 40,000 to 55,000 tons, and the deposit on
the hill above the plant, from 200,000 to 225,000 tons. Although an accurate estimate cannot be given for
the deposit to the southwest, the part shown on Plate 4 is estimated to contain from 60,000 to 75,000 tons.
It is highly possible that the tonnage in the latter deposit is much larger. If the deposit on the hill above
the plant extends farther to the north than is shown and is weathered to sufficient depth for mining, the re-serves
in it will be much larger than the figures given above.
Sample results are given on Plate 4.
As stated above, sufficient work has not been done on the southwestern deposit to determine accurately
its production possibilities. However, it is suggested that a more detailed examination be made to determine
size, texture, and mica content of this body.
ED EDGE DEPOSITS
Several alaskite bodies are on the property of Mr. Eel Edge, Route 2, Burnsville, in the eastern part of
Yancey County. This location is 3.3 miles S45°E of Micaville east of the Blue Rock Road. (Figure 5, Loca-tion
13).
Several deposits occur in this area but none of them were mapped in detail. In general, they contain
relatively high percentages of plus 8 mesh mica, however, the mica content varies considerably among the
deposits and within different portions of individual deposits.
Alaskite, exposed in the bank of the Blue Rock Road north of the DeWeld Mica Company's concentrat-ing
plant, strikes northeast and traverses the ridge above the road. The deposit apparently becomes finer
grained northeast of the crest of the ridge but is covered with overburden at numerous places.
The alaskite is relatively coarse grained from the road to a short distance northeast of the crest of the
ridge. Semi-kaolinized feldspar was encountered in hand auger holes in the woods on the ridge and hard
rock is known to occur at shallow depths at numerous places. In the field toward the southeast, however, it
appears to be weathered to a sufficient depth for mining.
Sufficient work was not done to give an accurate tonnage estimate for the deposit.
Sample Results
:
Sample No. Plus 8 Mesh Mica Minus 8 Mesh Mica Total Mica
1 4.0% 12.6% 16.6^
Sample No. 1. A composite sample from three hand auger holes taken across the strike of the deposit
on the crest of the ridge above the Blue Rock Road.
Another deposit traverses an old road in the woods east of Mr. Edge's house. Although this deposit
was not mapped in detail, it appears to have a maximum width of about 75 feet and an average width of
from 40 to 50 feet. It can be traced along the strike for a distance of over 200 feet. The width increases
down the ridge southwest of the old road. Indications are that hard rock will be encountered at a shallow
depth near the bottom of this ridge. To the northeast the formation becomes narrower and much of it is
30 The Scrap Mica Resources of North Carolina
covered with overburden. Hard rock is to be expected at a shallow depth 150 to 200 feet northeast of the
old road.
Most of the deposit appears to contain a relatively high percent of plus 8 mesh mica.
*
Sample Results
:
Sample No. Phis 8 Mesh Mica Minus 8 Mesh Mica Total Mica
1 10.0% 11.7% 21.7%
2 6.7 11.08 17.78
Sample No. 1. A composite sample from three hand auger holes taken across the strike of the deposit
in the old road.
Sample No. 2. A composite sample from four hand auger holes taken across the strike of the deposit
about 150 feet southwest of the location of Sample No. 1.
An alaskite body is exposed in tunnels and pits about one mile northeast of Mr. Edge's house, in the low
gap southeast of Blue Rock Knob. The deposit strikes northeast, is from 50 to 75 feet wide, and extends for
a considerable distance both to the northeast and southwest of the gap. The average plus 8 mesh mica con-tent
of the deposit is approximately 4 percent.
The alaskite appears to be weathered to a depth of nearly 30 feet in the gap but hard rock should be
encountered at a shallow depth along the sides of the ridge near the gap.
The inaccessibility of the deposit will make mining and processing difficult.
Sample Results:
Sample No. Plus 8 Mesh Mica Minus 8 Mesh Mica Total Mica
1 3.75% 11.86% 15.60%
Sample No. 1. A composite sample taken from tunnels and old mine pits near the gap.
Several other deposits examined in this area were fine grained, narrow, or inaccessible.
ED YOUNG SCRAP MICA DEPOSITS
The deposits are located in the eastern part of Yancey County, 2.2 miles S82°E of Micaville, and are
adjacent to U. S. Highway No. 19E and the Ed Young Road. (Figure 5, Location 14). They are on the
property of Ed Young and brothers of Newdale. The only workings are small prospect pits on the No. 2
deposit (see Plate No. 5) located in the woods above the northeast corner of the field.
The country rock is mica schist which, in general, strikes north but is folded and at places strikes north-west.
It dips steeply to the east.
The deposit is composed of several lens-shaped bodies, the largest of which traverses U. S. Highway No.
19E and the Ed Young Road. Smaller bodies are in the field above the road. The width of the alaskite varies
from a few feet to over 150 feet. There are two bodies on the ridge that have a width of 50 feet or more, one
of these being 85 feet wide near the center section and about 200 feet long. The width decreases rather uniform-ly
toward both ends. The No. 2 deposit has a maximum width of 60 feet and is about 250 feet long. Numerous
small alaskite stringers, not shown on Plate 5, occur in the schist. It is very probable that other mineable
lens-shaped bodies occur in the immediate area. No inclusions were observed in the alaskite. If inclusions
are encountered, it is believed they will be too small to interfere greatly with mining.
These deposits contain a relatively high percent of plus 8 mesh mica, however, the total content varies
considerably. Indications are that the plus 8 mesh mica content will average 6 percent or above. Very little
biotite was observed.
The depth of weathering varies considerably for the various deposits. Semi-kaolinized and some hard
feldspar occur in the road bank of U. S. Highway No. 19E and above the road. Hard rock will probably be
encountered at a depth of 20 or 25 feet in this area. Near the crest of the ridge, weathering is believed to
extend to a greater depth ; consequently, there should be 30 to 40 feet of mineable material.
A deposit composed of numerous lens-shaped bodies does not afford as good conditions for hydraulic
mining as is usually found in a larger consolidated deposit. Considering the quantity of ore and the topo-
The Scrap Mica Resources of North Carolina 31
N
SAMPLt RESULTS - PERCENT
NO. t DEPOSIT
Sample 8 Mesh -8 Mesh Total
No. Mica Mica Mica
1 8.0 14.40 22.40
2 1.17 20.20 21.37
3 3.86 13.50 17.36
4 6.25 13.78 20.03
5 3.32 8.60 11.92
6 4.97 12.48 17.45
7 4.29 9.20 13.49
8 6.54 8.53 15.07
9 554 10.12 15.66
10 8.42 12.78 21.20
II 8.54 1880 27.34
Note - Sample No. 6 and 8 are from 2 to 5 ft depth
Sample No 7 and 9 are from 5 to 15 ft depth
Hard
Alaskite
EXPLANATION
EHZ1 Alaskite With Relatively High Mica Content
ESS) Mica Schist
' Contact
Approximate Contact
• Sampled Hand Auger Holes
-2680-* Contour
. Fence
NO. I DEPOSIT
ED. YOUNG SCRAP MICA DEPOSIT
YANCEY COUNTY, NORTH CAROLINA
60 120 3
Bulletin 66
—
Plate 5
32 The Scrap Mica Resources of North Carolina
graphic location, it would be very difficult to mine the material and to wash it to a concentrating plant. This
would be especially true for the material from the deposit adjacent to the road, as sufficient fall cannot be
obtained there. The ore could be mined with power implements and hauled to either one of several plants
located close to the deposit.
i
Assuming an average depth of weathering of from 25 to 30 feet, the reserves are estimated to contain
from 100,000 to 120,000 tons of material that will average about 5 percent plus 8 mesh mica.
Sample results are given on Plate 5.
Another deposit is located approximately 0.3 of a mile south of Highway 19E and traverses the old Blue
Ruck Road below Clinton Brewer's house. This alaskite body is approximately 200 feet wide and strikes
from N10°E to N25 3 E. Although it was not outlined in detail, it is known to extend for a considerable dis-tance
to the southwest and apparently is an off-shoot from the large alaskite body described as the Brewer-
Robinson deposit. The alaskite is much finer grained than that of the deposits described on the Ed Young
property and is believed to contain an average plus 8 mesh mica content of over 3 percent with a total mica
content of around 15 percent. One sample contained 5.4 percent plus 8 mesh mica, however, there appears
to be only a small quantity of this material, as fine-grained alaskite was encountered in hand auger holes west
of the old road. No samples were taken there as it appeared to be representative of the material in Sample
No. 2.
Very little biotite was observed and the material appears to be weathered to a sufficient depth for min-ing.
The deposit appears to have commercial possibilities only if the minus 8 mesh mica is recovered.
Sample Results:
Sample No. Plus 8 Mesh Mica Minus 8 Mesh Mica Total Mica
1 5.40% 11.85% 17.25%
2 1.64 10.10 11.74
Sample No. 1. A composite sample from three hand auger holes taken in the old Blue Rock Road on the
north side of the deposit.
Sample No. 2. A trench sample taken from the bank of the old Blue Rock Road on the south side of the
deposit.
There are other alaskite deposits in the area but time did not permit a detailed investigation.
FAWN KNOB DEPOSIT
The Fawn Knob Deposit is located in the eastern part of Yancey County, 2.7 miles S50°E of Micaville
and 0.3 of a mile east of the Blue Rock Road. (Figure 5, Location 15).
The Newdale Mica Company has been producing scrap mica from the deposit since the spring of 1950.
The deposit consists of two alaskite bodies/ both of which contain a high percent of plus 8 mesh mica. The
deposit occurs on the crest of a steep ridge at an elevation in excess of 3000 feet. It is weathered much
deeper than most deposits with a similar topographic location.
A detailed examination of the deposit was not necessary since most of the workable material is exposed
by open cuts.
Sample Results
:
Sample No. Plus 8 Mesh Mica Minus 8 Mesh Mica Total Mica
1 4.5% 12.9% 17.4%
2 6.0 16.3 22.3
3 10.6 10.6 21.2
Sample No. 1. Average plant feed of the hard materials.
Sample No. 2. Average sample from the upper cut.
Sample No. 3. Average sample from the lower cut.
The Scrap Mica Resources of North Carolina 33
FREEMAN DEPOSIT
This occurrence is in the northeastern part of Yancey County, 2.8 miles N17"E of Micaville and is ad-jacent
to the abandoned clay pits near Lunday. (Figure 5, Location 16). It can best be reached by taking
the Micaville-Double Island School Road to the abandoned clay pits. The deposit is approximately 200 feet
above the road and is exposed in the road bank east of Theodore Freeman's house. It is on the properties
of Theodore Freeman, Route 1, Green Mountain, North Carolina, and Carolina Mineral Company, Kona,
North Carolina. The major part of the deposit is on Mr. Freeman's property. The only workings consist
of small prospect pits most of which are less than 3 or 4 feet deep. (See Plate 6).
The country rock bordering the alaskite body on the southeast is hornblende gneiss. Mica schist and
hornblende gneiss, occurring together in narrow bands and in varying proportions, are present along the
northwest contact. The rock strikes approximately N30°E and dips from 30 to 35° to the southeast. Over-burden,
consisting of clay and hornblende gneiss, ranges from 3 to 6 feet thick on the southeast side of the
deposit. This overburden completely obscures the contact. A hornblende gneiss inclusion, varying from 15
to 50 feet in width, occurs in the southeastern part of the body.
The major part of the deposit, which strikes approximately N30°E, varies from 120 to 375 feet in width
and is more than 800 feet long. Drilling on this deposit disclosed that the mica content varies considerably.
Samples from some of the drill holes contain a very low percent of mica, especially in an area from 75 to 200
feet south of Mr. Freeman's house. At numerous othsr drill holes, material with a low mica content was
encountered. Biotite occurs in varying proportions throughout the deposit but is most highly concentrated
near the hornblende inclusion.
When the alaskite was intruded into the gneiss, solutions undoubtedly reacted with and to some degree
dissolved some of the hornblende, thereby acquiring a relatively high iron content which is necessary to
produce biotite. It is estimated that biotite makes up from 2 to 10 percent of the mica throughout the body.
Zones of fine mica and areas that contain a high percent of biotite will make up at least 50 percent of the
deposit.
The greater portion of the alaskite appears to be weathered to a depth of 30 or 40 feet and in places to
50 feet or more. Hard rock will be encountered at a shallow depth in the broad hollow below the road and
probably in local areas on the southwest end of the body.
In general, the highest percent of plus 8 mesh mica is found on the southeast part of the deposit. Mate-rial
from this section appears to contain an average of from 4 to 5 percent plus 8 mesh mica, whereas that
in the northwestern part contains from 3.5 to 5 percent. Both average from 9.5 to 10 percent total mica.
At the present time this deposit is considered marginal. It will be very difficult to concentrate a high-grade
mica product because of the high percentage of biotite, although certain grades of roofing mica can
be produced. The topography surrounding the deposit would make hydraulic mining relatively easy, and
the deposit is close to an adequate water supply, being approximately 1200 feet from the South Toe River.
There is a good plant site and ample dumping ground north of the deposit.
It is estimated that inclusions will make up from 15 to 20 percent of the deposit and that 35 to 40 per-cent
of the deposit will be relatively fine grained. Assuming an average depth of weathering of from 35 to
40 feet the reserves are estimated at from 175,000 to 225,000 tons of material that will average from 4 to 5
percent plus 8 mesh mica and from 100,000 to 125,000 tons of material that will average from 3.5 to 4 percent
plus 8 mesh mica. It is estimated that the deposit contains from 275,000 to 350,000 tons of material having
a total mica content of from 9 to 10 percent.
Sample results are given on Plate 6.
GUSHER KNOB DEPOSIT
The deposit is located in the southwestern part of Avery County, 6 miles N42°E of Spruce Pine. (Fig-ure
5, Location 17). Harris Clay Company has been producing kaolin from the Gusher Knob deposit since
around 1944. Scrap mica is being recovered as a by-product.
A sizeable area east of Gusher Knob is underlain by a relatively fine-grained weathered alaskite con-taining
only a small percent of plus 8 mesh mica. The mica content varies considerably in different parts of
the deposit. Some of the alaskite contains as much as 15 percent mica but much of it has less than 10 percent.
34 The Scrap Mica Resources of North Carolina
P4
w
.J p
PQ
The Scrap Mica Resources of North Carolina 35
Weathering has progressed to a much greater depth than is generally found in alaskite in the Spruce
Pine district. Soft material has reportedly been encountered at depths greater than 80 feet at places on the
deposit.
The deposit was not examined in detail and no samples were taken.
H. W. YOUNG DEPOSITS
The deposits are located in the eastern part of Yancey County 2.7 miles S4CTE of Micaville, on the west
side of the Blue Rock Road and southwest of Fawn M untain. (Figure 5, Location 18). The property is
owned by H. W. Young, Route 2, Burnsville, North Carolina.
There are numerous mine and prospect pits in a deposit on the west side of the Blue Rock Road and
north of Mr. Young's house. This deposit is a continuation of the S. M. Edge deposit. It was not mapped
because much of the area is covered with overburden. It appears to consist of a series of lens-shaped alas-kite
bodies which probably vary in width from a few feet to about 100 feet. They have been exposed by
mine and prospect pits for a distance of over 800 feet to the southwest, although it is unlikely that alaskite
bodies occur over the entire area. Large areas, especially near the small branch southwest of the road, are
covered with overburden. Indications are that numerous inclusions will be found throughout the deposits.
In general the deposits contain a relatively high percent of plus 8 mesh mica, but the mica content and
size vary considerably. The depth of weathering appears to be very irregular. Since hard rock is exposed
in many of the mine pits, it is probable that hard rock will be encountered at shallow depths over much of the
area. This may be true especially on the sides of the hill near the branch as well as between the branch and
the Blue Rock Road.
Sufficient work has not been done to give estimates of the tonnage or accurately appraise the production
possibilities of the deposit, nevertheless it is believed worthy of a more detailed investigation, especially the
area southwest of the branch.
Sample Results
:
Sample No. Plus 8 Mesh Mica Minus 8 Mesh Mica Total Mica
1 5.00% 8.50% 13.50 r
r
2 2.60 7.78 10.38
3 5.90 7.35 13.25
4 4.50 9.00 13.50
5 16.20 11.64 27.84
6 9.67 10.88 20.55
7 7.45 14.80 22.25
Sample No. 1. Composite sample taken from three old mine pits near the fence approximately 150 feet
below the road.
Sample No. 2. Trench sample taken from the long open cut in the woods approximately 140 feet below
the road.
Sample No. 3. Composite sample taken from two small mine pits approximately 20 feet south of the lo-cation
of sample No. 2.
Sample No. 4. Composite sample taken from three small mine pits approximately 35 feet south of the
location of sample No. 3.
Sample No. 5. Trench sample from an old mine pit in the woods approximately 220 feet below the road
and 130 feet south of the fence.
Sample No. 6. Composite sample taken from two small mine pits on the hill southwest of the branch.
Sample No. 7. Composite sample taken from two mine pits on the western edge of the deposit approxi-mately
75 feet south of the location of sample No. 6.
Another deposit occurs in the small field south of the fork in the road approximately 400 yards south of
the deposit described above. It traverses the Blue Rock Road south of the fork. The deposit is lens-shaped.
has a width of 30 or 35 feet and appears to be from 150 to 175 feet in length. The alaskite is relatively
Sample Results
:
Sample No. ' Plus 8 Mesh Mica
1 5.36%
2 6.67
36 The Scrap Mica Resources of North Carolina
coarse grained, containing an average plus 8 mesh mica content of 6 or 7 percent. It is probably weathered
to a depth of 35 or 40 feet.
Minus 8 Mesh Mica Total Mica
12.21% 17.57%
10.00 16.67
Sample No. 1. A composite sample from three hand auger holes taken across the strike of the deposit.
Sample No. 2. A composite sample from two hand auger holes taken across the strike of the deposit on
the west side of the Blue Rock Road.
The Monaqua Mining Company has been producing scrap mica for about ten years from a series of lens-shaped
bodies on the ridge south of the road fork. The ore is pushed or hauled with a bulldozer to a stockpile
above the plant and washed from there to the plant.
These deposits seldom exceed 50 or 60 feet in width but contain a relatively high percent of plus 8 mesh
mica.
Sample Results
:
Sample No. Plus 8 Mesh Mica Minns 8 Mesh Mica Total Mica
1 7.80% 9.68% 17.48%
Sample No. 1. A trench sample from the northeast end of the large open cut on the crest of the ridge.
LONG BRANCH DEPOSIT
The deposit is located in the eastern part of Yancey County, 2 miles S85°E of Micaville and west of the
Newdale Presbyterian Church. (Figure 5, Location 19). The mineral rights on the property belong to
Harris Clay Company, Spruce Pine, North Carolina.
A large body of alaskite occurs on the side of the ridge north of Highway No. 19E. The present work-ings
consist of mine and prospect pits in the woods and a tunnel approximately 150 feet long near the old
road west of the church. This body has been drilled rather extensively to determine the quality and quan-tity
of kaolin.
The deposit is over 1500 feet long, in places as much as 1000 feet wide, and has a general northeast
strike. Numerous pegmatites are found near the contacts, especially on the northern side of the body, and
some sheet mica has been mined from them.
The alaskite is fine grained, but in places contains small pegmatites which have a high percent of plus
8 mesh mica. The pegmatites appear to be small and sporadic in occurrence and do not contian a large ton-nage
of ore. The main body, although fine grained, contains a relatively high percent of mica, especially
along the ridge north of the creek. In this area the average mica content is estimated to be approximately
16 percent. The alaskite is finer grained to the northwest.
The deposit has good production possibilities for the recovery of fine mica. Previous drilling indicates
that a good grade of kaolin occurs in the northwest part of the deposit. The recovery of kaolin should be
given serious consideration in the event of scrap mica production.
It is estimated that the deposit contains from 1,200,000 to 1,600,000 tons of ore.
Sample Results
:
Sample No. Plus 8 Mesh Mica Minus 8 Mesh Mica Total Mica
1 4.8% 11.3% 16.1%
Sample No. 1. A trench sample from the tunnel at the old road west of the church.
The Scrap Mica Resources of North Carolina 37
MAYBERRY DEPOSIT
The Mayberry Scrap Mica Deposit is located in the eastern part of Yancey County, 1.3 miles N80°E of
Celo, between Bailey Mountain and the South Toe River. (Figure 5, Location 20). The northern part of
the deposit traverses the Browns Creek Road at a point approximately 1.5 miles east of Celo. The mineral
rights on the property belong to Mr. Jim Mayberry, Spruce Pine, North Carolina.
Numerous mine and prospect pits occur in or near the deposit, the largest ones being in pegmatites near
the alaskite contacts. A considerable amount of' sheet mica has been produced from the Jimmy Cut and other
mines in these pegmatites.
The country rock is mica schist, which has a general strike of from north to N15°E. Near the road the
schist dips approximately 70° to the west, however, th3 prevailing dip of rocks in that area is to the east. It
is very probable that much of the schist surrounding the deposit dips steeply to the east. Numerous pegma-tites
occur in the schist, particularly along the west contact. Near the northern end of the deposit a rela-tively
long pegmatite, roughly paralleling the body, is well exposed by mine pits and shafts. This pegmatite
is located about 70 feet west of the alaskite body.
It is believed to be the largest undeveloped deposit containing a high percent of plus 8 mesh mica in the
Spruce Pine district. The width varies from 100 to over 200 feet with an average of from P20 to 150 feet.
The alaskite body has an overall length of over 2000 feet, although it appears to pinch out at one place.
Although the deposit varies some in width, the boundaries are relatively uniform for a distance of about 1200
feet north of the road. The contacts could not be determined accurately in the large draw north of the road
because of an excessive amount of overburden, but indications are that it pinches out at this point and that
a different body is present to the north. Hereinafter the southern body will be referred to as the No. 1
deposit and the northern body as the No. 2 deposit. Contacts were not accurately determined on the north-ern
end of the No. 2 deposit because of the presence of numerous schist inclusions and a considerable amount
of fine-grained material. (See Plate 7)
.
Schist inclusions occur at many places throughout the deposit, but are much larger and apparently more
plentiful on the northern end of the No. 2 deposit. It is estimated that inclusions make up approximately
10 percent of the deposit except on the northern end, where they comprise up to 50 percent in places.
The alaskite is coarse grained, containing a high percent of plus 8 mesh mica. Although there is some
variation, the No. 1 deposit appears to have a relatively uniform texture, and indications are that it will
average from 6 to 7 percent plus 8 mesh mica. Near the edge of the woods on the northern end it is fine
grained, although the amount of fine-grained material makes up only a very small percent of the dep