Magnetic iron ores of East Tennessee and western North Carolina

Book i NORTH CAROLINA GEOLOGICAL AND

ECONOMIC SURVEY

Joseph Hyde Pratt, Director.

T6

BULLETIN No. 32

MAGNETIC IRON ORES OF EAST TENNESSEE AND

WESTERN NORTH CAROLINA

W. S. BAYLEY, Geologist.

Prepared by

North Carolina Geological and Economic Survey

and the

Tennessee Geological Survey

as a joint report

In cooperation with the

United States Geological Survey.

jUU^' 9W ytfilON

M

i

GEOLOGICAL BOARD

Raleigh

Frank R. Hewitt,

Asheville

C. C. Smoot, III.

North Wilkesboro

John H. Small Washington

S. W estray Battle Asheville

Joseph Hyde Pratt, Director

Chapel Hill

LETTER OF TRANSMITTAL

To His Excellency , Cameron Morrison , Governor of North Carolina.

Chapel Hill, N. C.

April 1, 1923.

Sir:

The North Carolina Geological and Economic Survey has prepared in cooperation with the Tennessee Geological Survey and the United States Geological Survey, a detailed report on The Magnetic Iron Ores of East Tennessee and Western North Carolina. This is the second report that the Survey has prepared in cooperation with the Survey of a sister State, the first report being on the Yirgilina Copper District in cooperation with the Virginia Geological Survey.

As the problems that had to be considered and solved in connection with these magnetic iron ores were joint problems it was felt that better results could be obtained if the investigations v T ere carried on coopera¬ tively by the two Surveys and that the field w ork in both States be done by the same geologist. Prof. W. S. Bayley was employed by the two Surveys and has done all the field work, with the approval of the Direc¬ tors of the two State Surveys and of the United States Geological Sur¬ vey.

The report is a geological and economic investigation of these magnetic iron ores, and it is recommended that it be published as Bul¬ letin 32 of the reports of the North Carolina Geological and Economic Survey.

Yours respectfully,

Joseph Hyde Pratt, Director.

North Carolina Geological and Economic Survey.

Chapter III. The ores. 35

General features. 35

Chanter IV.

i.

Character. 37

Deposits in the mountain districts. 37

Geology. 37

Roan gneiss. 39

Bakersville gabbro. 41

Cranberry granite. 44

Relations between Roan gneiss, Cranberry granite and other rocks ... 47

Ore veins. 48

Vein-filling. 48

The ore. 52

The gangue. 58

Pegmatite. 62

Gneisses. 64

Relations ox the rocks in the vein-mass. 66

Age. 67

Utilization. 69

Chapter V. Instruments employed in exploration. 82

The dial compass. 82

The dip needle. 88

The magnetometer. 91

Sampling. 92

Chapter VI. General features. 97

Carter County, Tenn., and Avery and Mitchell counties, N. C. 97

The Cranberry belt. 97

Cranberry mine. 98

General description of mine and ore. 98

Smoky No. 1. 106

MAGNETIC IRON ORES OF EAST TENN. AND WESTERN N. C.

Smoky No. 2. 108

Firmstone opening. 112

Mine opening. 112

Other openings in the Cranberry belt. 117

Lee Johnson place. 117

Cooper place. 118

Ellers and Hardigraves Elk Park openings. 118

Wilder mine. 119

Greenlee and Ray and Tester property. 122

Red Rock mine. 122

Patrick mine. 123

Teegarden and Ellis mines. 123

Heupscup Ridge prospects. 126

Peg Leg and Old Forge mines. 126

Horse Shoe prospect. 128

Julian prospect. 129

Campbell prospect. 129

Chestnut Ridge prospects. 130

Magnetic City prospects. 130

Deposits between Magnetic City and Toe River. 131

Madison County, N. C. 132

Big I vy mine. 132

Chapter VII

Alleghany and Ashe counties, N. C. 134

Kirby opening.. 136

Deposits in the Poison Branch belt. 139

General description. 139

Pugh and Smith openings. 139

Deposits on Helton Knob. 140

Blevins openings. 140

Red Hill openings. 141

McClure's Knob deposits. 142

Poison Branch mine. 143

Openings between Silas and Piney creeks. 145

Piney Creek opening. 146

Francis and Henninger openings. 147

Openings on Turkey Knob. 148

Graybeal property. 149

Waughbank property. 153

Hampton Knob openings. 153

Openings southwest of Hampton Knob. 153

Openings southeast of Lansing. 154

Deposits in the New River belt. 155

General description. 155

Openings in Alleghany County. 155

Lunceford openings and Cox place. 156

Brown openings. 157

Ballou Home Place and Sand Bank openings. 157

Reserves in Ashe County. 160

CONTENTS

O

Chapter VIII. Deposits in the Piedmont area of North Carolina. 161

Catawba and Lincoln counties, N. C. 166

General description. 166

Deposits in the Catawba-Iron Station belt. 166

Pow r ell ore bank. 168

Little Mountain deposits. 168

Anderson Mountain openings. 169

Morgan and Stonew all banks. 169

Brevard and Big Ore banks. 170

Deposits near Iron Station. 172

Deposits in the Newdon belt. 172

Barringer mine. 172

Forney and Killian mines. 173

Exposures on Howards and Indian creeks. 174

Deposits in the Eastern belt. 175

Gaston County, N. C. 175

Deposits in the Eastern belt. 176

Crow r ders Mountain deposits. 176

Deposits in the Costner mine belt. 177

Costner mine. 177

Ellison mine. 178

Ferguson mine. 178

Fulenwider mine. 180

Yellow Ridge mine. 181

Chapter IX. General character. 183

Ashe Mining Company’s mine. 183

Chemical and mineralogical composition of ore. 184

Association of minerals in the ore-mass. 188

Pegmatite veins in the ore. 191

The ore-body. 192

Other marble-magnetite ores. 194

Pit on Dr. Jones’s property. 194

Red Rock mine. 194

Production and reserves.. 196

Chapter X. Characterization. 198

Utilization. 207

Chapter XI. Deposits in the mountain districts. ^09

Ashe County, N. C. ^09

Smith place. ^10

McCarter place. 215

Bauguess place. 215

Pennington opening. 216

Alleghany County, N. C. 217

Avery and Mitchell counties, N. C. 217

Senia deposit. 218

Avery place. 219

Grassy Bald of Roan Mountain. 219

Jenkins prospect. 220

Carter County, Tenn. 222

Lost Cove prospect. 222

Yancey County, N. C. 223

Madison County, N. C... 224

Macon County, N. C. 225

Dobson Mountain. 225

Chapter XII. Deposits in the Piedmont area, North Carolina. 228

Caldwell County, N. C. 228

Farthing place. 228

Richlands Cove. 229

Rockingham, Guilford and Davidson counties, N. C. 230

Tuscarora and Shaw belts. 230

Tuscarora and Dannemora mines. 234

Shaw mine. 237

Apple plantation. 238

Davie County, N. C. 238

Chapter XIII. Deposits in North Carolina. 240

Deposits in Tennessee and adjacent portions of Watauga County, N. C.. 241

Deposits in the valley of Laurel Creek. 241

Whitehead prospect. 241

School House prospect. 241

Deposits in Walnut and Beech mountains. 242

Big Ridge openings. 242

Explorations near Elk Mills. 242

Deposits on Lunsford Branch. 244

Scrawl Ridge openings. 244

Lunsford prospect. 244

Finney and Teegarden mine. 245

CONTENTS

ILLUSTRATIONS

Plate Page

I. Map showing principal mines and explorations on and near the

Cranberry belt, in Avery and Mitchell counties, N. C. 34

II. ( A ) Photomicrograph of Bakersville gabbro, near Cranberry, N. C... 43

( B ) Photomicrograph of ore from Peg Leg mine. Carter County, Tenn. 43

III. Polished surface of portion of vein-filling, Cranberry mine, Cran¬

berry, N. C., showing interlayering of ore and gangue. 49

IV. Polished surface of portion of vein-filling, Cranberry mine, Cran¬

berry, N. C., showing association of ore with hornblende. 51

^ . Polished surfaces of two specimens of pegmatite and ore, from vein

at Cranberry mine. Cranberry, N. C. 53

VI. (.4) Photomicrograph of lean ore, Cranberry mine, Cranberry, N. C. . 55

(B) Photomicrograph of schistose ore from Teegarden mine, near Shell

Creek, Carter County, Tenn. 55

VII. ( A ) Photomicrograph of garnetiferous magnetite ore, from Smoky No. 1,

Cranberry, N. C., in ordinary light. 57

• B) Same as A, between crossed nicols. 57

VIII. (A) View of pegmatite and ore in wall of open cut. Cranberry mine.

Cranberry, N. C. 59

(B) View of younger pegmatite cutting across ore vein in Teegarden

mine, near Shell Creek, Tenn. 59

IX. Polished surface of pegmatite streaks in vein-filling, Cranberry

mine. Cranberry, N. C. 01

X. (.4) Photomicrograph of epidotized pegmatite vein-filling, Cranberry

mine, Cranberry, N. C. 03

( B ) Photomicrograph of pyroxene-magnetite pegmatite, Cranberry

mine, Cranberry, N. C. 03

XI. (A) Photomicrograph in ordinary light of epidote-hornblende gneiss,

vein-filling, Cranberry mine. Cranberry, N. C. 05

( B ) Same as A, between crossed nicols. 05

XII. View of Cranberry mine, Cranberry, N. C. 99

XIII. V iew toward Smoky Mountain, Cranberry, N. C. 101

XIV. Cranberry Furnace, Johnson City, Tenn. 103

XV. Map of surface, Cranberry mine, Cranberry, N. C., with projec¬ tion of underground workings. 105

XVI. Plat of workings. Cranberry mine, Cranberry, N. C. 107

XVII. (A) View of Smoky No. 1 opening, showing hanging-wall granite, Cran¬ berry, N. C. 109

(B) View of part of wall, open cut, Cranberry mine, illustrating irregu¬ lar distribution of the ore. 109

XVIII. ( A ) View of wall of open cut, Cranberry mine, Cranberry, N. C., show¬ ing irregular distribution of pegmatite in the vein-filling. 113

(B) General view of wall of same cut, showing hanging-wall of foliated

Cranberry granite. 113

XIX. Isodynamic chart of Wilder mine property, near Shell Creek, Car¬ ter County, Tenn. 121

MAGNETIC IRON ORES OF EAST TENN. AND WESTERN N. C.

XX. ( A ) Photomicrograph of magnetite ore, from Kirby exploration, Stur¬

gill, Ashe County, N. C. 137

( B) Photomicrograph of hornblende granite ‘horse' in Cranberry vein,

showing epidotization of plagioclase. 137

XXI. Polished surfaces of marble-magnetite ore from Ashe Alining Co.’s

mine, Lansing, Ashe County, N. C. 185

XXII. {A) Photomicrograph of titaniferous magnetite, from Smith exploration,

showing alteration of ore mineral into rutile. 201

( B ) Photomicrograph of silicates associated with titaniferous magnetite

of Pennington exploration, Ashe County, N. C., showing prob¬ able pseudomorph after olivine. 201

(C) Photomicrograph of titaniferous magnetite from Pennington ex¬

ploration, Ashe County, N. C., showing presence of rutile in the ore mineral. 201

( D) Polished surface of ore, Tuscarora mine, Guilford Co., N. C. 201

XXIII. (A) Photomicrograph of titaniferous magnetite from Smith exploration

Ashe County, N. C., showing cracked magnetite. 211

( B ) Photomicrograph of another part of the same ore, showing rutile

in magnetite. 211

Figure Page

1. Index map of western North Carolina and East Tennessee, showing positions

of detail maps. 20

2. Dial compass. 83

3. Diagram illustrating horizontal deflection of compass needle caused by buried

magnetic strip. (After Smyth). 84

4. Diagram illustrating effect of strike of magnetic strips upon needle of dial

compass. (After Hotchkiss). 85

5. Dip needle. 88

6. Contour map of dip needle deflections over a band of magnetic ore. (After

Broderick). 89

7. Diagram illustrating effect of buried magnetic strip upon dip needle at dif¬

ferent positions. (After Hotchkiss). SO

8. Diagram illustrating use of dial compass and dip needle to trace a magnetic

line. (After Hotchkiss). 90

9. Magnetometer. 91

10. Map showing isodynamic lines over a belt of magnetic formation in a rough

country. (After Smyth). 92

11. Map of isodynamic lines over a series of magnetic lenses illustrating use as a

guide for drilling. (After Hamilton). 94

12. Diagram to illustrate how the meandering of a drill hole may result in missing

ore-body. (After Hamilton). 95

13. Map showing locations of magnetic iron ore deposits in Ashe County, North

Carolina. (After Nitze). 134

14. Sketch map of openings at Poison Branch Mine, Ashe County, North Caro-

Carolina. (After Nitze). 144

15. Map of portion of Ashe County, North Carolina, showing positions of the

Graybeal property and the Ashe Mining Co.’s mine near Lansing. 15 )

16. Map of explorations on Ballou and Calloway properties, Ashe County, North

Carolina. 158

CONTENTS

Figure Page

17. Map of iron ore deposits in Catawba, Lincoln, and Gaston counties, North

Carolina. (After Kerr, Hanna and Nitze). 161

18. Ideal section illustrating shapes and positions of ore-bodies in Lincoln County,

North Carolina. (After G. B. Hanna). 168

19. Map of openings at Big ore bank, Lincoln County, North Carolina. (After

Bailey Willis). 170

20. Plan and section of Ashe Mining Co.’s mine at Lansing, Ashe County, North

Carolina. (By Geo. W. Cooke). 186

21. Sketch of marble exposures at Intermont, Mitchell County, North Carolina. . 196

22 . Sketch map of northern portion of iron-ore belt in Guilford and Rockingham

counties, North Carolina. (After Lesley). 230

23 . Sketch map of southern portion of iron-ore belt in Guilford and Rockingham

counties, North Carolina. (After Lesley). 231

24 . Openings at the Tuscarora Iron Works, Guilford County, North Carolina.

(After Bailey Willis). 232

25 . Plan and sections at Danemora mine, Rockingham County, North Carolina.

(After Bailey Willis). 233

26. Map of explorations on Walnut Mountain, near Elk Mills, Carter County,

Tennessee. (After Keith and Hamilton). 243

27. Diagrammatic cross section through Finney and Teegarden mine. Carter

County, Tennessee. 245

28. Photomicrograph of hematitic magnetite ore from Finney and Teegarden mine.

Carter County, Tenn. 247

MAGNETIC IRON ORES OF EAST TENN. AND AVESTERN N. C.

Foreword

The present report, entitled “Magnetic Iron Ores of East Tennessee and Western North Carolina,” represents a joint investigation of an important magnetic iron ore district lying partly in each State, and which has been carried on cooperatively by the North Carolina Geological and Economic Survey, the Tennessee Geological Survey, and the United States Geological Survey.

Professor W. S. Bayley, of the University of Illinois, Avas selected as the geologist to make the surA^ey in these tAA 7 o States, and during the course of investigation he has had conferences AA T ith the State geologists of North Carolina and Tennessee and with E. F. Burchard, geologist of the United States Geological Survey in charge of iron.

The area coA^ered by the investigation includes Carter County* Tennessee, and parts of Ashe, Allegheny, Avery and Mitchell counties* North Carolina.

The report also considers briefly deposits of magnetite in CataAA r ba, Lincoln and Gaston counties, North Carolina. The topographical maps Avhich have been used as bases of the geological maps accompanying this report Avere prepared from the topographic quadrangles of the Lmited States Geological SurA r ey and by special mapping of portions of the area.

The United States Bureau of Mines has made the tests in regard to method of separation of the magnetites, using for this purpose samples of ore from the Cranberry mine, Avery County, North Carolina, col¬ lected by Professor Bayley and Mr. Burchard.

The author has been very materially assisted by the owners of the various iron properties, and others interested in the general region, and the state geologists desire to make grateful acknowledgement at this time to all who assisted in various ways in facilitating the work of this investigation.

W ilbur A. Nelson,

State Geologist for Tennessee.

Joseph Hyde Pratt,

State Geologist for North Carolina.

The purpose of the study of the magnetic iron ores of East Ten¬ nessee and Western North Carolina was to learn, if possible, something of their value as a source of supply to furnaces in the South. It was undertaken at the suggestion of the State Geologist of North Carolina because the existence of the large deposit at Cranberry had led many persons to suppose that there might be other similarly large deposits in other portions of the mountain district. It was learned, however, soon after the beginning of the field work, that the most promising un¬ developed deposits are in the extension of the Cranberry vein in Ten¬ nessee and that the topography of the region in which most of the mag¬ netites occur is such as to make Johnson City, where there is already a modern blast-furnace, the natural outlet of the ores.

I he furnace at Johnson City has utilized the ores of the Cranberry mine. It is desirable to learn whether or not there are other sources from which it may receive supplies. Rumors have been prevalent that there is an inexhaustible supply of iron ore in the area contributary to Johnson City. It is important to knoAv whether the rumors are well founded or not. These considerations led to the cooperation of the Tennessee Geological Survey in the publication of the results of the study—and the outcome is the present bulletin. Throughout the course of the study the U. S. Geological Survey cooperated with the two State Surveys, paying a large share of the expenses of the field study.

%j

Three 1 articles dealing with special phases of the subject, and a fourth 2 giving a summary of the entire study, have already been pub¬ lished.

The field work on which the report is based was done during parts of the summers of 1919, 1920, and 1921. In 1919 about seven weeks were devoted to the study of the magnetite deposits of Avery and Ashe counties, N. C., and that portion of Carter County, Tenn., contiguous to Avery County, and about two weeks to visiting the deposits in the Pied¬ mont area of North Carolina. In 1920 the openings in the Cranberry belt of deposits extending westward from Cranberry into Carter County were again visited, about two weeks being spent in the study of critical areas, and a week in Ashe County making a topographic map of the region around Lansing and in the vicinity of the explorations on the North Fork of New River. In 1921 the region was revisited in company with Mr. E. F. Burchard of the U. S. Geological Survey. A number of the most important deposits were again examined and the Cranberry

iThe magnetic ores of North Carolina—their origin: Econ. Geol., vol. 16, p. 142, 1921.

A magnetite-marble ore at Lansing, N. C.: Jour. Elisha Mitchell So., vol. 37, p. 138,

The occurrence of rutile in the titaniferous magnetites of Western North Carolina and Eastern Tennessee: Econ. Geol., vol. 18, p. 382, 1923.

3 General features of the magnetic ores of Western North Carolina and Eastern Ten¬ nessee: U. S. Geol. Surv. Bull. 735-G, 1922.

mine was sampled for an experimental study of the susceptibility of its ore to magnetic separation methods. At the close of the season a day was spent examining the deposits of hematitic ores in Carter County between Shell Creek and Butler.

The writer wishes to express his appreciation of all the courtesies extended to him by the people with whom he was brought in contact during this work. Not only did the dwellers in the district respond willingly to all his requests for information, but in many cases they went out of their way to aid him in the search for the hidden mine holes and exposures. Special thanks are due to Mr. F. P. Howe, President, and to the general officers of the Cranberry Furnace Company and to Mr. S. H. Odom, Superintendent of the Cranberry mine, for information that could not have been secured elsewhere, and for the use of maps of the Cranberry mine, and to Mr. George Cooke, President of the Ashe Mining Company, who served as guide to many of the explorations and exposures in the neighborhood of Lansing. Grateful mention should also be made of Messrs. L. W. Fischel and L. J. Phipps, students of the Lffiiversity of North Carolina for their painstaking work on the map portions of Ashe County. The writer is also under obligation to Mr. S. H. Hamilton from whose report, now in the possession of the Tennessee State Geological Survey, he has taken the description of a few deposits which were not visited, and has copied the magnetic map of the Wilder Mine. Finally thanks are due in large measure to Col. Joseph Hyde Pratt, State Geologist of North Carolina and Mr. Wilbur A. Nelson, State Geologist of Tennessee, for their generous cooperation with him during the prosecution of the investigation.

The principal results of the study may be summarized as follows:

(a) The magnetic ores contributory to Johnson City and those in the Piedmont area of North Carolina are of three types, viz.: hematitic magnetites, titaniferous magnetites and non-titaniferous magnetites, all of which are in rocks of pre-Cambrian age.

The first group is composed of small deposits scattered over the mountain district of the two States. The largest and most character¬ istically developed are in the northeast portion of Carter County, Tenn., on Lunsford Branch between Butler and Shell Creek. They are asso¬ ciated with old volcanic rocks that may be classed with Keith’s metarhyolites 1 which are thought to be of Algonkian Age. These are asso¬ ciated with chloritic schists that are probably metamorphised basic volcanics. Both acid and basic rocks are saturated with fluorite. Magnetite and hematite are so closely incorporated with the chloritic schists that it is thought iron emanations accompanied the basic mag¬ mas to their present positions, and formed the ores. It is possible that the presence of hematite is due to the presence of fluorine in the emana¬ tions.

‘Keith, Arthur, U. S. Geol. Surv. Geol. Atlas, Cranberry folio (No. 90), 1903.

At present the hematitic magnetites are not of practical importance as sources of iron-ore since the quantity available in the district is too small to warrant the expenditure of the funds necessary to place it on the railroad.

b. The titaniferous magnetites are present in the mountain dis¬ trict and in the Piedmont area. Some of the deposits are comparatively large, but most are too small to be of present value as sources of ore, even if they were acceptable to the furnace men. So long as there is a sufficient supply of non-titaniferous ore available there will be no de¬ mand for the titaniferous ore as a source of iron. In the future, when the supply of high-grade non-titaniferous ore is exhausted the titan¬ iferous ores will unquestionably become of importance. At present it would be necessary to separate from them concentrates nearly free from titanium before they could be utilized in the blast-furnace in competi¬ tion with non-titaniferous ores. This is possible in the case of some of them, but is so expensive that it is not practicable.

Singewald 1 had shown that for the most part the titanium in these ores is due to an intricate growth of some titanium mineral with magne¬ tite. He supposed the titanium mineral to be ilmenite in such small plates and needles that it could not be separated by magnetic methods from the magnetite without such fine grinding that the cost of concen¬ tration would be prohibitive. Analyses of some of the titaniferous ores indicate that the titanium is not always present as ilmenite but that in some cases, at least, it occurs as an oxide and the study of thin sections show that much, if not all, of the titanium is present as rutile. How¬ ever, the discovery of this fact does not modify Singewald's conclusion that the ores are unavailable at present as sources of iron. In one group of deposits—that on the Tuscacora and Shaw belts in Rocking¬ ham, Guilford and Davidson Counties, N. C., the intergrowth may be coarse enough to warrant an attempt at concentration, but the deposits are so far away from blast-furnaces that they are not now probable sources of ore.

In the field the titaniferous magnetites can usually be recognized by the fact that they are associated with basic rocks like gabbro. They are believed to consist mainly of segregations of ore minerals that were intruded into cooled portions of the same magma from which they were segregated.

c. The non-titaniferous magnetites are the most promising sources of ore for the North Carolina and East Tennessee furnaces. They are very low in phosphorus, sulphur, and titanium and consequently are utilized for making a very low-phosphorus iron. The ore that has not been concentrated by magnetic processes is comparatively low in iron, rarely reaching a content higher than 41 per cent. It is,

‘Singewald. J. T., Jr., U. S. Bur. Mines Bull. 64, 1913.

however, susceptible to concentration, yielding a concentrate which may contain from 50 to 71 per cent of metal, depending upon the fine¬ ness to which the crude ore is ground and the strength of the magnets used in the process. (See page 69.)

It has been learned that there are some large deposits of ore of this kind in the Piedmont area of North Carolina and in tlie mountain dis¬ trict of North Carolina and Tennessee. Those in the Piedmont area are not of immediate economic importance because they are too far from furnaces. Most of those in the mountain district are within an area that should be contributory to Johnson City, but at present some of them particularly those in Ashe County, N. C., are unavailable because too far from the railroad. The largest deposits in the entire district, so far as we know, are on a belt passing through Cran¬ berry in Avery County, N. C., and extending northwest into Carter Countv, Tenn. At Cranberry is the well-known Cranberry mine which has been furnishing ore to the blast-furnace at Johnson City for several decades. This is regarded as the type of all other non-titaniferous magnetites in the mountain district except one, at Lansing, Ashe County, which is in marble. The Cranberry vein is in a gneissoid granite.

One of the principal objects of the study was to determine the origin of the Cranberry deposit so that some notion might be gained as to whether it extends beneath the present workings of the mine or is merely a superficial phenomenon. Since the ore was found to be closely associated with an epidotized pegmatite which was originally an augite syenite-pegmatite, it is believed to be deep-seated in origin and consequently may be expected to continue to depth with approximately the same character as in the developed portion of the vein.

The ore occurs in the vein as a series of lenses connected with one another by thin strips of ore. If the vein, as appears probable, is as rich in ore beaneath the present bottom of the mine as above it, there is present in 1,800 feet of the vein and within a depth of 550 feet beneath the present lowest mine-level about 1,700,000 tons of ore of the same quality as that which has already been taken out.

The Cranberry vein continues without interruption for 5^ miles northwest of Cranberry into Carter County, Tennessee, and in it are lenses of ore which have been opened at the Wilder, Teegarden, Peg Leg and other mines. A conservative estimate of the ore existing in the vein between the Cranberry and Peg Leg mines is 2,250,000 tons for every 100 feet depth. (See pages 76 to 80.) It is not known how much of this ore might be mined and concentrated with profit, but it is probable that at a number of places the lenses are sufficiently large to warrant working, provided there were some provision made for their concen¬ tration at a point on the railroad within convenient reach of all the operations. Such a point is believed to be situated near Roan Mountain Station, to which the ore from any place on the vein might be trans¬ ported by a down-grade haul.

So far as has been determined there are no other deposits within reasonable distance of Johnson City that are large enough to warrant the construction near them of concentrating plants. Nor are there any, except those on the Cranberry vein, that are near enough to Roan Mountain to deliver crude ore to a concentrating plant at that point at a cost that would yield a profit. There is an abundance of ore scat¬ tered through the mountains but it is in such small deposits as to be unavailable at the present price of ore.

In Ashe County there are several deposits of fair size, but they are so far from railroads that they would be expensive to operate. The de¬ posits on New River contain at least 700,000 tons of merchantable ore and those near Lansing about 225,000 tons but the enormous tonnages that have been supposed to exist in this County have not been developed by exploration and are not suggested by surface indications.

d. The only deposit of economic importance in the mountain dis¬ trict that is not in gneissic rocks is that of the Ashe Mining Company at Lansing, Ashe County, which is in marble. The deposit is small and its content of iron is small, but because the gangue is marble the ore finds a ready sale. The ore consists of grains of magnetite in a white marble that contains in addition to magnetite small amounts of phlogopite, aetinolite, and quartz. It is cut by veins of actinolite and dark hornblende and of a fine-grained aplitic rock, believed to correspond to the pegmatite at the Cranberry mine. The ore is thought to have an origin analogous to that of the Cranberry ore, i. e. to have been de¬ posited by ferruginous materials accompanying pegmatitic intrusions. Marble ores are believed to be rare in the mountain district because marbles are rare among the pre-Cambrian rocks of the district.

e. Since the non-titaniferous magnetite deposits of the mountain district are found in the pre-Cambrian rocks of the district and are asso¬ ciated with pegmatites that are not known to penetrate the Cambrian rocks it is inferred that the ores are pre-Cambrian in age.

The non-titaniferous magnetites of the Piedmont area are all asso¬ ciated with gabbros and other basic rocks that are believed to be pre- Cambrian, and consequently, these ores are also inferred to be of pre- Cambrian age.

The titaniferous ores are thought to be genetically connected with peridotites of the same age as the peridotite rocks that are so common all along the east side of the Appalachian ranges. If these are pre- Cambrian the titaniferous ores are likewise pre-Cambrian.

The age of the hematitic magnetites is not known, but if the rocks associated with them are Algonian, as probably is the case, these ores are also pre-Cambrian.

.

The Magnetic Iron Ores of East Tennessee and Western North Carolina

By W. S. Bayley.