b96-13-34908536

xt7hdr2p5z5v https://exploreuk.uky.edu/dips/xt7hdr2p5z5v/data/mets.xml Moore, Philip North, b. 1849. 1878 books b96-13-34908536 English Stereotyped for the Survey by Major, Johnston & Barrett, Yeoman Press, : Frankfort, Ky. : Contact the Special Collections Research Center for information regarding rights and use of this collection. Iron ores Kentucky. Report on the iron ores in the vicinity of Cumberland Gap / by P.N. Moore. text Report on the iron ores in the vicinity of Cumberland Gap / by P.N. Moore. 1878 2002 true xt7hdr2p5z5v section xt7hdr2p5z5v

GEOLOGICAL SURVEY OF KENTUCKY.

N. S. SHALER, DIRECTOR.

REPORT

ON THEC

IRON ORES
IN THILE

VICINITY OF CUMBERLAND GAP.

BY P. N. MOORE.

PART V. VOL. IV. SECOND SERIES.
VlEKROTYPL D tot THg SURVEY 24 1AJOR, JONSTONRARETT, YROMAU FaRs, FRANKFORT, A2.
VOL. IV.-16 2 4 24

This page in the original text is blank.

ON THE IRON ORES IN THE VICINITY OF CUM-
BERLAND GAP.

The iron ores of economical importance in this region lie on
the southeast of Cumberland Mountain, usually in the range
of foot-hills known as the Poor Valley Ridge, which is almost
always seen at the base of the mountain. Occasionally, this
ridge disappears, and we find the ores on the flank of the
mountain proper, near its base; but their occurrence in this
position is exceptional.
The ores are, consequently, in Virginia and Tennessee;
but as they occur so close to the Kentucky line, and are so
intimately connected with Kentucky interests, in that they
cannot be fully developed without the use of Kentucky fuels,
an examination was made of them for a few miles up and
down the mountain, from Cumberland Gap, to ascertain some-
thing as to their method of occurrence, quantity and quality,
and to determine the capabilities of the region to sustain an
iron-manufacturing industry.
The manufacture of iron from these ores with charcoal fuel
has been, for a long time, carried on in this vicinity in a small
way, at a number of places; both pig iron and blooms having
been produced. It is, however, upon coal as a fuel that the
permanent iron industry must be founded, and the coal which
will, in the future, smelt the ores along the mountain for a con-
siderable distance below, and for a still greater distance above
Cumberland Gap, must come from Kentucky. There is no coal
to the southeast in either Tennessee or Virginia, and Cumber-
land Gap affords the most feasible passage by railroad through
the mountain, from the ore to the great Kentucky coal field.
Such being the case, these ores become of almost as much
importance to Kentucky as to the States in which they are
143

REPORT ON THE IRON ORES IN THE

situated, especially when we consider that their development
is dependent largely upon a Kentucky railroad enterprise to
give them access to market. Either of the projected railroads
through Kentucky to Cumberland Gap, will find in the trans-
portation of these ores, and of the iron made from them, one
of the most important sources of revenue.
The ores of this region are stratified hematites, belonging
to the Clinton Group of the Silurian formation, a group which
has been designated as the Dyestone Group by Prof. Safford,
in his report on the geology of Tennessee. The ore is vari-
ously known as the Dyestone or Fossil ore, and sometimes
simply as the Red ore. It is called the Dyestone ore, from
the fact that it is sometimes used for dyeing purposes by the
residents of the region where it is found.
The rocks with which it is associated are usually shales,
sometimes calcareous, which occasionally pass into thin-bed-
ded sandstones. There are also occasional interstratified
thin beds of limestone,- which increase in frequency toward
the lower part of the series, and below the ores.
The thickness of the group in Tennessee, as stated by Prof.
Safford, varies from two hundred to three hundred feet. In
this vicinity it is usually thicker, ranging from three hundred
to five hundred feet. These rocks pass almost imperceptibly
into the Medina sandstone below. This sandstone is here
thin-bedded, and less marked in every way than it is further
southeast, where it is the massive determining rock of Clinch
Mountain; but it is still heavy enough to form, with the lower
portion of the Clinton beds, the Poor Valley Ridge, or foot-
hill range of Cumberland Mountain. The 'Poor Valley,"
between the foot-hill and the mountain, is excavated in the
thin-bedded, soft, and easily eroded Clinton rocks, and it is
to their silicious nature, and the soil resulting from them, that
the infertility of the valley is due. The Devonian shale and
the Waverly also help in the formation of the valley to a cer-
tain extent, but the Clinton shales are particularly the valley
rocks. Usually the shale above the ore occurs in the valley,
and the upper ore (of the three to be hereafter described),
24

VICINITY OF CUMBERLAND GAP.

with a thin but hard sandstone immediately above it, is the
highest and crest-forming rock of the Poor Valley Ridge.
As already stated, the ore occurs in beds or layers, interstrat-
ified with shales and limestones. It differs much in quality in
the different beds; but when at its best, is an o6litic, greasy-
feeling, fossiliferous hematite, formed at places almost entirely
of fragments of crinoid stems. Other fossils ate numerous,
but by no means reach anything like the proportion of the
crinioidal remains.
The ore has not been studied in sufficient detail over a
large area, where it has been opened in depth, and the over-
lying rocks are fully exposed, to enable the writer to form a
theory of its formation satisfactory in every respect; but the
structure of the ore, in most cases, indicates, beyond rea-
sonable doubt, that it was originally a bed of fossiliferous
limestone. The original limestone has been dissolved and
removed by the solutions which brought the iron and depos-
ited it in the form and place of the limestone. The iron has
probably been derived fromn the rocks above, and has been
gradually removed by a process of leaching.
This ore is by no means a local deposit. It is characteristic
of the rocks of this period, from New York to Alabama, and
it is also found in the same formation in Wisconsin, of a qual-
ity that can hardly be distinguished from the New York or
Tennessee ore. This marked uniformity of quality and po-
sition of the ore show that the waters, at the time of the depo-
sition of these rocks, must have been very uniformly charged
with iron over an area hundreds of square miles in extent.
There is no similar formation in which iron ore is distributed
with anything like so great uniformity, or of which it is so
characteristic. Other ores are found usually connected with
rocks of a particular formation, but they are by no means
coextensive with that formation; they are, on the contrary,
pockety" and erratic. This, however, both in quality and
position, maintains its identity along the parallel mountains
of the Appalachian series for hundreds of miles. In the
aggregate, therefore, it presents a mass of ore which is
245

REPORT ON THE IRON ORES IN THE

practically inexhaustible, and is unequaled by any other de.
posit in the country.
In New York and Pennsylvania ore of this age is largely
;orked for the supply of blast furnaces; but south of those
States it is almost untouched, although in Virginia and Ten-
nessee a number of small charcoal furnaces and forges have
been using it for many years past. Their consumption is so
small that, in comparison with the vast amount remaining,
what ore they have used is too small for notice.
There are usually found in the region under consideration
three beds of ore. These have been found to extend with
considerable regularity for five or six miles each side of Cum-
berland Gap. Whether they are persistent at a greater dis-
tance above the Gap than this is not yet known. Ore is
found in good thickness at many places above; but the sec-
tions taken have not been detailed enough to prove the exist-
ence of more than one bed, although there is no reason to
doubt that the others will be found when properly sought
for. Below Cumberland Gap, at Speedwell Furnace, two ores
have been worked, apparently corresponding to the middle
and upper of the three above mentioned, with the distance
between them considerably increased.
The positions and relative distances apart of the three ores
are shown in the sections of the accompanying plate. These
sections were all taken within a few miles of Cumberland
Gap, and the most of them within one mile and a half. It
will be seen from them that the ores are sometimes found at
the foot of the mountain proper, and sometimes in the Poor
Valley Ridge.
They are of the most value when they occur in the ridge,
for the reason that there is then a larger amount of the ore
above drainage level, where it can be much more easily and
cheaply mined. It is also probable that, at a certain depth
below the drainage level, the soft fossiliferous ore becomes
hard, calcareous, and poor in iron; in other words, that it
approaches the condition of the original limestone, and is
no longer profitable to work in the furnace. This opinion is
246

VICINIT OF CUMBERLAND GAP.

not founded upon observations in this immediate region, for
mining has not yet been carried deep enough to ascertain
the fact; but it is based upon reports of mining operations
upon the same ores at other and widely separated places.
When the ore occurs in the Poor Valley Ridge, it dips nearly
with the slope of the ridge on the mountain side, so that
there is a large amount of it at a uniformly small depth below
the surface; while, when it is in the mountain, it dips directly
back from the surface; and even if it does not change its
character, and become lean, it will soon become difficult and
expensive to mine.
It will be seen from the accompanying sections, that the dis-
tance between the upper and middle ores varies from seventy
to one hundred and five feet. The distance between the mid-
dle and lower ores is from two hundred to two hundred and
fifteen feet.
The upper ore is-the most valuable of the three in this
region. It is soft, very fossiliferous, and much richer in iron
than the middle ore, although it is not nearly so thick. It
has been seen by the writer varying from fifteen to twenty-
two inches in thickness, and it is reported on good authority
at one place, where a full measurement could not be obtain-
ed at the time of visit, to be twenty-six inches thick. It is
the only ore that has been worked in the furnace at Cumber-
land Gap. There is such an abundance of it in the neigh-
borhbod, and it is won so cheaply, that there has been no
inducement to attempt to utilize the middle ore, which is both
thicker and leaner than the upper. It is hard, silicious, and
not very fossiliferous. It has been seen by the writer twenty-
seven inches thick, and is reported, at other places, to be
thirty inches. It seems to have been originally a silicious
limestone, which is now impregnated with iron. It appa-
rently corresponds to the "hard ore" of this same period in
Pennsylvania,'while the upper ore seems to be the counter-
part of the "Isoft ore " of the same State.
At Speedwell Furnace, about twenty miles below Cumber-
land Gap, the middle or hard ore has been used in consider-
247

REPORT ON THE IRON ORES IN THE

able quantities to mix with the soft ore, a purpose for which it
is well adapted. This is the way in which the two ores can be
profitably utilized. The hard ore, although richer and more
valuable than is now commonly supposed by iron-makers in
that region, is yet too silicious to work easily in the blast fur-
nace alone. Mixed with the soft ore, however, it can be used
with very good results.
Owing to its greater thickness, there is a larger quantity of
this ore in a given area than of the upper ore, although its
specific gravity is not so great.
The lower ore, which occurs about two hundred feet below
the middle, is but little known, and never, to the knowledge of
the writer, has been mined in this region. In quality, it very
much resembles the soft upper ore; so much so, that specimens
of it can scarcely be distinguished from the upper ore. It is,
however, thin, not having been seen by the writer more than
six or seven inches in thickness. Where this ore occurs in
the mountain proper, and dips away from the surface, it will
be of little value, as it is too thin to be profitably mined at
present under such circumstances; but where, as shown in
the lowest section of the accompanying plate, it lies near the
surface of the ridge for a considerable distance, it can be
worked at very reasonable rates, and a large amount of ore
be obtained; as, with a thickness of from six to seven inches,
each square yard covered by the ore will yield nearly half a
ton.
The lowest section of the accompanying plate shows the
position of the ores in the Poor Valley Ridge, at Cumberland
Gap, just below the Tazewell road. It will be seen that both
the lower and the upper ores lie here in the most favorable
position possible for easy and cheap mining, as they are both
near the surface, and only covered by a slight thickness of
overlying material. The upper ore has been mined for the
furnace at the Gap, beginning down in the valley and working
upwards towards the crest of the hill, throwing the earth be-
hind as each successive bench of ore is raised. In this way
248

VICINITY OF CUMBERLAND GAP.

the pits or benches are easily drained. The cost of mining
the ore here is only fifty cents per ton.
This fortunate position of the ores in the ridge is continued
for several miles below Cumberland Gap, interrupted occa-
sionally by changes in the topography, where longer spurs
than usual put out from the mountain, between streams, but
returning again to their position on the ridge as soon as these
are passed.
The section just referred to shows the slope of the ridge
on which the ore lies to be about six hundred feet in width.
At places below, on the ridge, it will exceed this measurement
by nearly one half. It will, therefore, be safe to estimate the
breadth above drainage of the ore stratum running along this
slope of the Poor Valley Ridge at six hundred feet, or two
hundred yards. The ore varies in thickness from fifteen to
twenty-four inches, and it is probably under rather than over
the average for this region to place it at eighteen inches; but
in the following estimate of the quantity of ore in this ridge
it is essential to keep within limits of safety. The ore has,
according to the determination by Mr. Talbutt of two sam-
ples, a specific gravity of 3.94 and 3.91. Assuming a specific
gravity of 3.9, a thickness of eighteen inches, and a breadth
of ore belt of six hundred feet, there will be present, for each
mile of the ridge holding the ore in this position, 538,319
gross tons. This estimate is, however, too great, in that it
assumes the ore stratum and the surface of the ridge to be
continuous, unbroken by ravines, gullies, and streams. No
accurate estimate of the amount lost in this way can be made
without a detailed contour map; but it is believed that one
fourth will be more than ample to cover it. Deducting one
fourth as lost in this way, we still have 403,740 tons of ore
present per mile of the ridge. This estimate is made exclu-
sive of any ore below drainage at the foot of the mountain
proper, for the reason that it is as yet uncertain to what depth
the ore will be found soft and rich; and it will be a long time
before there is any demand upon it in this position. It is
249

REPORT ON THE IRON ORES IN THE

simply desired to show how vast an amount of excellent and
easily obtainable ore there is lying almost at the surface.
Where the belt of soft ore is two hundred yards in width,
there will be in the same ridge above drainage one hundred
and fifty yards in width of the middle or hard ore. This, with
a specific gravity of 3. 1, and an average thickness of twenty-
seven inches, will contain for each mile of the ridge 462,404
gross tons of ore. Deducting one fourth, the same proportion
as in the former case, for ore lost by ravines, streams, &c.,
and there remain 349,303 gross tons per mile. The estimate
of one fourth loss in this case is much larger than in the
other, as the ore lies so deep that it is not reached by many
ravines which have cut the upper ore.
It is impossible to give accurate estimates of the quantity
of available ore above drainage, where it does not lie in this
favorable position on the Poor Valley Ridge, without a most
minute study along the whole outcrop of the ore, and a contour
line map showing its elevations at different points, as it varies
for every mile of the distance, running out on the ridge when
that is high enough to hold it, and again setting back at the
base of the mountain as the ridge falls away in height.
Prof. H. D. Rogers, in volume I, of the Geological Reports
of Pennsylvania, in giving an estimate of the quantity of ore
of this kind, eighteen inches thick, present in the region
around Danville and Bloomsburg, Pennsylvania, places it at
fifty thousand tons for each running mile of outcrop. This
is based upon the assumption that the soft ore will not be
found of more than an average depth of thirty yards, ere it
changes to hard, lean ore, which cannot be profitably mined.
This assumption does not, however, prove true in every case,
as Prof. J. P. Lesley states that mining operations at Bed-
ford, Pennsylvania, have yielded the ore in perfect condition,
at a depth of several hundred feet below the outcrop. It is
probably safe to assume that the amount of available soft
ore will average two hundred thousand tons, per mile, for
the whole distance, and at many localities will much exceed
this, as it grows thicker further up the valley.
aSo

VICINITY OF CUMBERLAND GAP.

About eighteen miles above Cumberland Gap, above where
Martin's creek cuts through the Poor Valley Ridge, an expo-
sure was seen, which showed the ore, slightly tumbled and
broken, as follows:
Hard silicions ore.1.0........... .. .. .. .. .. .. . toinches.
Good ore, somewhat broken.2.1......... . . .
Solid ore............. ... .. . . . . . ..... . . 21
Total ............................. . 52
The position of the ore at this point was such that it is barely
possible there may have been a repetition in this measurement
as it lay on a hill-side in a considerably disturbed position. It
is not believed that such is the case, however, for it was ex-
amined very carefully. A single block of ore was seen lying
near, twenty-seven inches in thickness.
At lower Pennington's Gap, the ore was found standing
nearly vegtical (dip 800) in the Poor Valley Ridge, and thirty-
five inches in thickness. It is commonly spoken of in this
region as three feet thick, and probably does reach that
thickness at many places. The ore at this point is unusually
coarse in structure, being formed of large rounded globules,
and containing numbers of small quartz pebbles. It is diffi-
cult to account for the presence of these in the ore on the
commonly received theory of its formation by replacement
of limestone.
At many other places between the above-mentioned points
the ore has been seen, but it was usually only in loose out-
crop, not in position where its thickness could be measured.
It was seen often enough, however, to prove that it extends
with great persistency all along the valley, although it may
vary in thickness.
The quantity of ore, per mile, increases by many tons for
each additional inch in thickness of the ore bed, so that when
the above noticed increase in thickness is considered, it will
le seen that the estimate of the amount of ore is considerably
tinder, rather than over, the probabilities.
Where the middle or hard ore is present, it is safe to
estimate an amount of it above drainage, for each mile, fully
251

I I

REPORT ON THE IRON ORES IN THE

equal to, or greater than the soft ore. It should be distinctly
remembered, however, that these last estimates are mere
approximations, and are not based upon sufficient data to
render them worthy the credit due to the first estimates,
which were founded upon more detailed observation.

QUALITY OF THE ORE.
The soft ore is of excellent quality, producing about fifty
per cent. of iron, and working easily in the furnace. The
hard ore is more silicious and poorer in iron, and will prob-
ably require admixture with the soft ore, to enable it to be
smelted successfully. The quality of three samples of ore,
from the immediate vicinity of Cumberland Gap, is shown
by the following analyses by Dr. Peter and Mr. Talbutt,
from samples collected by the writer:

I 2 3

Iron peroxide .................. . 73.935 77.380 47.965
Alumin.... . ..a.. ... . .. .. .. . . 5-776 3.941 2.130
Lime carbonate.4........ . . . . ... . 4-510 .420 1.230
Magnesia.. ...... .. .. . .. .. .. . . .266 .... .194
Phosphoric acid........ . .......... . .319 .319 .575
Sulphuric acid........... ..... ... ... trace.
Sihca and insoluble silicates ........... . 11.730 15.960 43.690
Combined water.................. .850 2.500 4.000
Total.... .. .. .. . .. .. .. .. . ..100.386 100.520 99 784

.Metallic iron........ .. .. .. . 51-754 54.166 33.575
Phosphorus... .. .. .. . .. .. .. 140 .140 .251

Specific gravity......... .. . .. .. . . 3-914 3-942 3.190

No. I is the upper or soft ore from the valley near the Vir-
ginia road, a short distance above Cumberland Gap.
No. 2 is the same ore from the ridge below Cumberland
Gap.
No. 3 is the middle or hard ore from the ridge near the
same place as last noted.
The above analyses show in all the samples a workable
per centage of iron. The amount of phosphorus present is
252

1 2

VICINITY OF CUMBERLAND GAP.

decidedly less than is usually characteristic of the ore at
other places. As a rule in other States, this ore is decidedly
phosphatic, and produces a cold-short iron; but it proves to
be exceptionally pure in this vicinity.
For comparison, there is herewith appended the following
analysis of the hard ore of the same geological period from
Dysart's mine, Huntingdon county, Pennsylvania, by Prof.
Percifer Frazer, of the University of Pennsylvania:

Sesquioxide of iron......... . .. .. . .. .. . .. .. . . 38.48
Protoxide of iron........ .. .. . .. . .. .. .. . .. . . 4.37
Silica.... . .. .. . .. .. . .. .. .. . .. .. . .. .. . 37.99
Alumina. .. .. . .. .. . .. .. .. . .. .. . .. .. . .. . 9. 56
Lime.s.... . .. .. . .. .. . .. .. .. . .. .. .. . . . 1.o6
Magnesia... .. .. . .. .. . .. .. . .. .. .. .. .' a trace.
Alkalies.'2.54
Phosphoric acid .1.48
Sulphur...0.5........ .. .. . .. . .. .. .. . .. .. . . .05
Loss by ignition..... .. .. . .. .. . .. .. .. . .. .. . . 4 So
Total .... 0...0.4. 100-04
Metallic iron.... . ....... . 30-34

It will be seen that it is very similar in constitution to No. 3
of the analyses just before given, except that it contains a
larger proportion of alumina and phosphorus.
There is also herewith given an analysis, by Dr. Peter and
Mr. Talbutt, of the pig iron made at the Cumberland Gap
Furnace from the soft ore of the upper bed. It is a cold-blast
charcoal iron, of excellent quality and great strength. It is
used for car-wheel purposes.
ANALYSIS OF COLD.BLAST, CHARCOAL PIG IRON, CUMBERLAND GAP
FURNACE.

Iron.. . .. .. . .. .. .. . .. .. . .. .. .. .. .. . . 92.828
Graphitic carbon............ ...... ........ 3.260
Combinedcarbon.. .. .. . .. .. . .. .. . .. .. .. . .. . .840
Silicon........ 1.668
Slag. . . ... .480
Manganese.. .. .. . .. .. . .. .. .. . .. .. .153
Alumnium. . .... ........ .766
Calcium. .. .. . .. .. . .. .. .. . .. .. . .. .. .. . . .112
Magnesium. I.. . .. .. .. . .. .. . .. .. . .. .. . .. . .270
Phosphorus.... .. .. . .. .. . .. ..... .. ...... . .145
Sulphur .... ..........I .o68
Total. .1.. ... . . .. .. .. .. ....0 . 590

233

REPORT ON THE IRON ORES fI THU

This iron is hauled to the Powell river and boated down to
market at Chattanooga at times of high water. It is manu-
factured very cheaply at the furnace; but the expense, risk.
and uncertainty of the transportation to market, greatly reduce
the profits on its manufacture, and leave only a narrow margin
at present prices for iron.
The cheapness with which iron can be manufactured at this
place will be realized when it is understood that the ore is
delivered at the furnace throat for one dollar per ton, thus
costing only two dollars to the ton of iron for the ore.
Furnaces.lower down in Tennessee and in Alabama, smelt-
ing ore of this kind with coal or coke, produce iron at as low
or lower prices than in any other part of this country. It is
stated, on very competent evidence, that the Roan Iron Fur-
naces of Rockwood, Tennessee, make iron for less than
fifteen dollars per ton.
With a railroad from the central part of the State through
the mountain at Cumberland Gap, so that the Kentucky coal
can be used with this ore, this locality can produce iron as
cheaply as any other point in this highly favored valley, and
can place it in market at lower rates.
It is destined to be one of the great iron-manufacturing
regions of the country, and only awaits facilities for the trans-
portation of its product to inaugurate a wonderful develop-
ment of its resources in this direction.
254

i-N-Xgi\ \

t He 5 Hi t 7

X X i

; t A X : ,

b96-13-34908536
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Report on the iron ores in the vicinity of Cumberland Gap / by P.N. Moore.
Moore, Philip North, b. 1849.

Stereotyped for the Survey by Major, Johnston & Barrett, Yeoman Press,
Frankfort, Ky. :
[1878]

14 p. : map ; 28 cm.
Coleman
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Iron ores Kentucky.

GEOLOGICAL SURVEY OF KENTUCKY.

N. S. SHALER, DIRECTOR.

REPORT

ON THEC

IRON ORES
IN THILE

VICINITY OF CUMBERLAND GAP.

BY P. N. MOORE.

PART V. VOL. IV. SECOND SERIES.
VlEKROTYPL D tot THg SURVEY 24 1AJOR, JONSTONRARETT, YROMAU FaRs, FRANKFORT, A2.
VOL. IV.-16 2 4 24

This page in the original text is blank.

ON THE IRON ORES IN THE VICINITY OF CUM-
BERLAND GAP.

REPORT ON THE IRON ORES IN THE