UNITED STATES DEPARTMENT OF THE INTERIOR 

Harold L. Ickes, Secretary

GEOLOGICAL SURVEY 

W. C. Mendenhall. Director

Bulletin 936-K

TIN DEPOSITS OF IRISH CREEK 

VIRGINIA

BY

A. H. KOSCHMANN, J. J. GLASS 

AND J. S. VHAY

Strategic Minerals Investigations, 1942 

(Pages 271-296)

UNITED STATES

GOVERNMENT PRINTING OFFICE 

WASHINGTON : 1942

For sale by the Superintendent of Documents, Washington, D. C. ------- Price 10 cents

CONTENTS

Page

Abstract................................................. 271

Introduction............................................. 272

Location............................................. 272

Previous investigations.............................. 274

I .' Field work and acknowledgments....................... 274

; : Geology.................................................. 275

Gneiss and schist.................................... 275

| Granodiorite......................................... 277

Aplite.............:................................. 277

 Basic dikes.......................................... 278

Structure............................................ 278

1 Tin deposits ............................................. 279

,i Quartz veins......................................... 279

1 , Greisen.............................................. 280

: I Late veins........................................... 282

w j r , Occurrence of cassiterite............................ 283

; '! Size and grade of ore bodies......................... 284

i, ! Mine descriptions........................................ 285

; p History of development............................... 285

k .; Production........................................... 287

j. ; Mine workings........................................ 287

i No. 1 workings................................... 287

: | The main lodes............................... 287

I Possible extensions of No. 1 lodes........... 289

i ! No. 2 workings................................... 290

j Nearby lodes................................. 293

; Outlying lodes................................... 294

i - Reserves................................................. 295

j Suggestions for prospecting.............................. 296

ILLUSTRATIONS

j Page

i

! Plate 43. Map of the No. 1 workings, Irish Creek, Va.,

; showing location of samples and list of

j assays...................................... 286

! 44. Map of the No. 2 workings, Irish Creek, Va.... 290

:Figure 29. Map of Virginia, showing location of the

Irish Creek tin. district.................... 273

30. Geologic map of the Panther Run area, showing 

> location of mine workings and prospect

pits.......r................................ 276

III

TIN DEPOSITS OF IRISH CREEK, VIRGINIA

By A. H. Koschmann, Jo J. Glass, and J. S. Vhay

ABSTRACT

Cassiterite was discovered along Irish Creek in the Blue 

Ridge in the northern part of Rockbridge County, Va., in 1846, 

but active prospecting and development work were not begun until 

1884. The production has been small, probably less than 1,000 

tons of ore, and has come chiefly from workings on Panther Run, 

a small tributary near the headwaters of Irish Creek.

The country rock in the district consists of gneiss intruded 

by granodlorite, which in turn is cut by small dikes of aplite 

and basic rock, all probably of pre-Cambrian age. So far as is 

known the tin-bearing lodes are restricted to the granodiorite.

The cassiterite occurs in lodes, each of which ordinarily 

consists of a quartz vein bordered by greisen.. The quartz veins 

range in width up to 9 feet, though most are less than a foot 

wide. The greisen forms a layer, which may be as much as 5 feet 

in thickness, on one or both sides of the quartz core. The 

 greisen grades into the granodiorite, and apparently was formed 

from it by replacement. Cassiterite grains are disseminated 

through the greisen, and the mineral occurs in veinlets and in 

scattered pockets adjacent to the quartz. Both the unfractured 

quartz and the granodiorite are barren.

The lodes are a product of four stages of mineral deposition 

with intervening stages of crushing. Quartz was deposited during the first stage, cassiterite, muscovite, beryl, and probably 

wolframite during the second, muscovite, siderite, ankerite, 

fluorite, biotite, phenakite and chlorite, together with rare 

grains of sulfides, during the third, and nontronite, vermiculite, hematite, montmorillonite, clinozoisite, and calcite during the fourth.

The main development work has been along Panther Run, a 

tributary of Irish Creek. The only workings now open are on the 

east side of Panther Run; they are known as the No. 1 workings. 

Other workings, known as the No. 2 group, are situated 1,200 

feet southwest of the No. 1 workings. Information regarding the 

number of lodes and the grade of ore is meager. Recent sampling 

of the accessible No. 1 workings shows that the greisen contains 

from 0.11 percent to 3.78 percent.of tin, the average being 

about 1 percent. Available reports concerning the grade of ore 

in the No. 2 workings are less favorable. Very little is known 

regarding the scattered lodes that occur outside of the No. 1 

and No. 2 workings, but assays from these lodes indicate that 

they contain appreciable quantities of tin. The occurrence of 

rich pockets of ore and the persistence of greisen in the 

explored lodes suggest that further prospecting in the area may 

be warranted.

271
272 STRATEGIC MINERALS INVESTIGATIONS, 1942

INTRODUCTION

Cassiterite (tin oxide) was discovered at Irish Creek, Va., 

in 1846. Since then there have been several attempts to produce 

tin commercially, notably in the periods 1883-85, 1889-92, and 

1918-19. No systematic work was done between 1919 and 1942. In 

1938 the writers, using funds granted by the Public Works Administration, made a detailed study of the workings now accessible, 

paying particular attention to the mode of occurrence of cassiterite and its associated minerals. This preliminary report presents some results of that study that are of economic significance .

Location

The Irish Creek district is in the central part of the Blue 

Ridge of west-central Virginia, near the boundary of Rockbridge, 

Nelson, and Amherst Counties, as shown on figure 29. The district is about 10 miles southeast of Steeles Tavern, a small 

village on U. S. Highway 11, midway between Staunton and Lexington, whence it can be reached by a well-graded dirt road. There 

is also a road from the east up the Tye River and another from 

Cornwall on the south.

Cassiterite has been found in an area of about 12 square 

miles along the headwaters of Irish Creek, at altitudes ranging 

from about 2,300 to 2,800 feet. The district is an area of considerable relief, but as the natural vegetation is -heavy and 'the 

soil cover is deep even on steep slopes, outcrops are relatively 

scarce.

The only lodes that could be studied in detail are exposed 

on the east side of Panther Run, in the open workings hereafter 

referred to as the No. 1 workings. The No. 2 workings, on the 

west side of Panther Run, are larger but are caved in.
TIN DEPOSITS OP IRISH CREEK, VIRGINIA 273
274 STRATEGIC MINERALS INVESTIGATIONS, 1942 

Previous investigations

The Irish Creek district was described by several investigators in the period 1883-85,-'and was mentioned briefly by Gra2/ 3/ ton in 1906. Ferguson,^in 1918, described the tin deposits

more fully and gave a brief account of the regional geology.

The geology of the region has been described in greater detail

4 / 5/ by Watson and Cline -^ and by Watson and Taber. '

Field work and acknowledgments

Koschmann spent five days at Irish Creek in November 1938, 

all three authors spent a week there in December 1938, and short 

visits were made at other times by the authors and their colleagues. A geologic map was made of an area on Panther Run, a 

small tributary to Irish Creek, where the most extensive workings of the district are situated.

Mr. W. Spencer Hutchlnson, consulting engineer, kindly supplied copies of his unpublished progress reports, containing 

maps and assays, which describe the development work done in 

1918-19 by the Richards Co., Inc., of Boston. These reports 

were made available to us with the consent of Mr. W. S. Young, 

treasurer of the company. We are also Indebted to Mr. G. W. 

Schultz of Reading, Pa., who made available to us a report on

I/ McCreath, A. S., and Pratt, Franklin, report to P. J. Kimball, dated 

October 15, 1883: The Virginias, vol. 5, pp. 150-151, 1883.

Campbell, H. D., letter to Jedediah Hotchkiss, October 23, 1883: The 

Virginias, vol. 5, p. 151, 1883.

Uassie, F. A., report to the Virginia Tin Mining & Manufacturing Co., 

quoted in Mineral Resources U. S., 1883-81*, pp. 60O-601, 1885.

Winslow, Arthur, Tin ore in Virginia: Eng. and Min. Jour., vol. UO, 

p. 320, 1885.

2/ Graton, L. C., Reconnaissance of some gold and tin deposits of the 

southern Appalechiens: U. S. Geol. Survey Bull. 2931 P» ^t 1906.

2/ Ferguson, H. G., Tin deposits near Irish Creek, Va.: Virginia Geol. 

Survey Bull. 15-A, 1918; Tin deposits of Irish Creek, Va.: Eng. and Min. 

Jour., vol. 105, pp. 5-7, 1918.

U/ Watson, T. L., and Cline, J. H., Hypersthene syenite and related 

rocks of the Blue Ridge region, Vs.: Geol. Soc, America Bull., vol. 27, pp. 

193-23H, 1516.

5/ Watson, T. L., end Taber, Stephen, Geology of the titanium end apatite deposits of Virginia: Virginia Geol. Survey Bull. 3-A, 1913.
TIN DEPOSITS OF IRISH CREEK, VIRGINIA 275

the district made in 1900 by Mr. A. C. Ledoux, and one made by 

Prof. W. 0. Crosby at an earlier, unspecified date, presumably 

1890 (see p. 286). C. S. Ross made microscopic determinations 

of the clay minerals; H. G. Ferguson and F. C. Calkins critically read the manuscript; and Ward C. Smith contributed valuable assistance in condensing and summarizing the more comprehensive draft of this paper.

GEOLOGY

The rocks exposed in the Panther Run area (see fig. 30) are 

gneiss and schist, granodiorite, aplite, and basic dikes. The 

gneiss and the granodiorite represent major rock types widespread in the Blue Ridge; the aplite and basic dikes are of 

minor importance. All the known tin deposits are in granodiorite.

These crystalline rocks are all believed to be of pre-Cambrian age. The granodiorite, which has no gneissic structure, 

appears to be younger than the gneiss .and older than the aplite 

and basic dikes.

Gneiss and schist

The gneiss is a banded rock consisting mainly of feldspar 

and quartz, with a minor proportion of dark minerals. The rock 

has been considerably altered to sericite and chlorite, and it 

encloses a few masses of chloritic schist. Some of the schist,

composed of pink feldspar in a chloritic groundmass, grades into

6/ the surrounding gneiss. Ferguson "^mentions a purple slate in

the No. 2 workings, but it was. not seen by the authors. None of 

these rocks was studied in detail.

6/ Ferguson, H. G., op. cit. (Bull. 15-A), p. 13. 

471317 O - 42 - 2
276 STRATEGIC MINERALS INVESTIGATIONS, 1942

EXPLANATION

Basic dike

Aplite

Mine workings 

B

Caved shaft

Granodiorite

Gneiss and schist

Portal 

X

Pit

Trench

cs> 

Caved workings

''»,< " 

Dump

100 0

I___I

5OO

I

1,000 Feet 

__I

Contour interval 2.5 feet 

Datum is mean sea level

Figure 30. Geologic map of the Panther Run area, showing location 

of mine workings and prospect pits.
TIN DEPOSITS OF IRISH CREEK, VIRGINIA 277 

Granodiorite

The granodiorite where fresh is a dark greenish-gray, 

coarse-grained rock, and has a porphyritic appearance because of 

the segregation of the light- and dark-colored minerals. The 

most abundant mineral is andesine; it is accompanied by much 

orthoclas.e, microcline, and microperthite and a little quartz. 

The principal dark mineral is pyroxene (hypersthene with some 

pigeonite); the minor ones are brown and green hornblende, a 

blue-green sodic (?) amphlbole, and biotite. The accessory minerals include zircon, apatite, and an opaque mineral thought to 

be titanomagnetite. These accessory minerals, especially the 

titanomagnetite, are notably abundant in clusters of pyroxene 

grains or their alteration products. The rock also contains 

some sericite and chlorite.

The granodiorite has apparently had a long and complex history of alteration, but no attempt has been made during this 

study to determine which of its minerals are primary and which 

were formed later. In addition to the widespread mineralogic 

alteration found in the granodiorite, other more local Intense 

mineralogic and structural alterations are conspicuous in some

places. Chief among these is the replacement of dark minerals

7/ by epidote; the resultant rock, called unakite, is common in

the Blue Ridge.

Some of the granodiorite has been altered to cassiteritebearing greisen, which forms an important part of the tin lodes, 

and is described in the section on the tin deposits.

A fine-grained light-colored rock is exposed along Panther 

< Run just south of the No. 1 tunnel. It consists chiefly of 

\ quartz, potash feldspar, and albite, all in grains that average

7/ Watson, T. L., nnd Cline, J. H., op. pit., p. ??0.
278 STRATEGIC MINERALS INVESTIGATIONS, 1942

 leas than 0.1 millimeter in diameter. Although the rock closely 

resembles aplite, it may possibly be a granitized inclusion of 

quartzlte in the granodiorite.

Basic dikes

Several small dikes of a fine-grained dark-colored rock were 

seen in the granodiorite, but only one is large enough'to be 

represented on the geologic map. The rock consists mainly of 

pigeonite, epidote, biotite, chlorite, with a little titanomagnetite, pyrite, leucoxene, and quartz. The rock is probably an 

altered diabase, though some of it may be altered pyroxenite,

like some bodies of similar rock that occur a few miles to the

§/ southwest.

Structure

The prevailing structural trend in the region is northeastward and the nearest important structure, a fault northwest of

9/ Panther Run described by Ferguson, strikes northeast. Shear

zones exposed in the No. 1 workings also strike northeast and 

dip southeast, but many small faults strike northwest and dip 

southwesto

The tin-bearing lodes, the location and orientation of which 

are believed to be fissure-controlled, trend N. 70° E. to 

N. 60° W. in the No. 1 workings, and dip steeply either northward or southward. In the No. 2 workings the lodes trend

10/ 

N. 45°-70° E. and dip.50°-70° S. ' Other lodes in the district

have different trends, and apparently there is no simple pattern 

for the entire district; although within small parts of it the 

lodes are probably more or less parallel, as are those in the 

No. 1 workings.

§ Watson, T. L., and Cline, J. H., op. cit., p. 231. 

Ferguson, H. G., op. clt. (Bull. 15-A), p. 3, fig. 2. 

__, Idem, fig. 3.
TIN DEPOSITS OP IRISH CREEK, VIRGINIA 279 

TIN' DEPOSITS

The tin deposits at Irish Creek are veinlike lodes in the 

granodiorite; none have been found in the other rocks. Typically, one of these lodes consists of a quartz vein, bordered on 

both sides by greisen. The quartz veins evidently were deposited as fissure fillings at the beginning of mineralization, and 

the greisen was formed afterward by replacement of granodiorite. 

Cassiterite, the only tin mineral, occurs in coarsely crystalline masses adjacent to the quartz veins, and as small grains 

disseminated in the greisen.

The minerals of the lodes were deposited in several stages 

separated by periods of fracturing, and the groups of minerals 

formed in each stage are distinguishable in part on the basis of 

difference in degree of deformation. Additional details on the 

sequence of mineralization are discernable also in such features 

as crosscutting veinlets, pseudomorphs, and residual structures, 

of which some may be seen in the field and others only under the 

microscope. From all these evidences the following sequence may 

be deduced: (1) Quartz veins; (2) greisen; (a) older minerals 

in the greisen, including cassiterite; (b) younger minerals in 

the greisen; (3) late minerals.

Quartz veins

The quartz veins branch and are rather irregular in trend 

and thickness; most of them are from 3 to 8 inches thick, but 

some attain a thickness of more than 12 inches, especially at 

intersections. Apparently the veins at the No. 2 workings are 

thicker; a single vein there is said to be 9 feet thick. ' Commonly the vein quartz forms a solid core, but in some places 

where it is much fractured it is criss-crossed with seams of 

greisen, or is even partly replaced by greisen so that only

ll/ Hutchinson, W. S., unpublished report.
280 STRATEGIC MINERALS INVESTIGATIONS, 1942

irregular inclusions of quartz remain. The quartz is dull bluish-gray in color, and under the microscope much of it displays 

wavy extinction.

Greisen

The. greisen occupies a narrow zone 1 inch to 5 feet in 

thickness between the irregular quartz veins and the granodiorite into which it grades. In most places the greisen zone is 

thicker than the quartz vein, but the relative thickness of the 

two differs greatly from place to place, and in some places the 

greisen is without a central quartz vein.

The greisen is dark gray to dark green, and for the most 

part fine-grained and crystalline. Its most conspicuous and 

abundant mineral is muscovite, which forms both isolated crystal 

plates, as much as 7 millimeters in diameter, and fine-grained 

aggregates. Quartz and fluo'rite are also abundant. One channel 

sample of typical greisen contained 49 percent of muscovite, 

27 percent of quartz, 17 percent of fluorite, and 7 percent of 

other constituents; some other samples contained more fluorite 

than quartz. It is uncertain just how much of the quartz i's 

residual from the original granodiorite and how much was introduced during the alteration to greisen, but it seems probable 

that most of the introduced quartz went into the veins and that 

relatively little was added in the greisen zones.

The greisen was formed mainly by replacement of granodiorite 

but partly by replacement of vein quartz. In partly replaced 

granodiorite there are altered but still recognizable feldspar 

grains and clusters of zircon, apatite, and titanomagnetite or 

leucoxene grains similar to those in the unaltered granodiorite. 

Greisen that apparently was formed from vein quartz does not 

contain these minerals.

The older group of minerals in the greisen includes cassiterite, beryl, coarse muscovite, and perhaps wolframite and
TIN DEPOSITS OP IRISH CREEK, VIRGINIA 281

Ilmenlte. Host grains of cassiterite and "beryl and some plates 

of muscovite are crushed or distorted and are more or less 

cemented or replaced "by other minerals, all of which indicates 

their early formation. Muscovite in 0.5- to 1-millimeter grains 

is common throughout the greisen, though generally most abundant 

and coarsest adjacent to the quartz veins or, in some places, 

next to coarse cassiterite crystals that are distributed along 

fractures. Muscovite is also abundant along fractures within 

the quartz veins, where It makes up some nearly solid masses of 

coarse mica. The beryl crystals are pale greenish or yellowish, 

commonly 1 to 2 centimeters long and about 2 millimeters in diameter. The beryl is most abundant at the edges of quartz veins, 

where there are masses of crystals; many crystals extend 1 to 2 

centimeters into the quartz vein. Smaller crystals are scattered in the greisen. Only one crystal of wolframite was found; 

its relation to the other greisen minerals is uncertain, but it 

may belong with this group. Ilmenlte may have been formed at 

this stage, for there are grains of leucoxene with a prismatic 

habit that suggests derivation from ilmenite. Cassiterite will 

be discussed more fully in a section that follows.

The younger group of minerals in the greisen includes muscovite of relatively fine grain, siderite, ankerite, leucoxene, 

sulfides, fluorite, biotite, phenakite, and chlorite 0 These 

minerals are undeformed except at the younger fractures containing the latest minerals. The fine-grained muscovite is notably 

undeformed, though otherwise it is much like the earlier-formed 

muscovite. The carbonate mineral in the greisen is close to 

siderite In composition, but a vein of ankerite 1 inch wide and 

about 5 feet long was found in the east-west tunnel (see pi. 43); 

this ankerite vein had apparently been formed by replacement of 

quartzo Most of the siderite is In small masses that surround 

little clusters of apatite, zircon, and leucoxene, but the mineral also forms veinlets in greisen, and it occurs, associated
282 STRATEGIC MINERALS INVESTIGATIONS, 1942

with coarse-grained fluorite, in fairly large masses adjacent to 

or within some veins of quartz. The leucoxene is partly in 

grains whose forms suggest derivation from titanomagnetlte and 

partly in prismatic grains as if derived from ilmenite. Pyrite 

and sphalerite are sparsely scattered through the greisen of the

No. 1 workings, and arsenopyrite was found in the No. 2 work12/ ings. ' Bismuthoplagionite (5 PbS^BigSj) containing specks and

veinlets of chalcopyrite and blebs of. an undetermined mineral 

was found in the No. 1 workings. The bismuthoplagionite resembles galena, but has a prismatic habit.

Fluorite occurs in small irregular grains widely disseminated through the greisen, in veinlets, and in relatively large 

masses associated with siderite.

Some irregular clusters and masses of biotite occur in the 

granodiorite adjacent to the lodes. Most of the greisen contains veinlets of chlorite, as well as much scattered chlorite 

formed by replacement of muscovite or biotite. Phenakite 

(beryllium orthosilicate) , usually associated with chlorite, 

occurs both as pseudomorphs after prismatic beryl and as irregular grains.

Late veins

, The late minerals are present in small' amounts and are spottily distributed. The final stages of mineralization are represented by small masses of nontronite and of a mineral that is 

probably vermiculite, and by veinlets of hematite. Montmorillonite occurs along a fault that cuts the lodes in the northwest 

part of the No. 1 workings (pi. 43), and in small irregular 

bunches nearby. Galcite and clinozolsite form a thin veinlet 

that seals a small fault in chloritic greisen at the face of the 

east-west tunnel.

12/ Ferguson, H. G., op. clt. (Bull. 15-A), p. 7.
TIN DEPOSITS OP IRISH CREEK, VIRGINIA 283 

Occurrence of cassiterite

As seen in hand specimens, the cassiterite Is dark brown and 

much stained with iron oxides. In thin sections, the prevailing 

color is grayish brown, and some of the larger grains are zoned. 

The best crystals have short pyramidal forms, but complete crystals are rarely found, especially in the coarser material, where 

nearly all the grains are thoroughly crushed. Even some very 

small crystals are crushed to a microscopic dust.

Cassiterite is unevenly distributed in the lodes. In the 

No. 1 workings, coarsely crystalline masses of cassiteri'te occur 

sporadically in greisen near the quartz veins or fractures. A 

few scattered crystals and clusters of crystals were seen in the 

fractured quartz veins, and in places there are narrow veins of 

nearly solid cassiterite. The association of coarse, easily 

recognizable cassiterite with the vein quartz tends to give the 

impression that quartz and cassiterite were formed at the same 

time, but this cannot be true, for a large part of the cassiterite is scattered through the greisen in small grains, evidently 

formed at the same time as the greisen and later than the vein 

quartz.

Although the tiny cassiterite grains in greisen generally 

cannot be seen with the unaided eye, their abundance is readily 

apparent under the microscope in concentrates of the heaviest 

minerals. These concentrates were prepared by crushing to minus 

60-mesh size and quartering the samples, which originally 

weighed from 10 to 50 pounds, and separating the crushed material into three parts with bromoform (sp. gr. 2.8) and methylene 

iodide (sp. gr. 3.3).

The largest portion of the separated samples is that having 

a specific gravity less than 2.8. It consists of the light minerals quartz, andesine, orthoclase, microcline, beryl, calcite, 

montmorillonite, nontronite, and vermiculite. The minerals in
284 STRATEGIC MINERALS INVESTIGATIONS, 1942

the intermediate portion are muscovite, biotite, chlorite, apatite, fluorite, phenakite, ankerite, pyroxene, hornblende, and 

rarely epidote. and tourmaline. 'The heaviest portion contains 

the cassiterite, accompanied by siderite, ilmenite, chalcopyrite, 

zircon, titanite, hematite, titanomagnetite, limonite, sphalerite, galena, and pyrrhotite.

Size and grade of ore bodies

The tin content of the richest sample collected from the 

No. 1 workings during the present study was 3.78 percent, and

the average for five samples was 1.12 percent. According to

13/

Hutchinson, samples cut in the main tunnel of the No. 1 workings, across the lode at 5-foot intervals, had an average tin 

content of 1.23 percent. As Hutchinson's samples had an average 

length of 3.7 feet, and thus represented minable widths of ore, 

his figures indicate that the average tenor for minable widths 

is at least 1 percent of tin.

Several lots of ore that were taken from the No. 1 workings 

were of much higher grade than these channel samples, but that 

was because rich pockets were mined selectively wherever possible. This fact can readily be deduced from Hutchinson's statement that 19.4 tons of ore assaying 13.9 percent tin was taken 

from a lode in the upper 25 feet of the shaft in the No. 1 workings. The shaft is 7 by 4-g feet, and if all the rock in the 

upper 25 feet had been included in the lot of ore the average 

grade would have been about 4 percent rather than 13.9 percent. 

Other lots of ore from the No. 1 workings contained 2.11, 3.33, 

and 20.00 percent of tin; these also came from rich pockets.

The tin content of the lodes in the No. 2 workings is said 

to be less than 1 percent. According to Hutchinson, of 14 samples cut across the lode in the main tunnel at 5-foot intervals,

1/5/ This and the following citations of Hutchinson 1 s findings are based 

on his unpublished reports.
TIN DEPOSITS OP IRISH CREEK, VIRGINIA 285

11 samples contained only a trace of tin and 3 contained 1.61, 

1.62, and 1.81 percent. Of two lots taken from pockets, one 

consisted of 1,800 pounds of ore containing 1.16 percent, and 

the other of 1,200 pounds containing 9.2 percent of tin.

The width of the lodes is suggested by the map of the No. 1 

workings (pi. 43), in which the main tunnel explores one lode 

for a length of 120 feet and lateral workings explore a faulted 

segment of a lode 50 feet long. The average width of the lode 

in the main tunnel, as indicated by the samples already mentioned, was 3.7 feet. The depth to which the lodes extend is 

unknown.

MINE DESCRIPTIONS 

History of development

Although cassiterite from Irish Creek was identified in 1846

14/ 

by Prof. Armstrong of Washington College, Lexington, there is

no record of prospecting in the district until after a specimen 

from the Martha D. Cash property, probably from the No. 1 group 

of lodes, was identified as cassiterite by T. Massie - ' in the 

spring of 1883.

The Virginia Tin Mining & Manufacturing Co., which was

16/ 

organized in the summer of 1884,. did considerable prospecting

and development work during the next two years. A shaft 40 feet 

deep was sunk on the No. 2 group of lodes and about 3,000 pounds 

of ore from this shaft was sent to England as a trial lot.

Apparently, also, about 1,000 tons of tin ore had accumulated on

17/ the dumps 'by the end of 1886, but information regarding its

source and the time at which it was mined is not available.

lU/ Mineral Resources U. S., 1893, ? 180,

15/ Letter from E. Whitehead in The Virginias, vol. 5, p. 38, 1SSU. The 

identification was confirmed by Prof. Bewey of the Smithsonian Institution 

and by J. P. Kimball of Lehigh, Pa.

l|/ The Virginias, vol. 5, p. l<fi, 18SU.

T?/ Mineral Resources U. S., 1889-90, p. 120, 1392.
286 STRATEGIC MINERALS INVESTIGATIONS, 1942

Several high-grade specimens of tin ore were sent to the New

pro; 

19/

18/ Orleans Exposition of 1884-85. In 1886 the property became

involved in litigation and operations stopped.

In 1886 the Lexington Tin Mining Co. was formed, and in a

20/ 

report to that company J. Hotchkiss described the prospecting

that had been done up to that time. The report lists about 40 

shafts, tunnels, and cuts, spread over an area "nearly 10 miles 

long by 4 miles wide." Apparently this company did no mining or 

development work.

Nothing definite about the district is again recorded until

1889, when the Boston Tin Mining Co. obtained an option and took

21/ 

steps to develop and test the deposits. In 1890 the district

was examined by W. 0. Crosby, and early in 1892, when 2,000 tons 

of ore had been mined, a $50,000 concentrating mill was put up. 

Three trial runs were made on a total of 290 tons of ore averaging 3.3 percent tin, and 2,400 pounds of concentrates averaging

22/

43 percent tin were shipped to Boston to be smelted. This

23/

work was stopped, however, in the spring of 1892 by litigation over ownership.

Because of uncertainty about the title of the property, no 

further systematic work was done until 1918, when explorations 

were begun by the Richards Co., Inc., of Boston. The work of 

cleaning out the old workings was begun in October 1918, and 

there followed a period of rather intensive development under 

the supervision of Mr. W. Spencer Hutchinson. The No. 2 workIngs were cleaned out and extended, and at the No. 1 workings 

some trenching was done and the present tunnel was driven. This 

work stopped in August 1919. In April 1942, the Bethlehem Steel

IS/ The Virginias, vol. 5, pp. 181, 196, 188U; vol. 6, p. 25, 1835. 

l^/ Miners! Resources U. S., 1893, pp. 180-152, 189*+. 

?0/ Eotchklss, Jededjah, in Mineral Resources U. S., 1885, PP. 371-^76, 18867"^

21/ Mineral Resources U. S., 1889-90, p. 1?1, 189?.

22/ Ulke, Titus, in Mineral Resources U. S., 1893, P. 181. 189U.

23_/ Idem, pp. 180-182.
UNITED STATES DEPARTMENT OF THE INTERIOR 

GEOLOGICAL SURVEY BULLETIN 936 PLATE 4 3

Sample 

number

11A 

13

13

14 B

15

22

23

24

25

Description

Composite

Greisen 

Country rock

Sheared 

country rock

Composite 

Composite

I0"greisen 

10" quartz

Sheared 

country rock

Granodiorite

Length of Tin content 

sample (percent)

5"

5' 

3' 

20" 

3'

O.67

.11 

Trace

.02

.29 

3.78

.74

.02 

None

EXPLANATION

Shear zone,showing dip

Shear zone, partly altered 

to clay (montmoril/oni-te)

Channel samples assayed

c . . . sVquartz vein .. ^ . ^"quartz vein 

5 quartz vein ^ 2-3quartz vein ..--{^j-jpr ___ 15 /

l'/2 carbonate vein 

with cassiterite

3"quartz vein

50 Feet

MAP OF THE NO. 1 WORKINGS, IRISH CREEK, VA. ( SHOWING LOCATION OF SAMPLES AND LIST OF ASSAYS

471317 O - 42 (Faces p. 286)
TIN DEPOSITS OP IRISH CREEK, VIRGINIA 287

Co. began a campaign of exploration by diamond drilling, and in 

May 1942 three drill holes, whose locations are shown on figure 30, had been completed. By June 1942 a fourth hole was completed, and a fifth had been begun.

Production

Presumably all the ore that has been mined in the district 

has come from the No. 1 and No. 2 workings. The recorded production, which is summarized in the table below, reflects the 

practice of mining rich pockets.

Tin ore mined from No. 1 and No. 2 workings

Date Tons

Tin content

No. 1:

Tunnel. ..................

Upper 25 feet of shaft...

No. 2:

40-foot shaft ............

Tunnel 201 ...............

Tunnel 201 ...............

Pit 214..................

Pit 214..................

Open cut north of

tunnel 202. ............

. . 1890-92

.. 1890-92

.. 1918-19

.. 1918-19

.. 1918-19

.. 1918-19

. . 1884-86

. . 1884-86

.. 1918-19

.. 1918-19

.. 1918-19

.. 1918-19

.. 1918-19

.. 1918-19

290 

1,710

1/90

.6

19.4

140.0

2.5

1.5

1,000

.9

.6

1.0

1.8

3.1

.6

.6

Percent Pounds

3.33 19,314 

Unknown Unknown

2.11 3,798

20.00 240

13.9 5,393

1.45 4,060

1.00 50

2/

Unknown Unknown

1.16 21

9.2 110

16.0 320

7.65 275

14.0 868

3/15.0 180

Unknown Unknown

\J Left on dump, according to W. S. Hutchinson. 

2/ This lot was shipped to England, nnd its grade is unknown. It was 

probably hand-sorted ore. 

'Estimated.

Mine workings 

No. 1 workings

The 'main lodes. The No. 1 workings Include about 340 feet 

of tunnels, which are still open, and an exploratory shaft, said 

to be 156 feet deep, which is now caved and filled with water. 

(See pi. 43. )
288 STRATEGIC MINERALS INVESTIGATIONS, 1942

The No. 1 workings expose a number of approximately parallel 

lodes and segments of lodes in the typical granodiorite. The 

number of individual lodes present is unknown, because it is 

impossible to correlate the various segments These strike 

approximately N. 65° W., and most are vertical or dip steeply to 

the south, though one in the northwest end of the workings dips 

65° N. The lodes are cut by several faults of unknown displacement and by many small slips.

The lodes consist of a medial vein of quartz from 2 to 7 

inches wide, bounded on one or both sides by 1 inch to 5 feet or 

more of greisen. The greisen, though not uniform in width, persists along the strike of the quartz vein; and in a few places 

greisen was found with no quartz vein.

Cassiterite occurs in large, widely scattered lenses, in 

veinlets, or as disseminated grains which are chiefly in the 

greisen but rarely in the quartz. Masses of cassiterite up to

14 inches wide are reported to have been found in the vein in

24/ 25/ the shaft, and Winslow, in describing the outcrop of the

lode, mentions a "veinlet of solid cassiterite an inch or more 

thick" cutting micaceous quartz.

An average tin content for the lodes in the No. 1 workings 

of about 1 percent, in minable widths, is indicated both by 

assays and by the records of ore that has been mined. The average tin content of five samples collected by the authors was 

1.12 percent. The location of these samples and the assays are 

shown on plate 43. The composite samples were taken across the 

entire width of the lodes; the length of cut ranged from 9 

inches up to 5 feet, and the samples include the quartz vein as 

well as the greisen. Cassiterite co\ild not readily be seen in 

the greisen except in sample 22. Samples taken in 1918-19 by 

W. S. Hutchinson averaged 1.23 percent of tin. These samples

g*4/ Hutchinson, W. S., unpublished report.

g5/ Winslow, Arthur, Tin ore in Virginia: Eng. and Min. Jour., vol. 

p. 320, 18S5.
TIN DEPOSITS OF IRISH CREEK, VIRGINIA 289

were cut along the back of the main tunnel at 5-foot intervals,

and the average length of cut was 3.7 feet.

26/ 

Possible extensions of No. 1 lodes. Perguson reports a

3-inch quartz "vein" found in a small open cut about 100 feet 

north of the No. 1 workings and states that it contained "a considerable amount of beryl in long, slender crystals and some 

muscovite in small plates. The granodiorite next to the vein is 

greatly altered, but the alteration here cons-ists of replacement 

of the original rock by an aggregate of muscovite and beryl, 

rather than of muscovite and fluorite as in the other veins. No 

cassiterite was seen in the specimens from this vein." This 

vein is probably the continuation of the lode exposed in the 

northwest workings of tunnel No. 1. What is believed to be the 

eastward extension of this same lode was prospected in a 160- 

foot open cut beginning about 410 feet N. 77° E. of the portal 

of the tunnel. Hutchinson reports that cassiterite was found in 

float below the opening and a "sample taken across the vein, 

including both walls, assayed 1.02 percent over a width of 10 

inches." Three other samples from the cut are reported as follows:

Tin Description , J- in . x

(percent)

General sample of 2-inch

"vein"...................... 4.76

Soft material picked out of

2-inch "vein"............... 6.31

Sample across 2 feet.......... 2.99

A 95-foot tunnel, 325 feet N. 73° E. of the portal of 

tunnel No. 1 and 106 feet above it, driven to explore this lode, 

failed to find it. The tunnel cut two diabase dikes which, 

according to Hutchinson, displaced the lode.

Another lode or set of Ipdes with a southerly dip was found

27/ in open cuts about 160 feet north of the main tunnel. A

5,000-pound sample yielded essays averaging 1 percent tin.

g6/ Perguson, H. 0., Tin deposits near Irish Creek, Va.: Virginia Geol. 

Survey Bull. 15-A, p. 11, ISIS.

2£/ Hutchinson, W. S., unpublished report.
290 STRATEGIC MINERALS INVESTIGATIONS, 1942

The large number of lodes in the immediate vicinity of the 

No. 1 workings indicates a rather broad zone or system of lodes. 

Although Information is too meager to determine whether the 

lodes are unsystematically scattered over the region or are 

closely spaced, forming a zone or system with barren ground 

beyond, the persistence of the greisen is an encouraging feature.

No. 2 workings

The early work at Irish Creek was concentrated principally 

on the No. 2 group of lodes, located on the hill west of .Panther 

Run about 1,200 feet south of the old mill. The workings on 

this group of lodes were caved in at the time of the present 

investigation, and the information presented here is gathered

chiefly from progress reports by W. Spencer Hutchinson. Other

28/ information is found in the accounts by Hotchkiss, Camp29/ 30/ 31/ 32/

bell, Brown, Winslow, and Perguson, of the early exploration. There are approximately 850 feet of workings, chiefly 

in three tunnels, shown in plate 44. Tunnel 201 is the easternmost and lowest in altitude of the No. 2 workings. It consists 

of about 220 feet of lateral workings and a 27-foot winze near 

the breast; also a 12-foot raise connecting with tunnel 204. 

Tunnel 204 has the most extensive workings. These lie essentially to the west of tunnel 201, and are about 12 feet higher 

in altitude. It has about 518 feet of crosscuts and drifts, all 

made prior to 1918. Several pits, shafts, and trenches are 

found at the surface. Tunnel 202 is the westernmost and highest 

of the workings exploring the No. 2 group of veins. It is 131

gg/ Hotchkiss, Jedediah, Tin ore In Virginia: The Virginias, vol. U, 

pp. 150-151, 1883, and vol. 5, p. 38, 18SU; Silver and gold in Virginia tin 

belt: The Virginias, vol. U, p. 168, 1883.

29/ Campbell, Harry D., Tin ore in the Blue Ridge of Virginia: The Virginias, vol. U, p. 151, 1383.

30/ Brown, W. G., On cnssiterlte from Irish Creek, Rockbridge County, 

Ya.: Am. Chem. Jour., vol. 6, pp. 185-18?! 1285.

Jl/ Winslow, Arthur, Tin ore in Virginia: Eng. and Min. Jour., vol. ^0, 

p. 320", 1885.

3j/ Perguson, H. 0., Tin deposits near Irish Creek, Va.: Virginia Geol. 

Survey Bull. 15-A, 1918.
GEOLOGICAL SURVEY

TUNNEL 201 ( 

ELEV. 2B3S\ \

\>

BULLETIN 936 PLATE 44

. OPEN CUT 3OI

EXPLANATION

Foot of raise

H 

Head of winze

CAVED SHAFT 

ELE.V.27S3'

QUARTZ CROPPING^

TUNNEL 2O2 

ELEV..27IO'

TUNNEL 2O4 

ELEV.26B3'

OPEN CUT 214

TUNNEL 201 

ELEV.2670'

PLAN

50

PROJECTION

o 100 Feet

MAP OF THE NO. 2 WORKINGS, IRISH CREEK, VIRGINIA

After W.Spencer Hutchinson 

March 1919

471317 O - 42 (Faces p. 290)
TIN DEPOSITS OP IRISH CREEK, VIRGINIA 291

feet long and connects with the bottom of a caved shaft. Scattered over the area are several other caved pits and trenches.

Not much is known of the character or composition of the 

lodes. Most of the descriptions refer to the quartz veins, but 

whether or not greisen is associated with the quartz is not 

clear. Greisen was found on some of the dumps, and Hutchinaon 

refers to altered tin-bearing granite or country rock next to 

the vein; it therefore seems probable that greisen is present, 

presumably accompanying the quartz veins.

Apparently the workings explored a group of lodes similar 

to the No. 1 group. According to Hutchinson the ground in the 

workings is much broken and the lodes are cut and displaced by 

slips. It is therefore impossible to state the number of individual lodes, or anything about their lengths or the relation 

of one to another. This group of lodes has a known length of 

approximately 500 feet and strikes about N. 70° E. Individual 

quartz veins range in strike from N. 45° E. to N. 70° E., and 

in dip from 50° southward to vertical. Whether or not this 

group of lodes is the faulted equivalent of the No. 1 group 

cannot be determined. The fault zone found in the westernmost 

part of the No. 1 workings has displaced the western extension 

of the No. 1 group of lodes, but nothing is known of the direction of movement nor of the amount of displacement along the 

fault.

In tunnel 201 a northwesterly crosscut 49 feet long at a 

point 67 feet from the portal passes through broken and decom- 

'posed granite said to be in a fault zone. No lod,es were found 

in the crosscut, although some quartz could be seen on the west 

side. It was thought that some lodes found farther west would 

be intersected by this crosscut, but they evidently were cut 

off by the fault.

At 110 feet from the portal of tunnel 201, a mass of arsenopyrite 10 feet long and 6 inches to 2 feet wide was found.
292 STRATEGIC MINERALS INVESTIGATIONS, 1942

Crystals of cassiterite were sparingly distributed through the 

arsenopyrite and a lens of cassiterite of unreported size was 

found nearby. A winze 27 feet deep and dipping 53° was sunk on 

this vein. The arsenopyrite continued to the bottom but pinched 

to a narrow stringer. Cassiterite was very scarce, and water 

coming in at the bottom discouraged further sinking.

According to Hutchinson, only 3 out of 14 samples taken 

across the back of tunnel 201 (pi. 44) at 5-foot intervals 

along the 35-foot stretch 94 to 129 feet from the portal, contained appreciable quantities of tin. These three best samples 

contained 1.61 to 1.81 percent of tin; the other 11 showed only 

a "trace.."

The workings of tunnel 204, driven before 1918, were thoroughly sampled by the Richards Co., but the sampling, according 

to Hutchinson, "disclosed nothing of consequence," and, he adds, 

"there are no stopes or other evidence of ore having been mined 

that would indicate that the former operators found anything 

either."

A small pit (No. 214) dug at the southwest end of an old 

caved pit above the crosscut about 60 feet from the portal (pi. 

44) struck a pocket which yielded about a ton of ore containing 

16 percent tin. A shaft 5 feet deep was sunk on the ore and 

yielded 3,600 pounds of ore which assayed 7.65 percent tia, but 

when this ore pinched out the work here was discontinued.

According to Hutchinson, two parallel quartz veins called 

the North vein and the South vein are exposed in tunnel 202. 

The North vein was followed for 60 feet and had a maximum 

thickness of 5^- feet, but it is said to have been less regular 

than the South vein, and assays of three samples from it showed 

no tin. The South vein, exposed for 33 feet, dips about 50° S.; 

it has an apparent maximum thickness of 9 feet, but in general 

it is 6 feet or less in thickness. Five samples, apparently 

representing the quartz vein, showed no tin in the assay; one
TIN DEPOSITS OP IRISH CREEK, VIRGINIA 293

sample across 5 feet of the vein assayed 2.92 percent tin, but 

a second sample showed none. A sample across 3^ feet of vein 

rock in the bottom of an open cut 30 feet east of the caved 

shaft, believed to be part of the South vein, assayed 0.70 percent tin. Here, then, as in the veins in the No. 1 workings, 

 cassiterite was found only in pockets. The high-grade specimens of cassiterite and wolframite which were found on the dump 

must have come from such pockets. A 9-foot north crosscut 60 

feet from the portal revealed no other quartz vein, and samples 

from a cut-out in the wall of the drift opposite, where it had 

been reported that ore was found in the earlier development, did 

not encourage further work in that direction.

Nearby lodes. Hutchinson also reported that a large amount 

of trenching was done to explore the veins between the old mine 

workings, and also what he calls the north vein probably the 

one just north of tunnel 202 (fig. 30 and pi. 44). A rich 

pocket here yielded 6,100 pounds of ore assaying 14 percent tin. 

A shaft was started in the bottom of an open cut, but the ore 

pinched out in about 6 feet. A narrow seam of ore showed in the 

end of the open cut, and a tunnel at least 40 feet long was 

driven from which 1,200 pounds of ore, estimated to run 15 percent tin, was produced. No ore showed in the face, however, and 

a short crosscut to the north failed to disclose ore. About 15 

feet north of the portal of this tunnel is a small prospect on 

a parallel vein; according to Hutchinson, 1,200 pounds of "good 

ore" was taken from this prospect and there was a showing of 

ore in the face.

Open cut No. 301 is apparently on a quartz vein. Samples 

of vein matter from the south side of a heavy quartz outcrop in 

the hanging wall, one 5 feet from the surface and another 10 

feet from the surface, are said to have showed no tin when 

assayed, but a footwall specimen, whose depth is not given, 

assayed 0.90 percent tin.
294 STRATEGIC MINERALS INVESTIGATIONS, 1942

The grade of ore in the No. 2 group of lodes, according to 

these data, is apparently lower than that in the No. 1 group. 

Here as in the No. 1 group, the ore seems to have occurred in 

rich pockets and in narrow veinlets, but it is not clear from 

the available reports whether or not the cassiterite was in 

greisen, nor whether the sampling was adequate. Apparently 

most of the sampling was of quartz and "altered rock" in which 

cassiterite was discernible to the eye. Even though rich 

pockets may have been found, that fact would hardly warrant 

further work unless it were known that greisen occurs persistently. Thorough mapping and sampling of the greisen needs still 

to be done before the value of this group of lodes can be fairly 

appraised.

Outlying lodes

Cassiterite has been reported to occur over a wide area

53/ adjacent to the No. 1 and No. 2 groups of lodes. Ferguson

found six scattered veins, "apparently of some promise," on the 

ridge north of Irish Creek, northwest of the No. 1 and No. 2 

workings. These veins have a more northerly strike than those 

just described. According to Perguson's report, they consist 

of quartz, and most of them contain mica, limonite, and some 

cassiterite.

Winslow 'showed the location of the known veins on the 

map accompanying his report. One group of five veins, on the 

south side of Irish Creek and about 6,500 feet west-southwest 

of the mill on Panther Run, have a general westerly strike and 

southerly dip. The middle vein is said to be 3 feet thick, and 

an average sample from it contained 1.12 percent tin. Another 

vein about 1 foot thick, situated about 2,400 feet west of the 

No. 2 workings, was reported to contain 0.63 percent tin.

33/ Ferguson, H. G., op. clt. (Bull. 15-A), pp. 13-lU, and fig. 2. 

Winslow Arthur o. cit. . 20
TIN DEPOSITS OF IRISH CREEK, VIRGINIA 295

Apparently greisen accompanies most of the veins, for Wins35/ 

low states that "the gangue of the veins * # ^generally is

a dark earthy rock composed largely of quartz, with iron pyrites, mica, and various earthy minerals, among which the cassiterite is disseminated in small crystals and in fine grains indistinguishable to the naked eye."

36/ 

Hotchkiss reports the presence of tin in many prospects

in an area of about 12 square miles, "about 3 miles wide from 

northwest to southeast, and about 4 miles long from northeast 

to southwest." Unfortunately the locations' are not described, 

and no maps accompany the report. Samples collected from 11 

localities, not including the No. 1 and No. 2 groups, contained

from 0.1 to 3.25 percent of tin and averaged 0.805 percent.

37/ Hotchkiss also points out that "the openings that have been

made are so located as actually to expose to inspection fully 

600 feet of the vertical depth of the tin veins of this region * * *." Hotchkiss concludes that ' "the prospecting that 

has been done, the condition of the veins as exposed and their 

richness in metallic tin » $« # warrant the conclusion that an 

abundance of high-grade ore can readily be obtained from these 

localities."

RESERVES

The ore body exposed in the No. 1 workings is the only 

potential reserve in the district that is even partly blocked 

out. Its average tin content is about 1 percent. The total 

length of the lode now exposed is about 330 feet and the average width about l^ feet, if one assumes that the width is about 

one-fourth that of the 5-foot wide drifts. Assuming 12 cubic

35/ Winslow, Arthur, op. cit., p. 320. 

W Hotchkiss, Jedediah, in Mineral Resources U. S., 1885, PP. 371-376, 

1886.

3J/ Idem, p. 376. 

3J/ Idem. p. 375.
296 STRATEGIC MINERALS INVESTIGATIONS, 1942

feet of ore to the ton, the ore body would contain about 3,400 

tons of ore per 100 feet of vertical extent. The general 

assumption that the lodes continue at least 100 feet seems 

warranted, although accurate vertical or horizontal projections 

cannot be made because of the many slips and faults.

No estimates can be made of possible reserves in the caved 

No. 2 workings or in outlying prospects.

SUGGESTIONS FOR.PROSPECTING

The small amount of exploration that has been done in the 

Irish Creek district leaves the extent of its tin deposits still 

undetermined. The principal need seems to be a general prospecting of the area underlain by granodiorite, which, so far as 

is known, is the only country rock of the tin lodes. In prospecting, the quartz veins are a convenient but not wholly reliable guide to possible tin deposits; the greisen zones, however, 

are a valuable guide to ore, because they probably are present 

wherever tin occurs. The greisen is readily distinguishable 

from the granodiorite, a fact which not only aids prospecting 

but is important in selective mining, as the granodiorite is 

barren.

At present it is not known whether the lodes are grouped 

into narrow systems or are scattered unsystematically in the 

granodiorite. Widespread trenching normal to the strike of 

known veins would seem to be the best means of determining the 

distribution or grouping of lodes, and later local diamond 

drilling should give a fairly accurate idea of the amount and 

grade of greisen in these zones.

o