THOMPSON MINE. 103 
No stoping nor drifting has been done below the 45-foot level, but from that level upward 
the ore has been about all extracted for 50 feet northeast and perhaps 150 feefsouthwest 
of the shaft. At least half of that stope, however, was made years ago. Since the writer's 
visit the shaft has been carried to a depth of 100 feet, where the vein is said to have pinched 
out entirely. Crosscuts were run in both directions, and while it is not known how care- 
fully this exploration was carried on and to what extent the influence of the wall-rock 
structure was studied and considered in directing this work, the continuation of the vein 
was not discovered. 
THOMPSON MINE. 
The Thompson mine lies in the western part of Union County, S. C, about a mile north- 
east of West Springs post-office and about 3 miles east of Glen Springs, Spartanburg County, 
the terminus of a branch of the Charleston and Western Carolina Railway. The mine is 
- the property of the Ophir Gold Mining Company, of Indianapolis, Ind., and is being worked 
under lease by Mr. M. C. Mayes. At the time of visit the mine was partially filled with 
water and thus inaccessible. Only meager information could be gleaned from an examina- 
tion of the dumps and old cuts and from a study of specimens found there. W T hat is here 
recorded has been obtained largely from the writings of others. 
As early as 1847 this was one of the well-known mines of the State a It is doubtless the 
same as that described by Tuomey b in 1844 as the Fair Forest mine. Work was continued 
in the fifties and perhaps until the beginning of the war. Little information can be obtained 
of more recent work, except that in the nineties Mr. O. J. Thies, now manager of the Black- 
mon mine, directed operations for a short time. Some hydraulicking, with attendant 
milling of the coarse material according to the so-called Dahlonega method, was done in 
1895. c The production may have been considerable — perhaps $100,000 or more. The 
only statement in print is that $6,000 was taken from one shoot in 1847. d 
The workings consist of a vertical shaft 165 feet deep and an incline reaching to about 
the same depth, connected by drifts and crosscuts. An open cut over 100 feet long repre- 
sents the work done in early days and the recent hydraulicking. A 20-stamp mill with 
two Wilfley concentrators is connected with the workings by a tramway. 
Two varieties of rock occur here. The one which is more widely exposed is a biotite 
schist of brown color and marked fissility. Feldspar is present as small grains with an 
albite core and labradorite interior. A little magnetite is present. The origin of this 
rock is unknown. The other rock is an amphibolitc which is said to occur as a dike-like 
band in the biotite schist . Only one contact was seen and at this place the foliation of the two 
rocks is parallel, and in a tunnel which starts near the mill this mass of amphibolite seems to be 
fairly wide. The foliation of both rocks strikes about N. 10° E. and dips to the west something 
like 70°. The mica schist is the ore-bearing rock. No very good idea of the veins could 
be had, but it is certain that very quartzose zones parallel to the foliation of the rock have 
been the richest portions. Small quartz stringers seen in the decomposed upper portions 
of the deposit indicate that filling of fissures has gone on.e On the other hand, specimens 
of quartz-pyrite ore, carrying gold, from greater depth indicate that extreme silicification of 
the mica schist has taken place along certain narrow zones. This ore is composed prin- 
cipally of white quartz grains, with scattered interstitial flakes of biotite, muscovite, or 
chlorite. Pyrite is abundant in places. The actual contact of this mass with the schist, 
which would probably have decided whether replacement had or had not gone on, was not 
seen, but schist from near the " vein " or ore-bearing zone shows the effects of vein metamor- 
phism; sharply defined plates of muscovite have been developed at the expense of the 
biotite, pyrite has been introduced, and well-crystallized prisms of a mineral of unknown 
a Lieber, op. cit., vol. 2, 1857, p. 70. 
bRept. Geol.and Agr. Survey South Carolina, 1844, p. 24; also Geology of South Carolina, 1848, p. 91. 
c Nitze and Wilkens, Bull. N. C. Geol. Survey No. 10, 1897, p. 77. 
d Lieber, op, cit., vol. 2, 1857, p. 70. 
e Becker, G. ¥ ., Gold fields of the Southern Appalachians: Sixteenth Ann. Rept. U. S. Geol. Survey, 
pt.3, 1895, p. 309. 
