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GOLD DEPOSITS OF THE WEST SPRINGS AREA
cessible. It was owned by Ophir Gold Mining Company of
Indianapolis, IN, and was leased to Mr. M.C. Mayes. The
workings at the Thompson mine during the time of Graton’s
visit were described as a vertical shaft 165 feet deep, an
incline to the same depth, and n open cut about 100 feet long
where hydraulic mining took place. There was a 20 stamp
mill with two Wilfley concentrators on site.
The ore bodies at the Thompson mine are described by
Graton (1908) as three approximately parallel chutes which
strike northerly, dip westerly and pitch southerly. The Pine
Tree and Gully veins are 51 feet apart and both veins, plus
the intervening auriferous slates, were worked through a
long open cut 65 feet wide to a depth of 48 feet where the
free milling ore was replaced by pyritic ore. A shaft was
sunk to a depth of 149 feet in the hanging wall to intercept
the Pine Tree vein at a depth of 130 feet. Cross cuts intercept
the other veins, or chutes, as described by Sloan (1908). The
Pine Tree vein is described as an ellipse in cross section with
a major axis of 60 feet and a diameter of 7 feet. It strikes
N10°E, dips 70° northwest, and pitches 43° southwest. The
Gully and Possum Tree veins, or shoots, are said to be five
feet and four feet thick, respectively, and the Possum Tree
vein lies 99 feet east of the Gully vein. The West vein is a
similar ore chute between two mafic dikes. It was worked
from an open pit 105 feet long and a drift from the Byers
shaft. Pyritic concentrates from the Thompson mine are
reported as $80/ton (4 ounces/ton) by Sloan (1908) and $100
by Graton (1906).
There are no reports of production since Sloan’s
description in 1908. When examining the Ophir and West
mines today, a line of open cuts, declines and shafts extends
in a north-south orientation for at least 5000 feet, and perhaps
farther, since some workings are now covered by a
small private lake (Figure 3). Gold mineralization is associated
with a zone of quartz-sericite alteration that is 300 to500
feet wide on the surface. This alteration can be traced for at
least 12,000 feet and is up to 3000 feet wide (unpublished
mapping by TexasGulf).
As mentioned earlier, two companies, U.S. Borax and
FMC drilled the Ophir mine in 1982 and 1985, respectively.
Ten holes were drilled with a total footage of 4066 feet (Figure
3). Their core and field or summary logs are stored at the
South Carolina Geological Survey. FMC summarized assay
data and Borax included assay sheets. The Borax program
analyzed for gold by atomic absorption and not fire assay.
Detection levels and accuracy at lower levels of gold is not
as accurate as with fire assay techniques. Drill data are summarized
in Table 1. Kennecott drilled the West mine, but
data and core were not released.
Mineralization is within intensely deformed, biotite
sericite quartz schist with variable amounts of fine- to
medium-grained pyrite, up to 5 percent. Distorted laminations,
layers, veins, and blebs of quartz are found in the
biotite-sericite matrix. Often the rock appears laminated. My
impression is that the quartz and laminated quartz-sericite
layers have been intensely distorted by shearing. Small
hook-shaped folds are noted in the quartz laminations and
the blebs of quartz veins are very distorted. The deformation
of the alteration suggests the alteration may predate shearing.
This is also substantiated by the historic descriptions of
the workings where the gold is described as occurring in
shoots with a southwestern plunge. These shoots may represent
tightly folded fold noses. If the shearing post-dates mineralization,
what age is it, and how significant of a disruption
is the shearing?
As noted in the literature and as shown in assay data and
logs, ore is hosted in the pyritic biotite sericite quartz schists.
Historically, where the rocks are more pyritic and siliceous,
the gold grades were higher. The drilling is too incomplete to
substantiate this.
U.S. Borax encountered gold in hole GSU-4D3 (Figure
3) in a sericitic limestone that was four feet thick. This was
the only hole reported to encounter this lithology. Limestone
is the main host rock for gold at the Kings Mountain mine in
North Carolina (LaPoint, 1992). Because of acidic soils, carbonates
are rarely reported in saprolite and may be leached
to depths of several hundred feet. Other unique lithologies
such as iron formation or alumino-silicate alteration were not
described in drill logs.
Neither company presented any analytical data other
than that for gold, however FMC reported visible molybdenite
in hole OP85-1 at 390 feet and in hole OP85-6 at 135-138
feet. None of the early reference (Tuomey, 1848; Lieber,
1858; Sloan, 1908) cites the occurrence of copper from these
two mines, in contrast to the Mud and Nott mines.
EXPLORATION POTENTIAL
Historic mining focused on the high grade ore shoots
which are thin, small and discontinuous. It is unlikely that
any of these individual ore shoots are now a viable mine.
However, Sloan’s (1908) description of the three veins at the
Ophir mine and assay data from drilling by Borax and FMC
show that a halo of lower gold values surrounds these shoots.
Prior drilling focused on drilling for high grade ore shoots
below the old workings, and it is not obvious that these
exploration programs considered a bulk tonnage deposit. To
do so would require more systematic testing with larger
diameter core drilling or reverse circulation rotary drilling,
recovering and assaying the saprolitic alteration, and gold
analysis using fire assay with low detection levels. More
complete geologic mapping of the extent of the alteration
system, better understanding of the structural controls on
mineralization, and geophysics, such as IP would also help
to locate and define an economic deposit. The Ophir-West
mine alteration system is large enough to contain bulk minable
gold targets. The Ridgeway mine owned by Kennecott
is economic because irregular high grade zones are mined in
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