98 GOLD AND TIN DEPOSITS OF SOUTHERN APPALACHIANS. 
from the 100-foot level. The quartz body represented continues upward toward the 
observer and downward away from the observer ; like nearly all the quartz lenses, it has a 
pitch to the northeast in the vein. The irregularities shown in the figure indicate that 
replacement has gone on. Besides the pyrite which can be shown in the sketch, minute 
crystals are scattered through the wall rock and doubtless contribute to it a small amount of 
gold. The tuff is silicified, too, as in the other replacement deposits. Filling is indicated, 
on the other hand, by the fact that some of the solid bodies of quartz include fragments of 
the wall rock with foliation not corresponding to that of the walls in place. Moreover, in 
the roof of the crosscut from the shaft, just where it reaches the vein, the quartz adjoins 
amphibolite instead of tuff. Here the pyrite is mainly contained in the quartz; the contact 
between quartz and amphibolite is sharp and is defined by a narrow band of black biotite 
scales which separate the two and which have doubtless been formed from the amphibolite 
by the action of the vein solutions. Under the microscope this biotite possesses the clear 
chestnut-brown color characteristic of contact-metamorphic biotite. Here and there the 
vein quartz contains little flakes or tufts of sericite, which have the appearance of being 
contemporaneous with the quartz, but the evidence is not certain. A few tiny flat crystals of 
black ilmenite occur in the quartz. This strengthens the relation between the gold-quartz 
veins and those ilmenite-b earing quartz veins which are not known to be auriferous. (See 
pp. 64-65.) Numerous crystalline grains of apatite in the replacement portion of the deposits 
emphasize the similarity to the Haile mine and suggest relation to the Dahlonega deposits, 
where apatite occurs in the veins (p. 124). Where the vein cuts amphibolite, the original 
magnetite (or ilmenite?) of the rock is in many instances partly or completely replaced by 
pyrite, and in a few cases magnetite has been deposited on the pyrite. In the amphibolite 
near the vein are scattered small bunches of crystalline calcite, surrounded by dark-green 
specular or micaceous chlorite, heavily impregnated by pyrite; this is undoubtedly a 
product of the vein solutions. 
The pyrite-bearing quartz ore from the vein averages $10 to $15 per ton. The replaced 
wall rock, impregnated by silica and pyrite, averages about $3. The amphibolite wall rock 
is said to average $1.50 per ton and the sheared sericite zone in the amphibolite $2. The 
concentrates average $100 and perfectly clean pyrite $150 to $175 per ton. 
So little of the gold is free that amalgamation is not practiced. The pulp, stamped to 
15-mesh, is run direct to the Wilfley table. The headings are stored, in the prospect of 
being either shipped or roasted and cyanided on the ground. The tailings are run to a 
pneumatic-cone separator, where the slimes, averaging 15 per cent of the tailings and run- 
ning $20 per ton, are taken out and cyanided during mechanical agitation, while the sands, 
carrying $6 to $7 in gold, are treated with strong cyanide solution without agitation. It is 
understood that the process is not yet wholly satisfactory. Possibly more careful crushing 
to avoid sliming, more efficient concentration and classification, and then roasting of all the 
headings and subsequent lixiviation might give a better extraction at perhaps no greater 
cost. 
The ore bodies of the Ferguson mine, like the other fissure-vein deposits, are influenced in 
their form by the structure of the surrounding rocks. In this case their form has been fur- 
ther modified by the effects of replacement. The result is rudely lenticular masses of quartz 
surrounded by low-grade zones of replaced wall rock. Four of these lenses are known and 
have been worked to some extent by separate shafts. Only one, the northeasternmost, is 
now being explored. Present work is being carried on as the downward continuation of a 
former slope. On the 100-foot level this stope is 4 to 8 feet wide and 25 to 35 feet long. It 
reaches upward to the surface and has been explored 30 feet below the level b}^ an inclined 
winze sunk on the pitch of the shoot, which is steep to the northeast. This work is being 
carried on solely with the idea of exploration, but in the hope that by following the ore it will 
pay for itself. The winze will be carried down to the 200-foot point if the ore continues, in 
which event the shaft will be sunk another 100 feet and connected with the vein. If the 
present dip of the vein continues, the shaft should cut the vein at approximately 300 feet. 
