HAILE GOLD MINE. 81 
very narrow fractures which allowed an especially easy passage for the solutions and 
consequently the extreme silicification of the adjoining rock. In a few instances these 
crevices have been wide enough to allow the deposition of quartz filling in addition to the 
replacement which has occurred along the walls. A few of these quartz veins are outside 
the limits of the ore bodies and nearly all of them carry little or no values. It is possible 
that they were formed a little later than the general silicification which produced the ore 
bodies. A large, worthless vein of this sort outcrops strongly back of the stamp mill, and 
is shown in fig. 8. A smaller vein or lens, practically barren, is encountered in the Bumalo 
cut, 
There are likewise places where the deposition of pyrite has been especially marked, 
producing masses which in some cases are nearly solid sulphide. These, too, are usually 
tabular in form, but can not be definitely referred to fractures, as can the quartz veins. 
Bodies of this kind, rich in pyrite, associated with molybdenite (heretofore assumed to 
be graphite) and carrying good gold values, occur near the hanging wall of the Haile ore 
body in the new Haile pit, The molybdenite occurs especially along narrow parallel bands 
in the pyrite and shows the effect of sliding motion, or slickensides. Gold occurs free on 
these smooth surfaces of the molybdenite in excessively thin flakes, which seem to have 
been deposited before motion ceased. Pyrrhotite occurs sparingly in some of the Beguelin 
ore, An irregular bunch of pyrite, said to contain a considerable proportion of zinc, but 
only a small amount of gold, was found at the northeast end of the Beguelin pit, at a depth 
of about 75 feet. 
Gold occurs in three conditions in the Haile ores — -native gold as originally deposited, 
free gold derived from the oxidation of inclosing pyrite, and gold in the pyrite. In either 
of the first two states the gold can usually be recovered by amalgamation, although the 
gold freed by oxidation is sometimes "rusty," i. e., covered with a thin film of resistant 
material, perhaps iron oxide, which protects the gold from the mercury and thereby pre- 
vents amalgamation. In the unaltered pyrite only a small proportion of the gold is 
attacked by mercury and another process is required in order to save the values. 
There is possibly still another way in which the gold occurs. Some specimens from the 
Beguelin cut, now in the Haile office, show thin flakes of gold in narrow cracks or joints in 
blue unoxidized rock. These specimens give the impression that the gold has been carried 
and deposited in these crevices by solutions later than the original ore solutions — probably 
by surface waters which have obtained the gold by dissolving it from the original ore. 
Thin sheets of pyrite, many of them with a radial structure, occur similarly in narrow cracks 
and likewise suggest secondary deposition. The free gold associated with molybdenite 
may also have been deposited in this way. It has been impossible to determine whether 
or not secondary enrichment, i. e,, solution from upper portions and redeposition at a 
lower level, has actually taken place; but the possibility that such has been the case seems 
rather strong and has already been considered on pages 65-67. 
Broken pyritic ore lying exposed to the air very readily undergoes oxidation, with the 
production of so much sulphuric acid that, to save the plates from injury, such ore is not 
amalgamated, but sent to the concentrators direct. In this case a narrow string of the 
liberated free gold leads the headings down the Wilfley tables. Oxidation underground 
is also proceeding rapidly, and in nearly every drift iron-laden waters are depositing layers 
of limonite. The comparatively small amount of water which the mine makes is held at 
the 350-foot level by pumping. 
VALUE OF THE ORE. 
The Haile is essentially a low-grade mine. Although rich nuggets have been found in 
the decomposed upper portions of the ore bodies, as already mentioned, and these upper 
portions as a whole doubtless held good values, the great bulk of the ore has been of so low 
a grade that the utmost care has been demanded in the extraction of the gold to make the 
operations profitable. 
Bull. 293—06 6 
