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The
layers of gold-slate exposed in the Mount Doran Company's works show
the indicator lines of drainage in pronounced form, and, as the lode
underlies at about right angles to the dip of the strata, it cuts
through the latter. Accordingly, we found that only at points or lines
of contact of the slate layers and their lines of drainage with the
lode (the " filter pack ") is the stone payable. In many instances the
pitch of the " country" has arranged such lines of contact, which,
being the lines of most pronounced deposition of gold, have become
known as " shoots." Few lodes run exactly parallel to the strata,
because all cracks in which lode stuff is stored are the result of a
greater or less twist strain to the rock layers. Of course, there are
instances in which stone is found on a sandstone layer, and having a
slate wall on its other side. Some lodes of this description are
certainly parallel to the strata, and in such instances it will be
found that, where rich in gold, an obstruction, fore and aft and below,
has made a " settling pit"—a " filter pack "—where the drainage from an
area of long extent on the lines of strata, and of wide extent between
the shrinkage cracks called " heads " and " floors " by the miners, has
been received, imprisoned, and relieved of its mineral contents. The
line of contact of slate drainage with the lode is the line of the
shoot of gold (governed by the pitch of the stone) only when the lode
underlies less than 45° from the horizontal. In the generation of
lodes, the stagnation of the fluids is not absolute. There is a coming
and going in the slowed circulation all the time. The strata at the
Mount Doran mine are charged with sulphides, and the slate layers show
many lines of drainage, at points of contact with which the lode was
rich in gold. This richness was confined to the thin stone of the
original passage on the hanging-wall side of the formation, and in the
big mass of stone immediately under this the gold values were not so
good. The lode opened is but one in a system of lodes passing through
the country here ; and the nature of their encasing gold-slate, the
general occurrence of sulphides, and the innumerable " indicator "
drains in slate, give promise of success of rational and comprehensive
mining. The company recently in charge had only a small winding and
crushing plant, but enough was seen during its term of work to warrant
further effort on a much larger scale. A well-timbered shaft is ready
for work.
Not
far from the Mount Doran area are the remains of a very old mine, known
as the Glencoe, where a shaft was sunk 200 feet in search of a
continuation of riches met with near the surface. It is said that the
water trouble put an end to sinking, and, judging by the appearance of
the mullock heap, the shaft entered a decomposed dyke formation. There
is much sulphide in the slate and quartz, and the general appearance is
favorable for payable gold. Rich wash-dirt has been mined in the
gullies here and a little to the north-west, near the Mount Doran mine.
On a range to the north, again, are remains of works known as
Davidson's, where a wing formation of quartz, having an average
thickness of 3 feet, it is said, was followed down for a couple of
hundred feet or more on the underlay, for returns said to have averaged
1 ounce to the ton. This mining was done over 30 years since, and the
area, with its system of vertical and wing lodes in gold-slate, invites
attention. Many lode systems of gold-bearing quartz lodes outcrop in
the Mount Doran ranges, none of which have received due attention,
although, as stated, numerous outcrops of favoured situations of lodes
have been "rooted " about for patches.
As
we proceed north and east (the Mount Doran ranges are a little to the
west of due south from Egerton) the country appears to have been
twisted more, many wing and fin-like quartz veins being visible in
various shallow works on which nuggety patches of gold have been met
with—as usual, at points where lines of drainage in slate, or between
slate and
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