Mines Department, Melbourne, June, 1903.
In
reading the literature on the Victorian Gold-fields, I have been always
struck by the fact that knowledge of the internal structure of our
gold-bearing quartz reefs has lagged far behind knowledge of their
distribution. The descriptions and surveys of the reefs at Bendigo,
Ballarat, Walhalla, and other gold-fields, which have been published by
the Mines Department, show, in abnndant detail, the main features in
the arrangement of the reefs, and in their relations to the surrounding
rocks. But the various reports give much less information as to the
distribution of the gold jn the reefs, or as to the causes of the
concentration of gold in lines or
patches in sheets of barren quartz.
There
are, of course, exceptions ; for Mr. Dunn's report on the Bendigo
gold-field gives a full account of the internal structure of the reefs
there ; and Messrs. Lidgey, Moon, and Bickard have quoted cases in
support of the view that ore shoots, or lines of gold ore, occur at the
intersection of a reef and some particular band of country rock. But
this view has not yet received much support from later observers, and
other localities in Victoria. .
On
being called to a temporary connexion with the Geological Survey Branch
of the Mines Department, I therefore recommended that special inquiries
should be made, with a view to discovery of the plan on which the gold
ores are distributed through our reefs. The proposal was approved by
the Hon. J. B. Burton, then the Minister for Mines. Mr. Win. Bradford,
of Ballarat East, whose previous reports had shown especial interest
and insight into this problem, was temporarily engaged to make a rapid
survey of some of the gold-fields, with special reference to the
genesis of the richer parts of the reefs.
This
problem is of high practical importance, for as the reefs are followed
to greater depths, where they generally become poorer, it is necessary
to lessen the amount of dead work, by the help of better clues to the
courses af the gold. The present report deals with the gold-fields of
the Pyrenees, to our limited knowledge of which it makes some
interesting additions.
J. W. G.
18th June, 1903.
