El Paso herald. (El Paso, Tex.) 1901-1931, 1910-03-25
PRODUCTION Of COBALT DISTRICT
HAS ALREADY TOTA[EO,s30, 900, 900
Bryan K. Morris Mining Engineer Describes Formation
in the Canadian Camps Analysis of Ores-Cost of
Production There Exceeds Cost in the Mining
Properties of the Southwest
MINING NEWS.

Bryan K. Morse. mining engineer,
formerly superintendent of the Ortega
Mining company, of Cananea. Mexico,
who has been in the city a few weeks.
left for Bisbee today He spent eight
months last year in the famous Cobalt
mining district, Ontario, Canada. in
geological and neurological eXamina-
tions, and furnishes the following ex-
cerptS from his notes on observations in
various localities of that district. which
will be of great interest to all mining
men of the southwest as showing the
conditions existing and methods used in
that district.
Describes Formations.
The country rocks of the proved bo-
nanZa circle of the silver deposits of
the Cobalt and South Lorrain camps
are all Pre- Cambrian and are classified
in three series: First. Keewatin: second.
Huronian; third. -iabase and Gabbro.
The Oldest series in the district con-
sists of an ingenious complex which con-
tains diabases and related rocks of diff
ferent periods of eruption, together with
granite porphyry and other ingneous
material. Sediments are represented by
the jasper iron ores. The basis rocks,
or greenstones occur in much larger
volume than do those of a more acid
piled to this series. The ore deposits
appear TO occur only in the diabases and
greenstones.
The Keewatin has been subjected to
folding and other disturbances and is
cut through by medium TO coarse
grained granite, especially in the town.
ship of Lorrain. TO which the name of
Laurentian is applied. The Keewatin
rocks, however, have been folded be-
fore the infrnciQn n he n
granite.
Cobalt I'm Huronfan.
The second series is the Huronian,
After the Laurentian intrusions the
surface was subjected to erosion, and
these rocks together with the Keewatin
were worn down. This period Of erosion
was a long one, and the surface was
rendered uneven. being cut into hills
and valleys. Government biologists
are rather inclined to the belief now
that the lakes were formed by glaciers.
The Oldest fragmental material. which
lies directly on the eroded Keewatin
and Laurentian surface, consists Of
coRglomerate. greywacke slate and i'm
pure quantities.. These rocks contain
fragments of the granite. greenstones.
diabases and other representatives OF
the older series, and their relationship
to the latter is quite easily proved by
contacts in quite number of local.
ties. This older or lower Huronian is
of special interest since it contains most
of the cooalt-si1ver veins.
The association of the members of
the lower Huronian is somewhat vari- !
able. There is usually a little coarser
material, conglomerate at the base. This |
is frequently followed by considerable |
thickness of well banded greywacke |
slate. The slate in many cases passes !
81 1T
or impure Quartzite. which is succeeded |
by a coarse conglomerate. The upper |
part of the conglomerate is undoubtedly |
younger than the more slaty members
Slate ConElO nerate.
The breccia and conglomerate of the |
lower Huronian are what were called 1
by Logan and others. slate-conglomer- |
ate, a name which well describes the 1
varieties possessing a slate-like base. |
through which are set pebbles and
boulders. The veins cut through all |
these series, but the most productive
parts of the veins are usually in rocks /
which contain more or less coarse frag-
ments.
The series of arkoses. or what have
been called by some writers sea- green
quantities., togethtr with conglomerate
and quantities of the township of Lor- |
rain, form another series in the Huron |
ldQ, MI O1lllcI SldllHS tldl lie mas Y
found them UNCOMFORTABLE to the Lower
Huronian.
Diabases and Gabbro.
The third series is Diabase and Cab |
bro. These rocks refer TO the post Up |
per Huronan intrusions Of the diabase
The two terms are employed in the
camp to distinguish between the fine
and coarse grained. Diabases repre- |
sent several periods of eruption. Kee-
watin to post middle Huronian are
found in the field and is very difficult
to distinguish them. The diabases of
the post upper Huronian are mucn
fresher in appearance and coarser in
grain than those of a similar compo-
sition which occur in the early series, |
and can thus be readily distinguished in |
the field from the latter.
In many cases, where associated with
the Huronian, the diabases seem to be
In the form of sheets or stills spreading
between or over the layers of the rocks
through which they cut. They show no
evidence, such as amygdaloid texture.
Of being surface flows. 1t is generally
conceded that the fractures and fis-
sures now occupied by the silver bear
ing veins, were dause1 by the in
trusions OF the diabase and other dis
following same.