Montana oil and mining journal. [volume] (Great Falls, Mont.) 1931-1953, 1937-07-17
Minerals
CONTINUED from Page Two)

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mines and that these mines occur mostly on
the lower outside slopes Of the mountains in
the shale and carboniferous limestones While
most Of the developed mines show more or less
porphyry, any man Of intelligence who will
stop running long enough to read the plain
characteristics Of the ore bodies. viii see that
the porphyry is later formation than the
ore.
The ore bodies are Of two classes One class
Of these ore bodies was evidently the result
Of the first mineral action in the country.
The mineral solution coming up through the
solid carboniferous lime by following assures
or other openings when the topography Of
the country was flat or comparatively so,
reached the iooser lines and penetrating
through the layers altered the rock into ore
thus forming flat ore bodies lying more or
less true with the shale formation. Later, as
the mountains were heaved up by internal
pressure, these ore bodies were tipped up on
edge and now lie on the lower slopes Of the
mountains near the prairie.
The Kendall-Barnes-King mines are ex-
amples and the outcrops Of such veins occur
all along the Gilt Edge slope Of the Judith
mountains for a distance Of over six miles
but not one Of them has been developed.
AS the internal pressure became stronger
and the Judith mountains began to round into
their present form, other ore bodies began
to form in the cracks and broken assures Of
the carboniferous or massive Imestones
dependent. Of course. on the direction taken
by the fractures In the limestones Some are
vertical some have a dip in the general d.
rection Of the formation layers, while quite
a number Of them have a slight dip back into
the main range Of mountains and through the
Standardization layers Of the limestone
The outcrop Of the outside shale ore
bodies consists Of yellow porous or honey
combed rock that usually breaks In rounded
or boulder form and the stuff generally as
says 40 cents to 81 per ton. r. K. Neill. former
superintendent at the Kendall told me that
wherever they sank on this formation they in
variably struck pay ore at 20 feet or less in
depth. No work has been done on this class
of veins in the Judiths
Geologically speaking. the Judith mountains
are young, and in many places these shale
veins extend well up the sides OF the main
mountains. The erosion has only extended |
down to the entrance edge Of the ore bodies
The lead outcrops in the massive lime are
different and generally consist Of |
q strata OF coarse. sandy silicious limestone
often stained with iron and usually well
rounded when broken. The lime cliffs near q
lead are nearly always well rounded. A num-
Der Of these ore bodies show pay ore at
points where there has been sufficient erosion |
The ore in the massive lime carries a much |
higher percentage Of silica than the ore in /
the shale lime some Of 1t being an extremely |
hard, cloSe-gralned quartz.
After these leads were formed It is evident /
that the internal volcanic pressure became /
stronger and lava rock or porphyry was forced |
up. In some places the porphyry came up |
slowly and followed the place Of least re-
sistance which was often along the soft ore |
sS4co ahCAhA AoAAIGd anu III pieces IL IoA- /
.acted the ore and then again left the ore and |
went through openings in the lime. This was /
the case at the Chickadee mine while at the
Standby an eruption dyke Of porphyry came
up right through the lead at nearly right
angles carrying much ore and other matter
along inside the porphyry mass.
In 1894 one Of the worlds greatest mining
experts OF that period Arthur L. Perase Of
London, came to Gilt Edge to examine the
mines. After his examination Of the porperty
ne told me there was no doubt but what the
oorphyry was a later formation than the
ore. told Mr. Pearse I had q theory that
this ore was found where there was no
7orphyry, the leads would be much more reg
lar Mr.. Pearse said my theory was quite
plausible. MY work since that time has proved
he theory to be a condition.
The foregoing Is as concise a history as
could make Of mining in the Judith noun
aims and touch on all the main mining APP
'rations that have occurred here during the
learly 90 years that have passed since the
irst discovery Of mineral in these mountains.
Yet what I have written Is merely q pro-
ogue. The real history Of mining here viii
'e written in some future generation when
mining engineers as wen as other people
ealize the truth OF the old saying gold is
where you find It," and will look for ore
instead for the place where ore ought 10 be.
! moments thought should tell an inteIligent
erson that IL mines could be found By rule,
hey would all have been found long ago. But
~ talks with old time prospectors as well
5 my own observations convince me that only
man fraction OF the leads have been