Nogales international., 1926-10-31
by Howard E. Davis, Consult
ing Engineer)

ing Engineer)
Exclusive for the Internationa
by Request.
The recent and current ore
discovery made by Big Jim Mines
in it's Patagonia property is
genuine, and of greater impor-
tance to Patagonia and to Santa
Cruz County than any mining de-
velopment of many years past.
| have spent about one year in
a study of the geology and min
eralogy of those mining districts
Of which Patagonia is the rail
way and supply center, and can
state that the Big Jim strike is
entirely in harmony with what the
visible geology and mineralogy
of that zone caused me to expect
My only surprise was that a
body of solid sulphide ore of the
general value of this body should
have been cut at the comparative
" shallow depth of 233 feet =
rioht at the top of the water
level.
Theory based upon actual min
ing experience causes the miner
to expect zone of considerable
impoverishment (marked by very
poor ore) in a zone ranging from
20 to 100 feet above AND .be-
low the water level.
When ore which is even of PAY
value to the company operating
its own mil is found in this zone,
the experienced miner is always
willing to, lay quite a bet that be-
fore the zone below the water
level has been penetrated more
than 100 feet picture" ore will
be found. By picture" ore the
miner means ore of excessive rich
ress which, in sulphide zones
means ore which is to the lay
mans eye full Of metal.
1t may here be explained that
by far more than SO percent of
the gold, silver, copper and lead
ores beng profitably milled
throughout the world do not ap-
pear to the layman to contain
much if any metal. In fact, most
of the milling ores do not show
their value even to the trained
eye, but require constant vigilance
hy assaying to distinguish be-
tween pay and barren rock.
Even the novice can see and
recognize mineral in the rock
which has been coming from the
Big Jim shaft ever since it pene-
trated the top Of the ore body.
| have studied samples of the ore
since the strike was made. There
Is nothing freakish or unusual
about it. 1t is true to form and
just what is to be expected in
similar geologic zones in the dis
trict.
At this time 1 am informed
that the shaft has penetrated
some 25 feet into this solid ore
body, and that the lower limits,
or footwalI, have not been reach
ed.
The ore body, according to
angles showing, dips through the
shaft from the easterly side, with
downward inclination toward
the west of about 45 degrees. AS
the orebody has been penetrated
for depth of 25 feet, then this
would indicate that the ore body
already has a known minimum
tnickness-at right angles OF
17.5 feet. How much thicker it
will prove to be no one knows.
l am informed that every bit
OF the rock "mucked" out in sink
ing the shaft since the ore was
hit has been put through the mill
1t is being carefully assayed aft
Ell every round. However, no as
sayed are necessary to show thai
most of this rock is "pay" ma
terial. Good mining requires thar
careful records of the values anC
nature of all rock strata be kept
and that their location, dip, strike
etc, be carefully mapped ant
charted.
Now if my opinion of Superin
tendent Peterson of the Big jim
is correct, he is not putting an!
ore through the mill which will