The diamond drill. (Crystal Falls, Iron County, Mich.) 1887-1996, 1914-03-21

tlOn, texture, geologic ana geographic
position, cost of mining, etc, so the ores
of lower grade which will be- used in
the future will show like variation In
availability. The only factor common
TO all ores which can be used TO sum-
marize and compare the different ores
is profit per ton. Profit now deter
mines whether a given ore can be used
and Will determine this in the future
II. therefore, we can approximate the
profit per ton for any given ore, at any
given time in the future, we can easily
calculate how much, If anything, one
can afford 20 spend now TO save this
ore. This profit can never be accur-
ately predicted in advance, but | be-
| lieve il may have much the same rela-
tion to values Of higher grade ores as
4 1t has al present. If a 80 per cent ore
now shows a mining profit of 81. 80
! per ton, the lower grades as calculated
from penalties will show profits of a
fraction of this amount. In certain
favored Lake Superior localities ~
TO 40 per cent low phosphorus. high
silica ore can be mined now at a
profit of 20 cents or less. In less ia.
vored localities. where now only the
higher grades ores are being mined,
the time will come when the lever
grade ores will necessarily be mined
but when this time arrives the profit
per ton will probably be at least as
low as the present profit for such low
grade ores mined from the most IA.
vored localities and as low MS the
price we now figure from penalties.
The total cost to the consumer may
be the same, but relatively more of the
cost will 90 TO fuel and 10 handling
the larger quantities Of material
necessary to produce a given unit OF
finished product.
For any given iron ore district. the
rate OF exhaustion of the higher grade
reserves may be roughly figured and
the time estimated in which the sue
cessively lower grades are likely TO 10
come into use. For instance. the
average percentage of iron in the Lake
Superior ores has been showing dur
ing the past decade drop OF about a
third OF per cent per year. With
present average of about 40 per cent
natural, at the present rate Of decrease
OF grade. 45 per cent ore would come
to be uesd In about i2 years This
time, OF course. would not be uniform
for all districts Certain ores will be
used long before others. This Is
minimum time, because we must
remember that as the grade falls the
tonnage of unavailable ores is enorm !,
ously larger. which will slow up the
rate Of the decrease of grade Also
u is 60 be remem bered that really only
small portion OF Lake Superior il
thoroughly explored / think that.
outside OF the Mesab, Tor hundred
years to come. high grade reserves will
DO added more or less in proportion 20
the expenditure made in exploration.
FINALLY, there is the. probability OF
effective competition OF foreign ores
snould say, roughly, that in any
district one would need to be opti-
mistic to predict the use of an average
grade per cent lower than the pres
ent prevailing grade Ia a period short.
or taan 30 years
With these Facts In mind let us as.
sumo that il costs now rs cents per
ton to conserve an ore which is FIVE
points lower than the present CONNER
cial grade. Let us also say that this
lower grade when mined is going 10
yield profit of 80 cents ton. IL is
apparent that such an ore must be
used in ~ years unless there is TO be
loss on the money invested in con.
serving the ore. IT, on the other hand.
IL costs only 10 cents per ton 70 con.
serve this ore, anil the profit IS assam
ed TO be 90 cents per ton in the future.
II would be possible 20 hold the ore
% years. II the profit per ton Is as.
sumed TO be 20 cents and the present
cost OF conserving IL is cents. it is
possible TO hold IL for % years
Without going into further iIlustra-
tions. and without arguing for any
specific figures of time and profit, it
seems clear that there is narrow
limit to the sums which II Is wise to
spend 70 conserve low grade ores I,
IL my opinion that 90 cents per ton az
period over 30 years away may Re
the condition under which the greater
part Of the ores five points lower than
the present standard will be- mined.
II IL apparent that IL would pay to
spend a very few cents ton to con-
serve the these ores. II this IL true. the
present value per ton in the ground of