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had partly or wholly replaced the country rock. It is possible that the
larger masses of nearly pure hematite formed in some such way.

_ In the foregoing discussion it has been assumed that the hematite
is an original mineral. Save for the minutely scoriaceous character, the
hematite gives no signs of having resulted from the alteration in place
of some other mineral. Even this minutely porous texture may be only
a surface character due to differential weathering. ‘

ECONOMIC CONSIDERATIONS

It is certain the mineralized occurrences on Iron Range mountain
occur in zones of mineralization striking in a general way north and south
and standing vertically or inclined at very high angles to the west. These
zones so far as known are confined to a narrow, band-like area 6 miles
long, in which natural and artificial outcrops are comparatively rare.
Individual zones are known to be at least 200 yards long, some are probably
longer than this, but it is highly improbable that any one zone extends
throughout the whole length of the mineralized band. Some of the min-
eralized zones are not less than 60 feet broad, others are possibly much
narrower. In places at least three distinct zones occur across the breadth
of the band-like area and it may be that as many or more distinct zones
occur in most places, for much of the band-like territory is drift-covered.

The individual zones are for the most part represented by limited
artificial exposures so widely separated from one another that it is seldom
by any means reasonably certain that two successive exposures do or
do not belong to a single zone. At many of the exposures no body of iron
ore is visible,even though in some cases pure or nearly pure hematite is
very abundant in seams and small masses distributed over widths of as
much as 50 feet. In other cases, bodies of hematite of good quality are
evident with widths of from 3 or 4 feet to as great as nearly 20 feet, but the
individual bodies have not been traced for lengths of more than 10 or 15
feet.

The available exposures are too limited both in number and size to
indicate whether some zones are uniformly barren and others are charac-
terized by the presence of workable bodies of hematite along parts or
perhaps even nearly the whole of their lengths. Several shafts sunk in
bodies of hematite have shown these bodies to persist to the bottom of
the shafts, but no greater depth than 35 or possibly 50 feet has been
reached except in the case of the diamond-drill hole on the Keepsake claim
and in this instance the available information is not precise in character.
One crosscut showed an 8-foot body of hematite to decrease to a width
of 4 feet in an horizontal distance of 10 feet.

The amount of available information is quite insufficient to permit
of making any estimate of the amount of minable ore likely to be present.
The O-Ray shaft is sunk on the widest known ore mass, in this case 18
feet wide. If this body continues for only 100 feet with the same average
width, it would have to maintain this length and breadth to a depth of
over 1,000 feet to yield 250,000 tons of ore. An ore-body 4 feet wide
would need to be 450 feet long to yield the same tonnage with the same
depth of over 1,000 feet. It is very improbable that a short ore-body
20 feet wide would maintain this width for a depth as great as 1,000 feet.
Unless, then, the ore-bodies are long, or wider bodies remain undiscovered,

17135—103