THE is scieiegsomgag! PACIFIC ROUTE. 
23 
range on sheet 2, p. 26), as now prospected and developed, extends 
fro 
m Aitkin, 
Randall. 
ae 1 om feet. 
Populatio: 
Bi. Peal 118 olla mined. 
ca iediiated to the vicinity of Randall. 
55 miles long, but its width has not been fully deter- 
No mining is done near this line of the 
about 27 miles northeast of Brainerd, 
Itis hat 
Northern Pacific Railway, but several mines are 
operated some 40 miles to the northeast. 
Little farming is carried 
1 Whoever wishes to see something of 
iron mining in Minnesota should make a 
short trip from Little Falls or Staples to 
Crosby or Ironton, on the Duluth line. 
The Pennington mine, which is within 
easy walking distance of either of these 
towns, consists of a large open pit from 
which the glacial drift was first stripped 
shovels. The o 
oxide, and has resulted from the deep 
weathering or decomposition of a slaty 
sedimentary rock that was originally rich 
in iron carbonate. 
closely, and dip at high angles. The 
workable deposits are vertical or steeply 
dipping lenses, which generally have a 
maximum width of 400 or 500 feet and an 
average depth of about 300 feet, but the 
maximum known depth is about 1,000 
feet. Some of the lenses extend for more 
than half a mile along the strike. The 
ores, some of which are soft and some hard, 
are in the main non-Bessemer—that is, 
they contain too much phosphorus to be 
converted into steel by the Bessemer pro- 
cess, which is one of the processes gener- 
ally used. Some of the ores contain con- 
siderable man; 
The traveler wishing t 
tended excursion into the iron country 
may go from Little Falls or Staples to 
Duluth and take either the Duluth, 
Missabe & Northern Railway or the 
Duluth & Tron Range Railroad to one of 
more er. 
Rust open pit at Hibbing is the largest 
iron mine in the world, producing in 1913 
nearly 3,500,000 long tons of ore. 
scription of the iron ranges is given by 
. H. Emmons, State ae - Minne- 
sota, in the following paragraphs 
The iron ore of the oe (me-sah’be) 
and Cuyuna ranges is contained in the 
Biwabik (be-wah’/bick) font, rer 
from one of the iron -minii n the 
Mesabi range. This peatoas ea pair of 
ferruginous cherts, iron ores, slates, iron 
silicate, and carbonate rocks, ‘ees a poe 
amount of coarse detrital niateeial at its 
t grades upward and in places 
laterally into more slaty rocks, known as 
the Virginia slate; snd it is underlain by 
: quartzite bat pining a conglom- 
rate at its bas 
are generally Mies as the Animikie 
(a-nim’i-kee) group and belong in the 
upper part of the Algonkian system as 
exposed in this region. All these rocks 
were laid down after the close folding 
which affected the lower 'Algonkia n rocks, 
Animi 
kie group are not on edge but ae 
dip at low an 
The Biwabik or r iron-bearing formation 
extends along the Mesabi range (see map 
onsheet 2, p. 26) for itsentirelength. Its 
average thickness is about 800 feet, but 
owing to the prevailing low dips ae 
exposed varies from a quarter ile to 
3 miles. The great bulk of the scantian 
is ferruginous (iron-bearing) chert, ne 
bestos 
some lime and iron carbonates, a bands 
and shoots of iron ore. Associated with 
the chert, mainly in the middle zone, is 
the iron ore, which occupies about 5 per 
cent of the total reece area of the forma- 
tion. Throughout the iron-bearing for- 
mation, Boe a in its upper part, 
