The Ely miner. [volume] (Ely, Minn.) 1895-1986, 1917-01-05
AN Achievement
Shaft House Construction a
"a" Shaft Of the Pioneer.

PioUlcIuS, anu Oue Ol IucSe Was
solved by the Oliver Iron Mining
Company, at their Pioneer mine,
at Ely, Mimi, on the Vermilion
range.
The story Of the problem that
was solved at GA" shaft Of this
great iron mine is one that will
interest and instruct. 1t tells how
it was made possible to save the
shaft and at the same time mine
the ore from around it. It is of
course not customary to sink a
reason that the ore in the imme-
diate vicinity cannot be mined
without losing the shaft, unless,
as in this instance, the manage
ment resolves to undertake it.
The first mine developed at Ely
was the Chandler, which began
shipping ore in the fall of 1887.
Soon after this "a" shaft, Pho
neer mine, was sunk by the origi~
nal operators. This shaft is wood
lined and consists of four COM
partments, two for skips, one for
cage and one for ladder, outside
dimensions 9 #. 6 in. x "a #.
The company that developed
this property desired to get the
shaft to produce ore at the earl
lest possible date; hence the shaft
was sunk in the ore body instead
Of in the rock formation back of
the ore body and a drift being
driven to the ore as is now the
practice. Consequently, it was nee
essary to leave a pillar Of ore. to
protect the shaft. Even with this
protection pillar a slip occurred
in the formation 1875 #. below the
collar Of the shaft, extending to
the surface and striking 4S #.
back Of the shaft, causing a set
Element in the surface Of the
ground.
A timber shaft house was con-
structed when the shaft was sunk
and served the shaft until the sea-
son of 1909, when it became nee
essary on account Of age and de
terioration to replace same with a
steel structure. In the design of,
the steel structure, the rear col.
anns were placed 20 #. back.
from the shaft on good permanent
ground and were supported on in
dependent concrete piers.
Due to the settlement near the
shaft, the front columns and ore
pocket columns were supported
on reinforced concrete base, 50
#, wide, IS #. long, and 3 #.
deep, reinforced both top and bot
tom with steel rods, and when set
Element occurred the entire struc-
ture would move uniformly, thus
causing no undue stress on the
steel members. At the base Of the
rear columns was provided
hinged joint, and on the front col
umns brackets were placed so that
jack screws could be placed
under same to hoist them to,
the new elevation to take up the.
settlement which would occur In
the ground. The settlement due
to the slip, which is represented
on the opposite page, amounted
to 9 inches in the shaft from 1909
to 1912, which was all taken up
by hosting the front columns of
the shaft house and blocking un-
der the bases. This was all ac-
complished without any distor-
ton to the shaft house members.
In 1912 it was decided to mine
the ore pillar left to protect the
shaft, and it was, therefore, con,
sidered unsafe to mine this ore
without making some provision
to support the shaft house. Three
different schemes were consi
dered:
First. Excavating and plac
ing concrete wall, from the frs
level, 1875 #. below the collar Of
shaft, to the underside Of the re
inforced concrete base supporting
the front portion of shaft house
This concrete wall would carry
the entire load of foundation
tracks, cars, front portion of shat
house, ore in shipping pockets, al
well as to support the rear por
| ton of the shaft from surface tt
the first level.
Second: Excavation building
concrete piers from the first leve
1876 #. below collar Of shaft t,
support steel ,girders which woult
be placed under the reinforcet
concrete base, and would carr,
/ the entire load Of foundations
tracks, cars and front portion O
shaft house, including ore in ship
ping pockets.
Third: Constructing stee
cantilever support, located on per
| manent ground, which woul,
| carry the portion Of shaft hous
i above stockpile trestle, consistin
\ Of skip dumps and headsheave:
Il and disconnecting all main co
umn members at spices at stock
pile floor elevation, except tn