Rock Island Argus. (Rock Island, Ill.) 1893-1920, 1896-11-07
HOW SALT Is MINED.
METHODS EMPLOYED At THE ExTeN-
sIvE WORKS IN MICHIGAN.

METHODS EMPLOYED At THE exrEN-
SIvE WORKS IN MICHIGAN.
The Supply Of Raw Material. which Is
Brine, L Practically Incxhaustfble-Thc
Industry Has Grown Enormously Since
1860. Mt Which Time It Really Ecsan.
The existence Of salt springs in the
lower peninsula of Michigan was knowI
to the Indians long prior to the advent
OF the white men in the country, and
they were resorted to by both Indians
and wild animals. So well known was
this fact Of the presence CT salt springs
that the general government made nu-
merous reservations of lands which were
supposed to contain salt deposits. By
the act Of admission of Michigan into
the UniCn the state was authorized to
select az sections of salt land, or land
where the presence Of saline springs in
dicated the occurrence of salt deposits.
On the organization Of the geological
survey the state geologist, DR.. Douglas
Houghton, made an examination, with
the view to the selection Of these lands.
and in 1888 reported tie results of his
observations Still these examinations
were limited to surface indications, and
no extended experiments were made to
probe the coast far below the surface.
However, borings were finally under
taken in several localities, resulting
generally in such a good measure of sue
cess as to stimulate still further trials,
developing such gratifying results, es-
pecially in the Saginaw valley, that in
1859 the first company was organized
Tor the manufacture Of salt, since which
period this industry has reached its
present stupendous proportions adding
greatly to the wealth and reputation of
the state and especially to the growth
of the cities and the region in which
the business is carried ON.
The origin of these deposits is not
known. Whence the waters, lying so
far beneath the surface, derive their sa-
line property there is no apparent means
OF determining, nor is the boundary Of
the surface known beneath which these
deposits of brine may be found. The
Michigan salt group has a wide extent
in the state, though thus far the great
est successes have come from the Sagi-
nav valley. Where the lowest horizon
is found in the salt group the brine is
found to be the strongest, greatest in
amount and best in quality. 1t is for
this reason that salt wells in the Sagi-
nav valley have proved to be more val
liable than elsewhere. 1t is the region
in which the greatest depression occurs.
The salt group here lies at q depth
reaching to more than 1000 feet below
the surface of the lake. At what depth
below the surface of the lake this brine
is found the writer is unable to state.
OF one thing there is an apparent GER
tainty. that the supply of the brine is
inexhaustible. The extent to which the
manufacture of salt in Michigan may
be carried on is one of cost and demand.
The brine may be assumed as existing
in quantity far in excess Of our ability
to diminish it.
OF the two modes Of securing the
evaporation Of the water, either by the
application Of solar or artificial heat,
the latter is the method mainly resort
ed to in the Saginaw valley. Solar evap-
Grafton is effected by exposing the brine
in shallow wooden watts. Such watts as
are used are about Is feet square and 6
inches deep. They are supported on
posts above the ground and are provided
with a roof, which is readily moved on
the watts or off from them to cover the
brine from the rain or to expose it to
the sun, as required. The process is be.
gun in March and the contents removed
in July, the product Of the second fill
ing is taken out the LIST of September,
and the third and final removal occurs
the last of October. The annual product
Of a single salt vat Of this sizo is 90
| bushels.
A kettle block contains so or GO ket.
| ties, set close together and in rows in-
| closed in stonework or brickwork. A
| launder connects with n cistern kept
filled with brine and ruIs along be-
| tween the rows of kettles, and from this
launder the brine is drawn out into the
kettles by opening lateral spout.
When 20 per cent of the water hes been
boiled away, the salt is dipped out into
basket or sieve to allow the water to
run out of it, after which It is emptiod
into bin, where, after q sufficient time
about two weeks-it is ready to be
| put into barrels. But the greatest ad-
vance il the way Of cheaponiug the cost
of the salt production has been achieved
| by the use Of steam 10 afford heat for
evaporation. Fer this purpose the ex-
haust steam of the great mills in the
| Saginaw region is used.
Pans are also made Use Of A SO call.
ed pan block, consisting Of SETTLER
pan. and packing roori ere inclc. cd in the
same building. The brine is drawn
from the settler into the pan, to the bot
tom of which the fire is directly APP
| piled, making the evaporation very rap
id and causing the salt 10 form confirm.
ously.
The salt business in Michigan has
swollen from the manufacture in 1860
of 1900 barrels to 8, 967, ESQ in 1895.
The estimated capacity of the 1I3
| firms now engaged in tie manufactur,