Smyrna times., 1896-12-02
HOW SALT rs MINED.
METHODS EMPLOYED AT THE ExTEN-
! SlVE WORKS IN MICHIGAN.

SlVE WORKS IN MICHIGAN.
The Supply of Raw Material, Which Is |
Brine, Is Practically Observation-Disclosures
Industry Has Grown Enormously Since i,
1860, at Which Time 1t Really Began.
The existence of salt springs in the
lower peninsula Of Michigan was known
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 of 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 Union the state was authorized to
select 70 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 the 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
for 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 tho state, though thus far the great
est successes have come from the Sagi-
nav valley. Where the lowest horizon
is found i'll the salt group the brine is
found to be the strongest, greatest i'll
amount and best i'll 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 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 i'll Michigan may
be carried Oh is one of cost and demand.
The brine may be assumed as existing
i'll quantity far i'll excess of our ability
to diminish it.
OF tho 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 G
inches deep. They are supported OH
posts above the ground and are provided
with 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 III March and the contents removed
in July, tho product of the second fill
ing is taken out the 1st of September,
and the third and final removal occurs
the last of October. The annual product
Of single salt vat Of this size is 90
bushels.
A kettle block contains so or 60 ket
ties, set close together and in rows in
closed in stonework or brickwork A
launder connects with a cistern KEEP
filled with brine and runs along be
tween the rows of kettles, and from thi
launder the brine is drawn out into thu
kettles by opening a lateral spout
When 70 per cent of the water has beel
boiled away, the salt is dipped out int
a basket or sieve to allow the water Il
run out of it, after which it is emptiet
into bin, where, after a sufficient tim
about two weeks-it is ready to b
put into barrels. But the greatest ad
vance in the way of cheapening the cos
of the salt production has been achieves
by the use of steam to afford heat fo
evaporation. For this purpose the ex
haust steam of the great mills in tn
Saginaw region is used.
Pans are also made use of. A SO call
ed pan block, consisting of ''settler'
pan, and packing room are inclosed in tn
same building. The brine is draw
from the settler into the pan, to the bot
tom of which the fire is directly az
piled, making the evaporation very raj
i'd and causing the salt to form continr
ously.
The salt business in Michigan ha
swollen from the manufacture in 1856
of 1000 barrels to 3,967, 286 in 1895.
The estimated capacity Of the II
firms now engaged in the manufactul
of salt i'll this state is 3, $50, 900 barre
per year.-Detroit Free Press.