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Hacker, Robert W. (ed.) / The Wisconsin engineer
Volume 53, Number 4 (January 1949)

Thisell, W. I.
The sulfur story,   pp. 13-14


Page 13


The SULFUR
STORY
by W. I. Thisell c'50
  Small boys smitten with spring fever probably take a
dim view of the sulfur n' molasses supply each year, but
Americans as a whole appreciate the fact that sulfur (us-
ually after first being turned into sulfuric acid) is applied
in various ways in most of our industries, for example:
textiles, rubber, fertilizer, soap, plastics, aircraft, paint,
steel, paper and cosmetics.
  The United States is the world's largest producer of
sulfur. We use more of this mineral than we do of cop-
per, rubber, tobacco, or nickel, and at a cost of less than
a cent a pound. Sulfur can be mined profitably in only
a few places, such as in Java where sulfur is collected
from the edges of volcanoes or hot springs. In Sicily, it
has been dug from shafts for centuries. At the present
time, the majority of the mineral mined comes from the
formations overlying the Texas and Louisiana salt domes.
  If one were to look at a cross-section of a typical dome,
it would look like a massive finger of rock salt sticking
straight upward into the gumbo and rock from un-
fathomed depths to about 500 feet from the surface. Its
top is about three miles in diameter and is covered with
barren caprock of limestone. Under this cap is a second
layer, a stratum of limestone impregnated with pure crys-
talline sulfur. Under this is found anhydrite, and last of
all is the rock-salt, extended pillar-like downward for
thousands of feet. It has never been determined how far
it does extend.
  In the late 1860's petroleum exploration in the Calcas-
cieu salt dome of Louisiana showed a great deposit of
sulfur buried nearly 500 feet underground. After sev-
eral attempts at tunnel mining were blocked by quicksand,
the deposit remained untouched until 1890 when Herman
Frasch, an oil company research director, discovered a
method of bringing the sulfur to the surface. His process
simply involved pumping superheated water underground
to melt the sulfur so it could be pumped to the surface.
  Essentially the method of mining today is the same as
Frasch's first attempt. A ten inch casing is driven to the
top of the deposit. Through this is put a six inch pipe,
perforated at its end, and extending to the bottom of the
deposit. Through this six inch tube, a three inch tube is
placed, it rests on a collar set a few feet from the bottom
of the six incher's terminal performation.
  Water heated under pressure to a temperature higher
than the 240 degree Fahrenheit melting point of sulfur is
pumped down the six inch pipe. The hot water enters the
porous limestone from the perforations above the bottom
collar. The melted mineral flows downward to form a pool
at the lower end of the pipe. From there it rises up the
inner tube, rising spontaneously to about 300 feet from
the surface. To bring the sulfur up from the 300 feet
level, compressed air is sent down a one inch pipe which
is inside the three incher. The compressed air bubbles up
through the sulfur, lowering its specific gravity and thus
allowing it to rise to the surface, and the brownish liquid
LIQUID
SULFUR
!:~~~~~~~'
             Xa
          I'
4-
4--
COMPRESSED AIR
       HOT WATER
Wa: UNCONSOLIDATED
   SEDIMENTS
-  .   -.a          ... - -
tI     5: ~: :   0 II fI I:   ., :I       I    __I
     f7L nf)j -lj~iflY -   a  -fl
F_ -   i i     g            ROCK SALT
A cross-section of typical sulfur producing ground.
JANUARY, 1949
13


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