New Iberia enterprise and independent observer. (New Iberia, La.) 1902-1944, 1920-04-10
A SOUNDING DEVICE.

Washington, D. c.. April 1o.-After a
series of important tests with the geo
phone, a listening device invented during
the war to detect and locate enemy UNDER
ground operations, the Bureau of Mines,
Department of the Interior. announces
that this delicate instrument may be put
TO a number of remarkable uses in min
ing and other industries.
The most extraordinary result of these
tests is that the Bureau of Mines mel
have neen able, not only to hear and lo
cate sounds through the earth, but have
actually understood talking through fifty
feet of solid coal and have detected the
human voice fully 80 feet away. What
this may mean in the near future can
only be conjectured. An engineer of tbs
bureau was able through 300 feet Of coal
TO distinguish nine out of ten different
coal mining tools that were nsed at
different times, so characteristic are the
sounds. In one mine where experiments
were being made at the face of a tunnel,
the mine foreman who was listening
heard workmen in another tunnel pre-
pairing to blast and ordered the engineers
to retire until the blast was fired. The
sounds were SO clear he did not realize
that the tunnel headings were over 300
feet apart.
The greatest value of the geophone in
mining, so far as known, will be in con-
nection with rescue work in mines. Quite
frequently miners are entombed in coal
mines following explosions, and these men
may be located quickly and accurately
through the geophone. In metal mines
also where men may be imprisoned be-
hind falls or be barricaded in some part
of the mine to which they have retreated
in order to protect themselves from the
fumes of lre-these too may be rescued
through prompt location.
When the bureau first began its ex-
periments with the geophone, it was
questionable whether the geophone could
hear sounds far enough away to make
it practicable. The experiments show
that sounds can be detected through the
earth distance of $500 feet in a mined
out area in a coal mine, through solid
coal, 1000 feet, and through solid rock
about half a mile.
The geophone is also Of great prac.
teal value in metal mines where two
tunnels have to be connected. At times
in spite of as correct surveying as is pos
sible the two tunnel headings fail to
come together. Just recently Bureau Of
Mines engineers were in mine where
two ends of the tunneel failed to meet,
and the geophones, locating the error.
showed the miners the right direction.
Observations with the geophone have
also been at mines which were on fire,
where il was found that the fire MADE
noise enough to be heard some distance,
either because Of its drawing air or the
breaking off of bits of coal and slate.
The geophones by thus locating the fire
gives information which may enable the
mine management to erect fire stopping
in the proper places or to make direct
attack on the fire as for example by
drilling holes for injecting water to the
seat of the fire.
It is also the custom in some mining
localities to drill hole from the surface
into mine to carry pipe lines or cables
Oftentimes these drill holes do not go to
the right places, and it is with consid-
cradle difficulty and expense that tun-
nels are driven to meet the drill hole.
With the aid of the geophone, the drills
can be guided better, especially since
drilling can be detected for nearly mile.
Very satisfactory results have been OBJ