In tank warfare the Russians have discovered that the Germans attached particular
importance to the use of mines. During the winter campaign, when the Russians were moving
ahead slowly in some sectors, the work of the mine-detecting crews and the sappers was
highly important. Some mines could be located by the small mounds of earth left after
planting them, but in clearing a suspected area a "mine detector" was generally used.
The detecting instrument is a light tubular bamboo or plastic rod at one end of which is a
metal ring about 1' 10" in diameter, bound with tape. At the other end is a
small wooden box containing a 3-tube amplifier, batteries, a terminal board, and earphones. The
box is carried in a haversack. The total weight of the box and rod
is 18 3/4 lbs. (see sketch A).
The operation of the detector depends on the change in capacity which takes place when a
mass of metal enters the magnetic field set up by the instrument. This change in capacity
upsets the frequency ratio which is established between the circuit in the detector ring
and the circuit in the amplifier when the instrument is tuned, and thus alters the tone
emitted by the earphones (see sketch B).
When the sappers are called upon to locate mines they usually form a line with
individuals 3 to 5 yards apart. Each man carries his "mine locator" puts on his
earphones, and adjusts the tuning dials until a steady low buzz is heard. He then
advances over the area to be searched with the rod in front of him so that the ring is
only a few inches above the ground. When the ring passes over, or near, a mass of metal
concealed in the ground or snow, the buzz rises in intensity of tone or fades out
altogether. The exact position of the mass can be found by passing the rod backward
and forward over the suspected area until the point of maximum interference with the
magnetic field is found.
The sapper marks the location of the mine and moves forward. The follow-up crews, which
are usually 40 to 60 yards to the rear, excavate the mine and remove the detonator. Although
mines have been found planted in rows and checkerboard pattern, generally they are
placed at irregular intervals. The Germans endeavor by their ingenuity to dull the
alertness of the Red Army sappers. To counteract their deception, it is necessary to
refrain from doing the obvious and guard against well-prepared traps.
For instance, mines sometimes are wired in series and, if the sapper does not investigate
after disarming the first mine, he will be blown to bits by the second. Another trick
common with the Germans is to plant tin cans, so that the Soviet sappers will either
become careless or have their attention diverted from the live mines. The enemy also
suspends mines from trees or sticks, particularly at night, for use against tanks or