Department of Labor
Mine Safety and Health Administration
Erratic Movement of Miner
Recently, after routine maintenance of a TX-3 remote-control
unit, a close-call incident occurred at a District 8 underground
mine. During the maintenance shift, the remote-control unit's
cover plate and membrane were removed. This was done to clean the
switch wells and the rest of the unit. As the repairman removed
the tram switches, a tram-lever magnet fell out. He reinstalled
the magnet into the switch, but in a reverse direction.
(Reversing a switch magnet will cause the corresponding
miner track to move in the wrong direction.) After
cleaning, the repairman reassembled the remote-control unit. He
then checked the machine for proper operation by briefly
actuating, (bumping) the control levers. At the beginning of the
next production shift, the continuous miner operator started to
move the machine forward. When the operator placed the controls
in the forward direction, the miner tracks moved in opposite
directions. This caused the continuous miner to slue around
rapidly. The continuous miner operator was in a safe location;
therefore, he was uninjured by this unexpected movement of the
miner. The switches were Revision-B switches, and they are noted
with a green marking.
Switch Magnet Reversed
- If Magnet is removed or falls out Replace the
Switch, and test functions for proper operation.
- When operating continuous miners, continuous miner operators
should position themselves in safe locations before moving their
- When continuous miners are being moved, ensure that all
persons are beyond the miner's turning radius.
- Remotes can fail or malfunction at any time! Always be
prepared for the unexpected.
- The manufacturer is distributing redesigned switches for
these remote-control units. The tram lever stems are gray, the
magnets have retaining clips, and the tram lever boots are
This information was provided by concerned
miners in an effort to eliminate accidents. Accident or "close
call" information within District 8 may be shared by contacting
the MSHA office at (812) 882-7617.