Making Synapses · Bringing Knowledge to Mankind
Mining & ExplosivesHorn signals and the line to the fresh air base
Under a face-piece, words get lost. The team uses a portable communication system to tell the fresh air base everything it finds, and the horn for the moves of the team: one blast to stop, two to advance, three to retreat, four for distress. If the communication fails, the team goes back to fix it.
Free to startScenarios
- Hard-wire system: the cable is strong enough to work as a manual communication system.
- Radios: intrinsically safe, with headsets at the fresh air base.
- The communication system fails deep in the mine.
The steps
- Check the horns before the problem and the portable communication system before the clock starts.
- 1 blast on the horn: stop, if the team is moving.
- 2 blasts: advance.
- 3 blasts: retreat.
- 4 blasts: distress.
- The captain gives the signal to advance, the rear captain relays it to the fresh air base, and the team moves when the signal is returned.
- Tell the fresh air base every condition found over the portable communication system; no external speakers at the fresh air base.
- At shaft stations, use the posted hoist signals; with none posted, say out loud calling or releasing the cage.
- If the communication system fails, return to the fresh air base to repair or replace it; on hard wire, use the standard signals in the meantime.
Safety rules that stop the station
- Never go into the mine without a working communication system, and never break it on purpose underground.
- In an explosive mixture, only intrinsically safe or sound-powered communication devices are used.
To pass
- Going in without a working communication system, or breaking it on purpose, endangers the whole team: 75 points.
- Each missed hoist signal costs 1 point; a shaft station gate left open costs 5.
- Every condition reported, and every move signaled and returned.
Official source
Federal · MSHA Mine Rescue Contest Rules 2026
2026 Metal and Nonmetal Mine Rescue Contest Rules
MSHA's mine rescue contest rules set the four horn signals, the communication systems teams may use and their discounts.
Making Synapses is not affiliated with, sponsored by or endorsed by MSHA, NASA or any mine rescue association. Agency names are named only to describe the content.