The leaky feeder is simply a cable with various booster and splitter boxes. If there is a vehicle fire for example in a main haulage way, then the fire will often destroy the leaky feeder cable and radio coverage below the fire goes down.

Phone lines are often run down to various points such as pump stations, mess rooms, refuge chambers, work shops, ventilation wall exit doors and pretty much anywhere people work for a prolonged time in a fixed position, or might move to in an emergency.

The phone lines are often run down a different path (often a vent shaft, which has the escape way ladders inside) to the leaky feeder to prevent a total communications loss in an emergency. You can also run multiple leaky feeder cables, but that isn't as common unless there are multiple higher use exits from a mine.