the original use of which commences with the taxpayer, and

which is placed in service by the taxpayer after the date of the enactment of this section.

Emergency communication technology or device which is used to allow a miner to maintain constant communication with an individual who is not in the mine.

Electronic identification and location device which allows an individual who is not in the mine to track at all times the movements and location of miners working in or at the mine.

Emergency oxygen-generating, self-rescue device which provides oxygen for at least 90 minutes.

Pre-positioned supplies of oxygen which (in combination with self-rescue devices) can be used to provide each miner on a shift, in the event of an accident or other event which traps the miner in the mine or otherwise necessitates the use of such a self-rescue device, the ability to survive for at least 48 hours.

Comprehensive atmospheric monitoring system which monitors the levels of carbon monoxide, methane, and oxygen that are present in all areas of the mine and which can detect smoke in the case of a fire in a mine.