The third fatality occurred early Sunday morning at the Jim Bridger coal mine in Wyoming when a bulldozer plunged off a 160-foot highwall.

Reports indicate 44-year-old dozer operator Mark Stassinos was ejected from the cabin and killed.

In the previous day a 47-year-old miner died in a vehicle-related accident at the Pattiki continuous miner operation in Illinois.

Investigators told AAP that the victim, Robert Smith, was in a cart when the vehicle veered off an underground path and overturned.

The day before this incident, on Friday, 62-year-old Roger King died on the way to hospital after an accident at the McElroy longwall mine in northern West Virginia.

According to the Charleston Gazette, the senior longwall maintenance coordinator died after he received head injuries when a conveyor chain broke during a longwall panel move.

The bad run is considered the first time the coal industry has had three deaths in three days since 2002.

According to the Associated Press, Main said the deaths were troubling.

Reportedly less than half of MSHA’s workforce is on the job, with inspections limited to the typically more problematic mines.

In uncharacteristic fashion, MSHA’s website has not yet mentioned anything about the three fatalities as it remains under-resourced due to the ongoing US federal government shutdown.