On this day in 1903, 169 miners were killed due to an explosion in a mine in Hanna, Wyoming. The bodies of 201 people, which also included rescuers, were not recovered and remain in the mine.

It was an area, originally called Chimney Springs, which later became Hanna, named after Marcus A. Hanna, a member of the Union Pacific Company.

In the year 1889, with the expansion of the railroad, it was thought that the Union Pacific Railroad needed reliable fuel to run its coal-fired train engines. The reason for the set up in Chimney Springs was because the fuel source in Carbon, Wyoming had run out.

On the backs of workers and dynamite was how coal was mined back in the day. In 1903, coal mine gas was ignited, which cased the mine to cave in due to the explosion. 169 miners lost their lives that day and 46 miners barely survived and escaped.

There is a cemetery near Hanna, Wyoming, where many of the miners are buried. There is also a gated memorial stone in the area to memorialize the miners who died in the mine explosion on June 30, 1903.

The explosion was blamed on a miner and the mine opened again for productivity about a month later.