It was June 8, 1917, just before midnight in a place they called the richest hill on earth.

Deep beneath Butte, nearly 2,500 feet below the surface, Ernest Salu stood inside the Granite Mountain Mine.

He was an assistant foreman, a man used to the weight of the earth pressing in around him

from all sides.

He was used to the thick air that carried the smell of damp rock, machine oil, and sweat that

never quite left your clothes.

That night, the job seemed pretty straightforward.

Ernest and three other men had been sent down to inspect a massive electrical cable that had been lowered into the shaft.

It was part of the new fire suppression system, something meant to make the mine shaft safer.

But something had already gone wrong before they even got to it.

The cable had slipped during installation.

It had fallen the full length of the shaft, all 2,500 feet of it, collapsing into a tangled heap at

the bottom. The impact had torn away its protective lead casing, exposing the inner insulation,

layers of paraffin-soaked paper that were never meant to see open

air.

What lay in front of them wasn't just damage equipment.

It was a three-ton fuse.

Ernest had his carbide lamp to examine the damage more closely.

In that era, a lamp like that wasn't contained or shielded.

It was essentially an open flame.

It was steady and reliable, but unforgiving if it touched the wrong thing at the wrong

time.

...