Dynamite was invented by Alfred Nobel on May 7, 1867 and became the explosive of choice for the mining companies of Park City. It was usually stored underground for safe keeping. The problem was, dynamite weeps or sweats nitroglycerin which causes it to become unstable. On July 16, 1902 at 11:20 p.m. the dynamite stored in the Daly mine exploded, killing dozens of miners instantly including two men that were about a mile away in the Ontario mine.
The mine filled with deadly gas as the survivors scramble up 1200' to the surface. Eight men survived, four plunged to their deaths as they were overcome with the fumes.
Risking their own lives, survivors, other miners and locals all worked together to try to save the men inside the mine on that bleak night in July.
Because of this great disaster the US government changed the law on how dynamite is stored. No longer is it allowed to be left open and stored underground but must be placed in sealed plastic bags and placed in wax coated cardboard.