Six men died of asphyxiation as a result of the detonation underground of approximately 600 pounds of 40-percent dynamite. The exact cause of the detonation was undetermined.
However, two factors presented possibilities:
(1) It was the practice to leave explosives at the 200-foot level station. Men were working in the inclined shaft above the station at the time of the explosion and could have caused the detonation of the explosives by dropping some tools or by loosening rock, which subsequently fell on the explosives. There was evidence that explosives had been at this station just prior to the explosion.
(2) Explosives were often stored in a thawer magazine (80 feet south of the 200-foot level station) to be thawed before they were sent to the working faces. Although the thawing
device had been used for some time, it was so constructed that if the explosives had been placed too close to the heating element, the temperature might have become high enough to detonate them.
||Historical Summary of Mine Disasters in the United States, Volume III