- "Marty plugged his ears. / Doc twisted the detonator. / The dynamite roared like the loudest, closest clap of thunder Marty had ever heard. He almost stumbled as the ground shook beneath his sneakers. A wall of dirt and bits of rock and brush rained down on top of them. / Marty threw an arm across his face. Doc had calculated that they would be safe here, a hundred yards from the blast. Safe, maybe. Clean, never."
- —From Back to the Future Part III by Craig Shaw Gardner (quote, page 17)
Dynamite was a high-explosive mixture containing nitroglycerin.
It was used by Dr. Emmett Brown and Marty McFly to blast their way into the Delgado Mine on November 14, 1955, when they recovered the DeLorean time machine where Doc's 1985 counterpart had hidden it after becoming stranded in 1885 when the DeLorean was struck by lightning on the night of November 12.
Bearing in mind the size of the resulting explosion and the amount of dirt and debris that rained down on them afterwards, it was fortunate that Doc and Marty were wearing miners' helmets at the time.