Fire in the hole - wikipedia Fire in the hole For other uses, see Fire in the hole ( disambiguation ). Blasting machine used in mining `` Fire in the hole '' is a warning that an explosive detonation in a confined space is imminent. It originated with miners, who needed to warn their fellows that a charge had been set. The phrase appears in this sense in state mining regulations, in military and corporate procedures, and in various mining and military blasting - related print books and narratives, e.g., during bomb disposal or throwing grenades into a confined space. In common parlance it has become a catchphrase for a warning of type `` Watch out ! '' or `` Heads up ! ''. NASA has used the term to describe a means of staging a multistage rocket vehicle by igniting the upper stage simultaneously with the ejection of the lower stage, without a usual delay of several seconds. On the Apollo 5 unmanned flight test of the first Apollo Lunar Module, a `` fire in the hole test '' used this procedure to simulate a lunar landing abort. Gene Kranz describes the test in his autobiography : The fire - in - the - hole test involved shutting down the descent rocket, blowing the bolts that attached the ascent and descent stages, switching control and power to the ascent stage, and igniting the ascent rocket while still nestled to the landing stage. References ^ Jump up to : `` Fire in the hole ''. The Word Detective. October 10, 2008. Jump up ^ `` Illinois Administrative Code 225.55 ''. Jump up ^ `` Idaho Administrative Code '' ( PDF ). Jump up ^ `` Here comes the boom ''. Jump up ^ `` Blasting Standard Operating Procedure, Raytheon Polar Services Company '' ( PDF ). Jump up ^ `` Google Books ''. Jump up ^ Kranz, Gene ( 2001 ). Failure is not an option. Berkley Books. p. 215. ISBN 0425179877. Retrieved from `` https://en.wikipedia.org/w/index.php?title=Fire_in_the_hole&oldid=810831046 '' Categories : English phrases Explosion protection Talk About Wikipedia Español Français 한국어 日本 語 Português Edit links This page was last edited on 17 November 2017, at 18 : 43. About Wikipedia

Question: where does the saying fire in the hole come from
Answer: miners, who needed to warn their fellows that a charge had been set