As an historical ballad, Robert Edward Gard's 'Ballad of the Frank Slide' is fairly inaccurate. Approximately 80 people died when the slide occurred and from what I can gather it took less than a minute and a half from start to finish. Also,

"Gard, Robert. "Six Alberta Folklore Plays: Twelve-Foot Davis; Hatfield the Rainmaker; Midnight; Ballad of Johnny Dunn; A Church on the River; Ballad of the Frank Slide." Written while Gard was at the University of Alberta." from http://www.gardfoundation.org/plays.html

'A rockslide from Turtle Mountain, which in 1903 buried much of the little town of Frank, Alta, was the subject years later of Robert Gard's "Ballad of the Frank Slide" (BMI Canada 1949) and Stompin' Tom Connors' "How the Mountain Came Down." ' from http://www.thecanadianencyclopedia.ca/en/article/disaster-songs-emc/

HOWever, the date of the song likely goes back to 1946 or earlier. A Google of    Ballad of the Frank Slide (Robert Gard)   will bring up many pages that talk about it as both a radio drama and a song. Anyway, that's it from me for now.