Green’s Dictionary of Slang

(US) a worker who handles dynamite.

1923		N. Anderson Hobo 93: A ‘dino’ is a man who works with and handles dynamite.
1930		‘Dean Stiff’ Milk and Honey Route 204: Dyno or dino – A rock man who handles dynamite.
1931		Irwin Amer. Tramp and Und. Sl. 62: Dine.– Dynamite. An old-time yegg, one who used dynamite or ‘soup,’ [...] to open safes or strong boxes.