1 hour ago, JoNorvelleWalker said:
I should hazard a powder monkey is someone who transports blasting powder, as opposed to baking powder.
Yes.
Quoteˈpowder-ˌmonkey
a.a A humorous term for a powder-boy on board ship. Also fig. Now also (U.S.) a term for a member of a blasting crew; = powder-man c.
OED
Quoteˈpowder-boy
A boy employed on board ship to carry gunpowder from the powder-room to the guns; a ‘powder-monkey’.
OED
Quoteˈpowder-man
†a.a ? A dealer in gunpowder. Obs. b.b A man who supplies the guns with powder on board a man-of-war. c.c One who attends to the powder used in blasting operations, etc.
OED