Think of the jaw strength of those old-timers! Imagine the power necessary to eat 40 granite blocks!
Or read another way, what the hell else can explain the 'consumption' of granite when you're making this recipe? What, granite burns in the cooking fire?!?
Oh wait,considering we're using steel girders to make a single can [yeah right, steel girders in 19th century wild west, where's the factory?], I suppose that smelting-plant pot fire needed to melt the steel into a single can will melt the granite as well.
And scale. You gotta love it. 10 steel girders (which can pretty much be used to hold an entire house) turn into 1 TIN can! Yes indeed. BTW, I regularly chop down Redwood trees to make a single box of toothpicks for my day job.
Or my all-time favorite absurdity for the field cook, that making a single dough of bread (water, jug, flour) 'consumes' the jug. I guess the jug is made of sugar and chocolate.
'Scuse me while I go light some cash on fire and bang my head against a brick wall. Both provide a better return on investment.
/rant off