I don't think we have such information.
check with your US supplier since that person will need to prepare the paperwork. Or see if you local supplier can import the kinds of crushed rocks you want.

Not much experience on that, other than going to the states for a couple of days and coming back with a few items from a home improvement store, including a few bags of crushed rock. I assume though you are referring more to a special order or having it shipped into Canada?