A nice trick I've found is that if you destroy all the earth around the vein the silver vein will collapse when you hit it a few times after making sure there is no earth touching it. Then its just transporting your stone and silver to a chest or cart. Me and my friends set up a longship at the tip of a mountain and load it full of silver and then launch it down one of the cliffs and it'll slide all the way to the bottom and into the ocean.