Riddle 2

Since i will be away for like 3 days, I shall leave a riddle in this post :)

I dig out tiny caves, and store silver and gold in them.
I also build bridges of silver and make crowns of gold.
They are the smallest you could imagine.
Sooner or later, everyone needs my help.
Yet, many people are afraid to let me help them.
Who am I?

Hint below.
Clue : Answer relates to a profession.