What types of people participated in the california gold rush

At first it was mostly poor americans from the east, hoping to make a lot of money. By the time they began digging into mountains, less and less americans agreed to do the dangerous work. using explosives and pickaxes to get at a chance for money wasn't worth it to them, so many companies began hiring chinese immigrants because they would work for much less, and were willing to risk it for a place to live and food to eat. 

The significance of the result is the change