Recently President Obama signed a bill alowing the mining of asteroids.  This bill encourages the commercial exploration of asteroids.  

What does this mean for space mining?

This is great for space mining!  This means that many more people will be interested in it and therefor a lot more research will be happening.  people will have a better understanding of what really has to happen before space mining happens.  we are many steps away from getting any resources from asteroids but with the rapid pace of this study there will be human miners on an asteroid. 

is this an american landmark in space exploration?

Yes this is.  this will pave the way of commercial space mining for america.  Having so many american companies working on this project and hopefully eventually succeeding will result in america being one of the largest suppliers of precious metals.

How do Americans feel abut this law being passed?

Americans are very happy to continue their post as the leading country in space exploration.  Many congress men and woman, and senators are looking forward to the continuation of space exploration.  And now it is not only NASA that is focused n space exploration they have opened it up to the commercial business.  this not only profit the country but opens up a lot more jobs.