Star Trek What was Nero doing for 25 years

Nero arrives in the Star Trek past all guns blazing. It s one of the finest sci fi action scenes ever committed to film, and is responsible for much of the goodwill the 2009 Star Trek garnered. Nero has the technology and the motive to wreak havoc across the galaxy. So what does he do? Apparently sits around in his mining ship for 25 years waiting for Spock to arrive. Uh, ok