So I'm getting paid $34000/year and my contract is up for renewal. I've recently found out someone who reports to me is getting paid around $80000/year. It's just me and him in the department .

I'm mid twenties and $80000 is a lot of money but at the same time I don't want to burn bridges. My boss doesn't know that I know how much the other guy is making.

What's the best way to present this? I have to send an email asking for renewal and how much money I want. It's such a big jump that I don't see how I can avoid mentioning that I know about the other guy's salary without coming across greedy or butthurt.