I found this old mantle a while back. I loved the shape of it, but it was too short for the fireplace that is in my house. So I stored it with all the odds and ends waiting for new homes.
I decided to sand, prime and paint it as it was originally oak. The thing is heavy. Pull the gyprock down in pieces heavy, so hanging it was a bit interesting. Luckily for me, the mantle was hollow on the inside. I used large bolts to attach a 2x4 to the wall studs in my room. The narrow side of the 2x4 was attached to the wall. Once that was level and secure, the mantle slid on to the 2x4. A couple of screws in the top of the mantle down into the 2x4 and this shelf "will see me out" as my dad says!