PS3 B/D Drive Grinding Noise

Whenever I put a game in about 30sec-1 minute later it has started to make a grinding/scratching sound.

Anyone know what this is?

It happened to me once when I put Xmen Origins: Wolverine (DVD, not blu ray) in to watch and it grinded and vibrated extremely. It stopped after 10 minutes of the movie playing though. One time I tried to watch back to the future on dvd and it grinded and didnt read it then I pressed eject, it didnt slide out rather spat out and it had a huge dep scratch. Its so weird

Its also normal with games and stuff. If its a deep heavy grind then its rare or dangerous. If its just a silent one, trying moving your ps3 about an inch. Sometimes it vibrates depending what its on. It has to be exactly horizontal or else brrrrrrr

What can possibly happen if it continues? Do you know?

Ok, so it seems to only grind during gameplay, browsing the menus is fine. So would it be only the drive reading heavily?