I have heared about it. Some pirate stations sell it. But if you save 500.000 credits, you can buy the leroy jenkins launcher, which is better.

Been awhile since I've played, but as I recall, I found mines to be most useful when flying a freighter; where I more wanted to outrun the enemies than the fight them.

For example, when jumping through a jumpgate (or whatever they were called) into expected enemy fire, you hit your afterburner, switch to the turret view, and blast away at the enemies now at your tail, while releasing mines at them (particularly homing mines).

That can reduce or eliminate you taking damage while getting up to speed and getting away (or maybe even prevent you from getting knocked out of afterburner).