solo (or if other person is super underleveled/geared) jump down and hide behind the wall and peek out every now and then and shoot him, an ar-pen sniper rifle is super good because you can basically shoot through the rocks at him and never get into hit range of anything. with the boss dmg being void you don't wanna try to use the hiding spot as splash dmg can kill you easy.
with 3 people stay up top and everyone kill the mino asap as it spawns, it dies really fast and all you have to do is spread apart a bit and strafe left/right so his bombs don't do much splash dmg. Since NF is void dmg and his shields are void dmg having all void weapons is very very helpful. Word of crota for example kills him in about 8 shots vs like 3 clips of any other hand cannon.
also the cliff ledge facing the boss is something you wanna never stand in the middle of, people should be on the the left or right and back up and heal when the boss starts shooting your side. mino spawns every 18 seconds so only have basically 1 clip of sniper rifle to empty before you have to turn around. a void sniper rifle does insane dmg, my efreets was doing 12k per hit with WoL and he was dead in under a minute (3 people with void snipers).
a final trick if you are desperate is that a lowbie can hang out in the cave before that where the ~15 vex spawn and lure the minotaur towards him and let him kill him. the mino will just hover over that body then and a new one won't respawn as long as the other 2 don't get too close, but now you only have 2 people DPSing the boss.
If you are solo a minotaur will also despawn in the cave if you go invis, either as a hunter or with Patience and Time. I don't really recommend that though since one fuckup and you are done. Just way easier going with 3 people and having most of them having void sniper/rockets.