Fix the mine's air purifier

Talk to the super mutant inside the house outside the mine's entrance.

He will tell you the mine needs a new air purifier and asks you to go to New Reno to pick it up.

DO NOT ASK FOR A REWARD!

Talk to Renesco the Rocket man in New Reno.

Return to the super mutant and he will ask you to enter the mine to fix the purifier.

The mine is filled with poison gas so make sure you have gas protection or equip a power armor when you do this quest.

The mine also has "giant ants" the the PC will commenting about...

Return to the super mutant and he will give you a combat shotgun (or 500$ if you asked for a reward earlier).