Fallout 3: The Pitt - Being the Best Mill Worker

10 ingots - Laborer's Outfit. It's a unique slave outfit. Not sure why you'd want it for long. It's not good for much besides some stat boosts and its low weight.

20 ingots - Filtration Helmet. A decent helmet that protects against radiation.

30 ingots - Steel Knuckles. Decent for players who like fist fighting. Otherwise they aren't that useful.

40 ingots - Metal Master Armor. This is decent armor. It's very light but provides a lot of protection. It's basically an hybrid of leather armor and power armor. Heavy gunners and gunfighters won't like it, but players who want to stay light will really like it.

50 ingots - Metal Blaster. An amazing gun. Each beam counts separately for critical strikes. This means that you'll usually get a few criticals and cause a ton of damage. Obviously not too effective over any real distance though.

60 ingots - Bombshell Armor. Not that great. Decent light armor with some boosts to Big Guns and Explosives, but not a great reward.

70 ingots - Leather Rebel. Another good piece of light armor. Gives good protection and a boost to Charisma. 

80 ingots - The Mauler. A unique auto axe that's pretty good. It will need to be repaired almost constantly though.

90 ingots - Perforator. A great weapon. It's a special version of the Infiltrator. It's silenced, fires fairly damaging shots, has a shot, and is quite accurate. It also breaks down almost constantly, so be ready to do a lot of maintanence if you like using it.

100 ingots - Tribal Power Armor. This is a copy of Ashur's armor that's actually a bit better. Getting this armor makes the two sides of the quest essentially equal, since you won't need to get Ashur's armor. It has a boost to luck, a boost to your AP, and a boost to melee weapons. Ashur's only has a boost to charisma and a boost to rad resistance. Regardless, this is one of the best suits of power armor in the game.

We might as well start in the supply plant.

Go inside and start walking forward. Hack the turret here to make it fire on all the trogs and wildmen in the room. This should make them panic and rush toward you on the catwalk. They will probably be officially fleeing, so just pick them off without a struggle. Get back on the terminal shut off the turret to pass. Go forward along the catwalks and look for three ingots lying on the floor in the next room.

Move forward to the next big room. Rush forward and get into the little office. Hack the terminal to turn on the turret and have it fire on the wildmen and trogs who might be alive below you. Stay crouched though, since it will happily shoot you through the window. Wait about 20 seconds and turn the turret off. Go to the ground level but be very careful. There is a short tripwire near the mine carts and the loading station. Triggering this will set off a massive explosion that will kill you if you are still in the room. So...avoid the tripwire. Go forward and look for the mine tracks. Kill any surviving trogs and follow the tracks to the right. There might be some wildmen hanging around still. It should just be a bunch of dead bodies with a trog or two left. Go down the tracks and look for 8 ingots lying in a cart.

Backtrack out and follow the tracks to the left. Stop at the supply closet with a bunch of skeletons lying near it. There are a bunch of bobby pins on the floor in front of it if you need some. Pick the lock and get inside the closet. There are 6 ingots here.

Leave and keep following the path up to the main room above. Kill any wildmen who might be guarding it, and then grab the last ingot off of the bed. Go ahead and get the Man Opener too. This is a decent unique auto axe. Go a bit further a use the switch next to the locked door to open a new exit and end up right back at the start.

That accounts for 18 ingots.

3 in the opening.

8 in the mine cart

6 in the supply closet

1 on the bed.