Mill Worker

Mill Worker is an unmarked quest and achievement/trophy in the Fallout 3 add-on The Pitt. The achievement is granted for collecting 100 Steel Ingots and delivering them all to Everett.

Detailed walkthrough
The quest is given by Everett at The Mill, where 10 must be returned to him as part of the larger quest line Unsafe Working Conditions. Additional ingots can be collected and returned in groups of 10, resulting in rewards such as weapons and armor. Steel ingots are found in the Steelyard, the Abandoned Area and the Supply Plant.

Locations
There are 79 Steel Ingots in the Pitt Steelyard, 18 in the Supply Plant, and three in the Abandoned Area, seen in the table below.

Bugs

 * In some cases Everett won't go into the mill and will refuse to accept any ingots, preventing the player from finishing the quest. This can be solved by holding on to the ingots the player has collected and advancing through the storyline. After defeating everyone in the Hole, return to Everett and he'll congratulate the player. At this point, his conversation options will return to normal, and he will accept any remaining ingots.
 * If the last few ingots are presented in a quantity less than 10, the player may not recive the achievement, nor the equipment.
 * When on the building which has 12 ingots, it is possible to fall through the roof straight to the ground which kills the player instantly. This bug occurs if Point Lookout has been installed. A solution is to save the game while on the roof, restart and load the save. When you enter to another area through a door, you have to restart the game again. Another way to fix this is by "firing" or using an auto axe or similar unique weapon (The Mauler or Man Opener) while walking along the rooftop.
 * Although Wild Bill's body may be looted after falling through the normally accessible map (see here), the two ingots normally present next to his body will not be found, thereby making the achievement or trophy impossible to get, and limiting the maximum obtainable ingots to 98.