Josey Aimes is based on Lois Jenson, who started working in the mines in 1975 and endured thirteen years of harassment, before filing her first lawsuit. Jenson v. Eveleth Mines was settled in 1998, ten years after it was first filed, and over twenty years after the harassment began.
All of the harassment depicted in the movie really happened to various women. Two women were trapped in porta-potties that were tipped while they were inside. Miners ejaculated onto female miner's clothes in lockers three times. Many more incidents of harassment occurred than could be shown in a two hour movie.
According to the book Class Action, the rape that produced Lois Jenson's son occurred after high school. In real life, Jenson put her daughter up for adoption as a toddler because she was overwhelmed trying to raise two children on her own, in low paying jobs. Her father supported her decision to work in the mine, because he thought it would help her provide for her son.
Charlize Theron wanted to react to the crowd in the Union meeting without rehearsal, so it would feel authentic. Because the heckling was unscripted, it took Richard Jenkins almost five minutes to quiet them. Theron was so uncomfortable during this scene, she broke out in hives. "That was, I think in my entire career, the most devastating thing I've ever encountered."
In real life there were multiple trials, not just the one depicted in the movie. In the first trial, Jenson and two other women petitioned to have the lawsuit designated a class action, on behalf of all women working in the mines. The judge certified a class action including only the hourly female mine workers, not the salaried female officer workers who were also sexually harassed. The second trial established that sexual harassment occurred and that the company was liable for it. The third trial was to determine the amount of monetary damages each woman suffered. The fourth trial, in the 8th Circuit Court of Appeals, reversed the award of damages. The company settled just before the fifth trial started, paying each plaintiff an average of 233,000 dollars. By the time Jenson received compensation from the company in 1999, her children were grown and she was too disabled to work.
Charlize Theron spent time at the houses of some of the female miners, to get to know them personally. "I spent as much time as I possibly could with the women. They don't wallow in self-pity, they're survivors."