Task: Question Answering
Input (English): Passage: Singing cowboy and rodeo star Gene Autry inherits half interest of a ranch and mining property from his late foster father, Henry "Dad" Erwin. The other half is left to Dad's niece, Barbara Erwin who arrives at the ranch from the East with her friend, Kitty Callahan. The will stipulates that each has an "undivided interest" in the inheritance—that each owns half of everything—and that nothing can be sold off without the approval of the other. In desperate need of money, Barbara expresses her desire to sell the mine as quickly as possible. Gene, however, wants to continue Dad's work on the mine, which employs Mexican rancheros whose land was ruined by dust storms. He explains that although the profits are currently put back into operations, eventually the mine will provide her with an income, and that without the mine, the rancheros will not survive.
With not enough money to return East, Barbara and Kitty decide to stay, and plan to use their feminine wiles on Gene and his sidekick, Frog Millhouse, to get gene to change his mind about selling. Meanwhile, Gene assures the rancheros that the mine will not be sold and that he will continue Dad Erwin's work. After her sweet-talking fails to win Gene over to her side, Barbara hires attorneys Arnold and Fry to sell the mine for her, giving them the power of attorney. Unknown to Barbara, the unscrupulous lawyers have been trying for years to gain control of the mine. They order their henchman Tommick to get rid of Gene. Tommick and his gang ride out to the mine and initiate a gunfight, but Gene and the rancheros are able to defend themselves. 
Question: Who did Henry "Dad" Erwin employee at the mine?
Output (English): Mexican rancheros.