During the early years of the 20th century, pyrite was used as a mineral detector in radio receivers, and is still used by 'crystal radio' hobbyists. Until the vacuum tube matured, the crystal detector was the most sensitive and dependable detector available – with considerable variation between mineral types and even individual samples within a particular type of mineral.
A newer commercial use for pyrite is as the cathode material in Energizer brand non-rechargeable lithium batteries
So I thought maybe Pyrite is the Secret Ingredient in Ramos's constructs that he uses to help control them by radio. And he already operates the Hollow Marsh Mine, here is has tricked 3 foolish crooked men into thinking they are mining for Soul Stones.