 Mining is focused mainly on coal mining from the late nineteenth century until the mid-twentieth century (in nearby town Puertollano) and in the silver mineral galena (lead and silver) in the valley or El Hoyo and Solanilla del Tamaral, leading to the creation of a new parish district, Las Navas de Riofrío, near the new mining locations, later abandoned in 1927.Due to international isolation, the government of General Franco decided to build an oil shale distillation plant in nearby Puertollano, requiring large amounts of water, so a dam was built, the Montoro Dam, which supply water to industrial plants through a tunnel in the mountains of Sierra de Mestanza, plus the necessary water pumping plants.The Montoro dam was opened by General Franco in 1950, and stores water from rivers Montoro and Tablillas.