The need for coal supply expanded at the same time as the development of the railway network that operated with coal imported from England. In those years, Francis Rickard's studies established in 1869 that the Marayes coal deposits in San Juan were the most promising. Various studies were carried out for decades in different parts of the country without being able to discover good-quality coal deposits. With the beginning of the Second World War, explorations were restarted in the extra-Andean region of northern Patagonia where there were deposits of a similar age to those being exploited in Chile on the other side of the mountain range at those latitudes. The studies carried out allowed the Pico Quemado mine in Río Negro to be exploited, but no important deposits could be developed. New geological studies, in which Angel Borrello and Mario Hünicken played an important role, allowed the identification of the deposits of the Río Turbio coal district in Southern Patagonia. Under the geological direction of Federico Bergmann, coal exploration and exploitation were concentrated in this region. A state-owned company created in 1958, Yacimientos Carboníferos Fiscales, was subsequently in charge of coal development and exploitation.