From introduction: The need for fluorspar in the manufacture of open-hearth steel, hydrofluoric acid, aluminum, certain insecticides, refrigerants and airconditioning compounds, welding rods, 100-octane gasoline, and many other products necessary to the prosecution of World War II resulted in unprecedented demands for this commodity. To help increase production to meet these demands, the War Production Board in 1942 asked the United States Geological Survey to plan a comprehensive study of the fluorspar deposits in the United States. This study has been carried on in many parts of the country in cooperation with geologists and engineers of State and Federal agencies and with local producers.