A technology for producing forming mixtures for casting molds based on various refractory fillers and a gypsum binder is developed. An optimum composition is suggested that includes 35% powdered KP-3 quartz calcined at 900°C, 35% fly ash, and 30% gypsum plus additions regulating the casting properties of the forming mixtures. The introduction of the developed composition and the technological process for the production of molds made it possible to decrease the thickness of aluminum-base castings by a factor of 2-3, the mass of cast parts by 30-50%, and the labor intensity by a factor of 2-3. © 1996 Plenum Publishing Corporation.