Production cycle characteristics of high-purity quartz opencasting
Introduction. Currently, the main raw material for obtaining transparent quartz glass, an indispensable component in the production of single-crystal silicon, is high-purity quartz concentrate. The concentrate is a product of grinding natural "pure” quartz, which has undergone a cycle of mechanical and deep chemical refining, with a particle size of 0.1-0.3 mm and a total impurity content of no more than 20-30ppm. However, in nature, deposits of pure quartz are quite rare, and it means that each explored site is ofparticular importance and is to be developed with minimal losses of quartz raw materials. Research aim is to develop technical solutions for processing small veins of high-purity granulated quartz. Methodology. Physical and mechanical properties and mining conditions for the individual quartz veins of the Kyshtym deposit are analyzed. Production cycle solutions for opencasting quartz veins have been developed allowing to reduce the degree of quartz over-grinding. Results. Granulated quartz, due to its structure, has the property of "avalanche ” destruction into small grains. This significantly reduces the yield of the conditioned fraction -400 +20 mm, and regarding small reserves of quartz in veins, on average 0.1-2 thousand tons, it raises the question as to whether the development is feasible and effective. To increase the yield of conditioned fractions of quartz raw materials, a non-explosive technology of quartz breaking is proposed with a hydraulic hammer on a hydraulic excavator in combination with quartz vein preliminary exposure from the host rocks using a special technology for blasting rocks in the contact zone of "quartz-rock”. Conclusions. The proposed technical solutions will allow to involve small quartz veins of high purity granulated quartz into the development and provide high productivity and efficiency of mining operations without significant losses of scarce raw materials.