Development of recommendations for controlling the lump size of construction rocks during blasting

Deposits of construction materials are most often found in the Ural region. Therefore, the issue of developing a methodology and technological parameters of mining to obtain the required lump size of the construction rocks is the most important task of modern mining enterprises in the Southern Urals. The paper studies the distribution of the particle size distribution of the construction rocks before and after blasting, after the excavation and haulage processes using the logarithmic normal law. Analysis of the obtained data helps to establish patterns in the change of the main distribution law indicators from the physical and technological properties of rocks and their structural and textural features. The obtained dependencies make it possible to promptly adjust the drilling and blasting parameters in order to obtain the required fragmentation of rocks of varying strength and fracturing. The required degree of blast fragmentation of the construction rocks is determined by the minimum total energy consumption for the entire cycle of preparation, extraction and processing (the primary crushing stage), taking into account the maximum yield of commercial size fractions. Research has shown that for different types of construction rocks, the yield of the commercial fractions at a constant degree of crushing will depend on the hardness and fracturing of the rock masses and can vary by up to 20–30%.