Abstract <p>The results of a study of the influence of basalt content on the basic physical and mechanical properties of composites based on random polypropylene copolymer are presented. Properties such as breaking stress, tensile yield strength, elongation, flexural strength, melt flow index and heat resistance were determined. The basalt content varied from 1.0 to 30 wt %. The results of the study showed that when basalt is introduced into the composition of a random copolymer of polypropylene, the maximum value of the breaking stress is achieved at 5.0 wt % content. In this case, with an increase in the filler content, a sharp decrease in the relative elongation and melt flow index is observed, but at the same time the value of the heat resistance of the composites increases. In order to improve the compatibility of the mixed components of the mixture and the properties of basalt-filled composites, a polypropylene copolymer with maleic anhydride brand Exxelor PO1020 was used as a compatibilizer. The introduction of a compatibilizer made it possible to significantly influence the increase in strength indicators, relative elongation and melt flow rate. In order to further modify the structure and properties of compatibilized composites based on random copolymer of polypropylene and basalt, cross-linking agents such as sulfur and dicumyl peroxide were used. The optimal concentrations of basalt and cross-linking agents have been established, at which the best performance in terms of basic physical and mechanical parameters is achieved.</p>