This paper is devoted to the topic of obtaining substitutes for natural aggregates in the city mining system. An article draws attention to the adverse effects of natural aggregate mining on the environment and presents its alternative based on processing waste mineral materials into aggregate form. Referring to the examples presented in the literature, technical possibilities of producing recycled aggregates from waste concrete, ceramic and glass materials were indicated. The system of collecting waste directly from potential users was also presented and the adaptation processes which waste must undergo were described. The research part of the study consisted of analyses of the environmental impact of the processes of obtaining natural aggregates and production of their substitutes from waste in the city mining system. The LCA (life cycle assessment) method was used to carry out the analyses. Using the available databases, calculations of the environmental impact of both processes were performed. The comparison of the obtained results proved that despite the unfavourable additional environmental effects caused by the adaptation processes required for waste, the environmental impact of the rational production of aggregates from recyclates is favourable, and such activities should be recommended for implementation in the industry.