The project is dedicated to developing recommendations for the production of a complex potassium, calcium and phosphorus fertilizer with a prolonged effect from mining waste from the Kovdors-mica and Kovdorskiy GOK mines. An important task is to dispose of the dumps accumulated over the years of operation of these actively operating mines. The relevance of creating a new complex potash fertilizer from phlogopite, apatite and calcite is determined by the fact that it will have a prolonged action without high solubility. In order to experimentally test the possibility of using these mineral wastes as fertilizer in summer 2001 we carried out a series of micro-daily field experiments with potato varieties Nevskiy, which are typical “potassium” plants. As a result, we found that not only phlogopite and calcite, but also the finely ground Francolite, which is a natural source of phosphorus, affect the plants. The experiment was accompanied by monitoring of the balance of the main chemical elements in the fertilizer-soil-plant chain. This is the next step towards the development of a new type of complex fertilizer of prolonged action, containing the necessary elements (K, Ca, Mg and P) in a form accessible to plants and not easily washed out of the soil by surface water.