The social effect of investments (increasing working capacity, reducing injuries and morbidity, increasing the prestige of the profession, the degree of job satisfaction, and the like) should always be positive. The economic results of investment are expressed in the form of the economic effect of the implementation of occupational safety measures and efficiency indicators. Improvement of normative documents for the safe conduct of mining operations in terms of the formation of hazardous properties of coal seams during geological processes, their reliable forecast, and the development of preventive measures are very relevant for all coal-mining countries of the world. The regularities of changes in the elemental content of the main components (carbon, oxygen, hydrogen, nitrogen and sulfur) of organic mass and mineral impurities (ash yield) for different states of coal samples under the influence of geological processes of coalification were established. Three characteristic stages of metamorphic transformations of coal seams have been established based on the change in elemental content per conventional organic mass of carbon and hydrogen, as well as moisture content of analytical samples. The introduction of new methods for forecasting the hazardous properties of coal seams and improving the regulatory framework for safe mining operations will increase the socio-economic effectiveness of investments in improving the working conditions of miners.