Opinion on the coal genesis. Content of coal: Organic and inorganic matter, water and gas, organic and inorganic compounds, major and trace elements. Distribution of the elements between the organic and inorganic parts of coal. Coal weathering and spontaneous ignition. Behaviour of the inorganic coal matter during its combustion and coking processes. Waste products of the coal treatment and their properties. Influence of the coal combustion on environment and population health. Minimisation of the coal treatment influence on environment.