Work is being carried out on possibilities of limiting the content of mercury in hard coal products by gravity concentration of run-of-mine coal in the Branch of the Institute of Mechanized Construction and Rock Mining in Katowice and on the Faculty of Energy and Fuels of the AGH University of Science and Technology in Krakow. Under domestic industrial conditions, gravity concentration is carried out with heavy medium liquids and in jigs. Preliminary - pilot studies have shown the possibility of mercury removal also by using the dry deshaling method involving vibratory air separators. Mercury is mainly found in the pyrite and the rubble formed by the mineral carbon, but also in the organic carbon. Some of it is located in layers of coal roof fields, which in the course of their exploitation go to coal. The mercury removal efficiency during the gravity concentration process will depend on the decomposition of the listed components in the density fractions. The paper presents the results of investigations of total mercury and total sulphur content in the separated coal fractions from four mines. These contents were determined in fractions: –1.5 g/cm3 (conventionally clean coal – concentrate), 1.5–1.8 g/cm3 (conventionally middlings) and +1.8 g/cm3 (conventionally rock – waste). The results are summarized in Tables 3–5 and in Charts 1–4. Conversely, graphs 5-8 show the relationship between mercury content and total sulphur content in the tested coal samples. The study, which can be called a preliminary analysis of the susceptibility of the coals to gravity concentration, showed that the dry deshaling method on the vibratory air separators would allow significant amounts of mercury accumulated in the middlings and waste fractions to be removed.