Аннотация:The aim of the study is to study the composition of coals from the Fan Yagnob and Shurab deposits, as well as to determine the optimal conditions for the oxidation of these caustobiolites.To achieve this goal, studies were carried out on the composition of the feedstock: coals from the Fan Yagnob and Shurab deposits of Tajikistan.It has been established that the brown coals of the Shurab deposit are characterized by a high content of humic acids. The study of the elemental composition of Tajik coals showed the presence of alkali metals in them, such as sodium, potassium, magnesium, as well as the presence of trace elements: manganese, copper.The effect of technological parameters, such as the concentration of nitric acid, the duration of oxidation, the ratio of initial substances on the yield of humic substances, has been studied. The optimal conditions for the oxidation of coal from the Fan Yagnob and Shurab deposits were: temperature 450C, oxidation time 90 minutes, ratio coal: HNO3 = 1:2.Experiments on the study of the kinetics of oxidation of coals from the Shurab and Fan Yagnob deposits showed that during the oxidation of coals for 120 minutes, the yield of humic acids increases.The elemental composition of the liquid phase after coal oxidation - in the filtrate, as well as the solid phase - coal after oxidation were determined. It has been established that some elements such as: boron, sodium, magnesium partially pass into the liquid phase. Due to this, the amount of some elements in the oxidized coal decreased.