The maintenance of furnaces is one of the most important problems for by-product coke production. Swelling pressure is one of the least studied factors affecting the lining of coke furnace walls. The results of studies of the swelling pressure of PJSC “Koks” feedstock coal are presented in this paper. Research has been carried out to identify the dependence of the swelling pressure on the coal quality indicators, estimated during the incoming control of the central plant laboratory of PJSC “Koks”. The plastic properties of PJSC “Koks” feedstock coals were studied using Gieseler plastometer. The relationship between the swelling pressure and the maximum coal fluidity is revealed.