<p>This research focuses on how steeping with industrial mixtures based on lime affects the oxidative pyrolysis of coal of limited metamorphic development that is inclined to self-ignition. Passivating solutions considered include the filtrate and suspension of a lime solution, which are traditionally used to suppress coal oxidation. Treatment of coal with lime solutions is accompanied both by physical adsorption of calcium ions on the nonuniform coal surface and by chemical reaction with functional groups that are susceptible to oxidation. The fundamental differences in the oxidation of coal of little and moderate metamorphic development with lime solutions are identified. After treatment of coal surfaces with lime solutions, less oxidation is observed.</p>