A method of comprehensive conversion of coal series caustobioliths, mostly brown coals and leonardite, into humic organic and organomineral fertilizers and into fuel briquettes using the residual coal, wherein said humic fertilizers are selected from: ballast organic fertilizers in the form of suspended gels, ballast organomineral fertilizers in the form of suspended gels, ballastless solutions of humic acid, ballastless solutions of fulvic acid, ballastless dry humic acid salts and ballastless dry fulvic acid salts; said method including: - the performance of the key processes in continuous flows; - mechanical separation of suspensions into solid and liquid phases in the centrifugal field, - the use of acidizing processes of the separated liquid phase with the withdrawal of humic acids from the liquid phase to the heavy phase (coagulated pulp), - recycling of the residual water, wherein - the raw material is ground in advance to 0 - 3 mm grade, - the water used in the process is previously purified and electrochemically softened; - the raw material is subjected to two consecutive mechanoactivation or mechanochemical activation treatments in a first reactor and in a second reactor, respectively, at a temperature not higher than 60 oC, wherein the treatment in the first reactor comprises either liquid-phase oxidation with hydrogen peroxide or treatment with water; and the treatment in the second reactor comprises leaching by aqueous alkaline treatment; and wherein the mechanoactivation and/or mechanochemical activation is performed with a duty of water curve ranging from 0.9 to 2.5, with the dispersion of reaction compositions by chafing and dynamic shift of the layers of the medium being converted, this mechanoactivation being accompanied by the metered introduction of 10 to 40 MJ per cubic meter of energy into this medium, by applying dynamic (hydraulic impulse) impact on the medium being converted with frequency range from infrasound to frequencies bordering on ultrasound; wherein the automatic maintenance of the maximum parameters of mechanical energy introduction into the medium being converted is ensured with its automatic limitation in the sub-cavitation area by detection of cavitation noises by acoustic probes within the reactors with a view to preventing the mechanochemical reactors from falling into cavitation modes. - the performance of the key processes in continuous flows; - mechanical separation of suspensions into solid and liquid phases in the centrifugal field, - the use of acidizing processes of the separated liquid phase with the withdrawal of humic acids from the liquid phase to the heavy phase (coagulated pulp), - recycling of the residual water, - the raw material is ground in advance to 0 - 3 mm grade, - the water used in the process is previously purified and electrochemically softened; - the raw material is subjected to two consecutive mechanoactivation or mechanochemical activation treatments in a first reactor and in a second reactor, respectively, at a temperature not higher than 60 oC, wherein the treatment in the first reactor comprises either liquid-phase oxidation with hydrogen peroxide or treatment with water; and the treatment in the second reactor comprises leaching by aqueous alkaline treatment; and wherein the mechanoactivation and/or mechanochemical activation is performed with a duty of water curve ranging from 0.9 to 2.5, with the dispersion of reaction compositions by chafing and dynamic shift of the layers of the medium being converted, this mechanoactivation being accompanied by the metered introduction of 10 to 40 MJ per cubic meter of energy into this medium, by applying dynamic (hydraulic impulse) impact on the medium being converted with frequency range from infrasound to frequencies bordering on ultrasound; wherein the automatic maintenance of the maximum parameters of mechanical energy introduction into the medium being converted is ensured with its automatic limitation in the sub-cavitation area by detection of cavitation noises by acoustic probes within the reactors with a view to preventing the mechanochemical reactors from falling into cavitation modes.