A novel biomass thermo-responsive composite gel (KGM@SSG) synthesized from konjac glucomannan (KGM), steel slag (SS), and silica fume (SF) prevents spontaneous coal combustion.This gel shows commendable flowability, accelerated gelation, excellent moisture retention, and superior flame-retardant properties.Compositional and structural changes were analyzed using XRD, FTIR, SEM, and TG.Results reveal that the amorphous compound Calcium (Aluminum) Silicate Hydrate (C-(A)-S-H), derived from hydrated SS and SF, integrates into KGM′s three-dimensional network, enhancing robustness.Thermogravimetric anal., thermal experiments, and in-situ IR spectroscopy confirm that KGM@SSG mitigates temperature surges during ignition and inhibits coal decompositionWhen applied to coal, it moisturizes the surface, forms a protective coating, slows temperature increases, blocks oxygen adsorption, reduces interactions between active components and oxygen species, and prevents thermal accumulation, supported by mol. dynamics simulations.