| Coal mining subsidence and bulk solid waste accumulation are bottlenecks in realizing green and low-carbon development in mining areas. Taking a coal mine in northern Shaanxi as an example of filling mining, a coal-based solid waste cementitious material was developed, and the new cementitious material was utilized to carry out a proportioning test with the filling gangue sand to test the uniaxial compressive strength and fluidity of the cementitious filler with different gray-to-sand ratios (1:3, 1:4, 1:5, and 1:6), biogaussite fly ash ratios (1:3, 1:4, 1:5, and 1:6), and modulus of fineness (2.32, 2.64, 2.91, and 3.19) conditions. The uniaxial compressive strength and mobility of the cemented filler. The study showed that the compressive strength of the filler was directly proportional to the ratio of fly ash and ash to sand ratio of metakaolin and inversely proportional to the fineness modulus, while the flowability of the filling slurry was inversely proportional to the ratio of fly ash and ash to sand ratio of metakaolin and directly proportional to the fineness modulus. Compared with the traditional cement-based filling material, the cost of the new filling material prepared from this coal-based solid waste cementitious material was reduced by 48.69%, the carbon dioxide emission was reduced by 64.71%, and the overall solid waste utilization rate reached 96.1%. |