Based on the actual situation, 104T granular ANFO explosive was processed with concrete mixers for a chamber blasting in the quarry of Tongkeng Tin Mine Daichang. Some essential safety measures were adopted to prevent spark occuring for friction between metals and the built-up of static electricity in the process of production. Practice shows that strict measurement,accurate mix proportion and proper mixing time are the key points for ensuring explosive quality.Under the circumstances of competent safety measures and good labour organization, this processing method is feasible and able to meet the requirements of large explosive-consumed chamber blasting projects with its high production and lower cost.