Abstract: Laboratory investigation is made on the change in the flowability and the harden paste strength of cement-tailing paste at different types of cement, cement addition and solid content. The results show that its flowability will be improved with the decrease in solid content, the flowability of the paste to which Portland cement is added will be better than that of the paste with ordinary Portland cement and the cement amount has small effect on the flowability. The strength of the harden paste will be increased with the increase of cement amount and the solid content, and the strength of the harden paste containing Portland cement will be higher than that of the harden paste with ordinary Portland cement. In tailing back-filling operation, the scheme of high solid content, ordinary Portland cement and appropriate cement addition which is in accordance with the requirement on the strength can be selected for the stopes where there is a small ratio of horizontal distance to vertical distance of the backfilling pipeline, and for the stopes where there is a large ratio, the scheme includes a filling paste with a small solid content and ordinary Portland cement for the bottom filling, and a paste with silicate cement and appropriate cement amount that is in accordance with the requirement on the strength for the upper part filling can be selected.

Key words: Tailings, Cement, Filling, Flowability, Harden body