Application of research on a new cementing material for full-tailings backfill in the layered filling mining method at the Gaoguanying Iron Mins

摘要

A new kind of binding material made from tailings powder (named KWFj was invented and put into practiceby the authors based on the stage subsequent-filling method in Sijiaying Iron Mine. To adapt KWF toGaoguanying Iron Mine with upward-layered cut-and-fill mining method, the authors analysed the tailings'particle size distribution, adjusted KWF's suitability to this mine, compared different binding materials testresults on pure cement and other cementitious material under the same conditions in order to compare withthose of KWF. The results showed that full-tailings backfill strength mixed with KWF is 1.3-1.6 times higherthan chat with cement and 1.7-1.9 times higher than that with the other cementitious material. Since thetailings at Gaoguanying mine contains more fine grains and higher clay content, full-tailings filling strengthmixed by KWF cannot meet the required design strength (mine requirement strength). Therefore, furtheropimisation trials were done to modify KWF compositions. New compositions are quicklime 3.5%,hemih/drate gypsum 15% and admixture 1.5%. The corresponding seven day cured fill mix unconfinedimpressive strength (UCS) reached 1.43 MPa. With 1.5% early strength agent added, the full-tailings KWF7 mix's strength increased to 1.54 MPa, which fully meets the design strength for a safe layered backfillethcd at Gaoguanying Iron Mine.