| Filling mining method has outstanding advantages such as energy-saving and emission reduction, safe and environmental protection, low dilution and high recovery. Filling stoping has already gained an increasingly wide utilization in gold mine, non-ferrous and precious metals mine. Compared with other mining methods, filling method is complicated process and high cost of mining.Jinchuan deposit includes such traits as high geostress, large buried depth, pressure and unstable rock which adopts underhand cutting and filling method, that has greatly increased the cost of mining. Jinchuan mine mainly uses rod milling scrubbers and cement materials to fill. The cost of materials is as high as147yuan/m3, and cement costs accounted for60%-70%of total filling material cost which is1/3of the mining cost. That situation brings great pressure to Jinchuan mining benefit, especially at present the international nickel prices low. Reduce the cost of filling mining is one of the important ways of Jinchuan resources development and economic benefit.Investigation and analysis on the solid waste around the Jinchuan mine, there have been developed low cost and high strength of early strength filling materials by using the low active slag. Througth the analysis of physicochemical properties of solid waste, compound activator orthogonal test and the hydration mechanism of cementitious materials, the main contents are as follows:(1) Through the mechanical grinding, the mechanochemical effect on particle size distribution of slag powder was analyzed. With the grinding time, the farther up accumulate of slag powder particle size, meanwhile the frequency distribution move to the left (small particles direction), the average particle size decreases from24.31μm to12.26μm. Comparing the90min after grinding and non grinding of slag, the3d and7d pressure strength of filling body are increased54.9%and25.2%, the results shown that the fineness is an important factor for activity of slag.(2) The grinding aids had been used in the grinding test to enhance the mechanochemical effect of low active slag, the characteristic particle size, average particle size and uniformity coefficient of slag powder between30min after0.1%grinding aids and90min after non grinding aids have difference of only2.77%,2.83%and6.43%, the results shown the grinding aids can ehance the grinding efficiency because the grinding aids can eliminate the particle agglomeration, improve the fluidity of the materials and reduce the surface free energy of crushed materials during the grinding process.(3) Using the packing density model to carry out the mixture test and mortars experiment by utilizating the whole tailings, rod-mill tailings and coarse aggregate sand tailings of Jinchuan mine, the results shown the3d,7d and28d pressure strength of filling body are increased from0.36MPa,3.31MPa and5.32MPa to0.54MPa,4.12MPa and6.09MPa with the paking density growth from0.568to0.702. The increasing rate of strength are50%,24.47%and14.47%. Obviously, the ratio of mixed aggregate plays an important role for improving the strength of filling body, especially in the early strength.(4) The early strength filling materials adopt slag powder as the main materials, lime, gypsum and clinker as main activator materials. With the method of Neural Network, Genetic Programming and Genetic Algorithm, a function formula of filling body compressive strength and activator ratio was built. The pressure strength of filling body can meet the requirements of filling strength and lowest cost of the activators when the lime is2.562%, gypsum is4.996%and clinker is1.956%, the3d and7d compressive strength of filling body are2.038MPa and3.172MPa.(5) By means of microscopic analysis such as XRD, SEM and so on, the variation of slag after different mechanical grinding was analyzed. The results showed that mechanical grinding did not affect the crystal texture and phase and composition of slag, but affected the partial shape and surface morphology of slag. After analyzing the hydration mechanism of early strength filling materials, the results showed that the surface of the filling was covered with compact hydration products which mainly including C-S-H gelatin, gismodine and ettringite.(6) By means of testing the mobility, slump, consistency, delamination degree of mortar, in order to industrial application of the early strength filling materials in Jinchuan mine, the results showed the filling mortar has good water-retaining property and stability when the slurry concentration ranges from82%-84%, which can meet the demand of mine self-flowing transportation.(7) There have been carried out the validation test and field experiment for the early strength filling materials. The3d,7d and28d compressive strength of filling body are1.765MPa、3.615MPa and5.35MPa, the results shown the strength of filling body can meet the performance requirement of filling materials for Jinchuan mine. Comparing with the cost of cement materials, the early strength filling materials cost decrease48.3yuan per ton, so popularization and application of the early strength filling materials can obtain remarkable economic and social benefits for Jinchuan mine. Reduing the filling cost is an important means to improve the mining efficiency. This paper carries out the research and development of early strength filling materials with low active slag to meet the strength requirement of cementitious materials for Jinchuan mine. The early strength filling materials has been industrial production in the Jinchang Xijin company and application in Jinchuan Longshou mine. Meanwhile, combined the application of early strength filling materials, the filling technology of mixed aggregate based on the unclassified tailing, waste rock and coarse aggregate are also being studied. The application of solid waste in the filling mining technique, not only can significantly improve the economic benefits of Jinchuan mine, but also reduce the solid waste and protect the environment. |
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