Abstract: The joint fissure of some copper mine is developed, and its surrounding rock and ore body are broken, which needs a great amount of reinforcement. The superfine cement grouting technology is selected, and then according to different ratio of water-cement (W/C) and volume ratio of cement slurry/sodium silicate (C/S), indoor mix optimization test and theoretical research is launched by using orthogonal designing test. Such parameters as the best W/C and C/S were put forward to meet the required strength of grouting pressure, and according to the recommended mix-proportion, test is conducted on the spot. Grouting pressure and diffusion radius are confirmed and in view of the above, the grouting system is built. Industrial application shows that into-hole rate is increased by 25%, with exposed area of the stope roof increased by 110 m2, the stope ore retention volume reduced by about 10%, and ore recovery ratio increased by 23.3% according to recommended grouting material proportion and grouting system. Goals of reinforcing ore body, improving blast holes rate and increasing ore recovery ratio are realized.

Key words: superfine cement grouting, water-cement ratio, mix optimization, sodium silicate, grouting system