Abstract: In view of higher rocks mixture rate of ore drawing under the coverage rocks， a method describing the effect of particle size space distribution in coverage rocks on rocks mixture was proposed based on the degree of membership. On the basis of coverage rocks gradation， the model-experiment method was used to construct three sorts of coverage rocks’ particle size space distribution with identical gradation， and the degree of membership was used to quantify the model-experiment. Firstly， three sorts of particle size space distribution in coverage rocks were constructed. Then the degree of membership about specific subset was used to quantify the particle size space distribution in coverage rocks and rocks mixture process was estimated. Finally， the results of rocks mixture rate at equal ore drawing were compared. The model-experimental results showed that the method can reveal the effect of particle size space distribution in coverage rocks on rocks mixture， and it is a significant and helpful method to understand the process of rocks mixture and ore dilution.

Key words: coverage rocks, particle size space distribution, model-experiment, degree of membership, rocks mixture