Abstract: In order to understand the tailings discarding effect of high pressure roller grinding products in Beishan part ore of Nanfen Concentrator，-3 mm，-5 mm dry tailings discarding test and -3 mm wet tailings discarding test were carried out on the basis of process mineralogy research. The comparative test results of dry and wet tailings discarding show that under the condition of magnetic field intensity of 240 kA/m，the concentrate yield，TFe content，mFe content，TFe recovery rate and mFe recovery rate of-3 mm wet tailings discarding of high pressure roller grinding products are 87.24%，36.21%，24.37%，95.13% and 99.74%， respectively. The tailings yield，TFe content，mFe content，TFe recovery rate and mFe recovery rate are 12.76%，12.69%，0.43%，4.87% and 0.26%，respectively. The wet tailings discarding method has high tailings discarding efficiency and easy control of subsequent production.

Key words: high pressure roller grinding products, dry tailings discarding, wet tailings discarding